using UnityEngine;

namespace Klak.Spout {

//
// Spout receiver class (main implementation)
//
[ExecuteInEditMode]
[AddComponentMenu("Klak/Spout/Spout Receiver")]
public sealed partial class SpoutReceiver : MonoBehaviour
{
    #region Receiver plugin object

    Receiver _receiver;

    void ReleaseReceiver()
    {
        _receiver?.Dispose();
        _receiver = null;
    }

    #endregion

    #region Buffer texture object

    RenderTexture _buffer;

    RenderTexture PrepareBuffer()
    {
        // Receive-to-Texture mode:
        // Destroy the internal buffer and return the target texture.
        if (_targetTexture != null)
        {
            if (_buffer != null)
            {
                Utility.Destroy(_buffer);
                _buffer = null;
            }
            return _targetTexture;
        }

        var src = _receiver.Texture;

        // If the buffer exists but has wrong dimensions, destroy it first.
        if (_buffer != null &&
            (_buffer.width != src.width || _buffer.height != src.height))
        {
            Utility.Destroy(_buffer);
            _buffer = null;
        }

        // Create a buffer if it hasn't been allocated yet.
        if (_buffer == null)
        {
            _buffer = new RenderTexture(src.width, src.height, 0);
            _buffer.hideFlags = HideFlags.DontSave;
            _buffer.Create();
        }

        return _buffer;
    }

    #endregion

    #region MonoBehaviour implementation

    void OnDisable()
      => ReleaseReceiver();

    void OnDestroy()
    {
        Utility.Destroy(_buffer);
        _buffer = null;
    }

    void Update()
    {
        // Receiver lazy initialization
        if (_receiver == null)
            _receiver = new Receiver(_sourceName);

        // Receiver plugin-side update
        _receiver.Update();

        // Do nothing further if no texture is ready yet.
        if (_receiver.Texture == null) return;

        // Received texture buffering
        var buffer = PrepareBuffer();
        Blitter.BlitFromSrgb(_resources, _receiver.Texture, buffer);

        // Renderer override
        if (_targetRenderer != null)
            RendererOverride.SetTexture
              (_targetRenderer, _targetMaterialProperty, buffer);
    }

    #endregion
}

} // namespace Klak.Spout