/*
 * Strawberry Music Player
 * This file was part of Amarok / Clementine
 * Copyright 2003 Mark Kretschmann
 * Copyright 2004 - 2005 Max Howell, <max.howell@methylblue.com>
 * Copyright 2010 David Sansome <me@davidsansome.com>
 * Copyright 2017-2021 Jonas Kvinge <jonas@jkvinge.net>
 *
 * Strawberry 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.
 *
 * Strawberry 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with Strawberry.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

#ifndef ENGINEBASE_H
#define ENGINEBASE_H

#include "config.h"

#include <sys/types.h>
#include <cstdint>
#include <vector>

#include <QtGlobal>
#include <QObject>
#include <QList>
#include <QMetaType>
#include <QVariant>
#include <QString>
#include <QUrl>

#include "core/enginemetadata.h"
#include "core/song.h"

class EngineBase : public QObject {
  Q_OBJECT

 protected:
  explicit EngineBase(QObject *parent = nullptr);

 public:
  ~EngineBase() override;

  // State:
  // Playing when playing,
  // Paused when paused
  // Idle when you still have a URL loaded (ie you have not been told to stop())
  // Empty when you have been told to stop(),
  // Error when an error occurred and you stopped yourself
  //
  // It is vital to be Idle just after the track has ended!

  enum class State {
    Empty,
    Idle,
    Playing,
    Paused,
    Error
  };

  enum class TrackChangeType {
    // One of:
    First = 0x01,
    Manual = 0x02,
    Auto = 0x04,
    Intro = 0x08,

    // Any of:
    SameAlbum = 0x10
  };
  Q_DECLARE_FLAGS(TrackChangeFlags, TrackChangeType)

  struct OutputDetails {
    QString name;
    QString description;
    QString iconname;
  };
  using OutputDetailsList = QList<OutputDetails>;

  using Scope = std::vector<int16_t>;

  virtual bool Init() = 0;
  virtual State state() const = 0;
  virtual void StartPreloading(const QUrl &media_url, const QUrl &stream_url, const bool force_stop_at_end, const qint64 beginning_offset_nanosec, const qint64 end_offset_nanosec);
  virtual bool Load(const QUrl &media_url, const QUrl &stream_url, const TrackChangeFlags track_change_flags, const bool force_stop_at_end, const quint64 beginning_offset_nanosec, const qint64 end_offset_nanosec, const std::optional<double> ebur128_integrated_loudness_lufs);
  virtual bool Play(const bool pause, const quint64 offset_nanosec) = 0;
  virtual void Stop(const bool stop_after = false) = 0;
  virtual void Pause() = 0;
  virtual void Unpause() = 0;
  virtual void Seek(const quint64 offset_nanosec) = 0;
  virtual void SetVolumeSW(const uint percent) = 0;

  virtual qint64 position_nanosec() const = 0;
  virtual qint64 length_nanosec() const = 0;

  virtual const Scope &scope(const int chunk_length) { Q_UNUSED(chunk_length); return scope_; }

  // Sets new values for the beginning and end markers of the currently playing song.
  // This doesn't change the state of engine or the stream's current position.
  virtual void RefreshMarkers(const quint64 beginning_offset_nanosec, const qint64 end_offset_nanosec) {
    beginning_offset_nanosec_ = beginning_offset_nanosec;
    end_offset_nanosec_ = end_offset_nanosec;
  }

  virtual OutputDetailsList GetOutputsList() const = 0;
  virtual bool ValidOutput(const QString &output) = 0;
  virtual QString DefaultOutput() const = 0;
  virtual bool CustomDeviceSupport(const QString &output) const = 0;
  virtual bool ALSADeviceSupport(const QString &output) const = 0;
  virtual bool ExclusiveModeSupport(const QString &output) const = 0;

  // Plays a media stream represented with the URL 'u' from the given 'beginning' to the given 'end' (usually from 0 to a song's length).
  // Both markers should be passed in nanoseconds. 'end' can be negative, indicating that the real length of 'u' stream is unknown.
  bool Play(const QUrl &media_url, const QUrl &stream_url, const bool pause, const TrackChangeFlags flags, const bool force_stop_at_end, const quint64 beginning_offset_nanosec, const qint64 end_offset_nanosec, const quint64 offset_nanosec, const std::optional<double> ebur128_integrated_loudness_lufs);
  void SetVolume(const uint volume);

 public Q_SLOTS:
  virtual void ReloadSettings();
  void UpdateVolume(const uint volume);
  void EmitAboutToFinish();
  void UpdateSpotifyAccessToken(const QString &spotify_access_token);

 public:
  // Simple accessors
  bool volume_control() const { return volume_control_; }
  bool volume_exponential() const { return volume_exponential_; }
  inline uint volume() const { return volume_; }

  bool is_fadeout_enabled() const { return fadeout_enabled_; }
  bool is_crossfade_enabled() const { return crossfade_enabled_; }
  bool is_autocrossfade_enabled() const { return autocrossfade_enabled_; }
  bool crossfade_same_album() const { return crossfade_same_album_; }
  bool IsEqualizerEnabled() const { return equalizer_enabled_; }

  static const int kScopeSize = 1024;

  QVariant device() { return device_; }

 public Q_SLOTS:
  virtual void SetStereoBalancerEnabled(const bool enabled) { Q_UNUSED(enabled) }
  virtual void SetStereoBalance(const float value) { Q_UNUSED(value) }
  virtual void SetEqualizerEnabled(const bool enabled) { Q_UNUSED(enabled) }
  virtual void SetEqualizerParameters(const int preamp, const QList<int> &band_gains) { Q_UNUSED(preamp) Q_UNUSED(band_gains) }

 Q_SIGNALS:
  // Emitted when crossfading is enabled and the track is crossfade_duration_ away from finishing
  void TrackAboutToEnd();

  void TrackEnded();

  void StatusText(const QString &text);
  void Error(const QString &text);

  // Emitted when there was a fatal error
  void FatalError();
  // Emitted when Engine was unable to play a song with the given QUrl.
  void InvalidSongRequested(const QUrl &url);
  // Emitted when Engine successfully started playing a song with the given QUrl.
  void ValidSongRequested(const QUrl &url);

  void MetaData(const EngineMetadata &metadata);

  // Signals that the engine's state has changed (a stream was stopped for example).
  // Always use the state from event, because it's not guaranteed that immediate subsequent call to state() won't return a stale value.
  void StateChanged(const EngineBase::State state);

  void VolumeChanged(const uint volume);

  void Finished();

 private:
#ifdef HAVE_SPOTIFY
  virtual void SetSpotifyAccessToken() {}
#endif

 protected:
  bool playbin3_enabled_;
  bool exclusive_mode_;
  bool volume_control_;
  bool volume_exponential_;
  uint volume_;
  quint64 beginning_offset_nanosec_;
  qint64 end_offset_nanosec_;
  QUrl media_url_;
  QUrl stream_url_;
  double ebur128_loudness_normalizing_gain_db_;
  Scope scope_;
  bool buffering_;
  bool equalizer_enabled_;

  // Settings
  QString output_;
  QVariant device_;

  // ReplayGain
  bool rg_enabled_;
  int rg_mode_;
  double rg_preamp_;
  double rg_fallbackgain_;
  bool rg_compression_;

  // EBU R 128 Loudness Normalization
  bool ebur128_loudness_normalization_;
  double ebur128_target_level_lufs_;

  // Buffering
  quint64 buffer_duration_nanosec_;
  double buffer_low_watermark_;
  double buffer_high_watermark_;

  // Audio device (DAC) warm-up delay in milliseconds inserted between preroll (PAUSED) and playback (PLAYING) to give the device time to become ready, avoiding the start of the track being cut off.
  int device_warmup_duration_ms_;

  // Fadeout
  bool fadeout_enabled_;
  bool crossfade_enabled_;
  bool autocrossfade_enabled_;
  bool crossfade_same_album_;
  bool fadeout_pause_enabled_;
  qint64 fadeout_duration_;
  qint64 fadeout_duration_nanosec_;
  qint64 fadeout_pause_duration_;
  qint64 fadeout_pause_duration_nanosec_;

  // Proxy
  QString proxy_address_;
  bool proxy_authentication_;
  QString proxy_user_;
  QString proxy_pass_;

  // Channels
  bool channels_enabled_;
  int channels_;

  // Options
  bool bs2b_enabled_;
  bool http2_enabled_;
  bool strict_ssl_enabled_;

  // Spotify
#ifdef HAVE_SPOTIFY
  QString spotify_access_token_;
#endif

  bool about_to_end_emitted_;

  Q_DISABLE_COPY(EngineBase)
};

Q_DECLARE_METATYPE(EngineBase::State)
Q_DECLARE_METATYPE(EngineBase::TrackChangeType)
Q_DECLARE_METATYPE(EngineBase::OutputDetails)
Q_DECLARE_OPERATORS_FOR_FLAGS(EngineBase::TrackChangeFlags)

#endif  // ENGINEBASE_H
