using Godot;
 
namespace Rokojori;

[Tool]
[GlobalClass] 
public partial class MusicChannelPlayer:Node
{
  [Export]
  public MusicChannel channel;

  [Export]
  public MusicData currentMusic;

  [Export]
  public AudioStreamPlayer currentPlayer;


  public void TweenVolume( AudioStreamPlayer target, float duration, float toVolume, bool clear, System.Action onReady = null )
  {
    var tl = TimeLineManager.Ensure( null );
    var start = tl.position;
    var fromVolume = target.VolumeLinear;

    TimeLineManager.ScheduleSpanIn( tl, 0, duration, 
      ( span, type )=>
      {         
        if ( ! GodotObject.IsInstanceValid( target ) )
        {
          return;
        }

        var lerpedVolume = Mathf.Lerp( fromVolume, toVolume, span.phase );
        target.VolumeLinear = lerpedVolume;

        if ( type == TimeLineSpanUpdateType.End && clear )
        {
          if ( clear )
          {
            ClearAudioPlayer( target );
          }

          if ( onReady != null )
          {
            onReady();
          }
         
        }

      },
      this
    );
  }

  async void ClearAudioPlayer( AudioStreamPlayer target )
  {
    await this.RequestNextFrame();
    target.DeleteSelf();
  }

  public void SchedulePlayer( MusicData nextMusic, float duration, System.Action onReady )
  {
    if ( currentMusic != null )
    {
      this.LogInfo( "Muting:", currentMusic );
      TweenVolume( currentPlayer, duration, 0f, true );
      currentMusic = null;
      currentPlayer = null;
    }

    this.LogInfo( "Playing:", nextMusic );

    var name = FilePath.Absolute( nextMusic.audio.ResourcePath ).fileName;
    var nextPlayer = this.CreateChild<AudioStreamPlayer>( "Player " + name );
    nextPlayer.VolumeLinear = 0f;
    nextPlayer.Stream = nextMusic.audio;
    nextPlayer.PitchScale = MathAudio.SemitonesToFrequencyScaler( nextMusic.pitchSemitonesOffset );
    nextPlayer.Bus = channel.audioBus;
   
    currentMusic = nextMusic;
    currentPlayer = nextPlayer;
    TweenVolume( nextPlayer, duration, nextMusic.volume, false, onReady );

    nextPlayer.Play();
  }

}