#include "ShaderLoader.h"
#include <fstream>

std::vector<VkShaderModule> ShaderLoader::loadShaders(
    VkDevice device, QVulkanDeviceFunctions *deviceFunctions,
    std::string const *shaderFilenames, std::size_t shaderFilenameCount) {
  loadedShaders.reserve(loadedShaders.size() + shaderFilenameCount);
  for (int i = 0; i < shaderFilenameCount; ++i) {
    std::ifstream shaderFile(shaderFilenames[i],
                             std::ios::ate | std::ios::binary);
    if (!shaderFile.is_open()) {
      qFatal("Could not open shader file %s", shaderFilenames[i].c_str());
    }
    // std::ios::ate starts at the end of file => position is the file size
    const std::fpos<mbstate_t> &fileSize = shaderFile.tellg();
    std::vector<uint32_t> buffer((fileSize / sizeof(uint32_t)) + 1);
    shaderFile.seekg(0);
    shaderFile.read(reinterpret_cast<char *>(buffer.data()), fileSize);
    shaderFile.close();

    VkShaderModuleCreateInfo createInfo{};
    createInfo.sType = VK_STRUCTURE_TYPE_SHADER_MODULE_CREATE_INFO;
    createInfo.codeSize = fileSize;
    createInfo.pCode = buffer.data();
    VkShaderModule shaderModule;
    VkResult result = deviceFunctions->vkCreateShaderModule(
        device, &createInfo, nullptr, &shaderModule);
    if (result != VK_SUCCESS) {
      qFatal("Could not create shader module: code %d", result);
    }
    loadedShaders.push_back(shaderModule);
  }
  return loadedShaders;
}

void ShaderLoader::destroyShaders(VkDevice device,
                                  QVulkanDeviceFunctions *devFuncs) {
  for (auto &shaderModule : loadedShaders) {
    devFuncs->vkDestroyShaderModule(device, shaderModule, nullptr);
  }
}