// Copyright 2017 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

import 'dart:async';
import 'dart:ui';

import 'package:flutter/widgets.dart';
import 'package:meta/meta.dart' show required, visibleForTesting;

import 'method_channel_video_player.dart';

/// The interface that implementations of video_player must implement.
///
/// Platform implementations should extend this class rather than implement it as `video_player`
/// does not consider newly added methods to be breaking changes. Extending this class
/// (using `extends`) ensures that the subclass will get the default implementation, while
/// platform implementations that `implements` this interface will be broken by newly added
/// [VideoPlayerPlatform] methods.
abstract class VideoPlayerPlatform {
  /// Only mock implementations should set this to true.
  ///
  /// Mockito mocks are implementing this class with `implements` which is forbidden for anything
  /// other than mocks (see class docs). This property provides a backdoor for mockito mocks to
  /// skip the verification that the class isn't implemented with `implements`.
  @visibleForTesting
  bool get isMock => false;

  /// The default instance of [VideoPlayerPlatform] to use.
  ///
  /// Platform-specific plugins should override this with their own
  /// platform-specific class that extends [VideoPlayerPlatform] when they
  /// register themselves.
  ///
  /// Defaults to [MethodChannelVideoPlayer].
  static VideoPlayerPlatform _instance = MethodChannelVideoPlayer();

  static VideoPlayerPlatform get instance => _instance;

  // TODO(amirh): Extract common platform interface logic.
  // https://github.com/flutter/flutter/issues/43368
  static set instance(VideoPlayerPlatform instance) {
    if (!instance.isMock) {
      try {
        instance._verifyProvidesDefaultImplementations();
      } on NoSuchMethodError catch (_) {
        throw AssertionError(
            'Platform interfaces must not be implemented with `implements`');
      }
    }
    _instance = instance;
  }

  /// Initializes the platform interface and disposes all existing players.
  ///
  /// This method is called when the plugin is first initialized
  /// and on every full restart.
  Future<void> init() {
    throw UnimplementedError('init() has not been implemented.');
  }

  /// Clears one video.
  Future<void> dispose(int textureId) {
    throw UnimplementedError('dispose() has not been implemented.');
  }

  /// Creates an instance of a video player and returns its textureId.
  Future<int> create(DataSource dataSource) {
    throw UnimplementedError('create() has not been implemented.');
  }

  /// Returns a Stream of [VideoEventType]s.
  Stream<VideoEvent> videoEventsFor(int textureId) {
    throw UnimplementedError('videoEventsFor() has not been implemented.');
  }

  /// Sets the looping attribute of the video.
  Future<void> setLooping(int textureId, bool looping) {
    throw UnimplementedError('setLooping() has not been implemented.');
  }

  /// Starts the video playback.
  Future<void> play(int textureId) {
    throw UnimplementedError('play() has not been implemented.');
  }

  /// Stops the video playback.
  Future<void> pause(int textureId) {
    throw UnimplementedError('pause() has not been implemented.');
  }

  /// Sets the volume to a range between 0.0 and 1.0.
  Future<void> setVolume(int textureId, double volume) {
    throw UnimplementedError('setVolume() has not been implemented.');
  }

  /// Sets the video position to a [Duration] from the start.
  Future<void> seekTo(int textureId, Duration position) {
    throw UnimplementedError('seekTo() has not been implemented.');
  }

  /// Gets the video position as [Duration] from the start.
  Future<Duration> getPosition(int textureId) {
    throw UnimplementedError('getPosition() has not been implemented.');
  }

  /// Returns a widget displaying the video with a given textureID.
  Widget buildView(int textureId) {
    throw UnimplementedError('buildView() has not been implemented.');
  }

  // This method makes sure that VideoPlayer isn't implemented with `implements`.
  //
  // See class doc for more details on why implementing this class is forbidden.
  //
  // This private method is called by the instance setter, which fails if the class is
  // implemented with `implements`.
  void _verifyProvidesDefaultImplementations() {}
}

class DataSource {
  DataSource({
    @required this.sourceType,
    this.uri,
    this.formatHint,
    this.asset,
    this.package,
  });

  final DataSourceType sourceType;
  final String uri;
  final VideoFormat formatHint;
  final String asset;
  final String package;
}

enum DataSourceType {
  asset,
  network,
  file,
}

enum VideoFormat {
  dash,
  hls,
  ss,
  other,
}

class VideoEvent {
  VideoEvent({
    @required this.eventType,
    this.duration,
    this.size,
    this.buffered,
  });

  final VideoEventType eventType;
  final Duration duration;
  final Size size;
  final List<DurationRange> buffered;
}

enum VideoEventType {
  initialized,
  completed,
  bufferingUpdate,
  bufferingStart,
  bufferingEnd,
  unknown,
}

class DurationRange {
  DurationRange(this.start, this.end);

  final Duration start;
  final Duration end;

  double startFraction(Duration duration) {
    return start.inMilliseconds / duration.inMilliseconds;
  }

  double endFraction(Duration duration) {
    return end.inMilliseconds / duration.inMilliseconds;
  }

  @override
  String toString() => '$runtimeType(start: $start, end: $end)';
}