From 4371857168a9f260aebe477b0d5f2a11f85234f7 Mon Sep 17 00:00:00 2001
From: oppiliappan <me@oppi.li>
Date: Sun, 21 Dec 2025 07:17:05 +0000
Subject: [PATCH] appview/pages: use robust handle regex from indigo/syntax
Change-Id: vtyvsnwqkrwrksmnloppspuxtuvvvoym

should cut down the false positives a bit. tests are included.

Signed-off-by: oppiliappan <me@oppi.li>
---
 appview/pages/markup/extension/atlink.go |   6 +-
 appview/pages/markup/markdown_test.go    | 121 +++++++++++++++++++++++
 2 files changed, 122 insertions(+), 5 deletions(-)
 create mode 100644 appview/pages/markup/markdown_test.go

diff --git a/appview/pages/markup/extension/atlink.go b/appview/pages/markup/extension/atlink.go
index 444a0678..005f4955 100644
--- a/appview/pages/markup/extension/atlink.go
+++ b/appview/pages/markup/extension/atlink.go
@@ -35,7 +35,7 @@ func (n *AtNode) Kind() ast.NodeKind {
 	return KindAt
 }
 
-var atRegexp = regexp.MustCompile(`(^|\s|\()(@)([a-zA-Z0-9.-]+)(\b)`)
+var atRegexp = regexp.MustCompile(`(^|\s|\()(@)([a-zA-Z0-9]([a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?\.)+[a-zA-Z]([a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?(\b)`)
 var markdownLinkRegexp = regexp.MustCompile(`(?ms)\[.*\]\(.*\)`)
 
 type atParser struct{}
@@ -57,10 +57,6 @@ func (s *atParser) Parse(parent ast.Node, block text.Reader, pc parser.Context)
 		return nil
 	}
 
-	if !util.IsSpaceRune(block.PrecendingCharacter()) {
-		return nil
-	}
-
 	// Check for all links in the markdown to see if the handle found is inside one
 	linksIndexes := markdownLinkRegexp.FindAllIndex(block.Source(), -1)
 	for _, linkMatch := range linksIndexes {
diff --git a/appview/pages/markup/markdown_test.go b/appview/pages/markup/markdown_test.go
new file mode 100644
index 00000000..73c2442e
--- /dev/null
+++ b/appview/pages/markup/markdown_test.go
@@ -0,0 +1,121 @@
+package markup
+
+import (
+	"bytes"
+	"testing"
+)
+
+func TestAtExtension_Rendering(t *testing.T) {
+	tests := []struct {
+		name     string
+		markdown string
+		expected string
+	}{
+		{
+			name:     "renders simple at mention",
+			markdown: "Hello @user.tngl.sh!",
+			expected: `<p>Hello <a href="/user.tngl.sh" class="mention">@user.tngl.sh</a>!</p>`,
+		},
+		{
+			name:     "renders multiple at mentions",
+			markdown: "Hi @alice.tngl.sh and @bob.example.com",
+			expected: `<p>Hi <a href="/alice.tngl.sh" class="mention">@alice.tngl.sh</a> and <a href="/bob.example.com" class="mention">@bob.example.com</a></p>`,
+		},
+		{
+			name:     "renders at mention in parentheses",
+			markdown: "Check this out (@user.tngl.sh)",
+			expected: `<p>Check this out (<a href="/user.tngl.sh" class="mention">@user.tngl.sh</a>)</p>`,
+		},
+		{
+			name:     "does not render email",
+			markdown: "Contact me at test@example.com",
+			expected: `<p>Contact me at <a href="mailto:test@example.com">test@example.com</a></p>`,
+		},
+		{
+			name:     "renders at mention with hyphen",
+			markdown: "Follow @user-name.tngl.sh",
+			expected: `<p>Follow <a href="/user-name.tngl.sh" class="mention">@user-name.tngl.sh</a></p>`,
+		},
+		{
+			name:     "renders at mention with numbers",
+			markdown: "@user123.test456.social",
+			expected: `<p><a href="/user123.test456.social" class="mention">@user123.test456.social</a></p>`,
+		},
+		{
+			name:     "at mention at start of line",
+			markdown: "@user.tngl.sh is cool",
+			expected: `<p><a href="/user.tngl.sh" class="mention">@user.tngl.sh</a> is cool</p>`,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			md := NewMarkdown()
+
+			var buf bytes.Buffer
+			if err := md.Convert([]byte(tt.markdown), &buf); err != nil {
+				t.Fatalf("failed to convert markdown: %v", err)
+			}
+
+			result := buf.String()
+			if result != tt.expected+"\n" {
+				t.Errorf("expected:\n%s\ngot:\n%s", tt.expected, result)
+			}
+		})
+	}
+}
+
+func TestAtExtension_WithOtherMarkdown(t *testing.T) {
+	tests := []struct {
+		name     string
+		markdown string
+		contains string
+	}{
+		{
+			name:     "at mention with bold",
+			markdown: "**Hello @user.tngl.sh**",
+			contains: `<strong>Hello <a href="/user.tngl.sh" class="mention">@user.tngl.sh</a></strong>`,
+		},
+		{
+			name:     "at mention with italic",
+			markdown: "*Check @user.tngl.sh*",
+			contains: `<em>Check <a href="/user.tngl.sh" class="mention">@user.tngl.sh</a></em>`,
+		},
+		{
+			name:     "at mention in list",
+			markdown: "- Item 1\n- @user.tngl.sh\n- Item 3",
+			contains: `<a href="/user.tngl.sh" class="mention">@user.tngl.sh</a>`,
+		},
+		{
+			name:     "at mention in link",
+			markdown: "[@regnault.dev](https://regnault.dev)",
+			contains: `<a href="https://regnault.dev">@regnault.dev</a>`,
+		},
+		{
+			name:     "at mention in link again",
+			markdown: "[check out @regnault.dev](https://regnault.dev)",
+			contains: `<a href="https://regnault.dev">check out @regnault.dev</a>`,
+		},
+		{
+			name:     "at mention in link again, multiline",
+			markdown: "[\ncheck out @regnault.dev](https://regnault.dev)",
+			contains: "<a href=\"https://regnault.dev\">\ncheck out @regnault.dev</a>",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			md := NewMarkdown()
+
+			var buf bytes.Buffer
+			if err := md.Convert([]byte(tt.markdown), &buf); err != nil {
+				t.Fatalf("failed to convert markdown: %v", err)
+			}
+
+			result := buf.String()
+			if !bytes.Contains([]byte(result), []byte(tt.contains)) {
+				t.Errorf("expected output to contain:\n%s\ngot:\n%s", tt.contains, result)
+			}
+		})
+	}
+}
-- 
2.43.0