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

#include "SimpleRenderTargetQuad.hpp"

using namespace Dawn;

SimpleRenderTargetQuad::SimpleRenderTargetQuad(SceneItem *i) :
  SceneItemComponent(i),
  renderTarget(nullptr)
{
}

std::vector<std::shared_ptr<SceneItemComponent>> SimpleRenderTargetQuad::getDependencies() {
  return {
    (this->meshHost = this->item->getComponent<MeshHost>())
  };
}

void SimpleRenderTargetQuad::onStart() {
  assertNotNull(this->meshHost, "SimpleRenderTargetQuad::onStart: MeshHost cannot be null");

  // Create quad mesh
  this->meshHost->mesh.createBuffers(QUAD_VERTICE_COUNT, QUAD_INDICE_COUNT);
  
  // Create teardown effect and keep track.
  auto initial = useEffectWithTeardown([&]{
    // No teardown needed.
    if(this->renderTarget == nullptr) return evtResized = [&]{ };

    // Update mesh
    QuadMesh::bufferQuadMesh(
      &this->meshHost->mesh,
      glm::vec2(0, 0), glm::vec2(0, 0),
      glm::vec2(
        ((RenderTarget*)this->renderTarget)->getWidth(),
        ((RenderTarget*)this->renderTarget)->getHeight()
      ),
      glm::vec2(1, 1),
      0, 0
    );

    // Subscribe to resize event.
    evtResized = useEvent([&](
      RenderTarget &target,
      const float_t w,
      const float_t h
    ) {
      QuadMesh::bufferQuadMesh(
        &this->meshHost->mesh,
        glm::vec2(0, 0), glm::vec2(0, 0),
        glm::vec2(w, h), glm::vec2(1, 1),
        0, 0
      );
    }, this->renderTarget->eventRenderTargetResized);

    // Teardown
    return evtResized;
  }, this->renderTarget);

  // Invoke immediate
  initial();
}