#include "xe_pipeline.hpp"

#include "xe_model.hpp"

#include <cstdint>
#include <fstream>
#include <stdexcept>
#include <vector>
#include <iostream>
#include <vulkan/vulkan_core.h>
#include <assert.h>

namespace xe {

  Pipeline::Pipeline(
      Device &device, 
      const std::string& vertFilepath, 
      const std::string& fragFilepath, 
      const PipelineConfigInfo& configInfo) 
      : xeDevice{device} {
    createGraphicsPipeline(vertFilepath, fragFilepath, configInfo);
  }

  Pipeline::~Pipeline() {
    vkDestroyShaderModule(xeDevice.device(), vertShaderModule, nullptr);
    vkDestroyShaderModule(xeDevice.device(), fragShaderModule, nullptr);
    vkDestroyPipeline(xeDevice.device(), graphicsPipeline, nullptr);
  }

  std::vector<char> Pipeline::readFile(const std::string& filepath) {

    std::ifstream file{filepath, std::ios::ate | std::ios::binary};

    if (!file.is_open()) {
      throw std::runtime_error("faile to open file " + filepath);
    }

    size_t fileSize = static_cast<size_t>(file.tellg());
    std::vector<char> buffer(fileSize);

    file.seekg(0);
    file.read(buffer.data(), fileSize);

    file.close();
    return buffer;
  };

  void Pipeline::createGraphicsPipeline(
    const std::string& vertFilePath, 
    const std::string& fragFilepath,
    const PipelineConfigInfo& configInfo) {

    assert(
      configInfo.pipelineLayout != VK_NULL_HANDLE &&
      "Cannot create graphics pipeline:: no pipelineLayout provided in configInfo");
    assert(
      configInfo.renderPass != VK_NULL_HANDLE &&
      "Cannot create graphics pipeline:: no renderPass provided in configInfo");
    auto vertCode = readFile(vertFilePath);
    auto fragCode = readFile(fragFilepath);

    createShaderModule(vertCode, &vertShaderModule);
    createShaderModule(fragCode, &fragShaderModule);

    VkPipelineShaderStageCreateInfo shaderStages[2];
    shaderStages[0].sType = VK_STRUCTURE_TYPE_PIPELINE_SHADER_STAGE_CREATE_INFO;
    shaderStages[0].stage = VK_SHADER_STAGE_VERTEX_BIT;
    shaderStages[0]. module = vertShaderModule;
    shaderStages[0].pName = "main";
    shaderStages[0].flags = 0;
    shaderStages[0].pNext = nullptr;
    shaderStages[0].pSpecializationInfo = nullptr;
    shaderStages[1].sType = VK_STRUCTURE_TYPE_PIPELINE_SHADER_STAGE_CREATE_INFO;
    shaderStages[1].stage = VK_SHADER_STAGE_FRAGMENT_BIT;
    shaderStages[1]. module = fragShaderModule;
    shaderStages[1].pName = "main";
    shaderStages[1].flags = 0;
    shaderStages[1].pNext = nullptr;
    shaderStages[1].pSpecializationInfo = nullptr;

    auto bindingDescriptions = Model::Vertex::getBindingDescriptions();
    auto attributeDescptions = Model::Vertex::getAttributeDescriptions();
    VkPipelineVertexInputStateCreateInfo vertexInputInfo{};
    vertexInputInfo.sType = VK_STRUCTURE_TYPE_PIPELINE_VERTEX_INPUT_STATE_CREATE_INFO;
    vertexInputInfo.vertexAttributeDescriptionCount = static_cast<uint32_t>(attributeDescptions.size());
    vertexInputInfo.vertexBindingDescriptionCount = static_cast<uint32_t>(bindingDescriptions.size());
    vertexInputInfo.pVertexAttributeDescriptions = attributeDescptions.data();
    vertexInputInfo.pVertexBindingDescriptions = bindingDescriptions.data();

    VkGraphicsPipelineCreateInfo pipelineInfo{};
    pipelineInfo.sType = VK_STRUCTURE_TYPE_GRAPHICS_PIPELINE_CREATE_INFO;
    pipelineInfo.stageCount = 2;
    pipelineInfo.pStages = shaderStages;
    pipelineInfo.pVertexInputState = &vertexInputInfo;
    pipelineInfo.pInputAssemblyState = &configInfo.inputAssemblyInfo;
    pipelineInfo.pViewportState = &configInfo.viewportInfo;
    pipelineInfo.pRasterizationState = &configInfo.rasterizationInfo;
    pipelineInfo.pMultisampleState = &configInfo.multisampleInfo;
    pipelineInfo.pColorBlendState = &configInfo.colorBlendInfo;
    pipelineInfo.pDepthStencilState = &configInfo.depthStencilInfo;
    pipelineInfo.pDynamicState = &configInfo.dynamicStateInfo;

    pipelineInfo.layout = configInfo.pipelineLayout;
    pipelineInfo.renderPass = configInfo.renderPass;
    pipelineInfo.subpass = configInfo.subpass;

    pipelineInfo.basePipelineIndex = -1;
    pipelineInfo.basePipelineHandle = VK_NULL_HANDLE;

    if(vkCreateGraphicsPipelines(xeDevice.device(), VK_NULL_HANDLE, 1, &pipelineInfo, nullptr, &graphicsPipeline) != VK_SUCCESS){
      throw std::runtime_error("failed to create graphics pipeline");
    }
  }

  void Pipeline::createShaderModule(const std::vector<char>& code, VkShaderModule* shaderModule) {
    VkShaderModuleCreateInfo createInfo{};
    createInfo.sType = VK_STRUCTURE_TYPE_SHADER_MODULE_CREATE_INFO;
    createInfo.codeSize = code.size();
    createInfo.pCode = reinterpret_cast<const uint32_t*>(code.data());

    if(vkCreateShaderModule(xeDevice.device(), &createInfo, nullptr, shaderModule) != VK_SUCCESS) {
      throw std::runtime_error("failed to create shader module");
    }

  }

  void Pipeline::bind(VkCommandBuffer commandBuffer) {
    vkCmdBindPipeline(commandBuffer, VK_PIPELINE_BIND_POINT_GRAPHICS, graphicsPipeline);
  }

  void Pipeline::defaultPipelineConfigInfo(PipelineConfigInfo& configInfo) {
    
    configInfo.inputAssemblyInfo.sType = VK_STRUCTURE_TYPE_PIPELINE_INPUT_ASSEMBLY_STATE_CREATE_INFO;
    configInfo.inputAssemblyInfo.topology = VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST;
    configInfo.inputAssemblyInfo.primitiveRestartEnable = VK_FALSE;

    configInfo.viewportInfo.sType = VK_STRUCTURE_TYPE_PIPELINE_VIEWPORT_STATE_CREATE_INFO;
    configInfo.viewportInfo.viewportCount = 1;
    configInfo.viewportInfo.pViewports = nullptr;
    configInfo.viewportInfo.scissorCount = 1;
    configInfo.viewportInfo.pScissors = nullptr;
  
    configInfo.rasterizationInfo.sType = VK_STRUCTURE_TYPE_PIPELINE_RASTERIZATION_STATE_CREATE_INFO;
    configInfo.rasterizationInfo.depthClampEnable = VK_FALSE;
    configInfo.rasterizationInfo.rasterizerDiscardEnable = VK_FALSE;
    configInfo.rasterizationInfo.polygonMode = VK_POLYGON_MODE_FILL;
    configInfo.rasterizationInfo.lineWidth = 1.0f;
    configInfo.rasterizationInfo.cullMode = VK_CULL_MODE_NONE;
    configInfo.rasterizationInfo.frontFace = VK_FRONT_FACE_CLOCKWISE;
    configInfo.rasterizationInfo.depthBiasEnable = VK_FALSE;
    configInfo.rasterizationInfo.depthBiasConstantFactor = 0.0f;
    configInfo.rasterizationInfo.depthBiasClamp = 0.0f;           
    configInfo.rasterizationInfo.depthBiasSlopeFactor = 0.0f;
  
    configInfo.multisampleInfo.sType = VK_STRUCTURE_TYPE_PIPELINE_MULTISAMPLE_STATE_CREATE_INFO;
    configInfo.multisampleInfo.sampleShadingEnable = VK_FALSE;
    configInfo.multisampleInfo.rasterizationSamples = VK_SAMPLE_COUNT_1_BIT;
    configInfo.multisampleInfo.minSampleShading = 1.0f;
    configInfo.multisampleInfo.pSampleMask = nullptr;
    configInfo.multisampleInfo.alphaToCoverageEnable = VK_FALSE;
    configInfo.multisampleInfo.alphaToOneEnable = VK_FALSE;
  
    configInfo.colorBlendAttachment.colorWriteMask =
        VK_COLOR_COMPONENT_R_BIT | VK_COLOR_COMPONENT_G_BIT | VK_COLOR_COMPONENT_B_BIT |
        VK_COLOR_COMPONENT_A_BIT;
    configInfo.colorBlendAttachment.blendEnable = VK_FALSE;
    configInfo.colorBlendAttachment.srcColorBlendFactor = VK_BLEND_FACTOR_ONE;
    configInfo.colorBlendAttachment.dstColorBlendFactor = VK_BLEND_FACTOR_ZERO;
    configInfo.colorBlendAttachment.colorBlendOp = VK_BLEND_OP_ADD;
    configInfo.colorBlendAttachment.srcAlphaBlendFactor = VK_BLEND_FACTOR_ONE;
    configInfo.colorBlendAttachment.dstAlphaBlendFactor = VK_BLEND_FACTOR_ZERO;
    configInfo.colorBlendAttachment.alphaBlendOp = VK_BLEND_OP_ADD;
  
    configInfo.colorBlendInfo.sType = VK_STRUCTURE_TYPE_PIPELINE_COLOR_BLEND_STATE_CREATE_INFO;
    configInfo.colorBlendInfo.logicOpEnable = VK_FALSE;
    configInfo.colorBlendInfo.logicOp = VK_LOGIC_OP_COPY;
    configInfo.colorBlendInfo.attachmentCount = 1;
    configInfo.colorBlendInfo.pAttachments = &configInfo.colorBlendAttachment;
    configInfo.colorBlendInfo.blendConstants[0] = 0.0f;
    configInfo.colorBlendInfo.blendConstants[1] = 0.0f;
    configInfo.colorBlendInfo.blendConstants[2] = 0.0f;
    configInfo.colorBlendInfo.blendConstants[3] = 0.0f;
  
    configInfo.depthStencilInfo.sType = VK_STRUCTURE_TYPE_PIPELINE_DEPTH_STENCIL_STATE_CREATE_INFO;
    configInfo.depthStencilInfo.depthTestEnable = VK_TRUE;
    configInfo.depthStencilInfo.depthWriteEnable = VK_TRUE;
    configInfo.depthStencilInfo.depthCompareOp = VK_COMPARE_OP_LESS;
    configInfo.depthStencilInfo.depthBoundsTestEnable = VK_FALSE;
    configInfo.depthStencilInfo.minDepthBounds = 0.0f;
    configInfo.depthStencilInfo.maxDepthBounds = 1.0f;
    configInfo.depthStencilInfo.stencilTestEnable = VK_FALSE;
    configInfo.depthStencilInfo.front = {};
    configInfo.depthStencilInfo.back = {};

    configInfo.dynamicStateEnables = {VK_DYNAMIC_STATE_VIEWPORT, VK_DYNAMIC_STATE_SCISSOR};
    configInfo.dynamicStateInfo.sType = VK_STRUCTURE_TYPE_PIPELINE_DYNAMIC_STATE_CREATE_INFO;
    configInfo.dynamicStateInfo.pDynamicStates = configInfo.dynamicStateEnables.data();
    configInfo.dynamicStateInfo.dynamicStateCount =
        static_cast<uint32_t>(configInfo.dynamicStateEnables.size());
    configInfo.dynamicStateInfo.flags = 0;

  }

}