// Copyright (c) 2023 Dominic Masters
// 
// This software is released under the MIT License.
// https://opensource.org/licenses/MIT

#pragma once
#include "dawnopenal.hpp"
#include "scene/SceneItemComponent.hpp"
#include "asset/assets/AudioAsset.hpp"

#define AUDIO_SOURCE_BUFFER_COUNT 3
#define AUDIO_SOURCE_BUFFER_SIZE 8192

namespace Dawn {
  enum AudioSourceState {
    AUDIO_SOURCE_STATE_STOPPED,
    AUDIO_SOURCE_STATE_PLAYING,
    AUDIO_SOURCE_STATE_PAUSED
  };

  enum AudioSourcePlayMode {
    AUDIO_PLAY_MODE_ALWAYS,
    AUDIO_PLAY_MODE_UNPAUSED
  };

  class AudioSource : public SceneItemComponent {
    private:
      ALuint source;
      bool_t ready = false;
      ALuint buffers[AUDIO_SOURCE_BUFFER_COUNT];
      size_t bufferPosition = 0;

      // Settings
      enum AudioSourceState internalState = AUDIO_SOURCE_STATE_STOPPED;
      int32_t layer = 0;
      AudioAsset *data = nullptr;

      /**
       * Internally update the audio's state based on the current settings.
       */
      void updateAudioSource();

      void fillBuffer(ALuint buffer);
      void detatchBuffers();
      void attachBuffers();

      // Events
      void onSceneUpdate();

    public:
      bool_t loop = false;
      enum AudioSourceState state = AUDIO_SOURCE_STATE_STOPPED;
      AudioSourcePlayMode playMode;

      Event<> eventPlaying;
      Event<> eventResumed;
      Event<> eventPaused;
      Event<> eventStopped;
      Event<> eventFinished;
      Event<> eventLooped;

      /**
       * Creates an Audio Source item component.
       * 
       * @param item SceneItem that this audio source is attached to.
       */
      AudioSource(SceneItem *item);

      /**
       * Returns the real current state of the sound. Refer to getPlayingState
       * but basically the actually requested play state and what the hardware
       * and internal logic is doing may result in the actual state being a 
       * little different. You cannot control this, but you can read it.
       * 
       * @return The actual current playing state.
       */
      AudioSourceState getRealState();

      /**
       * Rewinds the audio source. At the time of writing this comment (23017) I
       * am unsure of the behaviour when rewinding whilst the source is active.
       */
      void rewind();

      /**
       * Returns the current audio data for this source.
       * 
       * @return Audio data that is atached to this source.
       */
      AudioAsset * getAudioData();

      /**
       * Sets the audio data for this source. Currently switching between the
       * audio data during playback may have undefined behavior.
       * 
       * @param data Data to set.
       */
      void setAudioData(AudioAsset *data);

      /**
       * Stop playing this audio source. Shorthand for setting the state.
       */
      void stop();

      /**
       * Play this audio source. Shorthand for state setting.
       */
      void play();

      /**
       * Pause this audio source. Shorthand for state setting.
       */
      void pause();

      void onStart() override;
      void onDispose() override;
  };
}