From c67cdd02bc54d8004c1bc06a8b6968008959aceb Mon Sep 17 00:00:00 2001
From: un-pogaz <46523284+un-pogaz@users.noreply.github.com>
Date: Sun, 30 Apr 2023 14:28:59 +0200
Subject: [PATCH] improve Link, Image, LinkRef

---
 src/calibre/gui2/markdown_syntax_highlighter.py | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/src/calibre/gui2/markdown_syntax_highlighter.py b/src/calibre/gui2/markdown_syntax_highlighter.py
index a3c29383da..b131c8ddf4 100644
--- a/src/calibre/gui2/markdown_syntax_highlighter.py
+++ b/src/calibre/gui2/markdown_syntax_highlighter.py
@@ -20,8 +20,9 @@ class MarkdownHighlighter(QSyntaxHighlighter):
         'uItalic': re.compile('(?P<delim>_)(?P<text>([^_]{2,}?|[^_]))(?P=delim)'),
         'BoldItalic': re.compile(r'(?P<delim>\*\*\*)(?P<text>([^*]{2,}?|[^*]))(?P=delim)'),
         'uBoldItalic': re.compile(r'(?P<delim>___)(?P<text>([^_]{2,}?|[^_]))(?P=delim)'),
-        'Link': re.compile(r'(?u)(^|(?P<pre>[^!]))\[.*?\]:?[ ''\t'r']*\(?[^)]+\)?'),
-        'Image': re.compile(r'(?u)!\[.*?\]\(.+?\)'),
+        'Link': re.compile(r'(?u)(?<!!)\[.*?\](\[.+?\]|\(.+?\))'),
+        'Image': re.compile(r'(?u)!\[.*?\](\[.+?\]|\(.+?\))'),
+        'LinkRef': re.compile(r'(?u)^ *\[.*?\]:[ \t]*.*$'),
         'HeaderAtx': re.compile(r'(?u)^\#{1,6}(.*?)\#*(''\n|$)'),
         'Header': re.compile('^(.+)[ \t]*\n(=+|-+)[ \t]*\n+'),
         'CodeBlock': re.compile('^([ ]{4,}|\t).*'),
@@ -45,6 +46,7 @@ class MarkdownHighlighter(QSyntaxHighlighter):
         'uBoldItalic': "boldemphasis",
         'Link': "link",
         'Image': "image",
+        'LinkRef': "link",
         'HeaderAtx': "header",
         'Header': "header",
         'HeaderLine': "header",
@@ -219,9 +221,11 @@ class MarkdownHighlighter(QSyntaxHighlighter):
     def highlightLink(self, text, cursor, bf, strt):
         found = False
         for mo in re.finditer(self.MARKDOWN_KEYS_REGEX['Link'],text):
-            start_bracket = mo.group()[0][0] == '['
-            self.setFormat(mo.start() + strt + (0 if start_bracket else 1),
-                           mo.end() - mo.start() - strt - (0 if start_bracket else 1), self.MARKDOWN_KWS_FORMAT['Link'])
+            self.setFormat(mo.start() + strt, mo.end() - mo.start() - strt, self.MARKDOWN_KWS_FORMAT['Link'])
+            found = True
+
+        for mo in re.finditer(self.MARKDOWN_KEYS_REGEX['LinkRef'],text):
+            self.setFormat(mo.start() + strt, mo.end() - mo.start() - strt, self.MARKDOWN_KWS_FORMAT['LinkRef'])
             found = True
         return found