feat: sync chatlist sharing support

internal/links/links.go

@@ -0,0 +1,94 @@
+package links
+
+import (
+	"net/url"
+	"strings"
+)
+
+const DefaultPublicBaseURL = "https://telesrv.net"
+const MaxChatlistSlugBytes = 128
+
+func NormalizeBaseURL(raw string) string {
+	raw = strings.TrimSpace(raw)
+	if raw == "" {
+		raw = DefaultPublicBaseURL
+	}
+	if !strings.Contains(raw, "://") {
+		raw = "https://" + raw
+	}
+	return strings.TrimRight(raw, "/")
+}
+
+func Build(baseURL, path string, query url.Values) string {
+	baseURL = NormalizeBaseURL(baseURL)
+	parsed, err := url.Parse(baseURL)
+	if err != nil || parsed.Scheme == "" || parsed.Host == "" {
+		baseURL = DefaultPublicBaseURL
+		parsed, _ = url.Parse(baseURL)
+	}
+	basePath := strings.TrimRight(parsed.Path, "/")
+	path = strings.TrimLeft(path, "/")
+	if path != "" {
+		parsed.Path = basePath + "/" + path
+	} else if basePath != "" {
+		parsed.Path = basePath
+	}
+	parsed.RawQuery = query.Encode()
+	return parsed.String()
+}
+
+func Host(baseURL string) string {
+	parsed, err := url.Parse(NormalizeBaseURL(baseURL))
+	if err != nil || parsed.Host == "" {
+		return "telesrv.net"
+	}
+	if host := parsed.Hostname(); host != "" {
+		return host
+	}
+	return parsed.Host
+}
+
+func CleanChatlistSlug(raw string) string {
+	raw = strings.TrimSpace(raw)
+	if raw == "" {
+		return ""
+	}
+	if strings.Contains(raw, "://") {
+		if parsed, err := url.Parse(raw); err == nil {
+			if slug := parsed.Query().Get("slug"); slug != "" {
+				raw = slug
+			} else {
+				raw = strings.Trim(parsed.Path, "/")
+			}
+		}
+	}
+	raw = strings.TrimPrefix(raw, "addlist/")
+	raw = strings.Trim(raw, "/")
+	if idx := strings.LastIndex(raw, "/"); idx >= 0 {
+		raw = raw[idx+1:]
+	}
+	if idx := strings.IndexAny(raw, "?#"); idx >= 0 {
+		raw = raw[:idx]
+	}
+	if decoded, err := url.PathUnescape(raw); err == nil {
+		raw = decoded
+	}
+	return raw
+}
+
+func ValidChatlistSlug(slug string) bool {
+	if slug == "" || len(slug) > MaxChatlistSlugBytes {
+		return false
+	}
+	for _, r := range slug {
+		switch {
+		case r >= 'a' && r <= 'z':
+		case r >= 'A' && r <= 'Z':
+		case r >= '0' && r <= '9':
+		case r == '_' || r == '-' || r == '.':
+		default:
+			return false
+		}
+	}
+	return true
+}