import 'dart:async';
import 'dart:io';

import 'package:appflowy/env/cloud_env.dart';
import 'package:appflowy/startup/tasks/feature_flag_task.dart';
import 'package:appflowy/workspace/application/settings/prelude.dart';
import 'package:appflowy_backend/appflowy_backend.dart';
import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:get_it/get_it.dart';
import 'package:package_info_plus/package_info_plus.dart';

import 'deps_resolver.dart';
import 'entry_point.dart';
import 'launch_configuration.dart';
import 'plugin/plugin.dart';
import 'tasks/prelude.dart';

final getIt = GetIt.instance;

abstract class EntryPoint {
  Widget create(LaunchConfiguration config);
}

class FlowyRunnerContext {
  FlowyRunnerContext({required this.applicationDataDirectory});

  final Directory applicationDataDirectory;
}

Future<void> runAppFlowy({bool isAnon = false}) async {
  if (kReleaseMode) {
    await FlowyRunner.run(
      AppFlowyApplication(),
      integrationMode(),
      isAnon: isAnon,
    );
  } else {
    // When running the app in integration test mode, we need to
    // specify the mode to run the app again.
    await FlowyRunner.run(
      AppFlowyApplication(),
      FlowyRunner.currentMode,
      didInitGetItCallback: IntegrationTestHelper.didInitGetItCallback,
      rustEnvsBuilder: IntegrationTestHelper.rustEnvsBuilder,
      isAnon: isAnon,
    );
  }
}

class FlowyRunner {
  // This variable specifies the initial mode of the app when it is launched for the first time.
  // The same mode will be automatically applied in subsequent executions when the runAppFlowy()
  // method is called.
  static var currentMode = integrationMode();

  static Future<FlowyRunnerContext> run(
    EntryPoint f,
    IntegrationMode mode, {
    // This callback is triggered after the initialization of 'getIt',
    // which is used for dependency injection throughout the app.
    // If your functionality depends on 'getIt', ensure to register
    // your callback here to execute any necessary actions post-initialization.
    Future Function()? didInitGetItCallback,
    // Passing the envs to the backend
    Map<String, String> Function()? rustEnvsBuilder,
    // Indicate whether the app is running in anonymous mode.
    // Note: when the app is running in anonymous mode, the user no need to
    // sign in, and the app will only save the data in the local storage.
    bool isAnon = false,
  }) async {
    currentMode = mode;

    // Only set the mode when it's not release mode
    if (!kReleaseMode) {
      IntegrationTestHelper.didInitGetItCallback = didInitGetItCallback;
      IntegrationTestHelper.rustEnvsBuilder = rustEnvsBuilder;
    }

    // Clear and dispose tasks from previous AppLaunch
    if (getIt.isRegistered(instance: AppLauncher)) {
      await getIt<AppLauncher>().dispose();
    }

    // Clear all the states in case of rebuilding.
    await getIt.reset();

    final config = LaunchConfiguration(
      isAnon: isAnon,
      // Unit test can't use the package_info_plus plugin
      version: mode.isUnitTest
          ? '1.0.0'
          : await PackageInfo.fromPlatform().then((value) => value.version),
      rustEnvs: rustEnvsBuilder?.call() ?? {},
    );

    // Specify the env
    await initGetIt(getIt, mode, f, config);
    await didInitGetItCallback?.call();

    final applicationDataDirectory =
        await getIt<ApplicationDataStorage>().getPath().then(
              (value) => Directory(value),
            );

    // add task
    final launcher = getIt<AppLauncher>();
    launcher.addTasks(
      [
        // this task should be first task, for handling platform errors.
        // don't catch errors in test mode
        if (!mode.isUnitTest) const PlatformErrorCatcherTask(),
        // this task should be second task, for handling memory leak.
        // there's a flag named _enable in memory_leak_detector.dart. If it's false, the task will be ignored.
        MemoryLeakDetectorTask(),
        const DebugTask(),
        const FeatureFlagTask(),

        // localization
        const InitLocalizationTask(),
        // init the app window
        InitAppWindowTask(),
        // Init Rust SDK
        InitRustSDKTask(customApplicationPath: applicationDataDirectory),
        // Load Plugins, like document, grid ...
        const PluginLoadTask(),

        // init the app widget
        // ignore in test mode
        if (!mode.isUnitTest) ...[
          // The DeviceOrApplicationInfoTask should be placed before the AppWidgetTask to fetch the app information.
          // It is unable to get the device information from the test environment.
          const ApplicationInfoTask(),
          const HotKeyTask(),
          if (isSupabaseEnabled) InitSupabaseTask(),
          if (isAppFlowyCloudEnabled) InitAppFlowyCloudTask(),
          const InitAppWidgetTask(),
          const InitPlatformServiceTask(),
          const RecentServiceTask(),
        ],
      ],
    );
    await launcher.launch(); // execute the tasks

    return FlowyRunnerContext(
      applicationDataDirectory: applicationDataDirectory,
    );
  }
}

Future<void> initGetIt(
  GetIt getIt,
  IntegrationMode mode,
  EntryPoint f,
  LaunchConfiguration config,
) async {
  getIt.registerFactory<EntryPoint>(() => f);
  getIt.registerLazySingleton<FlowySDK>(
    () {
      return FlowySDK();
    },
    dispose: (sdk) async {
      await sdk.dispose();
    },
  );
  getIt.registerLazySingleton<AppLauncher>(
    () => AppLauncher(
      context: LaunchContext(
        getIt,
        mode,
        config,
      ),
    ),
    dispose: (launcher) async {
      await launcher.dispose();
    },
  );
  getIt.registerSingleton<PluginSandbox>(PluginSandbox());

  await DependencyResolver.resolve(getIt, mode);
}

class LaunchContext {
  LaunchContext(this.getIt, this.env, this.config);

  GetIt getIt;
  IntegrationMode env;
  LaunchConfiguration config;
}

enum LaunchTaskType {
  dataProcessing,
  appLauncher,
}

/// The interface of an app launch task, which will trigger
/// some nonresident indispensable task in app launching task.
abstract class LaunchTask {
  const LaunchTask();

  LaunchTaskType get type => LaunchTaskType.dataProcessing;

  Future<void> initialize(LaunchContext context);
  Future<void> dispose();
}

class AppLauncher {
  AppLauncher({
    required this.context,
  });

  final LaunchContext context;
  final List<LaunchTask> tasks = [];

  void addTask(LaunchTask task) {
    tasks.add(task);
  }

  void addTasks(Iterable<LaunchTask> tasks) {
    this.tasks.addAll(tasks);
  }

  Future<void> launch() async {
    for (final task in tasks) {
      await task.initialize(context);
    }
  }

  Future<void> dispose() async {
    for (final task in tasks) {
      await task.dispose();
    }
    tasks.clear();
  }
}

enum IntegrationMode {
  develop,
  release,
  unitTest,
  integrationTest;

  // test mode
  bool get isTest => isUnitTest || isIntegrationTest;
  bool get isUnitTest => this == IntegrationMode.unitTest;
  bool get isIntegrationTest => this == IntegrationMode.integrationTest;

  // release mode
  bool get isRelease => this == IntegrationMode.release;

  // develop mode
  bool get isDevelop => this == IntegrationMode.develop;
}

IntegrationMode integrationMode() {
  if (Platform.environment.containsKey('FLUTTER_TEST')) {
    return IntegrationMode.unitTest;
  }

  if (kReleaseMode) {
    return IntegrationMode.release;
  }

  return IntegrationMode.develop;
}

/// Only used for integration test
class IntegrationTestHelper {
  static Future Function()? didInitGetItCallback;
  static Map<String, String> Function()? rustEnvsBuilder;
}