//
// This file is part of Kepka,
// an unofficial desktop version of Telegram messaging app,
// see https://github.com/procxx/kepka
//
// Kepka is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// It is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// In addition, as a special exception, the copyright holders give permission
// to link the code of portions of this program with the OpenSSL library.
//
// Full license: https://github.com/procxx/kepka/blob/master/LICENSE
// Copyright (c) 2014-2017 John Preston, https://desktop.telegram.org
// Copyright (c) 2017- Kepka Contributors, https://github.com/procxx
//
#pragma once

#include "base/observer.h"
#include "history/history.h"
#include "structs.h"

namespace Notify {
struct PeerUpdate;
} // namespace Notify
class AudioMsgId;

namespace Media {
namespace Player {

void start();
void finish();

class Instance;
Instance *instance();

struct TrackState;

class Instance : private base::Subscriber {
public:
	void play(AudioMsgId::Type type);
	void pause(AudioMsgId::Type type);
	void stop(AudioMsgId::Type type);
	void playPause(AudioMsgId::Type type);
	bool next(AudioMsgId::Type type);
	bool previous(AudioMsgId::Type type);

	AudioMsgId::Type getActiveType() const;

	void play() {
		play(getActiveType());
	}
	void pause() {
		pause(getActiveType());
	}
	void stop() {
		stop(getActiveType());
	}
	void playPause() {
		playPause(getActiveType());
	}
	bool next() {
		return next(getActiveType());
	}
	bool previous() {
		return previous(getActiveType());
	}

	void playPauseCancelClicked(AudioMsgId::Type type);

	void play(const AudioMsgId &audioId);
	AudioMsgId current(AudioMsgId::Type type) const {
		if (auto data = getData(type)) {
			return data->current;
		}
		return AudioMsgId();
	}

	bool repeatEnabled(AudioMsgId::Type type) const {
		if (auto data = getData(type)) {
			return data->repeatEnabled;
		}
		return false;
	}
	void toggleRepeat(AudioMsgId::Type type) {
		if (auto data = getData(type)) {
			data->repeatEnabled = !data->repeatEnabled;
			_repeatChangedNotifier.notify(type);
		}
	}

	bool isSeeking(AudioMsgId::Type type) const {
		if (auto data = getData(type)) {
			return (data->seeking == data->current);
		}
		return false;
	}
	void startSeeking(AudioMsgId::Type type);
	void stopSeeking(AudioMsgId::Type type);

	QList<FullMsgId> playlist(AudioMsgId::Type type) const {
		if (auto data = getData(type)) {
			return data->playlist;
		}
		return QList<FullMsgId>();
	}

	struct Switch {
		AudioMsgId from;
		FullMsgId to;
	};

	base::Observable<Switch> &switchToNextNotifier() {
		return _switchToNextNotifier;
	}
	base::Observable<bool> &usePanelPlayer() {
		return _usePanelPlayer;
	}
	base::Observable<bool> &titleButtonOver() {
		return _titleButtonOver;
	}
	base::Observable<bool> &playerWidgetOver() {
		return _playerWidgetOver;
	}
	base::Observable<TrackState> &updatedNotifier() {
		return _updatedNotifier;
	}
	base::Observable<AudioMsgId::Type> &tracksFinishedNotifier() {
		return _tracksFinishedNotifier;
	}
	base::Observable<AudioMsgId::Type> &playlistChangedNotifier() {
		return _playlistChangedNotifier;
	}
	base::Observable<AudioMsgId::Type> &trackChangedNotifier() {
		return _trackChangedNotifier;
	}
	base::Observable<AudioMsgId::Type> &repeatChangedNotifier() {
		return _repeatChangedNotifier;
	}

	void documentLoadProgress(DocumentData *document);

	void clear();

private:
	Instance();
	friend void start();

	struct Data {
		Data(AudioMsgId::Type type, MediaOverviewType overview)
		    : type(type)
		    , overview(overview) {}

		AudioMsgId::Type type;
		MediaOverviewType overview;
		AudioMsgId current;
		AudioMsgId seeking;
		History *history = nullptr;
		History *migrated = nullptr;
		bool repeatEnabled = false;
		QList<FullMsgId> playlist;
		bool isPlaying = false;
	};

	// Observed notifications.
	void notifyPeerUpdated(const Notify::PeerUpdate &update);
	void handleSongUpdate(const AudioMsgId &audioId);

	void checkPeerUpdate(AudioMsgId::Type type, const Notify::PeerUpdate &update);
	void setCurrent(const AudioMsgId &audioId);
	void rebuildPlaylist(Data *data);
	bool moveInPlaylist(Data *data, int delta, bool autonext);
	void preloadNext(Data *data);
	void handleLogout();

	template <typename CheckCallback> void emitUpdate(AudioMsgId::Type type, CheckCallback check);

	Data *getData(AudioMsgId::Type type) {
		if (type == AudioMsgId::Type::Song) {
			return &_songData;
		} else if (type == AudioMsgId::Type::Voice) {
			return &_voiceData;
		}
		return nullptr;
	}

	const Data *getData(AudioMsgId::Type type) const {
		if (type == AudioMsgId::Type::Song) {
			return &_songData;
		} else if (type == AudioMsgId::Type::Voice) {
			return &_voiceData;
		}
		return nullptr;
	}

	Data _songData;
	Data _voiceData;

	base::Observable<Switch> _switchToNextNotifier;
	base::Observable<bool> _usePanelPlayer;
	base::Observable<bool> _titleButtonOver;
	base::Observable<bool> _playerWidgetOver;
	base::Observable<TrackState> _updatedNotifier;
	base::Observable<AudioMsgId::Type> _tracksFinishedNotifier;
	base::Observable<AudioMsgId::Type> _playlistChangedNotifier;
	base::Observable<AudioMsgId::Type> _trackChangedNotifier;
	base::Observable<AudioMsgId::Type> _repeatChangedNotifier;
};

} // namespace Player
} // namespace Media