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

#pragma once
#include "display/shader/Shader.hpp"

namespace Dawn {
  class ShaderManager {
    private:
      std::vector<std::shared_ptr<ShaderBase>> shaders;

    public:
      /**
       * Retreives an instance of the shader from the shader manager. If the
       * shader does not exist it will be created.
       * 
       * @tparam T Type of shader to retreive.
       * @return Shader instance.
       */
      template<class T>
      std::shared_ptr<T> getShader() {
        auto itShaders = shaders.begin();
        while(itShaders != shaders.end()) {
          // auto shader = itShaders->lock();
          // if(!shader) {
          //   itShaders = shaders.erase(itShaders);
          //   continue;
          // }
          // std::shared_ptr<T> casted = std::dynamic_pointer_cast<T>(shader);

          auto shader = *itShaders;
          std::shared_ptr<T> casted = std::dynamic_pointer_cast<T>(shader);
          if(casted) return casted;
          itShaders++;
        }

        auto newShader = std::make_shared<T>();
        shaders.push_back(newShader);
        newShader->init();
        return newShader;
      }
  };
}