require 'mail'
require 'sqlite3'
require 'eventmachine'

module MailCatcher::Mail
  class << self
    def db
      @@__db ||= begin
        SQLite3::Database.new(':memory:', :type_translation => true).tap do |db|
          db.execute(<<-SQL)
            CREATE TABLE message (
              id INTEGER PRIMARY KEY ASC,
              sender TEXT,
              recipients TEXT,
              subject TEXT,
              source BLOB,
              size TEXT,
              type TEXT,
              created_at DATETIME DEFAULT CURRENT_DATETIME
            )
          SQL
          db.execute(<<-SQL)
            CREATE TABLE message_part (
              id INTEGER PRIMARY KEY ASC,
              message_id INTEGER NOT NULL,
              cid TEXT,
              type TEXT,
              is_attachment INTEGER,
              filename TEXT,
              charset TEXT,
              body BLOB,
              size INTEGER,
              created_at DATETIME DEFAULT CURRENT_DATETIME
            )
          SQL
        end
      end
    end

    def add_message(message)
      @@add_message_query ||= db.prepare("INSERT INTO message (sender, recipients, subject, source, type, size, created_at) VALUES (?, ?, ?, ?, ?, ?, datetime('now'))")

      mail = Mail.new(message[:source])
      result = @@add_message_query.execute(message[:sender], message[:recipients].to_json, mail.subject, message[:source], mail.mime_type || 'text/plain', message[:source].length)
      message_id = db.last_insert_row_id
      parts = mail.all_parts
      parts = [mail] if parts.empty?
      parts.each do |part|
        body = part.body.to_s
        # Only parts have CIDs, not mail
        cid = part.cid if part.respond_to? :cid
        add_message_part(message_id, cid, part.mime_type || 'text/plain', part.attachment? ? 1 : 0, part.filename, part.charset, body, body.length)
      end

      EventMachine.next_tick do
        message = MailCatcher::Mail.message message_id
        MailCatcher::Events::MessageAdded.push message
      end
    end

    def add_message_part(*args)
      @@add_message_part_query ||= db.prepare "INSERT INTO message_part (message_id, cid, type, is_attachment, filename, charset, body, size, created_at) VALUES (?, ?, ?, ?, ?, ?, ?, ?, datetime('now'))"
      @@add_message_part_query.execute(*args)
    end

    def latest_created_at
      @@latest_created_at_query ||= db.prepare "SELECT created_at FROM message ORDER BY created_at DESC LIMIT 1"
      @@latest_created_at_query.execute.next
    end

    def messages
      @@messages_query ||= db.prepare "SELECT id, sender, recipients, subject, size, created_at FROM message ORDER BY created_at ASC"
      @@messages_query.execute.map do |row|
        Hash[row.fields.zip(row)].tap do |message|
          message["recipients"] &&= ActiveSupport::JSON.decode message["recipients"]
        end
      end
    end

    def message(id)
      @@message_query ||= db.prepare "SELECT * FROM message WHERE id = ? LIMIT 1"
      row = @@message_query.execute(id).next
      row && Hash[row.fields.zip(row)].tap do |message|
        message["recipients"] &&= ActiveSupport::JSON.decode message["recipients"]
      end
    end

    def message_has_html?(id)
      @@message_has_html_query ||= db.prepare "SELECT 1 FROM message_part WHERE message_id = ? AND is_attachment = 0 AND type IN ('application/xhtml+xml', 'text/html') LIMIT 1"
      (!!@@message_has_html_query.execute(id).next) || ['text/html', 'application/xhtml+xml'].include?(message(id)["type"])
    end

    def message_has_plain?(id)
      @@message_has_plain_query ||= db.prepare "SELECT 1 FROM message_part WHERE message_id = ? AND is_attachment = 0 AND type = 'text/plain' LIMIT 1"
      (!!@@message_has_plain_query.execute(id).next) || message(id)["type"] == "text/plain"
    end

    def message_parts(id)
      @@message_parts_query ||= db.prepare "SELECT cid, type, filename, size FROM message_part WHERE message_id = ? ORDER BY filename ASC"
      @@message_parts_query.execute(id).map do |row|
        Hash[row.fields.zip(row)]
      end
    end

    def message_attachments(id)
      @@message_parts_query ||= db.prepare "SELECT cid, type, filename, size FROM message_part WHERE message_id = ? AND is_attachment = 1 ORDER BY filename ASC"
      @@message_parts_query.execute(id).map do |row|
        Hash[row.fields.zip(row)]
      end
    end

    def message_part(message_id, part_id)
      @@message_part_query ||= db.prepare "SELECT * FROM message_part WHERE message_id = ? AND id = ? LIMIT 1"
      row = @@message_part_query.execute(message_id, part_id).next
      row && Hash[row.fields.zip(row)]
    end

    def message_part_type(message_id, part_type)
      @@message_part_type_query ||= db.prepare "SELECT * FROM message_part WHERE message_id = ? AND type = ? AND is_attachment = 0 LIMIT 1"
      row = @@message_part_type_query.execute(message_id, part_type).next
      row && Hash[row.fields.zip(row)]
    end

    def message_part_html(message_id)
      part = message_part_type(message_id, "text/html")
      part ||= message_part_type(message_id, "application/xhtml+xml")
      part ||= begin
        message = message(message_id)
        message if message.present? and ['text/html', 'application/xhtml+xml'].include? message["type"]
      end
    end

    def message_part_plain(message_id)
      message_part_type message_id, "text/plain"
    end

    def message_part_cid(message_id, cid)
      @@message_part_cid_query ||= db.prepare 'SELECT * FROM message_part WHERE message_id = ?'
      @@message_part_cid_query.execute(message_id).map do |row|
        part = Hash[row.fields.zip(row)]
      end.find do |part|
        part["cid"] == cid
      end
    end

    def delete!
      @@delete_messages_query ||= db.prepare 'DELETE FROM message'
      @@delete_message_parts_query ||= db.prepare 'DELETE FROM message_part'

      @@delete_messages_query.execute and
      @@delete_message_parts_query.execute
    end
  end
end