import 'package:flutter/cupertino.dart';
import '../../../get.dart';

abstract class _RouteMiddleware {
  /// The Order of the Middlewares to run.
  ///
  /// {@tool snippet}
  /// This Middewares will be called in this order.
  /// ```dart
  /// final middlewares = [
  ///   GetMiddleware(priority: 2),
  ///   GetMiddleware(priority: 5),
  ///   GetMiddleware(priority: 4),
  ///   GetMiddleware(priority: -8),
  /// ];
  /// ```
  ///  -8 => 2 => 4 => 5
  /// {@end-tool}
  int? priority;

  /// This function will be called when the page of
  /// the called route is being searched for.
  /// It take RouteSettings as a result an redirect to the new settings or
  /// give it null and there will be no redirecting.
  /// {@tool snippet}
  /// ```dart
  /// GetPage redirect(String route) {
  ///   final authService = Get.find<AuthService>();
  ///   return authService.authed.value ? null : RouteSettings(name: '/login');
  /// }
  /// ```
  /// {@end-tool}
  RouteSettings? redirect(String route);

  /// This function will be called when this Page is called
  /// you can use it to change something about the page or give it new page
  /// {@tool snippet}
  /// ```dart
  /// GetPage onPageCalled(GetPage page) {
  ///   final authService = Get.find<AuthService>();
  ///   return page.copyWith(title: 'Welcome ${authService.UserName}');
  /// }
  /// ```
  /// {@end-tool}
  GetPage? onPageCalled(GetPage page);

  /// This function will be called right before the [Bindings] are initialize.
  /// Here you can change [Bindings] for this page
  /// {@tool snippet}
  /// ```dart
  /// List<Bindings> onBindingsStart(List<Bindings> bindings) {
  ///   final authService = Get.find<AuthService>();
  ///   if (authService.isAdmin) {
  ///     bindings.add(AdminBinding());
  ///   }
  ///   return bindings;
  /// }
  /// ```
  /// {@end-tool}
  List<Bindings>? onBindingsStart(List<Bindings> bindings);

  /// This function will be called right after the [Bindings] are initialize.
  GetPageBuilder? onPageBuildStart(GetPageBuilder page);

  /// This function will be called right after the
  /// GetPage.page function is called and will give you the result
  /// of the function. and take the widget that will be showed.
  Widget onPageBuilt(Widget page);

  void onPageDispose();
}

/// The Page Middlewares.
/// The Functions will be called in this order
/// (( [redirect] -> [onPageCalled] -> [onBindingsStart] ->
/// [onPageBuildStart] -> [onPageBuilt] -> [onPageDispose] ))
class GetMiddleware implements _RouteMiddleware {
  @override
  int? priority = 0;

  GetMiddleware({this.priority});

  @override
  RouteSettings? redirect(String? route) => null;

  @override
  GetPage? onPageCalled(GetPage? page) => page;

  @override
  List<Bindings>? onBindingsStart(List<Bindings>? bindings) => bindings;

  @override
  GetPageBuilder? onPageBuildStart(GetPageBuilder? page) => page;

  @override
  Widget onPageBuilt(Widget page) => page;

  @override
  void onPageDispose() {}
}

class MiddlewareRunner {
  MiddlewareRunner(this._middlewares);

  final List<GetMiddleware>? _middlewares;

  List<GetMiddleware>? _getMiddlewares() {
    if (_middlewares != null) {
      _middlewares!.sort((a, b) => a.priority!.compareTo(b.priority!));
      return _middlewares;
    }
    return <GetMiddleware>[];
  }

  GetPage? runOnPageCalled(GetPage? page) {
    _getMiddlewares()?.forEach((element) {
      page = element.onPageCalled(page);
    });
    return page;
  }

  RouteSettings? runRedirect(String? route) {
    RouteSettings? to;
    _getMiddlewares()?.forEach((element) {
      to = element.redirect(route);
    });
    if (to != null) {
      Get.log('Redirect to $to');
    }
    return to;
  }

  List<Bindings>? runOnBindingsStart(List<Bindings>? bindings) {
    _getMiddlewares()?.forEach((element) {
      bindings = element.onBindingsStart(bindings);
    });
    return bindings;
  }

  GetPageBuilder? runOnPageBuildStart(GetPageBuilder? page) {
    _getMiddlewares()?.forEach((element) {
      page = element.onPageBuildStart(page);
    });
    return page;
  }

  Widget runOnPageBuilt(Widget page) {
    _getMiddlewares()?.forEach((element) {
      page = element.onPageBuilt(page);
    });
    return page;
  }

  void runOnPageDispose() =>
      _getMiddlewares()?.forEach((element) => element.onPageDispose());
}

class PageRedirect {
  GetPage? route;
  GetPage? unknownRoute;
  RouteSettings settings;
  bool isUnknown;

  PageRedirect(this.settings, this.unknownRoute,
      {this.isUnknown = false, this.route});

  // redirect all pages that needes redirecting
  GetPageRoute<T> page<T>() {
    while (needRecheck()) {}
    return isUnknown
        ? GetPageRoute<T>(
            page: unknownRoute!.page,
            parameter: unknownRoute!.parameter,
            settings: RouteSettings(
                name: unknownRoute!.name, arguments: settings.arguments),
            curve: unknownRoute!.curve,
            opaque: unknownRoute!.opaque,
            customTransition: unknownRoute!.customTransition,
            binding: unknownRoute!.binding,
            bindings: unknownRoute!.bindings,
            transitionDuration: (unknownRoute!.transitionDuration ??
                Get.defaultTransitionDuration),
            transition: unknownRoute!.transition,
            popGesture: unknownRoute!.popGesture,
            fullscreenDialog: unknownRoute!.fullscreenDialog,
            middlewares: unknownRoute!.middlewares,
          )
        : GetPageRoute<T>(
            page: route!.page,
            routeName: route!.name,
            parameter: route!.parameter,
            settings: settings,
            curve: route!.curve,
            opaque: route!.opaque,
            customTransition: route!.customTransition,
            binding: route!.binding,
            bindings: route!.bindings,
            transitionDuration:
                (route!.transitionDuration ?? Get.defaultTransitionDuration),
            transition: route!.transition,
            popGesture: route!.popGesture,
            fullscreenDialog: route!.fullscreenDialog,
            middlewares: route!.middlewares);
  }

  /// check if redirect is needed
  bool needRecheck() {
    final match = Get.routeTree.matchRoute(settings.name!);
    Get.parameters = match.parameters;

    // No Match found
    if (match.route == null) {
      isUnknown = true;
      return false;
    }

    final runner = MiddlewareRunner(match.route!.middlewares);
    route = runner.runOnPageCalled(match.route);
    addPageParameter(route!);

    // No middlewares found return match.
    if (match.route!.middlewares == null || match.route!.middlewares!.isEmpty) {
      return false;
    }
    final newSettings = runner.runRedirect(settings.name);
    if (newSettings == null) {
      return false;
    }
    settings = newSettings;
    return true;
  }

  void addPageParameter(GetPage route) {
    if (route.parameter == null) return;

    final parameters = Get.parameters;
    parameters.addEntries(route.parameter!.entries);
    Get.parameters = parameters;
  }
}