package com.fsck.k9.mail.store;

import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.Serializable;
import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Date;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.Set;
import java.util.UUID;
import java.util.regex.Pattern;

import org.apache.commons.io.IOUtils;

import android.app.Application;
import android.content.ContentResolver;
import android.content.ContentValues;
import android.content.Context;
import android.content.SharedPreferences;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;
import android.net.Uri;
import android.util.Log;

import com.fsck.k9.Account;
import com.fsck.k9.K9;
import com.fsck.k9.Preferences;
import com.fsck.k9.R;
import com.fsck.k9.Account.MessageFormat;
import com.fsck.k9.activity.Search;
import com.fsck.k9.controller.MessageRemovalListener;
import com.fsck.k9.controller.MessageRetrievalListener;
import com.fsck.k9.helper.HtmlConverter;
import com.fsck.k9.helper.StringUtils;
import com.fsck.k9.helper.Utility;
import com.fsck.k9.mail.Address;
import com.fsck.k9.mail.Body;
import com.fsck.k9.mail.BodyPart;
import com.fsck.k9.mail.FetchProfile;
import com.fsck.k9.mail.Flag;
import com.fsck.k9.mail.Folder;
import com.fsck.k9.mail.Message;
import com.fsck.k9.mail.Message.RecipientType;
import com.fsck.k9.mail.MessagingException;
import com.fsck.k9.mail.Part;
import com.fsck.k9.mail.Store;
import com.fsck.k9.mail.filter.Base64OutputStream;
import com.fsck.k9.mail.internet.MimeBodyPart;
import com.fsck.k9.mail.internet.MimeHeader;
import com.fsck.k9.mail.internet.MimeMessage;
import com.fsck.k9.mail.internet.MimeMultipart;
import com.fsck.k9.mail.internet.MimeUtility;
import com.fsck.k9.mail.internet.MimeUtility.ViewableContainer;
import com.fsck.k9.mail.internet.TextBody;
import com.fsck.k9.mail.store.LockableDatabase.DbCallback;
import com.fsck.k9.mail.store.LockableDatabase.WrappedException;
import com.fsck.k9.mail.store.StorageManager.StorageProvider;
import com.fsck.k9.provider.AttachmentProvider;
import com.fsck.k9.provider.EmailProvider;
import com.fsck.k9.search.LocalSearch;
import com.fsck.k9.search.SearchSpecification.Attribute;
import com.fsck.k9.search.SearchSpecification.SearchCondition;
import com.fsck.k9.search.SearchSpecification.Searchfield;
import com.fsck.k9.search.SqlQueryBuilder;

/**
 * <pre>
 * Implements a SQLite database backed local store for Messages.
 * </pre>
 */
public class LocalStore extends Store implements Serializable {

    private static final long serialVersionUID = -5142141896809423072L;

    private static final Message[] EMPTY_MESSAGE_ARRAY = new Message[0];
    private static final String[] EMPTY_STRING_ARRAY = new String[0];
    private static final Flag[] EMPTY_FLAG_ARRAY = new Flag[0];

    /*
     * a String containing the columns getMessages expects to work with
     * in the correct order.
     */
    static private String GET_MESSAGES_COLS =
        "subject, sender_list, date, uid, flags, messages.id, to_list, cc_list, "
        + "bcc_list, reply_to_list, attachment_count, internal_date, message_id, folder_id, preview, thread_root, thread_parent, deleted, read, flagged, answered, forwarded ";

    static private String GET_FOLDER_COLS = "folders.id, name, SUM(read=0), visible_limit, last_updated, status, push_state, last_pushed, SUM(flagged), integrate, top_group, poll_class, push_class, display_class";

    private static final String[] UID_CHECK_PROJECTION = { "uid" };

    /**
     * Number of UIDs to check for existence at once.
     *
     * @see LocalFolder#extractNewMessages(List)
     */
    private static final int UID_CHECK_BATCH_SIZE = 500;

    /**
     * Number of messages to perform flag updates at once.
     *
     * @see #setFlag(List, Flag, boolean, boolean)
     */
    private static final int FLAG_UPDATE_BATCH_SIZE = 500;

    public static final int DB_VERSION = 46;

    protected String uUid = null;

    private final Application mApplication;

    private LockableDatabase database;

    private ContentResolver mContentResolver;

    /**
     * local://localhost/path/to/database/uuid.db
     * This constructor is only used by {@link Store#getLocalInstance(Account, Application)}
     * @param account
     * @param application
     * @throws UnavailableStorageException if not {@link StorageProvider#isReady(Context)}
     */
    public LocalStore(final Account account, final Application application) throws MessagingException {
        super(account);
        database = new LockableDatabase(application, account.getUuid(), new StoreSchemaDefinition());

        mApplication = application;
        mContentResolver = application.getContentResolver();
        database.setStorageProviderId(account.getLocalStorageProviderId());
        uUid = account.getUuid();

        database.open();
    }

    public void switchLocalStorage(final String newStorageProviderId) throws MessagingException {
        database.switchProvider(newStorageProviderId);
    }

    protected SharedPreferences getPreferences() {
        return Preferences.getPreferences(mApplication).getPreferences();
    }

    private class StoreSchemaDefinition implements LockableDatabase.SchemaDefinition {
        @Override
        public int getVersion() {
            return DB_VERSION;
        }

        @Override
        public void doDbUpgrade(final SQLiteDatabase db) {
            Log.i(K9.LOG_TAG, String.format("Upgrading database from version %d to version %d",
                                            db.getVersion(), DB_VERSION));


            AttachmentProvider.clear(mApplication);

            db.beginTransaction();
            try {
                try {
                    // schema version 29 was when we moved to incremental updates
                    // in the case of a new db or a < v29 db, we blow away and start from scratch
                    if (db.getVersion() < 29) {

                        db.execSQL("DROP TABLE IF EXISTS folders");
                        db.execSQL("CREATE TABLE folders (id INTEGER PRIMARY KEY, name TEXT, "
                                   + "last_updated INTEGER, unread_count INTEGER, visible_limit INTEGER, status TEXT, "
                                   + "push_state TEXT, last_pushed INTEGER, flagged_count INTEGER default 0, "
                                   + "integrate INTEGER, top_group INTEGER, poll_class TEXT, push_class TEXT, display_class TEXT"
                                   + ")");

                        db.execSQL("CREATE INDEX IF NOT EXISTS folder_name ON folders (name)");
                        db.execSQL("DROP TABLE IF EXISTS messages");
                        db.execSQL("CREATE TABLE messages (" +
                                "id INTEGER PRIMARY KEY, " +
                                "deleted INTEGER default 0, " +
                                "folder_id INTEGER, " +
                                "uid TEXT, " +
                                "subject TEXT, " +
                                "date INTEGER, " +
                                "flags TEXT, " +
                                "sender_list TEXT, " +
                                "to_list TEXT, " +
                                "cc_list TEXT, " +
                                "bcc_list TEXT, " +
                                "reply_to_list TEXT, " +
                                "html_content TEXT, " +
                                "text_content TEXT, " +
                                "attachment_count INTEGER, " +
                                "internal_date INTEGER, " +
                                "message_id TEXT, " +
                                "preview TEXT, " +
                                "mime_type TEXT, "+
                                "thread_root INTEGER, " +
                                "thread_parent INTEGER, " +
                                "normalized_subject_hash INTEGER, " +
                                "empty INTEGER, " +
                                "read INTEGER default 0, " +
                                "flagged INTEGER default 0, " +
                                "answered INTEGER default 0, " +
                                "forwarded INTEGER default 0" +
                                ")");

                        db.execSQL("DROP TABLE IF EXISTS headers");
                        db.execSQL("CREATE TABLE headers (id INTEGER PRIMARY KEY, message_id INTEGER, name TEXT, value TEXT)");
                        db.execSQL("CREATE INDEX IF NOT EXISTS header_folder ON headers (message_id)");

                        db.execSQL("CREATE INDEX IF NOT EXISTS msg_uid ON messages (uid, folder_id)");
                        db.execSQL("DROP INDEX IF EXISTS msg_folder_id");
                        db.execSQL("DROP INDEX IF EXISTS msg_folder_id_date");
                        db.execSQL("CREATE INDEX IF NOT EXISTS msg_folder_id_deleted_date ON messages (folder_id,deleted,internal_date)");

                        db.execSQL("DROP INDEX IF EXISTS msg_empty");
                        db.execSQL("CREATE INDEX IF NOT EXISTS msg_empty ON messages (empty)");

                        db.execSQL("DROP INDEX IF EXISTS msg_thread_root");
                        db.execSQL("CREATE INDEX IF NOT EXISTS msg_thread_root ON messages (thread_root)");

                        db.execSQL("DROP INDEX IF EXISTS msg_thread_parent");
                        db.execSQL("CREATE INDEX IF NOT EXISTS msg_thread_parent ON messages (thread_parent)");

                        db.execSQL("DROP INDEX IF EXISTS msg_read");
                        db.execSQL("CREATE INDEX IF NOT EXISTS msg_read ON messages (read)");

                        db.execSQL("DROP INDEX IF EXISTS msg_flagged");
                        db.execSQL("CREATE INDEX IF NOT EXISTS msg_flagged ON messages (flagged)");

                        db.execSQL("DROP TABLE IF EXISTS attachments");
                        db.execSQL("CREATE TABLE attachments (id INTEGER PRIMARY KEY, message_id INTEGER,"
                                   + "store_data TEXT, content_uri TEXT, size INTEGER, name TEXT,"
                                   + "mime_type TEXT, content_id TEXT, content_disposition TEXT)");

                        db.execSQL("DROP TABLE IF EXISTS pending_commands");
                        db.execSQL("CREATE TABLE pending_commands " +
                                   "(id INTEGER PRIMARY KEY, command TEXT, arguments TEXT)");

                        db.execSQL("DROP TRIGGER IF EXISTS delete_folder");
                        db.execSQL("CREATE TRIGGER delete_folder BEFORE DELETE ON folders BEGIN DELETE FROM messages WHERE old.id = folder_id; END;");

                        db.execSQL("DROP TRIGGER IF EXISTS delete_message");
                        db.execSQL("CREATE TRIGGER delete_message BEFORE DELETE ON messages BEGIN DELETE FROM attachments WHERE old.id = message_id; "
                                   + "DELETE FROM headers where old.id = message_id; END;");
                    } else {
                        // in the case that we're starting out at 29 or newer, run all the needed updates

                        if (db.getVersion() < 30) {
                            try {
                                db.execSQL("ALTER TABLE messages ADD deleted INTEGER default 0");
                            } catch (SQLiteException e) {
                                if (! e.toString().startsWith("duplicate column name: deleted")) {
                                    throw e;
                                }
                            }
                        }
                        if (db.getVersion() < 31) {
                            db.execSQL("DROP INDEX IF EXISTS msg_folder_id_date");
                            db.execSQL("CREATE INDEX IF NOT EXISTS msg_folder_id_deleted_date ON messages (folder_id,deleted,internal_date)");
                        }
                        if (db.getVersion() < 32) {
                            db.execSQL("UPDATE messages SET deleted = 1 WHERE flags LIKE '%DELETED%'");
                        }
                        if (db.getVersion() < 33) {

                            try {
                                db.execSQL("ALTER TABLE messages ADD preview TEXT");
                            } catch (SQLiteException e) {
                                if (! e.toString().startsWith("duplicate column name: preview")) {
                                    throw e;
                                }
                            }

                        }
                        if (db.getVersion() < 34) {
                            try {
                                db.execSQL("ALTER TABLE folders ADD flagged_count INTEGER default 0");
                            } catch (SQLiteException e) {
                                if (! e.getMessage().startsWith("duplicate column name: flagged_count")) {
                                    throw e;
                                }
                            }
                        }
                        if (db.getVersion() < 35) {
                            try {
                                db.execSQL("update messages set flags = replace(flags, 'X_NO_SEEN_INFO', 'X_BAD_FLAG')");
                            } catch (SQLiteException e) {
                                Log.e(K9.LOG_TAG, "Unable to get rid of obsolete flag X_NO_SEEN_INFO", e);
                            }
                        }
                        if (db.getVersion() < 36) {
                            try {
                                db.execSQL("ALTER TABLE attachments ADD content_id TEXT");
                            } catch (SQLiteException e) {
                                Log.e(K9.LOG_TAG, "Unable to add content_id column to attachments");
                            }
                        }
                        if (db.getVersion() < 37) {
                            try {
                                db.execSQL("ALTER TABLE attachments ADD content_disposition TEXT");
                            } catch (SQLiteException e) {
                                Log.e(K9.LOG_TAG, "Unable to add content_disposition column to attachments");
                            }
                        }

                        // Database version 38 is solely to prune cached attachments now that we clear them better
                        if (db.getVersion() < 39) {
                            try {
                                db.execSQL("DELETE FROM headers WHERE id in (SELECT headers.id FROM headers LEFT JOIN messages ON headers.message_id = messages.id WHERE messages.id IS NULL)");
                            } catch (SQLiteException e) {
                                Log.e(K9.LOG_TAG, "Unable to remove extra header data from the database");
                            }
                        }

                        // V40: Store the MIME type for a message.
                        if (db.getVersion() < 40) {
                            try {
                                db.execSQL("ALTER TABLE messages ADD mime_type TEXT");
                            } catch (SQLiteException e) {
                                Log.e(K9.LOG_TAG, "Unable to add mime_type column to messages");
                            }
                        }

                        if (db.getVersion() < 41) {
                            try {
                                db.execSQL("ALTER TABLE folders ADD integrate INTEGER");
                                db.execSQL("ALTER TABLE folders ADD top_group INTEGER");
                                db.execSQL("ALTER TABLE folders ADD poll_class TEXT");
                                db.execSQL("ALTER TABLE folders ADD push_class TEXT");
                                db.execSQL("ALTER TABLE folders ADD display_class TEXT");
                            } catch (SQLiteException e) {
                                if (! e.getMessage().startsWith("duplicate column name:")) {
                                    throw e;
                                }
                            }
                            Cursor cursor = null;

                            try {

                                SharedPreferences prefs = getPreferences();
                                cursor = db.rawQuery("SELECT id, name FROM folders", null);
                                while (cursor.moveToNext()) {
                                    try {
                                        int id = cursor.getInt(0);
                                        String name = cursor.getString(1);
                                        update41Metadata(db, prefs, id, name);
                                    } catch (Exception e) {
                                        Log.e(K9.LOG_TAG, " error trying to ugpgrade a folder class", e);
                                    }
                                }
                            }


                            catch (SQLiteException e) {
                                Log.e(K9.LOG_TAG, "Exception while upgrading database to v41. folder classes may have vanished", e);

                            } finally {
                                Utility.closeQuietly(cursor);
                            }
                        }
                        if (db.getVersion() == 41) {
                            try {
                                long startTime = System.currentTimeMillis();
                                SharedPreferences.Editor editor = getPreferences().edit();

                                List <? extends Folder >  folders = getPersonalNamespaces(true);
                                for (Folder folder : folders) {
                                    if (folder instanceof LocalFolder) {
                                        LocalFolder lFolder = (LocalFolder)folder;
                                        lFolder.save(editor);
                                    }
                                }

                                editor.commit();
                                long endTime = System.currentTimeMillis();
                                Log.i(K9.LOG_TAG, "Putting folder preferences for " + folders.size() + " folders back into Preferences took " + (endTime - startTime) + " ms");
                            } catch (Exception e) {
                                Log.e(K9.LOG_TAG, "Could not replace Preferences in upgrade from DB_VERSION 41", e);
                            }
                        }
                        if (db.getVersion() < 43) {
                            try {
                                // If folder "OUTBOX" (old, v3.800 - v3.802) exists, rename it to
                                // "K9MAIL_INTERNAL_OUTBOX" (new)
                                LocalFolder oldOutbox = new LocalFolder("OUTBOX");
                                if (oldOutbox.exists()) {
                                    ContentValues cv = new ContentValues();
                                    cv.put("name", Account.OUTBOX);
                                    db.update("folders", cv, "name = ?", new String[] { "OUTBOX" });
                                    Log.i(K9.LOG_TAG, "Renamed folder OUTBOX to " + Account.OUTBOX);
                                }

                                // Check if old (pre v3.800) localized outbox folder exists
                                String localizedOutbox = K9.app.getString(R.string.special_mailbox_name_outbox);
                                LocalFolder obsoleteOutbox = new LocalFolder(localizedOutbox);
                                if (obsoleteOutbox.exists()) {
                                    // Get all messages from the localized outbox ...
                                    Message[] messages = obsoleteOutbox.getMessages(null, false);

                                    if (messages.length > 0) {
                                        // ... and move them to the drafts folder (we don't want to
                                        // surprise the user by sending potentially very old messages)
                                        LocalFolder drafts = new LocalFolder(mAccount.getDraftsFolderName());
                                        obsoleteOutbox.moveMessages(messages, drafts);
                                    }

                                    // Now get rid of the localized outbox
                                    obsoleteOutbox.delete();
                                    obsoleteOutbox.delete(true);
                                }
                            } catch (Exception e) {
                                Log.e(K9.LOG_TAG, "Error trying to fix the outbox folders", e);
                            }
                        }
                        if (db.getVersion() < 44) {
                            try {
                                db.execSQL("ALTER TABLE messages ADD thread_root INTEGER");
                                db.execSQL("ALTER TABLE messages ADD thread_parent INTEGER");
                                db.execSQL("ALTER TABLE messages ADD normalized_subject_hash INTEGER");
                                db.execSQL("ALTER TABLE messages ADD empty INTEGER");
                            } catch (SQLiteException e) {
                                if (! e.getMessage().startsWith("duplicate column name:")) {
                                    throw e;
                                }
                            }
                        }
                        if (db.getVersion() < 45) {
                            try {
                                db.execSQL("DROP INDEX IF EXISTS msg_empty");
                                db.execSQL("CREATE INDEX IF NOT EXISTS msg_empty ON messages (empty)");

                                db.execSQL("DROP INDEX IF EXISTS msg_thread_root");
                                db.execSQL("CREATE INDEX IF NOT EXISTS msg_thread_root ON messages (thread_root)");

                                db.execSQL("DROP INDEX IF EXISTS msg_thread_parent");
                                db.execSQL("CREATE INDEX IF NOT EXISTS msg_thread_parent ON messages (thread_parent)");
                            } catch (SQLiteException e) {
                                if (! e.getMessage().startsWith("duplicate column name:")) {
                                    throw e;
                                }
                            }
                        }
                        if (db.getVersion() < 46) {
                            db.execSQL("ALTER TABLE messages ADD read INTEGER default 0");
                            db.execSQL("ALTER TABLE messages ADD flagged INTEGER default 0");
                            db.execSQL("ALTER TABLE messages ADD answered INTEGER default 0");
                            db.execSQL("ALTER TABLE messages ADD forwarded INTEGER default 0");

                            String[] projection = { "id", "flags" };

                            ContentValues cv = new ContentValues();
                            List<Flag> extraFlags = new ArrayList<Flag>();

                            Cursor cursor = db.query("messages", projection, null, null, null, null, null);
                            try {
                                while (cursor.moveToNext()) {
                                    long id = cursor.getLong(0);
                                    String flagList = cursor.getString(1);

                                    boolean read = false;
                                    boolean flagged = false;
                                    boolean answered = false;
                                    boolean forwarded = false;

                                    if (flagList != null && flagList.length() > 0) {
                                        String[] flags = flagList.split(",");

                                        for (String flagStr : flags) {
                                            try {
                                                Flag flag = Flag.valueOf(flagStr);

                                                switch (flag) {
                                                    case ANSWERED: {
                                                        answered = true;
                                                        break;
                                                    }
                                                    case DELETED: {
                                                        // Don't store this in column 'flags'
                                                        break;
                                                    }
                                                    case FLAGGED: {
                                                        flagged = true;
                                                        break;
                                                    }
                                                    case FORWARDED: {
                                                        forwarded = true;
                                                        break;
                                                    }
                                                    case SEEN: {
                                                        read = true;
                                                        break;
                                                    }
                                                    case DRAFT:
                                                    case RECENT:
                                                    case X_DESTROYED:
                                                    case X_DOWNLOADED_FULL:
                                                    case X_DOWNLOADED_PARTIAL:
                                                    case X_GOT_ALL_HEADERS:
                                                    case X_REMOTE_COPY_STARTED:
                                                    case X_SEND_FAILED:
                                                    case X_SEND_IN_PROGRESS: {
                                                        extraFlags.add(flag);
                                                        break;
                                                    }
                                                }
                                            } catch (Exception e) {
                                                // Ignore bad flags
                                            }
                                        }
                                    }


                                    cv.put("flags", serializeFlags(extraFlags.toArray(EMPTY_FLAG_ARRAY)));
                                    cv.put("read", read);
                                    cv.put("flagged", flagged);
                                    cv.put("answered", answered);
                                    cv.put("forwarded", forwarded);

                                    db.update("messages", cv, "id = ?", new String[] { Long.toString(id) });

                                    cv.clear();
                                    extraFlags.clear();
                                }
                            } finally {
                                cursor.close();
                            }

                            db.execSQL("CREATE INDEX IF NOT EXISTS msg_read ON messages (read)");
                            db.execSQL("CREATE INDEX IF NOT EXISTS msg_flagged ON messages (flagged)");
                        }
                    }
                } catch (SQLiteException e) {
                    Log.e(K9.LOG_TAG, "Exception while upgrading database. Resetting the DB to v0");
                    db.setVersion(0);
                    throw new Error("Database upgrade failed! Resetting your DB version to 0 to force a full schema recreation.");
                }

                db.setVersion(DB_VERSION);

                db.setTransactionSuccessful();
            } finally {
                db.endTransaction();
            }

            if (db.getVersion() != DB_VERSION) {
                throw new Error("Database upgrade failed!");
            }

            // Unless we're blowing away the whole data store, there's no reason to prune attachments
            // every time the user upgrades. it'll just cost them money and pain.
            // try
            //{
            //        pruneCachedAttachments(true);
            //}
            //catch (Exception me)
            //{
            //   Log.e(K9.LOG_TAG, "Exception while force pruning attachments during DB update", me);
            //}
        }

        private void update41Metadata(final SQLiteDatabase  db, SharedPreferences prefs, int id, String name) {


            Folder.FolderClass displayClass = Folder.FolderClass.NO_CLASS;
            Folder.FolderClass syncClass = Folder.FolderClass.INHERITED;
            Folder.FolderClass pushClass = Folder.FolderClass.SECOND_CLASS;
            boolean inTopGroup = false;
            boolean integrate = false;
            if (mAccount.getInboxFolderName().equals(name)) {
                displayClass = Folder.FolderClass.FIRST_CLASS;
                syncClass =  Folder.FolderClass.FIRST_CLASS;
                pushClass =  Folder.FolderClass.FIRST_CLASS;
                inTopGroup = true;
                integrate = true;
            }

            try {
                displayClass = Folder.FolderClass.valueOf(prefs.getString(uUid + "." + name + ".displayMode", displayClass.name()));
                syncClass = Folder.FolderClass.valueOf(prefs.getString(uUid + "." + name + ".syncMode", syncClass.name()));
                pushClass = Folder.FolderClass.valueOf(prefs.getString(uUid + "." + name + ".pushMode", pushClass.name()));
                inTopGroup = prefs.getBoolean(uUid + "." + name + ".inTopGroup", inTopGroup);
                integrate = prefs.getBoolean(uUid + "." + name + ".integrate", integrate);
            } catch (Exception e) {
                Log.e(K9.LOG_TAG, " Throwing away an error while trying to upgrade folder metadata", e);
            }

            if (displayClass == Folder.FolderClass.NONE) {
                displayClass = Folder.FolderClass.NO_CLASS;
            }
            if (syncClass == Folder.FolderClass.NONE) {
                syncClass = Folder.FolderClass.INHERITED;
            }
            if (pushClass == Folder.FolderClass.NONE) {
                pushClass = Folder.FolderClass.INHERITED;
            }

            db.execSQL("UPDATE folders SET integrate = ?, top_group = ?, poll_class=?, push_class =?, display_class = ? WHERE id = ?",
                       new Object[] { integrate, inTopGroup, syncClass, pushClass, displayClass, id });

        }
    }


    public long getSize() throws UnavailableStorageException {

        final StorageManager storageManager = StorageManager.getInstance(mApplication);

        final File attachmentDirectory = storageManager.getAttachmentDirectory(uUid,
                                         database.getStorageProviderId());

        return database.execute(false, new DbCallback<Long>() {
            @Override
            public Long doDbWork(final SQLiteDatabase db) {
                final File[] files = attachmentDirectory.listFiles();
                long attachmentLength = 0;
                for (File file : files) {
                    if (file.exists()) {
                        attachmentLength += file.length();
                    }
                }

                final File dbFile = storageManager.getDatabase(uUid, database.getStorageProviderId());
                return dbFile.length() + attachmentLength;
            }
        });
    }

    public void compact() throws MessagingException {
        if (K9.DEBUG)
            Log.i(K9.LOG_TAG, "Before compaction size = " + getSize());

        database.execute(false, new DbCallback<Void>() {
            @Override
            public Void doDbWork(final SQLiteDatabase db) throws WrappedException {
                db.execSQL("VACUUM");
                return null;
            }
        });
        if (K9.DEBUG)
            Log.i(K9.LOG_TAG, "After compaction size = " + getSize());
    }


    public void clear() throws MessagingException {
        if (K9.DEBUG)
            Log.i(K9.LOG_TAG, "Before prune size = " + getSize());

        pruneCachedAttachments(true);
        if (K9.DEBUG) {
            Log.i(K9.LOG_TAG, "After prune / before compaction size = " + getSize());

            Log.i(K9.LOG_TAG, "Before clear folder count = " + getFolderCount());
            Log.i(K9.LOG_TAG, "Before clear message count = " + getMessageCount());

            Log.i(K9.LOG_TAG, "After prune / before clear size = " + getSize());
        }
        // don't delete messages that are Local, since there is no copy on the server.
        // Don't delete deleted messages.  They are essentially placeholders for UIDs of messages that have
        // been deleted locally.  They take up insignificant space
        database.execute(false, new DbCallback<Void>() {
            @Override
            public Void doDbWork(final SQLiteDatabase db) {
                db.execSQL("DELETE FROM messages WHERE deleted = 0 and uid not like 'Local%'");
                db.execSQL("update folders set flagged_count = 0, unread_count = 0");
                return null;
            }
        });

        compact();

        if (K9.DEBUG) {
            Log.i(K9.LOG_TAG, "After clear message count = " + getMessageCount());

            Log.i(K9.LOG_TAG, "After clear size = " + getSize());
        }
    }

    public int getMessageCount() throws MessagingException {
        return database.execute(false, new DbCallback<Integer>() {
            @Override
            public Integer doDbWork(final SQLiteDatabase db) {
                Cursor cursor = null;
                try {
                    cursor = db.rawQuery("SELECT COUNT(*) FROM messages", null);
                    cursor.moveToFirst();
                    return cursor.getInt(0);   // message count
                } finally {
                    Utility.closeQuietly(cursor);
                }
            }
        });
    }

    public int getFolderCount() throws MessagingException {
        return database.execute(false, new DbCallback<Integer>() {
            @Override
            public Integer doDbWork(final SQLiteDatabase db) {
                Cursor cursor = null;
                try {
                    cursor = db.rawQuery("SELECT COUNT(*) FROM folders", null);
                    cursor.moveToFirst();
                    return cursor.getInt(0);        // folder count
                } finally {
                    Utility.closeQuietly(cursor);
                }
            }
        });
    }

    @Override
    public LocalFolder getFolder(String name) {
        return new LocalFolder(name);
    }

    public LocalFolder getFolderById(long folderId) {
        return new LocalFolder(folderId);
    }

    // TODO this takes about 260-300ms, seems slow.
    @Override
    public List <? extends Folder > getPersonalNamespaces(boolean forceListAll) throws MessagingException {
        final List<LocalFolder> folders = new LinkedList<LocalFolder>();
        try {
            database.execute(false, new DbCallback < List <? extends Folder >> () {
                @Override
                public List <? extends Folder > doDbWork(final SQLiteDatabase db) throws WrappedException {
                    Cursor cursor = null;

                    try {
                        cursor = db.rawQuery("SELECT " + GET_FOLDER_COLS + " FROM folders " +
                                "LEFT JOIN messages ON (folder_id = folders.id AND" +
                                " (empty IS NULL OR empty != 1) AND deleted = 0) " +
                                "GROUP BY folders.id ORDER BY name ASC", null);
                        while (cursor.moveToNext()) {
                            if (cursor.isNull(0)) {
                                continue;
                            }
                            LocalFolder folder = new LocalFolder(cursor.getString(1));
                            folder.open(cursor.getInt(0), cursor.getString(1), cursor.getInt(2), cursor.getInt(3), cursor.getLong(4), cursor.getString(5), cursor.getString(6), cursor.getLong(7), cursor.getInt(8), cursor.getInt(9), cursor.getInt(10), cursor.getString(11), cursor.getString(12), cursor.getString(13));

                            folders.add(folder);
                        }
                        return folders;
                    } catch (MessagingException e) {
                        throw new WrappedException(e);
                    } finally {
                        Utility.closeQuietly(cursor);
                    }
                }
            });
        } catch (WrappedException e) {
            throw(MessagingException) e.getCause();
        }
        return folders;
    }

    @Override
    public void checkSettings() throws MessagingException {
    }

    public void delete() throws UnavailableStorageException {
        database.delete();
    }

    public void recreate() throws UnavailableStorageException {
        database.recreate();
    }

    public void pruneCachedAttachments() throws MessagingException {
        pruneCachedAttachments(false);
    }

    /**
     * Deletes all cached attachments for the entire store.
     * @param force
     * @throws com.fsck.k9.mail.MessagingException
     */
    private void pruneCachedAttachments(final boolean force) throws MessagingException {
        database.execute(false, new DbCallback<Void>() {
            @Override
            public Void doDbWork(final SQLiteDatabase db) throws WrappedException {
                if (force) {
                    ContentValues cv = new ContentValues();
                    cv.putNull("content_uri");
                    db.update("attachments", cv, null, null);
                }
                final StorageManager storageManager = StorageManager.getInstance(mApplication);
                File[] files = storageManager.getAttachmentDirectory(uUid, database.getStorageProviderId()).listFiles();
                for (File file : files) {
                    if (file.exists()) {
                        if (!force) {
                            Cursor cursor = null;
                            try {
                                cursor = db.query(
                                             "attachments",
                                             new String[] { "store_data" },
                                             "id = ?",
                                             new String[] { file.getName() },
                                             null,
                                             null,
                                             null);
                                if (cursor.moveToNext()) {
                                    if (cursor.getString(0) == null) {
                                        if (K9.DEBUG)
                                            Log.d(K9.LOG_TAG, "Attachment " + file.getAbsolutePath() + " has no store data, not deleting");
                                        /*
                                         * If the attachment has no store data it is not recoverable, so
                                         * we won't delete it.
                                         */
                                        continue;
                                    }
                                }
                            } finally {
                                Utility.closeQuietly(cursor);
                            }
                        }
                        if (!force) {
                            try {
                                ContentValues cv = new ContentValues();
                                cv.putNull("content_uri");
                                db.update("attachments", cv, "id = ?", new String[] { file.getName() });
                            } catch (Exception e) {
                                /*
                                 * If the row has gone away before we got to mark it not-downloaded that's
                                 * okay.
                                 */
                            }
                        }
                        if (!file.delete()) {
                            file.deleteOnExit();
                        }
                    }
                }
                return null;
            }
        });
    }

    public void resetVisibleLimits() throws UnavailableStorageException {
        resetVisibleLimits(mAccount.getDisplayCount());
    }

    public void resetVisibleLimits(int visibleLimit) throws UnavailableStorageException {
        final ContentValues cv = new ContentValues();
        cv.put("visible_limit", Integer.toString(visibleLimit));
        database.execute(false, new DbCallback<Void>() {
            @Override
            public Void doDbWork(final SQLiteDatabase db) throws WrappedException {
                db.update("folders", cv, null, null);
                return null;
            }
        });
    }

    public ArrayList<PendingCommand> getPendingCommands() throws UnavailableStorageException {
        return database.execute(false, new DbCallback<ArrayList<PendingCommand>>() {
            @Override
            public ArrayList<PendingCommand> doDbWork(final SQLiteDatabase db) throws WrappedException {
                Cursor cursor = null;
                try {
                    cursor = db.query("pending_commands",
                                      new String[] { "id", "command", "arguments" },
                                      null,
                                      null,
                                      null,
                                      null,
                                      "id ASC");
                    ArrayList<PendingCommand> commands = new ArrayList<PendingCommand>();
                    while (cursor.moveToNext()) {
                        PendingCommand command = new PendingCommand();
                        command.mId = cursor.getLong(0);
                        command.command = cursor.getString(1);
                        String arguments = cursor.getString(2);
                        command.arguments = arguments.split(",");
                        for (int i = 0; i < command.arguments.length; i++) {
                            command.arguments[i] = Utility.fastUrlDecode(command.arguments[i]);
                        }
                        commands.add(command);
                    }
                    return commands;
                } finally {
                    Utility.closeQuietly(cursor);
                }
            }
        });
    }

    public void addPendingCommand(PendingCommand command) throws UnavailableStorageException {
        try {
            for (int i = 0; i < command.arguments.length; i++) {
                command.arguments[i] = URLEncoder.encode(command.arguments[i], "UTF-8");
            }
            final ContentValues cv = new ContentValues();
            cv.put("command", command.command);
            cv.put("arguments", Utility.combine(command.arguments, ','));
            database.execute(false, new DbCallback<Void>() {
                @Override
                public Void doDbWork(final SQLiteDatabase db) throws WrappedException {
                    db.insert("pending_commands", "command", cv);
                    return null;
                }
            });
        } catch (UnsupportedEncodingException usee) {
            throw new Error("Aparently UTF-8 has been lost to the annals of history.");
        }
    }

    public void removePendingCommand(final PendingCommand command) throws UnavailableStorageException {
        database.execute(false, new DbCallback<Void>() {
            @Override
            public Void doDbWork(final SQLiteDatabase db) throws WrappedException {
                db.delete("pending_commands", "id = ?", new String[] { Long.toString(command.mId) });
                return null;
            }
        });
    }

    public void removePendingCommands() throws UnavailableStorageException {
        database.execute(false, new DbCallback<Void>() {
            @Override
            public Void doDbWork(final SQLiteDatabase db) throws WrappedException {
                db.delete("pending_commands", null, null);
                return null;
            }
        });
    }

    public static class PendingCommand {
        private long mId;
        public String command;
        public String[] arguments;

        @Override
        public String toString() {
            StringBuilder sb = new StringBuilder();
            sb.append(command);
            sb.append(": ");
            for (String argument : arguments) {
                sb.append(", ");
                sb.append(argument);
                //sb.append("\n");
            }
            return sb.toString();
        }
    }

    @Override
    public boolean isMoveCapable() {
        return true;
    }

    @Override
    public boolean isCopyCapable() {
        return true;
    }

    public Message[] searchForMessages(MessageRetrievalListener retrievalListener,
                                        LocalSearch search) throws MessagingException {

        StringBuilder query = new StringBuilder();
        List<String> queryArgs = new ArrayList<String>();
        SqlQueryBuilder.buildWhereClause(mAccount, search.getConditions(), query, queryArgs);

        // Avoid "ambiguous column name" error by prefixing "id" with the message table name
        String where = SqlQueryBuilder.addPrefixToSelection(new String[] { "id" },
                "messages.", query.toString());

        String[] selectionArgs = queryArgs.toArray(EMPTY_STRING_ARRAY);

        String sqlQuery = "SELECT " + GET_MESSAGES_COLS + "FROM messages " +
                "LEFT JOIN folders ON (folders.id = messages.folder_id) WHERE " +
                "((empty IS NULL OR empty != 1) AND deleted = 0)" +
                ((!StringUtils.isNullOrEmpty(where)) ? " AND (" + where + ")" : "") +
                " ORDER BY date DESC";

        if (K9.DEBUG) {
            Log.d(K9.LOG_TAG, "Query = " + sqlQuery);
        }

        return getMessages(retrievalListener, null, sqlQuery, selectionArgs);
    }

    /*
     * Given a query string, actually do the query for the messages and
     * call the MessageRetrievalListener for each one
     */
    private Message[] getMessages(
        final MessageRetrievalListener listener,
        final LocalFolder folder,
        final String queryString, final String[] placeHolders
    ) throws MessagingException {
        final ArrayList<LocalMessage> messages = new ArrayList<LocalMessage>();
        final int j = database.execute(false, new DbCallback<Integer>() {
            @Override
            public Integer doDbWork(final SQLiteDatabase db) throws WrappedException {
                Cursor cursor = null;
                int i = 0;
                try {
                    cursor = db.rawQuery(queryString + " LIMIT 10", placeHolders);

                    while (cursor.moveToNext()) {
                        LocalMessage message = new LocalMessage(null, folder);
                        message.populateFromGetMessageCursor(cursor);

                        messages.add(message);
                        if (listener != null) {
                            listener.messageFinished(message, i, -1);
                        }
                        i++;
                    }
                    cursor.close();
                    cursor = db.rawQuery(queryString + " LIMIT -1 OFFSET 10", placeHolders);

                    while (cursor.moveToNext()) {
                        LocalMessage message = new LocalMessage(null, folder);
                        message.populateFromGetMessageCursor(cursor);

                        messages.add(message);
                        if (listener != null) {
                            listener.messageFinished(message, i, -1);
                        }
                        i++;
                    }
                } catch (Exception e) {
                    Log.d(K9.LOG_TAG, "Got an exception", e);
                } finally {
                    Utility.closeQuietly(cursor);
                }
                return i;
            }
        });
        if (listener != null) {
            listener.messagesFinished(j);
        }

        return messages.toArray(EMPTY_MESSAGE_ARRAY);

    }

    public Message[] getMessagesInThread(final long rootId) throws MessagingException {
        String rootIdString = Long.toString(rootId);

        LocalSearch search = new LocalSearch();
        search.and(Searchfield.THREAD_ROOT, rootIdString, Attribute.EQUALS);
        search.or(new SearchCondition(Searchfield.ID, Attribute.EQUALS, rootIdString));

        return searchForMessages(null, search);
    }

    public AttachmentInfo getAttachmentInfo(final String attachmentId) throws UnavailableStorageException {
        return database.execute(false, new DbCallback<AttachmentInfo>() {
            @Override
            public AttachmentInfo doDbWork(final SQLiteDatabase db) throws WrappedException {
                String name;
                String type;
                int size;
                Cursor cursor = null;
                try {
                    cursor = db.query(
                                 "attachments",
                                 new String[] { "name", "size", "mime_type" },
                                 "id = ?",
                                 new String[] { attachmentId },
                                 null,
                                 null,
                                 null);
                    if (!cursor.moveToFirst()) {
                        return null;
                    }
                    name = cursor.getString(0);
                    size = cursor.getInt(1);
                    type = cursor.getString(2);
                    final AttachmentInfo attachmentInfo = new AttachmentInfo();
                    attachmentInfo.name = name;
                    attachmentInfo.size = size;
                    attachmentInfo.type = type;
                    return attachmentInfo;
                } finally {
                    Utility.closeQuietly(cursor);
                }
            }
        });
    }

    public static class AttachmentInfo {
        public String name;
        public int size;
        public String type;
    }

    public void createFolders(final List<LocalFolder> foldersToCreate, final int visibleLimit) throws UnavailableStorageException {
        database.execute(true, new DbCallback<Void>() {
            @Override
            public Void doDbWork(final SQLiteDatabase db) throws WrappedException {
                for (LocalFolder folder : foldersToCreate) {
                    String name = folder.getName();
                    final  LocalFolder.PreferencesHolder prefHolder = folder.new PreferencesHolder();

                    // When created, special folders should always be displayed
                    // inbox should be integrated
                    // and the inbox and drafts folders should be syncced by default
                    if (mAccount.isSpecialFolder(name)) {
                        prefHolder.inTopGroup = true;
                        prefHolder.displayClass = LocalFolder.FolderClass.FIRST_CLASS;
                        if (name.equalsIgnoreCase(mAccount.getInboxFolderName())) {
                            prefHolder.integrate = true;
                            prefHolder.pushClass = LocalFolder.FolderClass.FIRST_CLASS;
                        } else {
                            prefHolder.pushClass = LocalFolder.FolderClass.INHERITED;

                        }
                        if (name.equalsIgnoreCase(mAccount.getInboxFolderName()) ||
                                name.equalsIgnoreCase(mAccount.getDraftsFolderName())) {
                            prefHolder.syncClass = LocalFolder.FolderClass.FIRST_CLASS;
                        } else {
                            prefHolder.syncClass = LocalFolder.FolderClass.NO_CLASS;
                        }
                    }
                    folder.refresh(name, prefHolder);   // Recover settings from Preferences

                    db.execSQL("INSERT INTO folders (name, visible_limit, top_group, display_class, poll_class, push_class, integrate) VALUES (?, ?, ?, ?, ?, ?, ?)", new Object[] {
                                   name,
                                   visibleLimit,
                                   prefHolder.inTopGroup ? 1 : 0,
                                   prefHolder.displayClass.name(),
                                   prefHolder.syncClass.name(),
                                   prefHolder.pushClass.name(),
                                   prefHolder.integrate ? 1 : 0,
                               });

                }
                return null;
            }
        });
    }


    private String serializeFlags(Flag[] flags) {
        List<Flag> extraFlags = new ArrayList<Flag>();

        for (Flag flag : flags) {
            switch (flag) {
                case DELETED:
                case SEEN:
                case FLAGGED:
                case ANSWERED:
                case FORWARDED: {
                    break;
                }
                default: {
                    extraFlags.add(flag);
                }
            }
        }

        return Utility.combine(extraFlags.toArray(EMPTY_FLAG_ARRAY), ',').toUpperCase(Locale.US);
    }

    public class LocalFolder extends Folder implements Serializable {
        /**
         *
         */
        private static final long serialVersionUID = -1973296520918624767L;
        private String mName = null;
        private long mFolderId = -1;
        private int mUnreadMessageCount = -1;
        private int mFlaggedMessageCount = -1;
        private int mVisibleLimit = -1;
        private String prefId = null;
        private FolderClass mDisplayClass = FolderClass.NO_CLASS;
        private FolderClass mSyncClass = FolderClass.INHERITED;
        private FolderClass mPushClass = FolderClass.SECOND_CLASS;
        private boolean mInTopGroup = false;
        private String mPushState = null;
        private boolean mIntegrate = false;
        // mLastUid is used during syncs. It holds the highest UID within the local folder so we
        // know whether or not an unread message added to the local folder is actually "new" or not.
        private Integer mLastUid = null;

        public LocalFolder(String name) {
            super(LocalStore.this.mAccount);
            this.mName = name;

            if (LocalStore.this.mAccount.getInboxFolderName().equals(getName())) {

                mSyncClass =  FolderClass.FIRST_CLASS;
                mPushClass =  FolderClass.FIRST_CLASS;
                mInTopGroup = true;
            }


        }

        public LocalFolder(long id) {
            super(LocalStore.this.mAccount);
            this.mFolderId = id;
        }

        public long getId() {
            return mFolderId;
        }

        @Override
        public void open(final OpenMode mode) throws MessagingException {

            if (isOpen() && (getMode() == mode || mode == OpenMode.READ_ONLY)) {
                return;
            } else if (isOpen()) {
                //previously opened in READ_ONLY and now requesting READ_WRITE
                //so close connection and reopen
                close();
            }

            try {
                database.execute(false, new DbCallback<Void>() {
                    @Override
                    public Void doDbWork(final SQLiteDatabase db) throws WrappedException {
                        Cursor cursor = null;
                        try {
                            String baseQuery = "SELECT " + GET_FOLDER_COLS + " FROM folders " +
                                    "LEFT JOIN messages ON (folder_id = folders.id AND" +
                                    " (empty IS NULL OR empty != 1) AND deleted = 0) ";

                            if (mName != null) {
                                cursor = db.rawQuery(baseQuery + "where folders.name = ?", new String[] { mName });
                            } else {
                                cursor = db.rawQuery(baseQuery + "where folders.id = ?", new String[] { Long.toString(mFolderId) });
                            }

                            if (cursor.moveToFirst() && !cursor.isNull(0)) {
                                int folderId = cursor.getInt(0);
                                if (folderId > 0) {
                                    open(folderId, cursor.getString(1), cursor.getInt(2), cursor.getInt(3), cursor.getLong(4), cursor.getString(5), cursor.getString(6), cursor.getLong(7), cursor.getInt(8), cursor.getInt(9), cursor.getInt(10), cursor.getString(11), cursor.getString(12), cursor.getString(13));
                                }
                            } else {
                                Log.w(K9.LOG_TAG, "Creating folder " + getName() + " with existing id " + getId());
                                create(FolderType.HOLDS_MESSAGES);
                                open(mode);
                            }
                        } catch (MessagingException e) {
                            throw new WrappedException(e);
                        } finally {
                            Utility.closeQuietly(cursor);
                        }
                        return null;
                    }
                });
            } catch (WrappedException e) {
                throw(MessagingException) e.getCause();
            }
        }

        private void open(int id, String name, int unreadCount, int visibleLimit, long lastChecked, String status, String pushState, long lastPushed, int flaggedCount, int integrate, int topGroup, String syncClass, String pushClass, String displayClass) throws MessagingException {
            mFolderId = id;
            mName = name;
            mUnreadMessageCount = unreadCount;
            mVisibleLimit = visibleLimit;
            mPushState = pushState;
            mFlaggedMessageCount = flaggedCount;
            super.setStatus(status);
            // Only want to set the local variable stored in the super class.  This class
            // does a DB update on setLastChecked
            super.setLastChecked(lastChecked);
            super.setLastPush(lastPushed);
            mInTopGroup = topGroup == 1  ? true : false;
            mIntegrate = integrate == 1 ? true : false;
            String noClass = FolderClass.NO_CLASS.toString();
            mDisplayClass = Folder.FolderClass.valueOf((displayClass == null) ? noClass : displayClass);
            mPushClass = Folder.FolderClass.valueOf((pushClass == null) ? noClass : pushClass);
            mSyncClass = Folder.FolderClass.valueOf((syncClass == null) ? noClass : syncClass);

        }

        @Override
        public boolean isOpen() {
            return (mFolderId != -1 && mName != null);
        }

        @Override
        public OpenMode getMode() {
            return OpenMode.READ_WRITE;
        }

        @Override
        public String getName() {
            return mName;
        }

        @Override
        public boolean exists() throws MessagingException {
            return database.execute(false, new DbCallback<Boolean>() {
                @Override
                public Boolean doDbWork(final SQLiteDatabase db) throws WrappedException {
                    Cursor cursor = null;
                    try {
                        cursor = db.rawQuery("SELECT id FROM folders "
                                             + "where folders.name = ?", new String[] { LocalFolder.this
                                                     .getName()
                                                                                      });
                        if (cursor.moveToFirst()) {
                            int folderId = cursor.getInt(0);
                            return (folderId > 0);
                        }

                        return false;
                    } finally {
                        Utility.closeQuietly(cursor);
                    }
                }
            });
        }

        @Override
        public boolean create(FolderType type) throws MessagingException {
            return create(type, mAccount.getDisplayCount());
        }

        @Override
        public boolean create(FolderType type, final int visibleLimit) throws MessagingException {
            if (exists()) {
                throw new MessagingException("Folder " + mName + " already exists.");
            }
            List<LocalFolder> foldersToCreate = new ArrayList<LocalFolder>(1);
            foldersToCreate.add(this);
            LocalStore.this.createFolders(foldersToCreate, visibleLimit);

            return true;
        }

        private class PreferencesHolder {
            FolderClass displayClass = mDisplayClass;
            FolderClass syncClass = mSyncClass;
            FolderClass pushClass = mPushClass;
            boolean inTopGroup = mInTopGroup;
            boolean integrate = mIntegrate;
        }

        @Override
        public void close() {
            mFolderId = -1;
        }

        @Override
        public int getMessageCount() throws MessagingException {
            try {
                return database.execute(false, new DbCallback<Integer>() {
                    @Override
                    public Integer doDbWork(final SQLiteDatabase db) throws WrappedException {
                        try {
                            open(OpenMode.READ_WRITE);
                        } catch (MessagingException e) {
                            throw new WrappedException(e);
                        }
                        Cursor cursor = null;
                        try {
                            cursor = db.rawQuery("SELECT COUNT(*) FROM messages WHERE (empty IS NULL OR empty != 1) AND deleted = 0 and folder_id = ?",
                                                 new String[] {
                                                     Long.toString(mFolderId)
                                                 });
                            cursor.moveToFirst();
                            return cursor.getInt(0);   //messagecount
                        } finally {
                            Utility.closeQuietly(cursor);
                        }
                    }
                });
            } catch (WrappedException e) {
                throw(MessagingException) e.getCause();
            }
        }

        @Override
        public int getUnreadMessageCount() throws MessagingException {
            if (!isOpen()) {
                // open() sums up the number of unread messages in the database
                open(OpenMode.READ_WRITE);
                return mUnreadMessageCount;
            }

            // Folder was already opened. Unread count might be outdated so query the database now.
            try {
                return database.execute(false, new DbCallback<Integer>() {
                    @Override
                    public Integer doDbWork(final SQLiteDatabase db) throws WrappedException {
                        int unreadMessageCount = 0;
                        Cursor cursor = db.query("messages", new String[] { "SUM(read=0)" },
                                "folder_id = ? AND (empty IS NULL OR empty != 1) AND deleted = 0",
                                new String[] { Long.toString(mFolderId) }, null, null, null);

                        try {
                            if (cursor.moveToFirst()) {
                                unreadMessageCount = cursor.getInt(0);
                            }
                        } finally {
                            cursor.close();
                        }

                        return unreadMessageCount;
                    }
                });
            } catch (WrappedException e) {
                throw(MessagingException) e.getCause();
            }
        }

        @Override
        public int getFlaggedMessageCount() throws MessagingException {
            open(OpenMode.READ_WRITE);
            return mFlaggedMessageCount;
        }

        @Override
        public void setLastChecked(final long lastChecked) throws MessagingException {
            try {
                open(OpenMode.READ_WRITE);
                LocalFolder.super.setLastChecked(lastChecked);
            } catch (MessagingException e) {
                throw new WrappedException(e);
            }
            updateFolderColumn("last_updated", lastChecked);
        }

        @Override
        public void setLastPush(final long lastChecked) throws MessagingException {
            try {
                open(OpenMode.READ_WRITE);
                LocalFolder.super.setLastPush(lastChecked);
            } catch (MessagingException e) {
                throw new WrappedException(e);
            }
            updateFolderColumn("last_pushed", lastChecked);
        }

        public int getVisibleLimit() throws MessagingException {
            open(OpenMode.READ_WRITE);
            return mVisibleLimit;
        }

        public void purgeToVisibleLimit(MessageRemovalListener listener) throws MessagingException {
            //don't purge messages while a Search is active since it might throw away search results
            if (!Search.isActive()) {
                if (mVisibleLimit == 0) {
                    return ;
                }
                open(OpenMode.READ_WRITE);
                Message[] messages = getMessages(null, false);
                for (int i = mVisibleLimit; i < messages.length; i++) {
                    if (listener != null) {
                        listener.messageRemoved(messages[i]);
                    }
                    messages[i].destroy();
                }
            }
        }


        public void setVisibleLimit(final int visibleLimit) throws MessagingException {
            mVisibleLimit = visibleLimit;
            updateFolderColumn("visible_limit", mVisibleLimit);
        }

        @Override
        public void setStatus(final String status) throws MessagingException {
            updateFolderColumn("status", status);
        }
        public void setPushState(final String pushState) throws MessagingException {
            mPushState = pushState;
            updateFolderColumn("push_state", pushState);
        }

        private void updateFolderColumn(final String column, final Object value) throws MessagingException {
            try {
                database.execute(false, new DbCallback<Void>() {
                    @Override
                    public Void doDbWork(final SQLiteDatabase db) throws WrappedException {
                        try {
                            open(OpenMode.READ_WRITE);
                        } catch (MessagingException e) {
                            throw new WrappedException(e);
                        }
                        db.execSQL("UPDATE folders SET " + column + " = ? WHERE id = ?", new Object[] { value, mFolderId });
                        return null;
                    }
                });
            } catch (WrappedException e) {
                throw(MessagingException) e.getCause();
            }
        }

        public String getPushState() {
            return mPushState;
        }
        @Override
        public FolderClass getDisplayClass() {
            return mDisplayClass;
        }

        @Override
        public FolderClass getSyncClass() {
            return (FolderClass.INHERITED == mSyncClass) ? getDisplayClass() : mSyncClass;
        }

        public FolderClass getRawSyncClass() {
            return mSyncClass;
        }

        @Override
        public FolderClass getPushClass() {
            return (FolderClass.INHERITED == mPushClass) ? getSyncClass() : mPushClass;
        }

        public FolderClass getRawPushClass() {
            return mPushClass;
        }

        public void setDisplayClass(FolderClass displayClass) throws MessagingException {
            mDisplayClass = displayClass;
            updateFolderColumn("display_class", mDisplayClass.name());

        }

        public void setSyncClass(FolderClass syncClass) throws MessagingException {
            mSyncClass = syncClass;
            updateFolderColumn("poll_class", mSyncClass.name());
        }
        public void setPushClass(FolderClass pushClass) throws MessagingException {
            mPushClass = pushClass;
            updateFolderColumn("push_class", mPushClass.name());
        }

        public boolean isIntegrate() {
            return mIntegrate;
        }
        public void setIntegrate(boolean integrate) throws MessagingException {
            mIntegrate = integrate;
            updateFolderColumn("integrate", mIntegrate ? 1 : 0);
        }

        private String getPrefId(String name) {
            if (prefId == null) {
                prefId = uUid + "." + name;
            }

            return prefId;
        }

        private String getPrefId() throws MessagingException {
            open(OpenMode.READ_WRITE);
            return getPrefId(mName);

        }

        public void delete() throws MessagingException {
            String id = getPrefId();

            SharedPreferences.Editor editor = LocalStore.this.getPreferences().edit();

            editor.remove(id + ".displayMode");
            editor.remove(id + ".syncMode");
            editor.remove(id + ".pushMode");
            editor.remove(id + ".inTopGroup");
            editor.remove(id + ".integrate");

            editor.commit();
        }

        public void save() throws MessagingException {
            SharedPreferences.Editor editor = LocalStore.this.getPreferences().edit();
            save(editor);
            editor.commit();
        }

        public void save(SharedPreferences.Editor editor) throws MessagingException {
            String id = getPrefId();

            // there can be a lot of folders.  For the defaults, let's not save prefs, saving space, except for INBOX
            if (mDisplayClass == FolderClass.NO_CLASS && !mAccount.getInboxFolderName().equals(getName())) {
                editor.remove(id + ".displayMode");
            } else {
                editor.putString(id + ".displayMode", mDisplayClass.name());
            }

            if (mSyncClass == FolderClass.INHERITED && !mAccount.getInboxFolderName().equals(getName())) {
                editor.remove(id + ".syncMode");
            } else {
                editor.putString(id + ".syncMode", mSyncClass.name());
            }

            if (mPushClass == FolderClass.SECOND_CLASS && !mAccount.getInboxFolderName().equals(getName())) {
                editor.remove(id + ".pushMode");
            } else {
                editor.putString(id + ".pushMode", mPushClass.name());
            }
            editor.putBoolean(id + ".inTopGroup", mInTopGroup);

            editor.putBoolean(id + ".integrate", mIntegrate);

        }

        public void refresh(String name, PreferencesHolder prefHolder) {
            String id = getPrefId(name);

            SharedPreferences preferences = LocalStore.this.getPreferences();

            try {
                prefHolder.displayClass = FolderClass.valueOf(preferences.getString(id + ".displayMode",
                                          prefHolder.displayClass.name()));
            } catch (Exception e) {
                Log.e(K9.LOG_TAG, "Unable to load displayMode for " + getName(), e);
            }
            if (prefHolder.displayClass == FolderClass.NONE) {
                prefHolder.displayClass = FolderClass.NO_CLASS;
            }

            try {
                prefHolder.syncClass = FolderClass.valueOf(preferences.getString(id  + ".syncMode",
                                       prefHolder.syncClass.name()));
            } catch (Exception e) {
                Log.e(K9.LOG_TAG, "Unable to load syncMode for " + getName(), e);

            }
            if (prefHolder.syncClass == FolderClass.NONE) {
                prefHolder.syncClass = FolderClass.INHERITED;
            }

            try {
                prefHolder.pushClass = FolderClass.valueOf(preferences.getString(id  + ".pushMode",
                                       prefHolder.pushClass.name()));
            } catch (Exception e) {
                Log.e(K9.LOG_TAG, "Unable to load pushMode for " + getName(), e);
            }
            if (prefHolder.pushClass == FolderClass.NONE) {
                prefHolder.pushClass = FolderClass.INHERITED;
            }
            prefHolder.inTopGroup = preferences.getBoolean(id + ".inTopGroup", prefHolder.inTopGroup);
            prefHolder.integrate = preferences.getBoolean(id + ".integrate", prefHolder.integrate);

        }

        @Override
        public void fetch(final Message[] messages, final FetchProfile fp, final MessageRetrievalListener listener)
        throws MessagingException {
            try {
                database.execute(false, new DbCallback<Void>() {
                    @Override
                    public Void doDbWork(final SQLiteDatabase db) throws WrappedException {
                        try {
                            open(OpenMode.READ_WRITE);
                            if (fp.contains(FetchProfile.Item.BODY)) {
                                for (Message message : messages) {
                                    LocalMessage localMessage = (LocalMessage)message;
                                    Cursor cursor = null;
                                    MimeMultipart mp = new MimeMultipart();
                                    mp.setSubType("mixed");
                                    try {
                                        cursor = db.rawQuery("SELECT html_content, text_content, mime_type FROM messages "
                                                             + "WHERE id = ?",
                                                             new String[] { Long.toString(localMessage.mId) });
                                        cursor.moveToNext();
                                        String htmlContent = cursor.getString(0);
                                        String textContent = cursor.getString(1);
                                        String mimeType = cursor.getString(2);
                                        if (mimeType != null && mimeType.toLowerCase(Locale.US).startsWith("multipart/")) {
                                            // If this is a multipart message, preserve both text
                                            // and html parts, as well as the subtype.
                                            mp.setSubType(mimeType.toLowerCase(Locale.US).replaceFirst("^multipart/", ""));
                                            if (textContent != null) {
                                                LocalTextBody body = new LocalTextBody(textContent, htmlContent);
                                                MimeBodyPart bp = new MimeBodyPart(body, "text/plain");
                                                mp.addBodyPart(bp);
                                            }

                                            if (mAccount.getMessageFormat() != MessageFormat.TEXT) {
                                                if (htmlContent != null) {
                                                    TextBody body = new TextBody(htmlContent);
                                                    MimeBodyPart bp = new MimeBodyPart(body, "text/html");
                                                    mp.addBodyPart(bp);
                                                }

                                                // If we have both text and html content and our MIME type
                                                // isn't multipart/alternative, then corral them into a new
                                                // multipart/alternative part and put that into the parent.
                                                // If it turns out that this is the only part in the parent
                                                // MimeMultipart, it'll get fixed below before we attach to
                                                // the message.
                                                if (textContent != null && htmlContent != null && !mimeType.equalsIgnoreCase("multipart/alternative")) {
                                                    MimeMultipart alternativeParts = mp;
                                                    alternativeParts.setSubType("alternative");
                                                    mp = new MimeMultipart();
                                                    mp.addBodyPart(new MimeBodyPart(alternativeParts));
                                                }
                                            }
                                        } else if (mimeType != null && mimeType.equalsIgnoreCase("text/plain")) {
                                            // If it's text, add only the plain part. The MIME
                                            // container will drop away below.
                                            if (textContent != null) {
                                                LocalTextBody body = new LocalTextBody(textContent, htmlContent);
                                                MimeBodyPart bp = new MimeBodyPart(body, "text/plain");
                                                mp.addBodyPart(bp);
                                            }
                                        } else if (mimeType != null && mimeType.equalsIgnoreCase("text/html")) {
                                            // If it's html, add only the html part. The MIME
                                            // container will drop away below.
                                            if (htmlContent != null) {
                                                TextBody body = new TextBody(htmlContent);
                                                MimeBodyPart bp = new MimeBodyPart(body, "text/html");
                                                mp.addBodyPart(bp);
                                            }
                                        } else {
                                            // MIME type not set. Grab whatever part we can get,
                                            // with Text taking precedence. This preserves pre-HTML
                                            // composition behaviour.
                                            if (textContent != null) {
                                                LocalTextBody body = new LocalTextBody(textContent, htmlContent);
                                                MimeBodyPart bp = new MimeBodyPart(body, "text/plain");
                                                mp.addBodyPart(bp);
                                            } else if (htmlContent != null) {
                                                TextBody body = new TextBody(htmlContent);
                                                MimeBodyPart bp = new MimeBodyPart(body, "text/html");
                                                mp.addBodyPart(bp);
                                            }
                                        }

                                    } catch (Exception e) {
                                        Log.e(K9.LOG_TAG, "Exception fetching message:", e);
                                    } finally {
                                        Utility.closeQuietly(cursor);
                                    }

                                    try {
                                        cursor = db.query(
                                                     "attachments",
                                                     new String[] {
                                                         "id",
                                                         "size",
                                                         "name",
                                                         "mime_type",
                                                         "store_data",
                                                         "content_uri",
                                                         "content_id",
                                                         "content_disposition"
                                                     },
                                                     "message_id = ?",
                                                     new String[] { Long.toString(localMessage.mId) },
                                                     null,
                                                     null,
                                                     null);

                                        while (cursor.moveToNext()) {
                                            long id = cursor.getLong(0);
                                            int size = cursor.getInt(1);
                                            String name = cursor.getString(2);
                                            String type = cursor.getString(3);
                                            String storeData = cursor.getString(4);
                                            String contentUri = cursor.getString(5);
                                            String contentId = cursor.getString(6);
                                            String contentDisposition = cursor.getString(7);
                                            Body body = null;

                                            if (contentDisposition == null) {
                                                contentDisposition = "attachment";
                                            }

                                            if (contentUri != null) {
                                                body = new LocalAttachmentBody(Uri.parse(contentUri), mApplication);
                                            }

                                            MimeBodyPart bp = new LocalAttachmentBodyPart(body, id);
                                            bp.setHeader(MimeHeader.HEADER_CONTENT_TRANSFER_ENCODING, "base64");
                                            if (name != null) {
                                                bp.setHeader(MimeHeader.HEADER_CONTENT_TYPE,
                                                             String.format("%s;\n name=\"%s\"",
                                                                           type,
                                                                           name));
                                                bp.setHeader(MimeHeader.HEADER_CONTENT_DISPOSITION,
                                                             String.format("%s;\n filename=\"%s\";\n size=%d",
                                                                           contentDisposition,
                                                                           name, // TODO: Should use encoded word defined in RFC 2231.
                                                                           size));
                                            } else {
                                                bp.setHeader(MimeHeader.HEADER_CONTENT_TYPE, type);
                                                bp.setHeader(MimeHeader.HEADER_CONTENT_DISPOSITION,
                                                        String.format("%s;\n size=%d",
                                                                      contentDisposition,
                                                                      size));
                                            }

                                            bp.setHeader(MimeHeader.HEADER_CONTENT_ID, contentId);
                                            /*
                                             * HEADER_ANDROID_ATTACHMENT_STORE_DATA is a custom header we add to that
                                             * we can later pull the attachment from the remote store if necessary.
                                             */
                                            bp.setHeader(MimeHeader.HEADER_ANDROID_ATTACHMENT_STORE_DATA, storeData);

                                            mp.addBodyPart(bp);
                                        }
                                    } finally {
                                        Utility.closeQuietly(cursor);
                                    }

                                    if (mp.getCount() == 0) {
                                        // If we have no body, remove the container and create a
                                        // dummy plain text body. This check helps prevents us from
                                        // triggering T_MIME_NO_TEXT and T_TVD_MIME_NO_HEADERS
                                        // SpamAssassin rules.
                                        localMessage.setHeader(MimeHeader.HEADER_CONTENT_TYPE, "text/plain");
                                        localMessage.setBody(new TextBody(""));
                                    } else if (mp.getCount() == 1 && (mp.getBodyPart(0) instanceof LocalAttachmentBodyPart) == false)

                                    {
                                        // If we have only one part, drop the MimeMultipart container.
                                        BodyPart part = mp.getBodyPart(0);
                                        localMessage.setHeader(MimeHeader.HEADER_CONTENT_TYPE, part.getContentType());
                                        localMessage.setBody(part.getBody());
                                    } else {
                                        // Otherwise, attach the MimeMultipart to the message.
                                        localMessage.setBody(mp);
                                    }
                                }
                            }
                        } catch (MessagingException e) {
                            throw new WrappedException(e);
                        }
                        return null;
                    }
                });
            } catch (WrappedException e) {
                throw(MessagingException) e.getCause();
            }
        }

        @Override
        public Message[] getMessages(int start, int end, Date earliestDate, MessageRetrievalListener listener)
        throws MessagingException {
            open(OpenMode.READ_WRITE);
            throw new MessagingException(
                "LocalStore.getMessages(int, int, MessageRetrievalListener) not yet implemented");
        }

        /**
         * Populate the header fields of the given list of messages by reading
         * the saved header data from the database.
         *
         * @param messages
         *            The messages whose headers should be loaded.
         * @throws UnavailableStorageException
         */
        private void populateHeaders(final List<LocalMessage> messages) throws UnavailableStorageException {
            database.execute(false, new DbCallback<Void>() {
                @Override
                public Void doDbWork(final SQLiteDatabase db) throws WrappedException, UnavailableStorageException {
                    Cursor cursor = null;
                    if (messages.isEmpty()) {
                        return null;
                    }
                    try {
                        Map<Long, LocalMessage> popMessages = new HashMap<Long, LocalMessage>();
                        List<String> ids = new ArrayList<String>();
                        StringBuilder questions = new StringBuilder();

                        for (int i = 0; i < messages.size(); i++) {
                            if (i != 0) {
                                questions.append(", ");
                            }
                            questions.append("?");
                            LocalMessage message = messages.get(i);
                            Long id = message.getId();
                            ids.add(Long.toString(id));
                            popMessages.put(id, message);

                        }

                        cursor = db.rawQuery(
                                     "SELECT message_id, name, value FROM headers " + "WHERE message_id in ( " + questions + ") ORDER BY id ASC",
                                     ids.toArray(EMPTY_STRING_ARRAY));


                        while (cursor.moveToNext()) {
                            Long id = cursor.getLong(0);
                            String name = cursor.getString(1);
                            String value = cursor.getString(2);
                            //Log.i(K9.LOG_TAG, "Retrieved header name= " + name + ", value = " + value + " for message " + id);
                            popMessages.get(id).addHeader(name, value);
                        }
                    } finally {
                        Utility.closeQuietly(cursor);
                    }
                    return null;
                }
            });
        }

        public String getMessageUidById(final long id) throws MessagingException {
            try {
                return database.execute(false, new DbCallback<String>() {
                    @Override
                    public String doDbWork(final SQLiteDatabase db) throws WrappedException, UnavailableStorageException {
                        try {
                            open(OpenMode.READ_WRITE);
                            Cursor cursor = null;

                            try {
                                cursor = db.rawQuery(
                                             "SELECT uid FROM messages " +
                                              "WHERE id = ? AND folder_id = ?",
                                             new String[] {
                                                 Long.toString(id), Long.toString(mFolderId)
                                             });
                                if (!cursor.moveToNext()) {
                                    return null;
                                }
                                return cursor.getString(0);
                            } finally {
                                Utility.closeQuietly(cursor);
                            }
                        } catch (MessagingException e) {
                            throw new WrappedException(e);
                        }
                    }
                });
            } catch (WrappedException e) {
                throw(MessagingException) e.getCause();
            }
        }

        @Override
        public LocalMessage getMessage(final String uid) throws MessagingException {
            try {
                return database.execute(false, new DbCallback<LocalMessage>() {
                    @Override
                    public LocalMessage doDbWork(final SQLiteDatabase db) throws WrappedException, UnavailableStorageException {
                        try {
                            open(OpenMode.READ_WRITE);
                            LocalMessage message = new LocalMessage(uid, LocalFolder.this);
                            Cursor cursor = null;

                            try {
                                cursor = db.rawQuery(
                                             "SELECT "
                                             + GET_MESSAGES_COLS
                                             + "FROM messages WHERE uid = ? AND folder_id = ?",
                                             new String[] {
                                                 message.getUid(), Long.toString(mFolderId)
                                             });
                                if (!cursor.moveToNext()) {
                                    return null;
                                }
                                message.populateFromGetMessageCursor(cursor);
                            } finally {
                                Utility.closeQuietly(cursor);
                            }
                            return message;
                        } catch (MessagingException e) {
                            throw new WrappedException(e);
                        }
                    }
                });
            } catch (WrappedException e) {
                throw(MessagingException) e.getCause();
            }
        }

        @Override
        public Message[] getMessages(MessageRetrievalListener listener) throws MessagingException {
            return getMessages(listener, true);
        }

        @Override
        public Message[] getMessages(final MessageRetrievalListener listener, final boolean includeDeleted) throws MessagingException {
            try {
                return database.execute(false, new DbCallback<Message[]>() {
                    @Override
                    public Message[] doDbWork(final SQLiteDatabase db) throws WrappedException, UnavailableStorageException {
                        try {
                            open(OpenMode.READ_WRITE);
                            return LocalStore.this.getMessages(
                                       listener,
                                       LocalFolder.this,
                                       "SELECT " + GET_MESSAGES_COLS
                                       + "FROM messages WHERE (empty IS NULL OR empty != 1) AND "
                                       + (includeDeleted ? "" : "deleted = 0 AND ")
                                       + " folder_id = ? ORDER BY date DESC"
                                       , new String[] {
                                           Long.toString(mFolderId)
                                       }
                                   );
                        } catch (MessagingException e) {
                            throw new WrappedException(e);
                        }
                    }
                });
            } catch (WrappedException e) {
                throw(MessagingException) e.getCause();
            }
        }

        @Override
        public Message[] getMessages(String[] uids, MessageRetrievalListener listener)
        throws MessagingException {
            open(OpenMode.READ_WRITE);
            if (uids == null) {
                return getMessages(listener);
            }
            ArrayList<Message> messages = new ArrayList<Message>();
            for (String uid : uids) {
                Message message = getMessage(uid);
                if (message != null) {
                    messages.add(message);
                }
            }
            return messages.toArray(EMPTY_MESSAGE_ARRAY);
        }

        @Override
        public Map<String, String> copyMessages(Message[] msgs, Folder folder) throws MessagingException {
            if (!(folder instanceof LocalFolder)) {
                throw new MessagingException("copyMessages called with incorrect Folder");
            }
            return ((LocalFolder) folder).appendMessages(msgs, true);
        }

        @Override
        public Map<String, String> moveMessages(final Message[] msgs, final Folder destFolder) throws MessagingException {
            if (!(destFolder instanceof LocalFolder)) {
                throw new MessagingException("moveMessages called with non-LocalFolder");
            }

            final LocalFolder lDestFolder = (LocalFolder)destFolder;

            final Map<String, String> uidMap = new HashMap<String, String>();

            try {
                database.execute(false, new DbCallback<Void>() {
                    @Override
                    public Void doDbWork(final SQLiteDatabase db) throws WrappedException, UnavailableStorageException {
                        try {
                            lDestFolder.open(OpenMode.READ_WRITE);
                            for (Message message : msgs) {
                                LocalMessage lMessage = (LocalMessage)message;

                                String oldUID = message.getUid();

                                if (K9.DEBUG) {
                                    Log.d(K9.LOG_TAG, "Updating folder_id to " + lDestFolder.getId() + " for message with UID "
                                          + message.getUid() + ", id " + lMessage.getId() + " currently in folder " + getName());
                                }

                                String newUid = K9.LOCAL_UID_PREFIX + UUID.randomUUID().toString();
                                message.setUid(newUid);

                                uidMap.put(oldUID, newUid);

                                // Message threading in the target folder
                                ThreadInfo threadInfo = lDestFolder.doMessageThreading(db, message);

                                /*
                                 * "Move" the message into the new folder and thread structure
                                 */
                                long id = lMessage.getId();
                                String[] idArg = new String[] { Long.toString(id) };

                                ContentValues cv = new ContentValues();
                                cv.put("folder_id", lDestFolder.getId());
                                cv.put("uid", newUid);

                                if (threadInfo.rootId != -1) {
                                    cv.put("thread_root", threadInfo.rootId);
                                }

                                if (threadInfo.parentId != -1) {
                                    cv.put("thread_parent", threadInfo.parentId);
                                }

                                db.update("messages", cv, "id = ?", idArg);

                                if (threadInfo.id != -1) {
                                    String[] oldIdArg =
                                            new String[] { Long.toString(threadInfo.id) };

                                    cv.clear();
                                    cv.put("thread_root", id);
                                    db.update("messages", cv, "thread_root = ?", oldIdArg);

                                    cv.clear();
                                    cv.put("thread_parent", id);
                                    db.update("messages", cv, "thread_parent = ?", oldIdArg);
                                }

                                /*
                                 * Add a placeholder message so we won't download the original
                                 * message again if we synchronize before the remote move is
                                 * complete.
                                 */

                                // We need to open this folder to get the folder id
                                open(OpenMode.READ_WRITE);

                                cv.clear();
                                cv.put("uid", oldUID);
                                cv.putNull("flags");
                                cv.put("read", 1);
                                cv.put("deleted", 1);
                                cv.put("folder_id", mFolderId);

                                String messageId = message.getMessageId();
                                if (messageId != null) {
                                    cv.put("message_id", messageId);
                                    cv.put("empty", 1);

                                    long rootId = lMessage.getRootId();
                                    if (rootId != -1) {
                                        cv.put("thread_root", rootId);
                                    }

                                    long parentId = lMessage.getParentId();
                                    if (parentId != -1) {
                                        cv.put("thread_parent", parentId);
                                    }
                                }

                                final long newId;
                                if (threadInfo.id != -1) {
                                    // There already existed an empty message in the target folder.
                                    // Let's use it as placeholder.

                                    newId = threadInfo.id;

                                    db.update("messages", cv, "id = ?",
                                            new String[] { Long.toString(newId) });
                                } else {
                                    newId = db.insert("messages", null, cv);
                                }

                                /*
                                 * Replace all "thread links" to the original message with links to
                                 * the placeholder message.
                                 */

                                String[] whereArgs = new String[] {
                                        Long.toString(mFolderId),
                                        Long.toString(id) };

                                // Note: If there was an empty message in the target folder we
                                // already reconnected some messages to point to 'id'. We don't
                                // want to change those links again, so we limit the update
                                // statements below to the source folder.
                                cv.clear();
                                cv.put("thread_root", newId);
                                db.update("messages", cv, "folder_id = ? AND thread_root = ?",
                                        whereArgs);

                                cv.clear();
                                cv.put("thread_parent", newId);
                                db.update("messages", cv, "folder_id = ? AND thread_parent = ?",
                                        whereArgs);
                            }
                        } catch (MessagingException e) {
                            throw new WrappedException(e);
                        }
                        return null;
                    }
                });

                notifyChange();

                return uidMap;
            } catch (WrappedException e) {
                throw(MessagingException) e.getCause();
            }

        }

        /**
         * Convenience transaction wrapper for storing a message and set it as fully downloaded. Implemented mainly to speed up DB transaction commit.
         *
         * @param message Message to store. Never <code>null</code>.
         * @param runnable What to do before setting {@link Flag#X_DOWNLOADED_FULL}. Never <code>null</code>.
         * @return The local version of the message. Never <code>null</code>.
         * @throws MessagingException
         */
        public Message storeSmallMessage(final Message message, final Runnable runnable) throws MessagingException {
            return database.execute(true, new DbCallback<Message>() {
                @Override
                public Message doDbWork(final SQLiteDatabase db) throws WrappedException, UnavailableStorageException {
                    try {
                        appendMessages(new Message[] { message });
                        final String uid = message.getUid();
                        final Message result = getMessage(uid);
                        runnable.run();
                        // Set a flag indicating this message has now be fully downloaded
                        result.setFlag(Flag.X_DOWNLOADED_FULL, true);
                        return result;
                    } catch (MessagingException e) {
                        throw new WrappedException(e);
                    }
                }
            });
        }

        /**
         * The method differs slightly from the contract; If an incoming message already has a uid
         * assigned and it matches the uid of an existing message then this message will replace the
         * old message. It is implemented as a delete/insert. This functionality is used in saving
         * of drafts and re-synchronization of updated server messages.
         *
         * NOTE that although this method is located in the LocalStore class, it is not guaranteed
         * that the messages supplied as parameters are actually {@link LocalMessage} instances (in
         * fact, in most cases, they are not). Therefore, if you want to make local changes only to a
         * message, retrieve the appropriate local message instance first (if it already exists).
         */
        @Override
        public Map<String, String> appendMessages(Message[] messages) throws MessagingException {
            return appendMessages(messages, false);
        }

        public void destroyMessages(final Message[] messages) {
            try {
                database.execute(true, new DbCallback<Void>() {
                    @Override
                    public Void doDbWork(final SQLiteDatabase db) throws WrappedException, UnavailableStorageException {
                        for (Message message : messages) {
                            try {
                                message.destroy();
                            } catch (MessagingException e) {
                                throw new WrappedException(e);
                            }
                        }
                        return null;
                    }
                });
            } catch (MessagingException e) {
                throw new WrappedException(e);
            }
        }

        /**
         * Get the (database) ID of the message with the specified message ID.
         *
         * @param db
         *         A {@link SQLiteDatabase} instance to access the database.
         * @param messageId
         *         The message ID to search for.
         * @param onlyEmptyMessages
         *         {@code true} if only "empty messages" (placeholders for threading) should be
         *         searched
         *
         * @return If exactly one message with the specified message ID was found, the database ID
         *         of this message; {@code -1} otherwise.
         */
        private long getDatabaseIdByMessageId(SQLiteDatabase db, String messageId,
                boolean onlyEmptyMessages) {
            long id = -1;

            Cursor cursor = db.query("messages",
                    new String[] { "id" },
                    (onlyEmptyMessages) ?
                            "empty=1 AND folder_id=? AND message_id=?" :
                            "folder_id=? AND message_id=?",
                    new String[] { Long.toString(mFolderId), messageId },
                    null, null, null);

            if (cursor != null) {
                try {
                    if (cursor.getCount() == 1) {
                        cursor.moveToFirst();
                        id = cursor.getLong(0);
                    }
                } finally {
                    cursor.close();
                }
            }

            return id;
        }

        private ThreadInfo getThreadInfo(SQLiteDatabase db, String messageId) {
            Cursor cursor = db.query("messages",
                    new String[] { "id", "thread_root", "thread_parent" },
                            "folder_id=? AND message_id=?",
                    new String[] { Long.toString(mFolderId), messageId },
                    null, null, null);

            if (cursor != null) {
                try {
                    if (cursor.getCount() == 1) {
                        cursor.moveToFirst();
                        long id = cursor.getLong(0);
                        long rootId = (cursor.isNull(1)) ? -1 : cursor.getLong(1);
                        long parentId = (cursor.isNull(2)) ? -1 : cursor.getLong(2);

                        return new ThreadInfo(id, messageId, rootId, parentId);
                    }
                } finally {
                    cursor.close();
                }
            }

            return null;
        }

        /**
         * The method differs slightly from the contract; If an incoming message already has a uid
         * assigned and it matches the uid of an existing message then this message will replace
         * the old message. This functionality is used in saving of drafts and re-synchronization
         * of updated server messages.
         *
         * NOTE that although this method is located in the LocalStore class, it is not guaranteed
         * that the messages supplied as parameters are actually {@link LocalMessage} instances (in
         * fact, in most cases, they are not). Therefore, if you want to make local changes only to a
         * message, retrieve the appropriate local message instance first (if it already exists).
         * @param messages
         * @param copy
         * @return Map<String, String> uidMap of srcUids -> destUids
         */
        private Map<String, String> appendMessages(final Message[] messages, final boolean copy) throws MessagingException {
            open(OpenMode.READ_WRITE);
            try {
                final Map<String, String> uidMap = new HashMap<String, String>();
                database.execute(true, new DbCallback<Void>() {
                    @Override
                    public Void doDbWork(final SQLiteDatabase db) throws WrappedException, UnavailableStorageException {
                        try {
                            for (Message message : messages) {
                                if (!(message instanceof MimeMessage)) {
                                    throw new Error("LocalStore can only store Messages that extend MimeMessage");
                                }

                                long oldMessageId = -1;
                                String uid = message.getUid();
                                if (uid == null || copy) {
                                    /*
                                     * Create a new message in the database
                                     */
                                    String randomLocalUid = K9.LOCAL_UID_PREFIX +
                                            UUID.randomUUID().toString();

                                    if (copy) {
                                        // Save mapping: source UID -> target UID
                                        uidMap.put(uid, randomLocalUid);
                                    } else {
                                        // Modify the Message instance to reference the new UID
                                        message.setUid(randomLocalUid);
                                    }

                                    // The message will be saved with the newly generated UID
                                    uid = randomLocalUid;
                                } else {
                                    /*
                                     * Replace an existing message in the database
                                     */
                                    LocalMessage oldMessage = getMessage(uid);

                                    if (oldMessage != null) {
                                        oldMessageId = oldMessage.getId();
                                    }

                                    deleteAttachments(message.getUid());
                                }

                                long rootId = -1;
                                long parentId = -1;

                                if (oldMessageId == -1) {
                                    // This is a new message. Do the message threading.
                                    ThreadInfo threadInfo = doMessageThreading(db, message);
                                    oldMessageId = threadInfo.id;
                                    rootId = threadInfo.rootId;
                                    parentId = threadInfo.parentId;
                                }

                                boolean isDraft = (message.getHeader(K9.IDENTITY_HEADER) != null);

                                List<Part> attachments;
                                String text;
                                String html;
                                if (isDraft) {
                                    // Don't modify the text/plain or text/html part of our own
                                    // draft messages because this will cause the values stored in
                                    // the identity header to be wrong.
                                    ViewableContainer container =
                                            MimeUtility.extractPartsFromDraft(message);

                                    text = container.text;
                                    html = container.html;
                                    attachments = container.attachments;
                                } else {
                                    ViewableContainer container =
                                            MimeUtility.extractTextAndAttachments(mApplication, message);

                                    attachments = container.attachments;
                                    text = container.text;
                                    html = HtmlConverter.convertEmoji2Img(container.html);
                                }

                                String preview = calculateContentPreview(text);

                                try {
                                    ContentValues cv = new ContentValues();
                                    cv.put("uid", uid);
                                    cv.put("subject", message.getSubject());
                                    cv.put("sender_list", Address.pack(message.getFrom()));
                                    cv.put("date", message.getSentDate() == null
                                           ? System.currentTimeMillis() : message.getSentDate().getTime());
                                    cv.put("flags", serializeFlags(message.getFlags()));
                                    cv.put("deleted", message.isSet(Flag.DELETED) ? 1 : 0);
                                    cv.put("read", message.isSet(Flag.SEEN) ? 1 : 0);
                                    cv.put("flagged", message.isSet(Flag.FLAGGED) ? 1 : 0);
                                    cv.put("answered", message.isSet(Flag.ANSWERED) ? 1 : 0);
                                    cv.put("forwarded", message.isSet(Flag.FORWARDED) ? 1 : 0);
                                    cv.put("folder_id", mFolderId);
                                    cv.put("to_list", Address.pack(message.getRecipients(RecipientType.TO)));
                                    cv.put("cc_list", Address.pack(message.getRecipients(RecipientType.CC)));
                                    cv.put("bcc_list", Address.pack(message.getRecipients(RecipientType.BCC)));
                                    cv.put("html_content", html.length() > 0 ? html : null);
                                    cv.put("text_content", text.length() > 0 ? text : null);
                                    cv.put("preview", preview.length() > 0 ? preview : null);
                                    cv.put("reply_to_list", Address.pack(message.getReplyTo()));
                                    cv.put("attachment_count", attachments.size());
                                    cv.put("internal_date",  message.getInternalDate() == null
                                           ? System.currentTimeMillis() : message.getInternalDate().getTime());
                                    cv.put("mime_type", message.getMimeType());
                                    cv.put("empty", 0);

                                    String messageId = message.getMessageId();
                                    if (messageId != null) {
                                        cv.put("message_id", messageId);
                                    }

                                    if (rootId != -1) {
                                        cv.put("thread_root", rootId);
                                    }
                                    if (parentId != -1) {
                                        cv.put("thread_parent", parentId);
                                    }

                                    long messageUid;

                                    if (oldMessageId == -1) {
                                        messageUid = db.insert("messages", "uid", cv);
                                    } else {
                                        db.update("messages", cv, "id = ?", new String[] { Long.toString(oldMessageId) });
                                        messageUid = oldMessageId;
                                    }
                                    for (Part attachment : attachments) {
                                        saveAttachment(messageUid, attachment, copy);
                                    }
                                    saveHeaders(messageUid, (MimeMessage)message);
                                } catch (Exception e) {
                                    throw new MessagingException("Error appending message", e);
                                }
                            }
                        } catch (MessagingException e) {
                            throw new WrappedException(e);
                        }
                        return null;
                    }
                });

                notifyChange();

                return uidMap;
            } catch (WrappedException e) {
                throw(MessagingException) e.getCause();
            }
        }

        /**
         * Update the given message in the LocalStore without first deleting the existing
         * message (contrast with appendMessages). This method is used to store changes
         * to the given message while updating attachments and not removing existing
         * attachment data.
         * TODO In the future this method should be combined with appendMessages since the Message
         * contains enough data to decide what to do.
         * @param message
         * @throws MessagingException
         */
        public void updateMessage(final LocalMessage message) throws MessagingException {
            open(OpenMode.READ_WRITE);
            try {
                database.execute(false, new DbCallback<Void>() {
                    @Override
                    public Void doDbWork(final SQLiteDatabase db) throws WrappedException, UnavailableStorageException {
                        try {
                            message.buildMimeRepresentation();

                            ViewableContainer container =
                                    MimeUtility.extractTextAndAttachments(mApplication, message);

                            List<Part> attachments = container.attachments;
                            String text = container.text;
                            String html = HtmlConverter.convertEmoji2Img(container.html);

                            String preview = calculateContentPreview(text);

                            try {
                                db.execSQL("UPDATE messages SET "
                                           + "uid = ?, subject = ?, sender_list = ?, date = ?, flags = ?, "
                                           + "folder_id = ?, to_list = ?, cc_list = ?, bcc_list = ?, "
                                           + "html_content = ?, text_content = ?, preview = ?, reply_to_list = ?, "
                                           + "attachment_count = ?, read = ?, flagged = ?, answered = ?, forwarded = ? "
                                           + "WHERE id = ?",
                                           new Object[] {
                                               message.getUid(),
                                               message.getSubject(),
                                               Address.pack(message.getFrom()),
                                               message.getSentDate() == null ? System
                                               .currentTimeMillis() : message.getSentDate()
                                               .getTime(),
                                               serializeFlags(message.getFlags()),
                                               mFolderId,
                                               Address.pack(message
                                                            .getRecipients(RecipientType.TO)),
                                               Address.pack(message
                                                            .getRecipients(RecipientType.CC)),
                                               Address.pack(message
                                                            .getRecipients(RecipientType.BCC)),
                                               html.length() > 0 ? html : null,
                                               text.length() > 0 ? text : null,
                                               preview.length() > 0 ? preview : null,
                                               Address.pack(message.getReplyTo()),
                                               attachments.size(),
                                               message.isSet(Flag.SEEN) ? 1 : 0,
                                               message.isSet(Flag.FLAGGED) ? 1 : 0,
                                               message.isSet(Flag.ANSWERED) ? 1 : 0,
                                               message.isSet(Flag.FORWARDED) ? 1 : 0,
                                               message.mId
                                           });

                                for (int i = 0, count = attachments.size(); i < count; i++) {
                                    Part attachment = attachments.get(i);
                                    saveAttachment(message.mId, attachment, false);
                                }
                                saveHeaders(message.getId(), message);
                            } catch (Exception e) {
                                throw new MessagingException("Error appending message", e);
                            }
                        } catch (MessagingException e) {
                            throw new WrappedException(e);
                        }
                        return null;
                    }
                });
            } catch (WrappedException e) {
                throw(MessagingException) e.getCause();
            }

            notifyChange();
        }

        /**
         * Save the headers of the given message. Note that the message is not
         * necessarily a {@link LocalMessage} instance.
         * @param id
         * @param message
         * @throws com.fsck.k9.mail.MessagingException
         */
        private void saveHeaders(final long id, final MimeMessage message) throws MessagingException {
            database.execute(true, new DbCallback<Void>() {
                @Override
                public Void doDbWork(final SQLiteDatabase db) throws WrappedException, UnavailableStorageException {

                    deleteHeaders(id);
                    for (String name : message.getHeaderNames()) {
                            String[] values = message.getHeader(name);
                            for (String value : values) {
                                ContentValues cv = new ContentValues();
                                cv.put("message_id", id);
                                cv.put("name", name);
                                cv.put("value", value);
                                db.insert("headers", "name", cv);
                            }
                    }

                    // Remember that all headers for this message have been saved, so it is
                    // not necessary to download them again in case the user wants to see all headers.
                    List<Flag> appendedFlags = new ArrayList<Flag>();
                    appendedFlags.addAll(Arrays.asList(message.getFlags()));
                    appendedFlags.add(Flag.X_GOT_ALL_HEADERS);

                    db.execSQL("UPDATE messages " + "SET flags = ? " + " WHERE id = ?",
                               new Object[]
                               { serializeFlags(appendedFlags.toArray(EMPTY_FLAG_ARRAY)), id });

                    return null;
                }
            });
        }

        private void deleteHeaders(final long id) throws UnavailableStorageException {
            database.execute(false, new DbCallback<Void>() {
                @Override
                public Void doDbWork(final SQLiteDatabase db) throws WrappedException, UnavailableStorageException {
                    db.execSQL("DELETE FROM headers WHERE message_id = ?", new Object[]
                               { id });
                    return null;
                }
            });
        }

        /**
         * @param messageId
         * @param attachment
         * @param saveAsNew
         * @throws IOException
         * @throws MessagingException
         */
        private void saveAttachment(final long messageId, final Part attachment, final boolean saveAsNew)
        throws IOException, MessagingException {
            try {
                database.execute(true, new DbCallback<Void>() {
                    @Override
                    public Void doDbWork(final SQLiteDatabase db) throws WrappedException, UnavailableStorageException {
                        try {
                            long attachmentId = -1;
                            Uri contentUri = null;
                            int size = -1;
                            File tempAttachmentFile = null;

                            if ((!saveAsNew) && (attachment instanceof LocalAttachmentBodyPart)) {
                                attachmentId = ((LocalAttachmentBodyPart) attachment).getAttachmentId();
                            }

                            final File attachmentDirectory = StorageManager.getInstance(mApplication).getAttachmentDirectory(uUid, database.getStorageProviderId());
                            if (attachment.getBody() != null) {
                                Body body = attachment.getBody();
                                if (body instanceof LocalAttachmentBody) {
                                    contentUri = ((LocalAttachmentBody) body).getContentUri();
                                } else if (body instanceof Message) {
                                    // It's a message, so use Message.writeTo() to output the
                                    // message including all children.
                                    Message message = (Message) body;
                                    tempAttachmentFile = File.createTempFile("att", null, attachmentDirectory);
                                    FileOutputStream out = new FileOutputStream(tempAttachmentFile);
                                    try {
                                        message.writeTo(out);
                                    } finally {
                                        out.close();
                                    }
                                    size = (int) (tempAttachmentFile.length() & 0x7FFFFFFFL);
                                } else {
                                    /*
                                     * If the attachment has a body we're expected to save it into the local store
                                     * so we copy the data into a cached attachment file.
                                     */
                                    InputStream in = attachment.getBody().getInputStream();
                                    try {
                                        tempAttachmentFile = File.createTempFile("att", null, attachmentDirectory);
                                        FileOutputStream out = new FileOutputStream(tempAttachmentFile);
                                        try {
                                            size = IOUtils.copy(in, out);
                                        } finally {
                                            out.close();
                                        }
                                    } finally {
                                        try { in.close(); } catch (Throwable ignore) {}
                                    }
                                }
                            }

                            if (size == -1) {
                                /*
                                 * If the attachment is not yet downloaded see if we can pull a size
                                 * off the Content-Disposition.
                                 */
                                String disposition = attachment.getDisposition();
                                if (disposition != null) {
                                    String s = MimeUtility.getHeaderParameter(disposition, "size");
                                    if (s != null) {
                                        try {
                                            size = Integer.parseInt(s);
                                        } catch (NumberFormatException e) { /* Ignore */ }
                                    }
                                }
                            }
                            if (size == -1) {
                                size = 0;
                            }

                            String storeData =
                                Utility.combine(attachment.getHeader(
                                                    MimeHeader.HEADER_ANDROID_ATTACHMENT_STORE_DATA), ',');

                            String name = MimeUtility.getHeaderParameter(attachment.getContentType(), "name");
                            String contentId = MimeUtility.getHeaderParameter(attachment.getContentId(), null);

                            String contentDisposition = MimeUtility.unfoldAndDecode(attachment.getDisposition());
                            String dispositionType = contentDisposition;

                            if (dispositionType != null) {
                                int pos = dispositionType.indexOf(';');
                                if (pos != -1) {
                                    // extract the disposition-type, "attachment", "inline" or extension-token (see the RFC 2183)
                                    dispositionType = dispositionType.substring(0, pos);
                                }
                            }

                            if (name == null && contentDisposition != null) {
                                name = MimeUtility.getHeaderParameter(contentDisposition, "filename");
                            }
                            if (attachmentId == -1) {
                                ContentValues cv = new ContentValues();
                                cv.put("message_id", messageId);
                                cv.put("content_uri", contentUri != null ? contentUri.toString() : null);
                                cv.put("store_data", storeData);
                                cv.put("size", size);
                                cv.put("name", name);
                                cv.put("mime_type", attachment.getMimeType());
                                cv.put("content_id", contentId);
                                cv.put("content_disposition", dispositionType);

                                attachmentId = db.insert("attachments", "message_id", cv);
                            } else {
                                ContentValues cv = new ContentValues();
                                cv.put("content_uri", contentUri != null ? contentUri.toString() : null);
                                cv.put("size", size);
                                db.update("attachments", cv, "id = ?", new String[]
                                          { Long.toString(attachmentId) });
                            }

                            if (attachmentId != -1 && tempAttachmentFile != null) {
                                File attachmentFile = new File(attachmentDirectory, Long.toString(attachmentId));
                                tempAttachmentFile.renameTo(attachmentFile);
                                contentUri = AttachmentProvider.getAttachmentUri(
                                                 mAccount,
                                                 attachmentId);
                                attachment.setBody(new LocalAttachmentBody(contentUri, mApplication));
                                ContentValues cv = new ContentValues();
                                cv.put("content_uri", contentUri != null ? contentUri.toString() : null);
                                db.update("attachments", cv, "id = ?", new String[]
                                          { Long.toString(attachmentId) });
                            }

                            /* The message has attachment with Content-ID */
                            if (contentId != null && contentUri != null) {
                                Cursor cursor = db.query("messages", new String[]
                                                         { "html_content" }, "id = ?", new String[]
                                                         { Long.toString(messageId) }, null, null, null);
                                try {
                                    if (cursor.moveToNext()) {
                                        String htmlContent = cursor.getString(0);

                                        if (htmlContent != null) {
                                            String newHtmlContent = htmlContent.replaceAll(
                                                                        Pattern.quote("cid:" + contentId),
                                                                        contentUri.toString());

                                            ContentValues cv = new ContentValues();
                                            cv.put("html_content", newHtmlContent);
                                            db.update("messages", cv, "id = ?", new String[]
                                                      { Long.toString(messageId) });
                                        }
                                    }
                                } finally {
                                    Utility.closeQuietly(cursor);
                                }
                            }

                            if (attachmentId != -1 && attachment instanceof LocalAttachmentBodyPart) {
                                ((LocalAttachmentBodyPart) attachment).setAttachmentId(attachmentId);
                            }
                            return null;
                        } catch (MessagingException e) {
                            throw new WrappedException(e);
                        } catch (IOException e) {
                            throw new WrappedException(e);
                        }
                    }
                });
            } catch (WrappedException e) {
                final Throwable cause = e.getCause();
                if (cause instanceof IOException) {
                    throw (IOException) cause;
                }

                throw (MessagingException) cause;
            }
        }

        /**
         * Changes the stored uid of the given message (using it's internal id as a key) to
         * the uid in the message.
         * @param message
         * @throws com.fsck.k9.mail.MessagingException
         */
        public void changeUid(final LocalMessage message) throws MessagingException {
            open(OpenMode.READ_WRITE);
            final ContentValues cv = new ContentValues();
            cv.put("uid", message.getUid());
            database.execute(false, new DbCallback<Void>() {
                @Override
                public Void doDbWork(final SQLiteDatabase db) throws WrappedException, UnavailableStorageException {
                    db.update("messages", cv, "id = ?", new String[]
                              { Long.toString(message.mId) });
                    return null;
                }
            });

            //TODO: remove this once the UI code exclusively uses the database id
            notifyChange();
        }

        @Override
        public void setFlags(final Message[] messages, final Flag[] flags, final boolean value)
        throws MessagingException {
            open(OpenMode.READ_WRITE);

            // Use one transaction to set all flags
            try {
                database.execute(true, new DbCallback<Void>() {
                    @Override
                    public Void doDbWork(final SQLiteDatabase db) throws WrappedException,
                            UnavailableStorageException {

                        for (Message message : messages) {
                            try {
                                message.setFlags(flags, value);
                            } catch (MessagingException e) {
                                Log.e(K9.LOG_TAG, "Something went wrong while setting flag", e);
                            }
                        }

                        return null;
                    }
                });
            } catch (WrappedException e) {
                throw(MessagingException) e.getCause();
            }
        }

        @Override
        public void setFlags(Flag[] flags, boolean value)
        throws MessagingException {
            open(OpenMode.READ_WRITE);
            for (Message message : getMessages(null)) {
                message.setFlags(flags, value);
            }
        }

        @Override
        public String getUidFromMessageId(Message message) throws MessagingException {
            throw new MessagingException("Cannot call getUidFromMessageId on LocalFolder");
        }

        private void clearMessagesWhere(final String whereClause, final String[] params)  throws MessagingException {
            open(OpenMode.READ_ONLY);
            Message[] messages  = LocalStore.this.getMessages(
                                      null,
                                      this,
                                      "SELECT " + GET_MESSAGES_COLS + "FROM messages WHERE (empty IS NULL OR empty != 1) AND (" + whereClause + ")",
                                      params);

            for (Message message : messages) {
                deleteAttachments(message.getUid());
            }
            database.execute(false, new DbCallback<Void>() {
                @Override
                public Void doDbWork(final SQLiteDatabase db) throws WrappedException, UnavailableStorageException {
                    db.execSQL("DELETE FROM messages WHERE " + whereClause, params);
                    return null;
                }
            });

            notifyChange();
        }

        public void clearMessagesOlderThan(long cutoff) throws MessagingException {
            final String where = "folder_id = ? and date < ?";
            final String[] params = new String[] {
                Long.toString(mFolderId), Long.toString(cutoff)
            };

            clearMessagesWhere(where, params);
        }



        public void clearAllMessages() throws MessagingException {
            final String where = "folder_id = ?";
            final String[] params = new String[] {
                Long.toString(mFolderId)
            };


            clearMessagesWhere(where, params);
            setPushState(null);
            setLastPush(0);
            setLastChecked(0);
            setVisibleLimit(mAccount.getDisplayCount());
        }

        @Override
        public void delete(final boolean recurse) throws MessagingException {
            try {
                database.execute(false, new DbCallback<Void>() {
                    @Override
                    public Void doDbWork(final SQLiteDatabase db) throws WrappedException, UnavailableStorageException {
                        try {
                            // We need to open the folder first to make sure we've got it's id
                            open(OpenMode.READ_ONLY);
                            Message[] messages = getMessages(null);
                            for (Message message : messages) {
                                deleteAttachments(message.getUid());
                            }
                        } catch (MessagingException e) {
                            throw new WrappedException(e);
                        }
                        db.execSQL("DELETE FROM folders WHERE id = ?", new Object[]
                                   { Long.toString(mFolderId), });
                        return null;
                    }
                });
            } catch (WrappedException e) {
                throw(MessagingException) e.getCause();
            }
        }

        @Override
        public boolean equals(Object o) {
            if (o instanceof LocalFolder) {
                return ((LocalFolder)o).mName.equals(mName);
            }
            return super.equals(o);
        }

        @Override
        public int hashCode() {
            return mName.hashCode();
        }

        private void deleteAttachments(final long messageId) throws MessagingException {
            open(OpenMode.READ_WRITE);
            database.execute(false, new DbCallback<Void>() {
                @Override
                public Void doDbWork(final SQLiteDatabase db) throws WrappedException, UnavailableStorageException {
                    Cursor attachmentsCursor = null;
                    try {
                        String accountUuid = mAccount.getUuid();
                        Context context = mApplication;

                        // Get attachment IDs
                        String[] whereArgs = new String[] { Long.toString(messageId) };
                        attachmentsCursor = db.query("attachments", new String[] { "id" },
                                "message_id = ?", whereArgs, null, null, null);

                        final File attachmentDirectory = StorageManager.getInstance(mApplication)
                                .getAttachmentDirectory(uUid, database.getStorageProviderId());

                        while (attachmentsCursor.moveToNext()) {
                            String attachmentId = Long.toString(attachmentsCursor.getLong(0));
                            try {
                                // Delete stored attachment
                                File file = new File(attachmentDirectory, attachmentId);
                                if (file.exists()) {
                                    file.delete();
                                }

                                // Delete thumbnail file
                                AttachmentProvider.deleteThumbnail(context, accountUuid,
                                        attachmentId);
                            } catch (Exception e) { /* ignore */ }
                        }

                        // Delete attachment metadata from the database
                        db.delete("attachments", "message_id = ?", whereArgs);
                    } finally {
                        Utility.closeQuietly(attachmentsCursor);
                    }
                    return null;
                }
            });
        }

        private void deleteAttachments(final String uid) throws MessagingException {
            open(OpenMode.READ_WRITE);
            try {
                database.execute(false, new DbCallback<Void>() {
                    @Override
                    public Void doDbWork(final SQLiteDatabase db) throws WrappedException, UnavailableStorageException {
                        Cursor messagesCursor = null;
                        try {
                            messagesCursor = db.query("messages", new String[]
                                                      { "id" }, "folder_id = ? AND uid = ?", new String[]
                                                      { Long.toString(mFolderId), uid }, null, null, null);
                            while (messagesCursor.moveToNext()) {
                                long messageId = messagesCursor.getLong(0);
                                deleteAttachments(messageId);

                            }
                        } catch (MessagingException e) {
                            throw new WrappedException(e);
                        } finally {
                            Utility.closeQuietly(messagesCursor);
                        }
                        return null;
                    }
                });
            } catch (WrappedException e) {
                throw(MessagingException) e.getCause();
            }
        }

        /*
         * calculateContentPreview
         * Takes a plain text message body as a string.
         * Returns a message summary as a string suitable for showing in a message list
         *
         * A message summary should be about the first 160 characters
         * of unique text written by the message sender
         * Quoted text, "On $date" and so on will be stripped out.
         * All newlines and whitespace will be compressed.
         *
         */
        public String calculateContentPreview(String text) {
            if (text == null) {
                return null;
            }

            // Only look at the first 8k of a message when calculating
            // the preview.  This should avoid unnecessary
            // memory usage on large messages
            if (text.length() > 8192) {
                text = text.substring(0, 8192);
            }

            // try to remove lines of dashes in the preview
            text = text.replaceAll("(?m)^----.*?$", "");
            // remove quoted text from the preview
            text = text.replaceAll("(?m)^[#>].*$", "");
            // Remove a common quote header from the preview
            text = text.replaceAll("(?m)^On .*wrote.?$", "");
            // Remove a more generic quote header from the preview
            text = text.replaceAll("(?m)^.*\\w+:$", "");
            // Remove horizontal rules.
            text = text.replaceAll("\\s*([-=_]{30,}+)\\s*", " ");

            // URLs in the preview should just be shown as "..." - They're not
            // clickable and they usually overwhelm the preview
            text = text.replaceAll("https?://\\S+", "...");
            // Don't show newlines in the preview
            text = text.replaceAll("(\\r|\\n)+", " ");
            // Collapse whitespace in the preview
            text = text.replaceAll("\\s+", " ");
            // Remove any whitespace at the beginning and end of the string.
            text = text.trim();

            return (text.length() <= 512) ? text : text.substring(0, 512);
        }

        @Override
        public boolean isInTopGroup() {
            return mInTopGroup;
        }

        public void setInTopGroup(boolean inTopGroup) throws MessagingException {
            mInTopGroup = inTopGroup;
            updateFolderColumn("top_group", mInTopGroup ? 1 : 0);
        }

        public Integer getLastUid() {
            return mLastUid;
        }

        /**
         * <p>Fetches the most recent <b>numeric</b> UID value in this folder.  This is used by
         * {@link com.fsck.k9.controller.MessagingController#shouldNotifyForMessage} to see if messages being
         * fetched are new and unread.  Messages are "new" if they have a UID higher than the most recent UID prior
         * to synchronization.</p>
         *
         * <p>This only works for protocols with numeric UIDs (like IMAP). For protocols with
         * alphanumeric UIDs (like POP), this method quietly fails and shouldNotifyForMessage() will
         * always notify for unread messages.</p>
         *
         * <p>Once Issue 1072 has been fixed, this method and shouldNotifyForMessage() should be
         * updated to use internal dates rather than UIDs to determine new-ness. While this doesn't
         * solve things for POP (which doesn't have internal dates), we can likely use this as a
         * framework to examine send date in lieu of internal date.</p>
         * @throws MessagingException
         */
        public void updateLastUid() throws MessagingException {
            Integer lastUid = database.execute(false, new DbCallback<Integer>() {
                @Override
                public Integer doDbWork(final SQLiteDatabase db) {
                    Cursor cursor = null;
                    try {
                        open(OpenMode.READ_ONLY);
                        cursor = db.rawQuery("SELECT MAX(uid) FROM messages WHERE folder_id=?", new String[] { Long.toString(mFolderId) });
                        if (cursor.getCount() > 0) {
                            cursor.moveToFirst();
                            return cursor.getInt(0);
                        }
                    } catch (Exception e) {
                        Log.e(K9.LOG_TAG, "Unable to updateLastUid: ", e);
                    } finally {
                        Utility.closeQuietly(cursor);
                    }
                    return null;
                }
            });
            if (K9.DEBUG)
                Log.d(K9.LOG_TAG, "Updated last UID for folder " + mName + " to " + lastUid);
            mLastUid = lastUid;
        }

        public Long getOldestMessageDate() throws MessagingException {
            return database.execute(false, new DbCallback<Long>() {
                @Override
                public Long doDbWork(final SQLiteDatabase db) {
                    Cursor cursor = null;
                    try {
                        open(OpenMode.READ_ONLY);
                        cursor = db.rawQuery("SELECT MIN(date) FROM messages WHERE folder_id=?", new String[] { Long.toString(mFolderId) });
                        if (cursor.getCount() > 0) {
                            cursor.moveToFirst();
                            return cursor.getLong(0);
                        }
                    } catch (Exception e) {
                        Log.e(K9.LOG_TAG, "Unable to fetch oldest message date: ", e);
                    } finally {
                        Utility.closeQuietly(cursor);
                    }
                    return null;
                }
            });
        }

        private ThreadInfo doMessageThreading(SQLiteDatabase db, Message message)
                throws MessagingException {
            long rootId = -1;
            long parentId = -1;

            String messageId = message.getMessageId();

            // If there's already an empty message in the database, update that
            long id = getDatabaseIdByMessageId(db, messageId, true);

            // Get the message IDs from the "References" header line
            String[] referencesArray = message.getHeader("References");
            List<String> messageIds = null;
            if (referencesArray != null && referencesArray.length > 0) {
                messageIds = Utility.extractMessageIds(referencesArray[0]);
            }

            // Append the first message ID from the "In-Reply-To" header line
            String[] inReplyToArray = message.getHeader("In-Reply-To");
            String inReplyTo = null;
            if (inReplyToArray != null && inReplyToArray.length > 0) {
                inReplyTo = Utility.extractMessageId(inReplyToArray[0]);
                if (inReplyTo != null) {
                    if (messageIds == null) {
                        messageIds = new ArrayList<String>(1);
                        messageIds.add(inReplyTo);
                    } else if (!messageIds.contains(inReplyTo)) {
                        messageIds.add(inReplyTo);
                    }
                }
            }

            if (messageIds == null) {
                // This is not a reply, nothing to do for us.
                return new ThreadInfo(id, messageId, -1, -1);
            }

            for (String reference : messageIds) {
                ThreadInfo threadInfo = getThreadInfo(db, reference);

                if (threadInfo == null) {
                    // Create placeholder message
                    ContentValues cv = new ContentValues();
                    cv.put("message_id", reference);
                    cv.put("folder_id", mFolderId);
                    cv.put("empty", 1);

                    if (rootId != -1) {
                        cv.put("thread_root", rootId);
                    }
                    if (parentId != -1) {
                        cv.put("thread_parent", parentId);
                    }

                    parentId = db.insert("messages", null, cv);
                    if (rootId == -1) {
                        rootId = parentId;
                    }
                } else {
                    if (rootId != -1 && threadInfo.rootId == -1 && rootId != threadInfo.id) {
                        // We found an existing root container that is not
                        // the root of our current path (References).
                        // Connect it to the current parent.

                        // Let all children know who's the new root
                        ContentValues cv = new ContentValues();
                        cv.put("thread_root", rootId);
                        db.update("messages", cv, "thread_root=?",
                                new String[] { Long.toString(threadInfo.id) });

                        // Connect the message to the current parent
                        cv.put("thread_parent", parentId);
                        db.update("messages", cv, "id=?",
                                new String[] { Long.toString(threadInfo.id) });
                    } else {
                        rootId = (threadInfo.rootId == -1) ? threadInfo.id : threadInfo.rootId;
                    }
                    parentId = threadInfo.id;
                }
            }

            //TODO: set in-reply-to "link" even if one already exists

            return new ThreadInfo(id, messageId, rootId, parentId);
        }

        public List<Message> extractNewMessages(final List<Message> messages)
                throws MessagingException {

            try {
                return database.execute(false, new DbCallback<List<Message>>() {
                    @Override
                    public List<Message> doDbWork(final SQLiteDatabase db) throws WrappedException {
                        try {
                            open(OpenMode.READ_WRITE);
                        } catch (MessagingException e) {
                            throw new WrappedException(e);
                        }

                        List<Message> result = new ArrayList<Message>();

                        List<String> selectionArgs = new ArrayList<String>();
                        Set<String> existingMessages = new HashSet<String>();
                        int start = 0;

                        while (start < messages.size()) {
                            StringBuilder selection = new StringBuilder();

                            selection.append("folder_id = ? AND UID IN (");
                            selectionArgs.add(Long.toString(mFolderId));

                            int count = Math.min(messages.size() - start, UID_CHECK_BATCH_SIZE);

                            for (int i = start, end = start + count; i < end; i++) {
                                if (i > start) {
                                    selection.append(",?");
                                } else {
                                    selection.append("?");
                                }

                                selectionArgs.add(messages.get(i).getUid());
                            }

                            selection.append(")");

                            Cursor cursor = db.query("messages", UID_CHECK_PROJECTION,
                                    selection.toString(), selectionArgs.toArray(EMPTY_STRING_ARRAY),
                                    null, null, null);

                            try {
                                while (cursor.moveToNext()) {
                                    String uid = cursor.getString(0);
                                    existingMessages.add(uid);
                                }
                            } finally {
                                Utility.closeQuietly(cursor);
                            }

                            for (int i = start, end = start + count; i < end; i++) {
                                Message message = messages.get(i);
                                if (!existingMessages.contains(message.getUid())) {
                                    result.add(message);
                                }
                            }

                            existingMessages.clear();
                            selectionArgs.clear();
                            start += count;
                        }

                        return result;
                    }
                });
            } catch (WrappedException e) {
                throw(MessagingException) e.getCause();
            }
        }
    }

    public static class LocalTextBody extends TextBody {
        /**
         * This is an HTML-ified version of the message for display purposes.
         */
        private String mBodyForDisplay;

        public LocalTextBody(String body) {
            super(body);
        }

        public LocalTextBody(String body, String bodyForDisplay) {
            super(body);
            this.mBodyForDisplay = bodyForDisplay;
        }

        public String getBodyForDisplay() {
            return mBodyForDisplay;
        }

        public void setBodyForDisplay(String mBodyForDisplay) {
            this.mBodyForDisplay = mBodyForDisplay;
        }

    }//LocalTextBody

    public class LocalMessage extends MimeMessage {
        private long mId;
        private int mAttachmentCount;
        private String mSubject;

        private String mPreview = "";

        private boolean mHeadersLoaded = false;
        private boolean mMessageDirty = false;

        private long mRootId;
        private long mParentId;

        public LocalMessage() {
        }

        LocalMessage(String uid, Folder folder) {
            this.mUid = uid;
            this.mFolder = folder;
        }

        private void populateFromGetMessageCursor(Cursor cursor)
        throws MessagingException {
            final String subject = cursor.getString(0);
            this.setSubject(subject == null ? "" : subject);

            Address[] from = Address.unpack(cursor.getString(1));
            if (from.length > 0) {
                this.setFrom(from[0]);
            }
            this.setInternalSentDate(new Date(cursor.getLong(2)));
            this.setUid(cursor.getString(3));
            String flagList = cursor.getString(4);
            if (flagList != null && flagList.length() > 0) {
                String[] flags = flagList.split(",");

                for (String flag : flags) {
                    try {
                        this.setFlagInternal(Flag.valueOf(flag), true);
                    }

                    catch (Exception e) {
                        if (!"X_BAD_FLAG".equals(flag)) {
                            Log.w(K9.LOG_TAG, "Unable to parse flag " + flag);
                        }
                    }
                }
            }
            this.mId = cursor.getLong(5);
            this.setRecipients(RecipientType.TO, Address.unpack(cursor.getString(6)));
            this.setRecipients(RecipientType.CC, Address.unpack(cursor.getString(7)));
            this.setRecipients(RecipientType.BCC, Address.unpack(cursor.getString(8)));
            this.setReplyTo(Address.unpack(cursor.getString(9)));

            this.mAttachmentCount = cursor.getInt(10);
            this.setInternalDate(new Date(cursor.getLong(11)));
            this.setMessageId(cursor.getString(12));

            final String preview = cursor.getString(14);
            mPreview = (preview == null ? "" : preview);

            if (this.mFolder == null) {
                LocalFolder f = new LocalFolder(cursor.getInt(13));
                f.open(LocalFolder.OpenMode.READ_WRITE);
                this.mFolder = f;
            }

            mRootId = (cursor.isNull(15)) ? -1 : cursor.getLong(15);
            mParentId = (cursor.isNull(16)) ? -1 : cursor.getLong(16);

            boolean deleted = (cursor.getInt(17) == 1);
            boolean read = (cursor.getInt(18) == 1);
            boolean flagged = (cursor.getInt(19) == 1);
            boolean answered = (cursor.getInt(20) == 1);
            boolean forwarded = (cursor.getInt(21) == 1);

            setFlagInternal(Flag.DELETED, deleted);
            setFlagInternal(Flag.SEEN, read);
            setFlagInternal(Flag.FLAGGED, flagged);
            setFlagInternal(Flag.ANSWERED, answered);
            setFlagInternal(Flag.FORWARDED, forwarded);
        }

        /**
         * Fetch the message text for display. This always returns an HTML-ified version of the
         * message, even if it was originally a text-only message.
         * @return HTML version of message for display purposes or null.
         * @throws MessagingException
         */
        public String getTextForDisplay() throws MessagingException {
            String text = null;    // First try and fetch an HTML part.
            Part part = MimeUtility.findFirstPartByMimeType(this, "text/html");
            if (part == null) {
                // If that fails, try and get a text part.
                part = MimeUtility.findFirstPartByMimeType(this, "text/plain");
                if (part != null && part.getBody() instanceof LocalStore.LocalTextBody) {
                    text = ((LocalStore.LocalTextBody) part.getBody()).getBodyForDisplay();
                }
            } else {
                // We successfully found an HTML part; do the necessary character set decoding.
                text = MimeUtility.getTextFromPart(part);
            }
            return text;
        }


        /* Custom version of writeTo that updates the MIME message based on localMessage
         * changes.
         */

        @Override
        public void writeTo(OutputStream out) throws IOException, MessagingException {
            if (mMessageDirty) buildMimeRepresentation();
            super.writeTo(out);
        }

        private void buildMimeRepresentation() throws MessagingException {
            if (!mMessageDirty) {
                return;
            }

            super.setSubject(mSubject);
            if (this.mFrom != null && this.mFrom.length > 0) {
                super.setFrom(this.mFrom[0]);
            }

            super.setReplyTo(mReplyTo);
            super.setSentDate(this.getSentDate());
            super.setRecipients(RecipientType.TO, mTo);
            super.setRecipients(RecipientType.CC, mCc);
            super.setRecipients(RecipientType.BCC, mBcc);
            if (mMessageId != null) super.setMessageId(mMessageId);

            mMessageDirty = false;
        }

        @Override
        public String getPreview() {
            return mPreview;
        }

        @Override
        public String getSubject() {
            return mSubject;
        }


        @Override
        public void setSubject(String subject) throws MessagingException {
            mSubject = subject;
            mMessageDirty = true;
        }


        @Override
        public void setMessageId(String messageId) {
            mMessageId = messageId;
            mMessageDirty = true;
        }

        @Override
        public boolean hasAttachments() {
            return (mAttachmentCount > 0);
        }

        public int getAttachmentCount() {
            return mAttachmentCount;
        }

        @Override
        public void setFrom(Address from) throws MessagingException {
            this.mFrom = new Address[] { from };
            mMessageDirty = true;
        }


        @Override
        public void setReplyTo(Address[] replyTo) throws MessagingException {
            if (replyTo == null || replyTo.length == 0) {
                mReplyTo = null;
            } else {
                mReplyTo = replyTo;
            }
            mMessageDirty = true;
        }


        /*
         * For performance reasons, we add headers instead of setting them (see super implementation)
         * which removes (expensive) them before adding them
         */
        @Override
        public void setRecipients(RecipientType type, Address[] addresses) throws MessagingException {
            if (type == RecipientType.TO) {
                if (addresses == null || addresses.length == 0) {
                    this.mTo = null;
                } else {
                    this.mTo = addresses;
                }
            } else if (type == RecipientType.CC) {
                if (addresses == null || addresses.length == 0) {
                    this.mCc = null;
                } else {
                    this.mCc = addresses;
                }
            } else if (type == RecipientType.BCC) {
                if (addresses == null || addresses.length == 0) {
                    this.mBcc = null;
                } else {
                    this.mBcc = addresses;
                }
            } else {
                throw new MessagingException("Unrecognized recipient type.");
            }
            mMessageDirty = true;
        }

        public void setFlagInternal(Flag flag, boolean set) throws MessagingException {
            super.setFlag(flag, set);
        }

        @Override
        public long getId() {
            return mId;
        }

        @Override
        public void setFlag(final Flag flag, final boolean set) throws MessagingException {

            try {
                database.execute(true, new DbCallback<Void>() {
                    @Override
                    public Void doDbWork(final SQLiteDatabase db) throws WrappedException, UnavailableStorageException {
                        try {
                            if (flag == Flag.DELETED && set) {
                                delete();
                            }

                            LocalMessage.super.setFlag(flag, set);
                        } catch (MessagingException e) {
                            throw new WrappedException(e);
                        }
                        /*
                         * Set the flags on the message.
                         */
                        ContentValues cv = new ContentValues();
                        cv.put("flags", serializeFlags(getFlags()));
                        cv.put("read", isSet(Flag.SEEN) ? 1 : 0);
                        cv.put("flagged", isSet(Flag.FLAGGED) ? 1 : 0);
                        cv.put("answered", isSet(Flag.ANSWERED) ? 1 : 0);
                        cv.put("forwarded", isSet(Flag.FORWARDED) ? 1 : 0);

                        db.update("messages", cv, "id = ?", new String[] { Long.toString(mId) });

                        return null;
                    }
                });
            } catch (WrappedException e) {
                throw(MessagingException) e.getCause();
            }

            notifyChange();
        }

        /*
         * If a message is being marked as deleted we want to clear out it's content
         * and attachments as well. Delete will not actually remove the row since we need
         * to retain the uid for synchronization purposes.
         */
        private void delete() throws MessagingException

        {
            /*
             * Delete all of the message's content to save space.
             */
            try {
                database.execute(true, new DbCallback<Void>() {
                    @Override
                    public Void doDbWork(final SQLiteDatabase db) throws WrappedException,
                            UnavailableStorageException {
                        String[] idArg = new String[] { Long.toString(mId) };

                        ContentValues cv = new ContentValues();
                        cv.put("deleted", 1);
                        cv.put("empty", 1);
                        cv.putNull("subject");
                        cv.putNull("sender_list");
                        cv.putNull("date");
                        cv.putNull("to_list");
                        cv.putNull("cc_list");
                        cv.putNull("bcc_list");
                        cv.putNull("preview");
                        cv.putNull("html_content");
                        cv.putNull("text_content");
                        cv.putNull("reply_to_list");

                        db.update("messages", cv, "id = ?", idArg);

                        /*
                         * Delete all of the message's attachments to save space.
                         * We do this explicit deletion here because we're not deleting the record
                         * in messages, which means our ON DELETE trigger for messages won't cascade
                         */
                        try {
                            ((LocalFolder) mFolder).deleteAttachments(mId);
                        } catch (MessagingException e) {
                            throw new WrappedException(e);
                        }

                        db.delete("attachments", "message_id = ?", idArg);
                        return null;
                    }
                });
            } catch (WrappedException e) {
                throw(MessagingException) e.getCause();
            }
            ((LocalFolder)mFolder).deleteHeaders(mId);

            notifyChange();
        }

        /*
         * Completely remove a message from the local database
         *
         * TODO: document how this updates the thread structure
         */
        @Override
        public void destroy() throws MessagingException {
            try {
                database.execute(true, new DbCallback<Void>() {
                    @Override
                    public Void doDbWork(final SQLiteDatabase db) throws WrappedException,
                        UnavailableStorageException {
                        try {
                            LocalFolder localFolder = (LocalFolder) mFolder;

                            localFolder.deleteAttachments(mId);

                            String id = Long.toString(mId);

                            // Check if this message has children in the thread hierarchy
                            Cursor cursor = db.query("messages", new String[] { "COUNT(id)" },
                                    "thread_root = ? OR thread_parent = ?",
                                    new String[] {id, id},
                                    null, null, null);

                            try {
                                if (cursor.moveToFirst() && cursor.getLong(0) > 0) {
                                    // Make the message an empty message
                                    ContentValues cv = new ContentValues();
                                    cv.put("id", mId);
                                    cv.put("folder_id", localFolder.getId());
                                    cv.put("deleted", 0);
                                    cv.put("message_id", getMessageId());
                                    cv.put("empty", 1);

                                    if (getRootId() != -1) {
                                        cv.put("thread_root", getRootId());
                                    }

                                    if (getParentId() != -1) {
                                        cv.put("thread_parent", getParentId());
                                    }

                                    db.replace("messages", null, cv);

                                    // Nothing else to do
                                    return null;
                                }
                            } finally {
                                cursor.close();
                            }

                            long parentId = getParentId();

                            // Check if 'parentId' is empty
                            cursor = db.query("messages", new String[] { "id" },
                                    "id = ? AND empty = 1",
                                    new String[] { Long.toString(parentId) },
                                    null, null, null);

                            try {
                                if (cursor.getCount() == 0) {
                                    // If the message isn't empty we skip the loop below
                                    parentId = -1;
                                }
                            } finally {
                                cursor.close();
                            }

                            while (parentId != -1) {
                                String parentIdString = Long.toString(parentId);

                                // Get the parent of the message 'parentId'
                                cursor = db.query("messages", new String[] { "thread_parent" },
                                        "id = ? AND empty = 1",
                                        new String[] { parentIdString },
                                        null, null, null);
                                try {
                                    if (cursor.moveToFirst() && !cursor.isNull(0)) {
                                        parentId = cursor.getLong(0);
                                    } else {
                                        parentId = -1;
                                    }
                                } finally {
                                    cursor.close();
                                }

                                // Check if (the old) 'parentId' has any children
                                cursor = db.query("messages", new String[] { "COUNT(id)" },
                                        "thread_parent = ? AND id != ?",
                                        new String[] { parentIdString, id },
                                        null, null, null);

                                try {
                                    if (cursor.moveToFirst() && cursor.getLong(0) == 0) {
                                        // If it has no children we can remove it
                                        db.delete("messages", "id = ?",
                                                new String[] { parentIdString });
                                    } else {
                                        break;
                                    }
                                } finally {
                                    cursor.close();
                                }
                            }

                            // Remove the placeholder message
                            db.delete("messages", "id = ?",  new String[] { id });
                        } catch (MessagingException e) {
                            throw new WrappedException(e);
                        }
                        return null;
                    }
                });
            } catch (WrappedException e) {
                throw(MessagingException) e.getCause();
            }

            notifyChange();
        }

        private void loadHeaders() throws UnavailableStorageException {
            ArrayList<LocalMessage> messages = new ArrayList<LocalMessage>();
            messages.add(this);
            mHeadersLoaded = true; // set true before calling populate headers to stop recursion
            ((LocalFolder) mFolder).populateHeaders(messages);

        }

        @Override
        public void addHeader(String name, String value) throws UnavailableStorageException {
            if (!mHeadersLoaded)
                loadHeaders();
            super.addHeader(name, value);
        }

        @Override
        public void setHeader(String name, String value) throws UnavailableStorageException {
            if (!mHeadersLoaded)
                loadHeaders();
            super.setHeader(name, value);
        }

        @Override
        public String[] getHeader(String name) throws UnavailableStorageException {
            if (!mHeadersLoaded)
                loadHeaders();
            return super.getHeader(name);
        }

        @Override
        public void removeHeader(String name) throws UnavailableStorageException {
            if (!mHeadersLoaded)
                loadHeaders();
            super.removeHeader(name);
        }

        @Override
        public Set<String> getHeaderNames() throws UnavailableStorageException {
            if (!mHeadersLoaded)
                loadHeaders();
            return super.getHeaderNames();
        }

        @Override
        public LocalMessage clone() {
            LocalMessage message = new LocalMessage();
            super.copy(message);

            message.mId = mId;
            message.mAttachmentCount = mAttachmentCount;
            message.mSubject = mSubject;
            message.mPreview = mPreview;
            message.mHeadersLoaded = mHeadersLoaded;
            message.mMessageDirty = mMessageDirty;

            return message;
        }

        public long getRootId() {
            return mRootId;
        }

        public long getParentId() {
            return mParentId;
        }
    }

    public static class LocalAttachmentBodyPart extends MimeBodyPart {
        private long mAttachmentId = -1;

        public LocalAttachmentBodyPart(Body body, long attachmentId) throws MessagingException {
            super(body);
            mAttachmentId = attachmentId;
        }

        /**
         * Returns the local attachment id of this body, or -1 if it is not stored.
         * @return
         */
        public long getAttachmentId() {
            return mAttachmentId;
        }

        public void setAttachmentId(long attachmentId) {
            mAttachmentId = attachmentId;
        }

        @Override
        public String toString() {
            return "" + mAttachmentId;
        }
    }

    public static class LocalAttachmentBody implements Body {
        private static final byte[] EMPTY_BYTE_ARRAY = new byte[0];
        private Application mApplication;
        private Uri mUri;

        public LocalAttachmentBody(Uri uri, Application application) {
            mApplication = application;
            mUri = uri;
        }

        @Override
        public InputStream getInputStream() throws MessagingException {
            try {
                return mApplication.getContentResolver().openInputStream(mUri);
            } catch (FileNotFoundException fnfe) {
                /*
                 * Since it's completely normal for us to try to serve up attachments that
                 * have been blown away, we just return an empty stream.
                 */
                return new ByteArrayInputStream(EMPTY_BYTE_ARRAY);
            }
        }

        @Override
        public void writeTo(OutputStream out) throws IOException, MessagingException {
            InputStream in = getInputStream();
            Base64OutputStream base64Out = new Base64OutputStream(out);
            try {
                IOUtils.copy(in, base64Out);
            } finally {
                base64Out.close();
            }
        }

        public Uri getContentUri() {
            return mUri;
        }
    }

    static class ThreadInfo {
        public final long id;
        public final String messageId;
        public final long rootId;
        public final long parentId;

        public ThreadInfo(long id, String messageId, long rootId, long parentId) {
            this.id = id;
            this.messageId = messageId;
            this.rootId = rootId;
            this.parentId = parentId;
        }
    }

    public LockableDatabase getDatabase() {
        return database;
    }

    private void notifyChange() {
        Uri uri = Uri.withAppendedPath(EmailProvider.CONTENT_URI, "account/" + uUid + "/messages");
        mContentResolver.notifyChange(uri, null);
    }

    /**
     * Split database operations with a large set of arguments into multiple SQL statements.
     *
     * <p>
     * At the time of this writing (2012-12-06) SQLite only supports around 1000 arguments. That's
     * why we have to split SQL statements with a large set of arguments into multiple SQL
     * statements each working on a subset of the arguments.
     * </p>
     *
     * @param selectionCallback
     *         Supplies the argument set and the code to query/update the database.
     * @param batchSize
     *         The maximum size of the selection set in each SQL statement.
     *
     * @throws MessagingException
     */
    public void doBatchSetSelection(final BatchSetSelection selectionCallback, final int batchSize)
            throws MessagingException {

        final List<String> selectionArgs = new ArrayList<String>();
        int start = 0;

        while (start < selectionCallback.getListSize()) {
            final StringBuilder selection = new StringBuilder();

            selection.append(" IN (");

            int count = Math.min(selectionCallback.getListSize() - start, batchSize);

            for (int i = start, end = start + count; i < end; i++) {
                if (i > start) {
                    selection.append(",?");
                } else {
                    selection.append("?");
                }

                selectionArgs.add(selectionCallback.getListItem(i));
            }

            selection.append(")");

            try {
                database.execute(true, new DbCallback<Void>() {
                    @Override
                    public Void doDbWork(final SQLiteDatabase db) throws WrappedException,
                            UnavailableStorageException {

                        selectionCallback.doDbWork(db, selection.toString(),
                                selectionArgs.toArray(EMPTY_STRING_ARRAY));

                        return null;
                    }
                });

                selectionCallback.postDbWork();

            } catch (WrappedException e) {
                throw(MessagingException) e.getCause();
            }

            selectionArgs.clear();
            start += count;
        }
    }

    /**
     * Defines the behavior of {@link LocalStore#doBatchSetSelection(BatchSetSelection, int)}.
     */
    public interface BatchSetSelection {
        /**
         * @return The size of the argument list.
         */
        int getListSize();

        /**
         * Get a specific item of the argument list.
         *
         * @param index
         *         The index of the item.
         *
         * @return Item at position {@code i} of the argument list.
         */
        String getListItem(int index);

        /**
         * Execute the SQL statement.
         *
         * @param db
         *         Use this {@link SQLiteDatabase} instance for your SQL statement.
         * @param selectionSet
         *         A partial selection string containing place holders for the argument list, e.g.
         *         {@code " IN (?,?,?)"} (starts with a space).
         * @param selectionArgs
         *         The current subset of the argument list.
         * @throws UnavailableStorageException
         */
        void doDbWork(SQLiteDatabase db, String selectionSet, String[] selectionArgs)
                throws UnavailableStorageException;

        /**
         * This will be executed after each invocation of
         * {@link #doDbWork(SQLiteDatabase, String, String[])} (after the transaction has been
         * committed).
         */
        void postDbWork();
    }

    /**
     * Change the state of a flag for a list of messages.
     *
     * <p>
     * The goal of this method is to be fast. Currently this means using as few SQL UPDATE
     * statements as possible.<br>
     * Current benchmarks show that updating 1000 messages takes about 8 seconds on a Nexus 7. So
     * there should be room for further improvement.
     * </p>
     *
     * @param messageIds
     *         A list of primary keys in the "messages" table.
     * @param flag
     *         The flag to change. This must be a flag with a separate column in the database.
     * @param newState
     *         {@code true}, if the flag should be set. {@code false}, otherwise.
     * @param threadRootIds
     *         If this is {@code true}, {@code messageIds} contains the IDs of the messages at the
     *         root of a thread. In that case the flag is changed for all messages in these threads.
     *         If this is {@code false} only the messages in {@code messageIds} are changed.
     *
     * @throws MessagingException
     */
    public void setFlag(final List<Long> messageIds, final Flag flag,
            final boolean newState, final boolean threadRootIds) throws MessagingException {

        final ContentValues cv = new ContentValues();

        switch (flag) {
            case SEEN: {
                cv.put("read", newState);
                break;
            }
            case FLAGGED: {
                cv.put("flagged", newState);
                break;
            }
            case ANSWERED: {
                cv.put("answered", newState);
                break;
            }
            case FORWARDED: {
                cv.put("forwarded", newState);
                break;
            }
            default: {
                throw new IllegalArgumentException("Flag must be a special column flag");
            }
        }

        doBatchSetSelection(new BatchSetSelection() {

            @Override
            public int getListSize() {
                return messageIds.size();
            }

            @Override
            public String getListItem(int index) {
                return Long.toString(messageIds.get(index));
            }

            @Override
            public void doDbWork(SQLiteDatabase db, String selectionSet, String[] selectionArgs)
                    throws UnavailableStorageException {

                db.update("messages", cv, "(empty IS NULL OR empty != 1) AND id" + selectionSet,
                        selectionArgs);

                if (threadRootIds) {
                    db.update("messages", cv, "(empty IS NULL OR empty != 1) AND thread_root" +
                            selectionSet, selectionArgs);
                }
            }

            @Override
            public void postDbWork() {
                notifyChange();
            }
        }, FLAG_UPDATE_BATCH_SIZE);
    }

    /**
     * Get folder name and UID for the supplied messages.
     *
     * @param messageIds
     *         A list of primary keys in the "messages" table.
     * @param threadedList
     *         If this is {@code true}, {@code messageIds} contains the IDs of the messages at the
     *         root of a thread. In that case return UIDs for all messages in these threads.
     *         If this is {@code false} only the UIDs for messages in {@code messageIds} are
     *         returned.
     *
     * @return The list of UIDs for the messages grouped by folder name.
     *
     * @throws MessagingException
     */
    public Map<String, List<String>> getFoldersAndUids(final List<Long> messageIds,
            final boolean threadedList) throws MessagingException {

        final Map<String, List<String>> folderMap = new HashMap<String, List<String>>();

        doBatchSetSelection(new BatchSetSelection() {

            @Override
            public int getListSize() {
                return messageIds.size();
            }

            @Override
            public String getListItem(int index) {
                return Long.toString(messageIds.get(index));
            }

            @Override
            public void doDbWork(SQLiteDatabase db, String selectionSet, String[] selectionArgs)
                    throws UnavailableStorageException {

                String sqlPrefix =
                        "SELECT m.uid, f.name " +
                        "FROM messages m " +
                        "JOIN folders f ON (m.folder_id = f.id) " +
                        "WHERE (m.empty IS NULL OR m.empty != 1) AND ";

                String sql = sqlPrefix + "m.id" + selectionSet;
                getDataFromCursor(db.rawQuery(sql, selectionArgs));

                if (threadedList) {
                    String threadSql = sqlPrefix + "m.thread_root" + selectionSet;
                    getDataFromCursor(db.rawQuery(threadSql, selectionArgs));
                }
            }

            private void getDataFromCursor(Cursor cursor) {
                try {
                    while (cursor.moveToNext()) {
                        String uid = cursor.getString(0);
                        String folderName = cursor.getString(1);

                        List<String> uidList = folderMap.get(folderName);
                        if (uidList == null) {
                            uidList = new ArrayList<String>();
                            folderMap.put(folderName, uidList);
                        }

                        uidList.add(uid);
                    }
                } finally {
                    cursor.close();
                }
            }

            @Override
            public void postDbWork() {
                notifyChange();

            }
        }, UID_CHECK_BATCH_SIZE);

        return folderMap;
    }
}