import 'dart:async';
import 'dart:collection';

import '../../get_core/get_core.dart';

import 'lifecycle.dart';

class InstanceInfo {
  final bool? isPermanent;
  final bool? isSingleton;
  bool get isCreate => !isSingleton!;
  final bool isRegistered;
  final bool isPrepared;
  final bool? isInit;
  const InstanceInfo({
    required this.isPermanent,
    required this.isSingleton,
    required this.isRegistered,
    required this.isPrepared,
    required this.isInit,
  });
}

class GetInstance {
  factory GetInstance() => _getInstance ??= GetInstance._();

  const GetInstance._();

  static GetInstance? _getInstance;

  T call<T>() => find<T>();

  /// Holds references to every registered Instance when using
  /// `Get.put()`
  static final Map<String, _InstanceBuilderFactory> _singl = {};

  /// Holds a reference to every registered callback when using
  /// `Get.lazyPut()`
  // static final Map<String, _Lazy> _factory = {};

  /// Holds a reference to `Get.reference` when the Instance was
  /// created to manage the memory.
  static final Map<String, String?> _routesKey = {};

  /// Stores the onClose() references of instances created with `Get.create()`
  /// using the `Get.reference`.
  /// Experimental feature to keep the lifecycle and memory management with
  /// non-singleton instances.
  static final Map<String?, HashSet<Function>> _routesByCreate = {};

  void printInstanceStack() {
    Get.log(_routesKey.toString());
  }

  void injector<S>(
    InjectorBuilderCallback<S> fn, {
    String? tag,
    bool fenix = false,
    //  bool permanent = false,
  }) {
    lazyPut(
      () => fn(this),
      tag: tag,
      fenix: fenix,
      // permanent: permanent,
    );
  }

  /// async version of `Get.put()`.
  /// Awaits for the resolution of the Future from `builder()` parameter and
  /// stores the Instance returned.
  Future<S> putAsync<S>(
    AsyncInstanceBuilderCallback<S> builder, {
    String? tag,
    bool permanent = false,
  }) async {
    return put<S>(await builder(), tag: tag, permanent: permanent);
  }

  /// Injects an instance `<S>` in memory to be globally accessible.
  ///
  /// No need to define the generic type `<S>` as it's inferred from
  /// the [dependency]
  ///
  /// - [dependency] The Instance to be injected.
  /// - [tag] optionally, use a [tag] as an "id" to create multiple records of
  /// the same Type<[S]>
  /// - [permanent] keeps the Instance in memory, not following
  /// `Get.smartManagement` rules.
  S put<S>(
    S dependency, {
    String? tag,
    bool permanent = false,
    @deprecated InstanceBuilderCallback<S>? builder,
  }) {
    _insert(
        isSingleton: true,
        name: tag,
        permanent: permanent,
        builder: builder ?? (() => dependency));
    return find<S>(tag: tag);
  }

  /// Creates a new Instance<S> lazily from the `<S>builder()` callback.
  ///
  /// The first time you call `Get.find()`, the `builder()` callback will create
  /// the Instance and persisted as a Singleton (like you would
  /// use `Get.put()`).
  ///
  /// Using `Get.smartManagement` as [SmartManagement.keepFactory] has
  /// the same outcome as using `fenix:true` :
  /// The internal register of `builder()` will remain in memory to recreate
  /// the Instance if the Instance has been removed with `Get.delete()`.
  /// Therefore, future calls to `Get.find()` will return the same Instance.
  ///
  /// If you need to make use of GetxController's life-cycle
  /// (`onInit(), onStart(), onClose()`) [fenix] is a great choice to mix with
  /// `GetBuilder()` and `GetX()` widgets, and/or `GetMaterialApp` Navigation.
  ///
  /// You could use `Get.lazyPut(fenix:true)` in your app's `main()` instead
  /// of `Bindings()` for each `GetPage`.
  /// And the memory management will be similar.
  ///
  /// Subsequent calls to `Get.lazyPut()` with the same parameters
  /// (<[S]> and optionally [tag] will **not** override the original).
  void lazyPut<S>(
    InstanceBuilderCallback<S> builder, {
    String? tag,
    bool? fenix,
    bool permanent = false,
  }) {
    _insert(
      isSingleton: true,
      name: tag,
      permanent: permanent,
      builder: builder,
      fenix: fenix ?? Get.smartManagement == SmartManagement.keepFactory,
    );
  }

  /// Creates a new Class Instance [S] from the builder callback[S].
  /// Every time [find]<[S]>() is used, it calls the builder method to generate
  /// a new Instance [S].
  /// It also registers each `instance.onClose()` with the current
  /// Route `Get.reference` to keep the lifecycle active.
  /// Is important to know that the instances created are only stored per Route.
  /// So, if you call `Get.delete<T>()` the "instance factory" used in this
  /// method (`Get.create<T>()`) will be removed, but NOT the instances
  /// already created by it.
  ///
  /// Example:
  ///
  /// ```create(() => Repl());
  /// Repl a = find();
  /// Repl b = find();
  /// print(a==b); (false)```
  void create<S>(
    InstanceBuilderCallback<S> builder, {
    String? tag,
    bool permanent = true,
  }) {
    _insert(
      isSingleton: false,
      name: tag,
      builder: builder,
      permanent: permanent,
    );
  }

  /// Injects the Instance [S] builder into the `_singleton` HashMap.
  void _insert<S>({
    bool? isSingleton,
    String? name,
    bool permanent = false,
    required InstanceBuilderCallback<S> builder,
    bool fenix = false,
  }) {
    final key = _getKey(S, name);
    _singl.putIfAbsent(
      key,
      () => _InstanceBuilderFactory<S>(
        isSingleton,
        builder,
        permanent,
        false,
        fenix,
        name,
      ),
    );
  }

  /// Clears from memory registered Instances associated with [routeName] when
  /// using `Get.smartManagement` as [SmartManagement.full] or
  /// [SmartManagement.keepFactory]
  /// Meant for internal usage of `GetPageRoute` and `GetDialogRoute`
  void removeDependencyByRoute(String routeName) {
    final keysToRemove = <String>[];
    _routesKey.forEach((key, value) {
      if (value == routeName) {
        keysToRemove.add(key);
      }
    });

    /// Removes `Get.create()` instances registered in `routeName`.
    if (_routesByCreate.containsKey(routeName)) {
      for (final onClose in _routesByCreate[routeName]!) {
        // assure the [DisposableInterface] instance holding a reference
        // to onClose() wasn't disposed.
        onClose();
      }
      _routesByCreate[routeName]!.clear();
      _routesByCreate.remove(routeName);
    }

    for (final element in keysToRemove) {
      delete(key: element);
      _routesKey.remove(element);
    }

    keysToRemove.clear();
  }

  void reloadDependencyByRoute(String routeName) {
    final keysToRemove = <String>[];
    _routesKey.forEach((key, value) {
      if (value == routeName) {
        keysToRemove.add(key);
      }
    });

    /// Removes `Get.create()` instances registered in `routeName`.
    if (_routesByCreate.containsKey(routeName)) {
      for (final onClose in _routesByCreate[routeName]!) {
        // assure the [DisposableInterface] instance holding a reference
        // to onClose() wasn't disposed.
        onClose();
      }
      _routesByCreate[routeName]!.clear();
      _routesByCreate.remove(routeName);
    }

    for (final element in keysToRemove) {
      reload(key: element);
      //_routesKey.remove(element);
    }

    keysToRemove.clear();
  }

  /// Initializes the dependencies for a Class Instance [S] (or tag),
  /// If its a Controller, it starts the lifecycle process.
  /// Optionally associating the current Route to the lifetime of the instance,
  /// if `Get.smartManagement` is marked as [SmartManagement.full] or
  /// [SmartManagement.keepFactory]
  /// Only flags `isInit` if it's using `Get.create()`
  /// (not for Singletons access).
  /// Returns the instance if not initialized, required for Get.create() to
  /// work properly.
  S? _initDependencies<S>({String? name}) {
    final key = _getKey(S, name);
    final isInit = _singl[key]!.isInit;
    S? i;
    if (!isInit) {
      i = _startController<S>(tag: name);
      if (_singl[key]!.isSingleton!) {
        _singl[key]!.isInit = true;
        if (Get.smartManagement != SmartManagement.onlyBuilder) {
          _registerRouteInstance<S>(tag: name);
        }
      }
    }
    return i;
  }

  /// Links a Class instance [S] (or [tag]) to the current route.
  /// Requires usage of `GetMaterialApp`.
  void _registerRouteInstance<S>({String? tag}) {
    _routesKey.putIfAbsent(_getKey(S, tag), () => Get.reference);
  }

  InstanceInfo getInstanceInfo<S>({String? tag}) {
    final build = _getDependency<S>(tag: tag);

    return InstanceInfo(
      isPermanent: build?.permanent,
      isSingleton: build?.isSingleton,
      isRegistered: isRegistered<S>(tag: tag),
      isPrepared: !(build?.isInit ?? true),
      isInit: build?.isInit,
    );
  }

  _InstanceBuilderFactory? _getDependency<S>({String? tag, String? key}) {
    final newKey = key ?? _getKey(S, tag);

    if (!_singl.containsKey(newKey)) {
      Get.log('Instance "$newKey" is not registered.', isError: true);
      return null;
    } else {
      return _singl[newKey];
    }
  }

  /// Initializes the controller
  S _startController<S>({String? tag}) {
    final key = _getKey(S, tag);
    final i = _singl[key]!.getDependency() as S;
    if (i is GetLifeCycleBase) {
      i.onStart();
      if (tag == null) {
        Get.log('Instance "$S" has been initialized');
      } else {
        Get.log('Instance "$S" with tag "$tag" has been initialized');
      }
      if (!_singl[key]!.isSingleton!) {
        _routesByCreate[Get.reference] ??= HashSet<Function>();
        // _routesByCreate[Get.reference]!.add(i.onDelete as Function);
        _routesByCreate[Get.reference]!.add(i.onDelete);
      }
    }
    return i;
  }

  S putOrFind<S>(InstanceBuilderCallback<S> dep, {String? tag}) {
    final key = _getKey(S, tag);

    if (_singl.containsKey(key)) {
      return _singl[key]!.getDependency() as S;
    } else {
      return GetInstance().put(dep(), tag: tag);
    }
  }

  /// Finds the registered type <[S]> (or [tag])
  /// In case of using Get.[create] to register a type <[S]> or [tag],
  /// it will create an instance each time you call [find].
  /// If the registered type <[S]> (or [tag]) is a Controller,
  /// it will initialize it's lifecycle.
  S find<S>({String? tag}) {
    final key = _getKey(S, tag);
    if (isRegistered<S>(tag: tag)) {
      if (_singl[key] == null) {
        if (tag == null) {
          throw 'Class "$S" is not registered';
        } else {
          throw 'Class "$S" with tag "$tag" is not registered';
        }
      }

      /// although dirty solution, the lifecycle starts inside
      /// `initDependencies`, so we have to return the instance from there
      /// to make it compatible with `Get.create()`.
      final i = _initDependencies<S>(name: tag);
      return i ?? _singl[key]!.getDependency() as S;
    } else {
      // ignore: lines_longer_than_80_chars
      throw '"$S" not found. You need to call "Get.put($S())" or "Get.lazyPut(()=>$S())"';
    }
  }

  /// Generates the key based on [type] (and optionally a [name])
  /// to register an Instance Builder in the hashmap.
  String _getKey(Type type, String? name) {
    return name == null ? type.toString() : type.toString() + name;
  }

  /// Clears all registered instances (and/or tags).
  /// Even the persistent ones.
  ///
  /// [clearFactory] clears the callbacks registered by [lazyPut]
  /// [clearRouteBindings] clears Instances associated with routes.
  ///
  bool reset({bool clearFactory = true, bool clearRouteBindings = true}) {
    //  if (clearFactory) _factory.clear();
    if (clearRouteBindings) _routesKey.clear();
    _singl.clear();
    return true;
  }

  /// Delete registered Class Instance [S] (or [tag]) and, closes any open
  /// controllers `DisposableInterface`, cleans up the memory
  ///
  /// /// Deletes the Instance<[S]>, cleaning the memory.
  //  ///
  //  /// - [tag] Optional "tag" used to register the Instance
  //  /// - [key] For internal usage, is the processed key used to register
  //  ///   the Instance. **don't use** it unless you know what you are doing.

  /// Deletes the Instance<[S]>, cleaning the memory and closes any open
  /// controllers (`DisposableInterface`).
  ///
  /// - [tag] Optional "tag" used to register the Instance
  /// - [key] For internal usage, is the processed key used to register
  ///   the Instance. **don't use** it unless you know what you are doing.
  /// - [force] Will delete an Instance even if marked as `permanent`.
  bool delete<S>({String? tag, String? key, bool force = false}) {
    final newKey = key ?? _getKey(S, tag);

    if (!_singl.containsKey(newKey)) {
      Get.log('Instance "$newKey" already removed.', isError: true);
      return false;
    }

    final builder = _singl[newKey]!;

    if (builder.permanent && !force) {
      Get.log(
        // ignore: lines_longer_than_80_chars
        '"$newKey" has been marked as permanent, SmartManagement is not authorized to delete it.',
        isError: true,
      );
      return false;
    }
    final i = builder.dependency;

    if (i is GetxServiceMixin && !force) {
      return false;
    }

    if (i is GetLifeCycleBase) {
      i.onDelete();
      Get.log('"$newKey" onDelete() called');
    }

    if (builder.fenix) {
      builder.dependency = null;
      builder.isInit = false;
    } else {
      _singl.remove(newKey);
      if (_singl.containsKey(newKey)) {
        Get.log('Error removing object "$newKey"', isError: true);
      } else {
        Get.log('"$newKey" deleted from memory');
      }
    }

    return true;
  }

  /// Delete all registered Class Instances and, closes any open
  /// controllers `DisposableInterface`, cleans up the memory
  ///
  /// - [force] Will delete the Instances even if marked as `permanent`.
  void deleteAll({bool force = false}) {
    _singl.forEach((key, value) {
      delete(key: key, force: force);
    });
  }

  void reloadAll({bool force = false}) {
    _singl.forEach((key, value) {
      if (value.permanent && !force) {
        Get.log('Instance "$key" is permanent. Skipping reload');
      } else {
        value.dependency = null;
        value.isInit = false;
        Get.log('Instance "$key" was reloaded.');
      }
    });
  }

  void reload<S>({String? tag, String? key, bool force = false}) {
    final newKey = key ?? _getKey(S, tag);

    final builder = _getDependency<S>(tag: tag, key: newKey);
    if (builder == null) return;

    if (builder.permanent && !force) {
      Get.log(
        '''Instance "$newKey" is permanent. Use [force = true] to force the restart.''',
        isError: true,
      );
      return;
    }

    final i = builder.dependency;

    if (i is GetxServiceMixin && !force) {
      return;
    }

    if (i is GetLifeCycleBase) {
      i.onDelete();
      Get.log('"$newKey" onDelete() called');
    }

    builder.dependency = null;
    builder.isInit = false;
    Get.log('Instance "$newKey" was restarted.');
  }

  /// Check if a Class Instance<[S]> (or [tag]) is registered in memory.
  /// - [tag] is optional, if you used a [tag] to register the Instance.
  bool isRegistered<S>({String? tag}) => _singl.containsKey(_getKey(S, tag));

  /// Checks if a lazy factory callback `Get.lazyPut()` that returns an
  /// Instance<[S]> is registered in memory.
  /// - [tag] is optional, if you used a [tag] to register the lazy Instance.
  bool isPrepared<S>({String? tag}) {
    final newKey = _getKey(S, tag);

    final builder = _getDependency<S>(tag: tag, key: newKey);
    if (builder == null) {
      return false;
    }

    if (!builder.isInit) {
      return true;
    }
    return false;
  }
}

typedef InstanceBuilderCallback<S> = S Function();

typedef InjectorBuilderCallback<S> = S Function(GetInstance);

typedef AsyncInstanceBuilderCallback<S> = Future<S> Function();

/// Internal class to register instances with `Get.put<S>()`.
class _InstanceBuilderFactory<S> {
  /// Marks the Builder as a single instance.
  /// For reusing [dependency] instead of [builderFunc]
  bool? isSingleton;

  /// When fenix mode is avaliable, when a new instance is need
  /// Instance manager will recreate a new instance of S
  bool fenix;

  /// Stores the actual object instance when [isSingleton]=true.
  S? dependency;

  /// Generates (and regenerates) the instance when [isSingleton]=false.
  /// Usually used by factory methods
  InstanceBuilderCallback<S> builderFunc;

  /// Flag to persist the instance in memory,
  /// without considering `Get.smartManagement`
  bool permanent = false;

  bool isInit = false;

  String? tag;

  _InstanceBuilderFactory(
    this.isSingleton,
    this.builderFunc,
    this.permanent,
    this.isInit,
    this.fenix,
    this.tag,
  );

  void _showInitLog() {
    if (tag == null) {
      Get.log('Instance "$S" has been created');
    } else {
      Get.log('Instance "$S" has been created with tag "$tag"');
    }
  }

  /// Gets the actual instance by it's [builderFunc] or the persisted instance.
  S getDependency() {
    if (isSingleton!) {
      if (dependency == null) {
        _showInitLog();
        dependency = builderFunc();
      }
      return dependency!;
    } else {
      return builderFunc();
    }
  }
}