import 'package:url_launcher/url_launcher.dart';

class SCUrlLauncherUtils {
  static const Set<String> _httpSchemes = {'http', 'https'};

  static bool isHttpUrl(String url) {
    final uri = Uri.tryParse(url);
    if (uri == null) {
      return false;
    }
    return _httpSchemes.contains(uri.scheme.toLowerCase());
  }

  static bool isCustomSchemeUrl(String url) {
    final uri = Uri.tryParse(url);
    if (uri == null || uri.scheme.isEmpty) {
      return false;
    }
    return !_httpSchemes.contains(uri.scheme.toLowerCase());
  }

  static bool isWhatsAppUrl(String url) {
    final uri = Uri.tryParse(url);
    if (uri == null) {
      return false;
    }
    final scheme = uri.scheme.toLowerCase();
    final host = uri.host.toLowerCase();
    return scheme == 'whatsapp' ||
        host == 'wa.me' ||
        host == 'api.whatsapp.com' ||
        host == 'whatsapp.com' ||
        host.endsWith('.whatsapp.com');
  }

  static bool shouldOpenExternally(String url) {
    return isCustomSchemeUrl(url) || isWhatsAppUrl(url);
  }

  static Future<bool> launchExternal(String url) async {
    final uri = Uri.tryParse(url);
    if (uri == null || uri.scheme.isEmpty) {
      return false;
    }

    final launchTargets = <Uri>[];
    final normalizedUri = _normalizeWhatsAppUri(uri);
    if (normalizedUri != null && normalizedUri.toString() != uri.toString()) {
      launchTargets.add(normalizedUri);
    }
    launchTargets.add(uri);

    for (final target in launchTargets) {
      try {
        final launched = await launchUrl(
          target,
          mode: LaunchMode.externalApplication,
        );
        if (launched) {
          return true;
        }
      } catch (_) {}
    }

    return false;
  }

  static Uri? _normalizeWhatsAppUri(Uri uri) {
    if (uri.scheme.toLowerCase() == 'whatsapp') {
      return uri;
    }

    final scheme = uri.scheme.toLowerCase();
    final host = uri.host.toLowerCase();
    if (!_httpSchemes.contains(scheme)) {
      return null;
    }

    if (host == 'wa.me') {
      final pathSegments =
          uri.pathSegments.where((segment) => segment.isNotEmpty).toList();
      if (pathSegments.length != 1 ||
          !_looksLikeWhatsAppPhone(pathSegments.first)) {
        return null;
      }
      return Uri(
        scheme: 'whatsapp',
        host: 'send',
        queryParameters: {
          'phone': pathSegments.first,
          if ((uri.queryParameters['text'] ?? '').isNotEmpty)
            'text': uri.queryParameters['text']!,
        },
      );
    }

    if (host == 'api.whatsapp.com' && uri.path.toLowerCase() == '/send') {
      final phone = uri.queryParameters['phone'] ?? '';
      final text = uri.queryParameters['text'] ?? '';
      if (phone.isEmpty && text.isEmpty) {
        return null;
      }
      return Uri(
        scheme: 'whatsapp',
        host: 'send',
        queryParameters: {
          if (phone.isNotEmpty) 'phone': phone,
          if (text.isNotEmpty) 'text': text,
        },
      );
    }

    return null;
  }

  static bool _looksLikeWhatsAppPhone(String value) {
    return RegExp(r'^\d+$').hasMatch(value);
  }
}