change message styling rules

Message styling purposly doesn’t require a whitespace after a closing
tag to make something like ~un~believable work. However it also breaks
_Programmierer_innen_ and other example where the tag is repeated as a
non tag in the word.
Therefor we change the rules that if a closing tag is followed by a higher
order closing tag (a closing tag followed by an end block or white space)
we ignore the first closing tag. But only if we don’t read another tag open.

1 files changed, 24 insertions, 0 deletions

diff --git a/src/main/java/de/pixart/messenger/utils/ImStyleParser.java b/src/main/java/de/pixart/messenger/utils/ImStyleParser.java
index 9f008d76c..118f3179f 100644
--- a/src/main/java/de/pixart/messenger/utils/ImStyleParser.java
+++ b/src/main/java/de/pixart/messenger/utils/ImStyleParser.java
@@ -34,10 +34,12 @@ import java.util.Arrays;
 import java.util.List;
 
 public class ImStyleParser {
+
     private final static List<Character> KEYWORDS = Arrays.asList('*', '_', '~', '`');
     private final static List<Character> NO_SUB_PARSING_KEYWORDS = Arrays.asList('`');
     private final static List<Character> BLOCK_KEYWORDS = Arrays.asList('`');
     private final static boolean ALLOW_EMPTY = false;
+    private final static boolean PARSE_HIGHER_ORDER_END = true;
 
     public static List<Style> parse(CharSequence text) {
         return parse(text, 0, text.length() - 1);
@@ -86,6 +88,28 @@ public class ImStyleParser {
         for (int i = start; i <= end; ++i) {
             char c = text.charAt(i);
             if (c == needle && !Character.isWhitespace(text.charAt(i - 1))) {
+                if (!PARSE_HIGHER_ORDER_END || followedByWhitespace(text, i, end)) {
+                    return i;
+                } else {
+                    int higherOrder = seekHigherOrderEndWithoutNewBeginning(text, needle, i + 1, end);
+                    if (higherOrder != -1) {
+                        return higherOrder;
+                    }
+                    return i;
+                }
+            } else if (c == '\n') {
+                return -1;
+            }
+        }
+        return -1;
+    }
+
+    private static int seekHigherOrderEndWithoutNewBeginning(CharSequence text, char needle, int start, int end) {
+        for (int i = start; i <= end; ++i) {
+            char c = text.charAt(i);
+            if (c == needle && precededByWhiteSpace(text, i, start) && !followedByWhitespace(text, i, end)) {
+                return -1; // new beginning
+            } else if (c == needle && !Character.isWhitespace(text.charAt(i - 1)) && followedByWhitespace(text, i, end)) {
                 return i;
             } else if (c == '\n') {
                 return -1;