fix(render): replace rune cast with IndexByte and add autolink unit tests

internal/tui/render/markdown.go

@@ -231,7 +231,7 @@ func isMarkdownAutolinkTarget(target string) bool {
 func escapeMarkdownLiteral(input string) string {
 	var out strings.Builder
 	for i := 0; i < len(input); i++ {
-		if strings.ContainsRune(markdownSpecialChars, rune(input[i])) {
+		if strings.IndexByte(markdownSpecialChars, input[i]) >= 0 {
 			out.WriteByte('\\')
 		}
 		out.WriteByte(input[i])

internal/tui/render/markdown_autolink_test.go

@@ -0,0 +1,207 @@
+package render
+
+import (
+	"testing"
+)
+
+func TestIsMarkdownAutolinkTarget(t *testing.T) {
+	tests := []struct {
+		name   string
+		target string
+		want   bool
+	}{
+		// Valid http/https/mailto
+		{"http url", "http://example.com", true},
+		{"https url", "https://example.com/path?q=1", true},
+		{"mailto", "mailto:user@example.com", true},
+		// Case-insensitive
+		{"uppercase HTTP", "HTTP://EXAMPLE.COM", true},
+		{"uppercase HTTPS", "HTTPS://example.com", true},
+		{"mixed case Http", "Http://example.com", true},
+		{"mixed case MailTo", "MailTo:user@example.com", true},
+		// Invalid
+		{"empty string", "", false},
+		{"no protocol", "example.com", false},
+		{"wrong protocol ftp", "ftp://example.com", false},
+		{"wrong protocol file", "file:///tmp/foo", false},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := isMarkdownAutolinkTarget(tt.target); got != tt.want {
+				t.Fatalf("isMarkdownAutolinkTarget(%q) = %v, want %v", tt.target, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestEscapeMarkdownLiteral(t *testing.T) {
+	tests := []struct {
+		name  string
+		input string
+		want  string
+	}{
+		{"no special chars", "https://example.com", `https://example\.com`},
+		{"asterisk in URL", "https://example.com/a*b*c", `https://example\.com/a\*b\*c`},
+		{"underscore in URL", "https://example.com/a_b", `https://example\.com/a\_b`},
+		{"parentheses in URL", "https://example.com/a(b)c", `https://example\.com/a\(b\)c`},
+		{"brackets in URL", "https://example.com/a[b]c", `https://example\.com/a\[b\]c`},
+		{"backtick in URL", "https://example.com/a`b", "https://example\\.com/a\\`b"},
+		{"hash in URL", "https://example.com/a#b", `https://example\.com/a\#b`},
+		{"multiple special chars", "https://a*b(c).d", `https://a\*b\(c\)\.d`},
+		{"mailto no specials but dot", "mailto:user@example.com", `mailto:user@example\.com`},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := escapeMarkdownLiteral(tt.input); got != tt.want {
+				t.Fatalf("escapeMarkdownLiteral(%q) = %q, want %q", tt.input, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestParseMarkdownAutolink(t *testing.T) {
+	strip := stripAutolinkBracketsOnly
+	escape := escapeAutolinksForRenderer
+
+	tests := []struct {
+		name     string
+		input    string
+		start    int
+		escaping autolinkEscaping
+		wantRepl string
+		wantNext int
+		wantOK   bool
+	}{
+		{
+			name:     "strip brackets only - simple URL",
+			input:    "see <https://example.com> more",
+			start:    4,
+			escaping: strip,
+			wantRepl: "https://example.com",
+			wantNext: 25,
+			wantOK:   true,
+		},
+		{
+			name:     "escape for renderer - simple URL",
+			input:    "<https://example.com>",
+			start:    0,
+			escaping: escape,
+			wantRepl: `https://example\.com`,
+			wantNext: 21,
+			wantOK:   true,
+		},
+		{
+			name:     "escape for renderer - URL with asterisk",
+			input:    "<https://example.com/a*b>",
+			start:    0,
+			escaping: escape,
+			wantRepl: `https://example\.com/a\*b`,
+			wantNext: 25,
+			wantOK:   true,
+		},
+		{
+			name:     "strip - mailto",
+			input:    "<mailto:user@example.com>",
+			start:    0,
+			escaping: strip,
+			wantRepl: "mailto:user@example.com",
+			wantNext: 25,
+			wantOK:   true,
+		},
+		{
+			name:     "empty brackets",
+			input:    "<>",
+			start:    0,
+			escaping: strip,
+			wantRepl: "",
+			wantNext: 0,
+			wantOK:   false,
+		},
+		{
+			name:     "no closing bracket",
+			input:    "<https://example.com",
+			start:    0,
+			escaping: strip,
+			wantRepl: "",
+			wantNext: 0,
+			wantOK:   false,
+		},
+		{
+			name:     "space inside brackets",
+			input:    "<https://example .com>",
+			start:    0,
+			escaping: strip,
+			wantRepl: "",
+			wantNext: 0,
+			wantOK:   false,
+		},
+		{
+			name:     "HTML tag is not autolink",
+			input:    `<p align="center">`,
+			start:    0,
+			escaping: escape,
+			wantRepl: "",
+			wantNext: 0,
+			wantOK:   false,
+		},
+		{
+			name:     "not at angle bracket",
+			input:    "hello",
+			start:    0,
+			escaping: strip,
+			wantRepl: "",
+			wantNext: 0,
+			wantOK:   false,
+		},
+		{
+			name:     "multiple autolinks - first",
+			input:    "<https://a.com> and <https://b.com>",
+			start:    0,
+			escaping: strip,
+			wantRepl: "https://a.com",
+			wantNext: 15,
+			wantOK:   true,
+		},
+		{
+			name:     "multiple autolinks - second",
+			input:    "<https://a.com> and <https://b.com>",
+			start:    20,
+			escaping: strip,
+			wantRepl: "https://b.com",
+			wantNext: 35,
+			wantOK:   true,
+		},
+		{
+			name:     "autolink inside blockquote text",
+			input:    "> see <https://x.com> now",
+			start:    6,
+			escaping: strip,
+			wantRepl: "https://x.com",
+			wantNext: 21,
+			wantOK:   true,
+		},
+		{
+			name:     "autolink after text with punctuation",
+			input:    "URL: <https://example.com>.",
+			start:    5,
+			escaping: strip,
+			wantRepl: "https://example.com",
+			wantNext: 26,
+			wantOK:   true,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			gotRepl, gotNext, gotOK := parseMarkdownAutolink(tt.input, tt.start, tt.escaping)
+			if gotOK != tt.wantOK {
+				t.Fatalf("parseMarkdownAutolink(%q, %d, %v) ok = %v, want %v", tt.input, tt.start, tt.escaping, gotOK, tt.wantOK)
+			}
+			if gotRepl != tt.wantRepl {
+				t.Fatalf("parseMarkdownAutolink(%q, %d, %v) repl = %q, want %q", tt.input, tt.start, tt.escaping, gotRepl, tt.wantRepl)
+			}
+			if gotNext != tt.wantNext {
+				t.Fatalf("parseMarkdownAutolink(%q, %d, %v) next = %d, want %d", tt.input, tt.start, tt.escaping, gotNext, tt.wantNext)
+			}
+		})
+	}
+}