#include "simple_render_system.hpp"

#include <stdexcept>
#include <array>

#define GLM_FORCE_RADIANS
#define GLM_FORCE_DEPTH_ZERO_TO_ONE
#include <glm/glm.hpp>
#include <glm/gtc/constants.hpp>

namespace cve {
  struct SimplePushConstantData{
    glm::mat2 transform{1.f}; // Identity matrix
    glm::vec2 offset;
    alignas(16) glm::vec3 color;
  };

  SimpleRenderSystem::SimpleRenderSystem(CveDevice& device, VkRenderPass renderPass): 
  cveDevice{device} {
    createPipelineLayout();
    createPipeline(renderPass);
  }

  SimpleRenderSystem::~SimpleRenderSystem() {
    vkDestroyPipelineLayout(cveDevice.device(), pipelineLayout, nullptr);
  }

  void SimpleRenderSystem::createPipelineLayout() {
    VkPushConstantRange pushConstantRange{};
    pushConstantRange.stageFlags = VK_SHADER_STAGE_VERTEX_BIT | VK_SHADER_STAGE_FRAGMENT_BIT;
    pushConstantRange.offset = 0;
    pushConstantRange.size = sizeof(SimplePushConstantData);
    
    VkPipelineLayoutCreateInfo pipelineLayoutInfo{};
    pipelineLayoutInfo.sType = VK_STRUCTURE_TYPE_PIPELINE_LAYOUT_CREATE_INFO;
    pipelineLayoutInfo.setLayoutCount = 0;
    pipelineLayoutInfo.pSetLayouts = nullptr;
    pipelineLayoutInfo.pushConstantRangeCount = 1;
    pipelineLayoutInfo.pPushConstantRanges = &pushConstantRange;
    if (vkCreatePipelineLayout(cveDevice.device(), &pipelineLayoutInfo, nullptr, &pipelineLayout) !=
        VK_SUCCESS) {
      throw std::runtime_error("Failed to create pipeline layout");
    }
  }

  void SimpleRenderSystem::createPipeline(VkRenderPass renderPass) {
    assert(pipelineLayout != nullptr && "Cannot create pipeline before pipeline layout");
    
    PipelineConfigInfo pipelineConfig{};
    CvePipeline::defaultPipelineConfigInfo(pipelineConfig);
    pipelineConfig.renderPass = renderPass;
    pipelineConfig.pipelineLayout = pipelineLayout;
    cvePipeline = std::make_unique<CvePipeline>(
      cveDevice,
      "shaders/simple_shader.vert.spv",
      "shaders/simple_shader.frag.spv",
      pipelineConfig
    );
  }

  void SimpleRenderSystem::renderGameObjects(VkCommandBuffer commandBuffer, std::vector<CveGameObject> &gameObjects) {
    cvePipeline->bind(commandBuffer);

    for (auto& obj: gameObjects) {
      obj.transform2d.rotation = glm::mod(obj.transform2d.rotation + 0.001f, glm::two_pi<float>());

      SimplePushConstantData push{}; 
      push.offset = obj.transform2d.translation;
      push.color = obj.color;
      push.transform = obj.transform2d.mat2();

      vkCmdPushConstants(
        commandBuffer, 
        pipelineLayout, 
        VK_SHADER_STAGE_VERTEX_BIT | VK_SHADER_STAGE_FRAGMENT_BIT, 
        0, 
        sizeof(SimplePushConstantData),
        &push
      );

      obj.model->bind(commandBuffer);
      obj.model->draw(commandBuffer);
    }
  }
}