From 3f62e43b705a9108eeb1d6491a64540819969508 Mon Sep 17 00:00:00 2001
From: Dima Krasner <dima@dimakrasner.com>
Date: Fri, 5 Jan 2024 15:13:33 +0200
Subject: [PATCH] fix bad HTML when links overlap

---
 front/text/plain/convert.go      | 28 +++++++++++++++++-----------
 front/text/plain/convert_test.go |  8 ++++++++
 2 files changed, 25 insertions(+), 11 deletions(-)

diff --git a/front/text/plain/convert.go b/front/text/plain/convert.go
index b1885c65..1f6b5dd0 100644
--- a/front/text/plain/convert.go
+++ b/front/text/plain/convert.go
@@ -117,25 +117,31 @@ func FromHTML(text string) (string, data.OrderedMap[string, string]) {
 	return strings.TrimRight(res, " \n\r\t"), links
 }
 
-func getPlainLinks(text string) map[string]struct{} {
-	links := map[string]struct{}{}
-	for _, link := range urlRegex.FindAllString(text, -1) {
-		links[link] = struct{}{}
-	}
-	return links
-}
-
 func ToHTML(text string, mentions []ap.Mention) string {
 	if text == "" {
 		return ""
 	}
 
-	for link := range getPlainLinks(text) {
-		text = strings.ReplaceAll(text, link, fmt.Sprintf(`<a href="%s" target="_blank">%s</a>`, link, link))
+	var b strings.Builder
+
+	foundLink := false
+	for {
+		loc := urlRegex.FindStringIndex(text)
+		if loc == nil {
+			break
+		}
+		b.WriteString(text[:loc[0]])
+		b.WriteString(fmt.Sprintf(`<a href="%s" target="_blank">%s</a>`, text[loc[0]:loc[1]], text[loc[0]:loc[1]]))
+		text = text[loc[1]:]
+		foundLink = true
+	}
+	if foundLink {
+		b.WriteString(text)
+		text = b.String()
 	}
 
 	if len(mentions) > 0 {
-		var b strings.Builder
+		b.Reset()
 	mentions:
 		for _, mention := range mentions {
 			if mention.Type != ap.MentionMention {
diff --git a/front/text/plain/convert_test.go b/front/text/plain/convert_test.go
index 2a8162de..8c20416b 100644
--- a/front/text/plain/convert_test.go
+++ b/front/text/plain/convert_test.go
@@ -287,6 +287,14 @@ func TestToHTML_Link(t *testing.T) {
 	assert.Equal(t, expected, html)
 }
 
+func TestToHTML_OverlappingLink(t *testing.T) {
+	post := `this is a plain post with overlapping links: gemini://aa.bb.com/cc gemini://aa.bb.com/cc?dd=ee&ff=gg%20hh`
+	expected := `<p>this is a plain post with overlapping links: <a href="gemini://aa.bb.com/cc" target="_blank">gemini://aa.bb.com/cc</a> <a href="gemini://aa.bb.com/cc?dd=ee&ff=gg%20hh" target="_blank">gemini://aa.bb.com/cc?dd=ee&ff=gg%20hh</a></p>`
+
+	html := ToHTML(post, nil)
+	assert.Equal(t, expected, html)
+}
+
 func TestToHTML_LinkAndLineBreak(t *testing.T) {
 	post := "this is a plain post with a link: gemini://aa.bb.com/cc?dd=ee&ff=gg%20hh\n... and a line break"
 	expected := `<p>this is a plain post with a link: <a href="gemini://aa.bb.com/cc?dd=ee&ff=gg%20hh" target="_blank">gemini://aa.bb.com/cc?dd=ee&ff=gg%20hh</a><br/>... and a line break</p>`