#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);
    assert(shaderFile.is_open());
    // std::ios::ate starts at the end of file => position is the file size
    const std::fpos<mbstate_t> &fileSize = shaderFile.tellg();
    std::vector<char> buffer(fileSize);
    shaderFile.seekg(0);
    shaderFile.read(buffer.data(), fileSize);
    shaderFile.close();

    VkShaderModuleCreateInfo createInfo{};
    createInfo.sType = VK_STRUCTURE_TYPE_SHADER_MODULE_CREATE_INFO;
    createInfo.codeSize = buffer.size();
    createInfo.pCode = reinterpret_cast<const uint32_t *>(buffer.data());
    VkShaderModule shaderModule;
    VkResult result = deviceFunctions->vkCreateShaderModule(
        device, &createInfo, nullptr, &shaderModule);
    assert(result == VK_SUCCESS);
    loadedShaders.push_back(shaderModule);
  }
  return loadedShaders;
}

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