Convert quote characters in plain text messages to blockquotes in the html version. "Be like Thunderbird."

src/com/fsck/k9/helper/HtmlConverter.java

@@ -190,6 +190,11 @@ public class HtmlConverter {
         return buff.toString();
     }
 
+    private static final String HTML_BLOCKQUOTE_START = "<blockquote class=\"gmail_quote\" " +
+        "style=\"margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;\">";
+    private static final String HTML_BLOCKQUOTE_END = "</blockquote>";
+    private static final String HTML_NEWLINE = "<br />";
+
     /**
      * Convert a text string into an HTML document.
      *
@@ -217,14 +222,19 @@ public class HtmlConverter {
         }
         StringReader reader = new StringReader(text);
         StringBuilder buff = new StringBuilder(text.length() + TEXT_TO_HTML_EXTRA_BUFFER_LENGTH);
-        int c;
+        boolean isStartOfLine = false;  // Are we currently at the start of a line?
+        int quoteDepth = 0; // Number of DIVs deep we are.
+        int quotesThisLine = 0; // How deep we should be quoting for this line.
         try {
+            int c;
             while ((c = reader.read()) != -1) {
                 switch (c) {
                 case '\n':
                     // pine treats <br> as two newlines, but <br/> as one newline.  Use <br/> so our messages aren't
                     // doublespaced.
-                    buff.append("<br />");
+                    buff.append(HTML_NEWLINE);
+                    isStartOfLine = true;
+                    quotesThisLine = 0;
                     break;
                 case '&':
                     buff.append("&amp;");
@@ -233,11 +243,39 @@ public class HtmlConverter {
                     buff.append("&lt;");
                     break;
                 case '>':
+                    if(isStartOfLine) {
+                        quotesThisLine++;
+                    } else {
                         buff.append("&gt;");
+                    }
                     break;
                 case '\r':
                     break;
+                case ' ':
+                    if(isStartOfLine) {
+                        // If we're still in the start of the line and we have spaces, don't output them, since they
+                        // may be collapsed by our div-converting magic.
+                        break;
+                    }
                 default:
+                    if(isStartOfLine) {
+                        // Not a quote character and not a space.  Content is starting now.
+                        isStartOfLine = false;
+                        if(K9.DEBUG) {
+                            Log.d(K9.LOG_TAG, "currentQuoteDepth: " + quoteDepth + " quotesThisLine: " + quotesThisLine);
+                        }
+                        // Add/remove blockquotes by comparing this line's quotes to the previous line's quotes.
+                        if(quotesThisLine > quoteDepth) {
+                            for(int i = quoteDepth; i < quotesThisLine; i++) {
+                                buff.append(HTML_BLOCKQUOTE_START);
+                            }
+                        } else if(quotesThisLine < quoteDepth) {
+                            for(int i = quoteDepth; i > quotesThisLine; i--) {
+                                buff.append(HTML_BLOCKQUOTE_END);
+                            }
+                        }
+                        quoteDepth = quotesThisLine;
+                    }
                     buff.append((char)c);
                 }//switch
             }
@@ -245,8 +283,21 @@ public class HtmlConverter {
             //Should never happen
             Log.e(K9.LOG_TAG, "Could not read string to convert text to HTML:", e);
         }
+        // Close off any quotes we may have opened.
+        if (quoteDepth > 0) {
+            for (int i = quoteDepth; i > 0; i--) {
+                buff.append(HTML_BLOCKQUOTE_END);
+            }
+        }
         text = buff.toString();
 
+        // Make newlines at the end of blockquotes nicer by putting newlines beyond the first one outside of the
+        // blockquote.
+        text = text.replaceAll(
+            "\\Q" + HTML_NEWLINE + "\\E((\\Q" + HTML_NEWLINE + "\\E)+?)\\Q" + HTML_BLOCKQUOTE_END + "\\E",
+            HTML_BLOCKQUOTE_END + "$1"
+        );
+
         // Replace lines of -,= or _ with horizontal rules
         text = text.replaceAll("\\s*([-=_]{30,}+)\\s*", "<hr />");
 

tests/src/com/fsck/k9/helper/HtmlConverterTest.java

@@ -0,0 +1,66 @@
+package com.fsck.k9.helper;
+
+import junit.framework.Assert;
+import org.junit.Test;
+
+import java.io.BufferedWriter;
+import java.io.File;
+import java.io.FileWriter;
+
+public class HtmlConverterTest {
+    // Useful if you want to write stuff to a file for debugging in a browser.
+    private static final boolean WRITE_TO_FILE = false;
+    private static final String OUTPUT_FILE = "C:/temp/parse.html";
+
+    @Test
+    public void testTextQuoteToHtmlBlockquote() {
+        String message = "Panama!\n" +
+            "\n" +
+            "Bob Barker <bob@aol.com> wrote:\n" +
+            "> a canal\n" +
+            ">\n" +
+            "> Dorothy Jo Gideon <dorothy@aol.com> espoused:\n" +
+            "> >A man, a plan...\n" +
+            "> Too easy!\n" +
+            "\n" +
+            "Nice job :)\n" +
+            ">> Guess!";
+        String result = HtmlConverter.textToHtml(message, false);
+        writeToFile(result);
+        Assert.assertEquals("<pre style=\"white-space: pre-wrap; word-wrap:break-word; font-family: sans-serif\">Panama!<br /><br />Bob Barker &lt;bob@aol.com&gt; wrote:<br /><blockquote class=\"gmail_quote\" style=\"margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;\">a canal<br /><br />Dorothy Jo Gideon &lt;dorothy@aol.com&gt; espoused:<br /><blockquote class=\"gmail_quote\" style=\"margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;\">A man, a plan...<br /></blockquote>Too easy!</blockquote><br />Nice job :)<br /><blockquote class=\"gmail_quote\" style=\"margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;\"><blockquote class=\"gmail_quote\" style=\"margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;\">Guess!</blockquote></blockquote></pre>", result);
+    }
+
+    @Test
+    public void testTextQuoteToHtmlBlockquoteIndented() {
+        String message = "*facepalm*\n" +
+            "\n" +
+            "Bob Barker <bob@aol.com> wrote:\n" +
+            "> A wise man once said...\n" +
+            ">\n" +
+            ">     LOL F1RST!!!!!\n" +
+            ">\n" +
+            "> :)";
+        String result = HtmlConverter.textToHtml(message, false);
+        writeToFile(result);
+        Assert.assertEquals("<pre style=\"white-space: pre-wrap; word-wrap:break-word; font-family: sans-serif\">*facepalm*<br /><br />Bob Barker &lt;bob@aol.com&gt; wrote:<br /><blockquote class=\"gmail_quote\" style=\"margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;\">A wise man once said...<br /><br />LOL F1RST!!!!!<br /><br />:)</blockquote></pre>", result);
+    }
+
+    private void writeToFile(final String content) {
+        if(!WRITE_TO_FILE) {
+            return;
+        }
+        try {
+            System.err.println(content);
+
+            File f = new File(OUTPUT_FILE);
+            f.delete();
+
+            FileWriter fstream = new FileWriter(OUTPUT_FILE);
+            BufferedWriter out = new BufferedWriter(fstream);
+            out.write(content);
+            out.close();
+        } catch (Exception e) {
+            e.printStackTrace();
+        }
+    }
+}