import '../../get_navigation.dart';
import '../routes/get_route.dart';

class RouteDecoder {
  final GetPage route;
  final Map<String, String> parameters;
  const RouteDecoder(this.route, this.parameters);
}

class ParseRouteTree {
  final _routes = <GetPage>[];

  RouteDecoder matchRoute(String name) {
    final uri = Uri.parse(name);
    final route = _findRoute(uri.path);
    final params = Map<String, String>.from(uri.queryParameters);
    final parsedParams = _parseParams(name, route?.path);
    if (parsedParams != null && parsedParams.isNotEmpty) {
      params.addAll(parsedParams);
    }
    return RouteDecoder(route, params);
  }

  void addRoutes(List<GetPage> getPages) {
    for (final route in getPages) {
      addRoute(route);
    }
  }

  void addRoute(GetPage route) {
    _routes.add(route);

    // Add Page children.
    for (var page in _flattenPage(route)) {
      addRoute(page);
    }
  }

  List<GetPage> _flattenPage(GetPage route) {
    final result = <GetPage>[];
    if (route.children == null || route.children.isEmpty) {
      return result;
    }

    final parentPath = route.name;
    for (var page in route.children) {
      // Add Parent middlewares to children
      final pageMiddlewares = page.middlewares ?? <GetMiddleware>[];
      pageMiddlewares.addAll(route.middlewares ?? <GetMiddleware>[]);
      result.add(_addChild(page, parentPath, pageMiddlewares));
      final children = _flattenPage(page);
      for (var child in children) {
        pageMiddlewares.addAll(child.middlewares ?? <GetMiddleware>[]);
        result.add(_addChild(child, parentPath, pageMiddlewares));
      }
    }
    return result;
  }

  /// Change the Path for a [GetPage]
  GetPage _addChild(
          GetPage origin, String parentPath, List<GetMiddleware> middlewares) =>
      GetPage(
        name: parentPath + origin.name,
        page: origin.page,
        title: origin.title,
        alignment: origin.alignment,
        transition: origin.transition,
        binding: origin.binding,
        bindings: origin.bindings,
        curve: origin.curve,
        customTransition: origin.customTransition,
        fullscreenDialog: origin.fullscreenDialog,
        maintainState: origin.maintainState,
        opaque: origin.opaque,
        parameter: origin.parameter,
        popGesture: origin.popGesture,
        settings: origin.settings,
        transitionDuration: origin.transitionDuration,
        middlewares: middlewares,
      );

  GetPage _findRoute(String name) {
    final route = _routes.firstWhere(
      (route) {
        return _match(
          name,
          route.path['regex'] as RegExp,
        );
      },
      orElse: () => null,
    );

    return route;
  }

  Map<String, String> _parseParams(
      String path, Map<String, dynamic> routePath) {
    final params = <String, String>{};
    Match paramsMatch = (routePath['regex'] as RegExp).firstMatch(path);
    for (var i = 0; i < (routePath['keys'].length as int); i++) {
      String param;
      try {
        param = Uri.decodeQueryComponent(paramsMatch[i + 1]);
      } on Exception catch (_) {
        param = paramsMatch[i + 1];
      }
      params[routePath['keys'][i] as String] = param;
    }
    return params;
  }

  bool _match(String name, RegExp path) {
    return path.hasMatch(name);
  }
}