#include "cve_pipeline.hpp"

#include <fstream>
#include <stdexcept>
#include <iostream>
#include <cassert>

namespace cve {
  CvePipeline::CvePipeline(CveDevice &device, const std::string& vertFilepath, 
          const std::string& fragFilepath, const PipelineConfigInfo &configInfo) : cveDevice{device} {
    createGraphicsPipeline(vertFilepath, fragFilepath, configInfo);
  }

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

  std::vector<char> CvePipeline::readFile(const std::string& filepath) {
    std::ifstream file{filepath, std::ios::ate | std::ios::binary};
    
    if (!file.is_open()) {
      throw std::runtime_error("Failed 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 CvePipeline::createGraphicsPipeline(const std::string& vertFilepath, 
          const std::string& fragFilepath, const PipelineConfigInfo &configInfo) {
    auto vertCode = readFile(vertFilepath);
    auto fragCode = readFile(fragFilepath);

    assert(configInfo.pipelineLayout != VK_NULL_HANDLE &&
        "Unable to create graphics pipeline");
    assert(configInfo.renderPass != VK_NULL_HANDLE &&
        "Unable to create graphics pipeline");
    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;

    VkPipelineVertexInputStateCreateInfo vertexInputInfo{};
    vertexInputInfo.sType = VK_STRUCTURE_TYPE_PIPELINE_VERTEX_INPUT_STATE_CREATE_INFO;
    vertexInputInfo.vertexBindingDescriptionCount = 0;
    vertexInputInfo.vertexAttributeDescriptionCount = 0;
    vertexInputInfo.pVertexBindingDescriptions = nullptr;
    vertexInputInfo.pVertexAttributeDescriptions = nullptr;

    VkPipelineViewportStateCreateInfo viewportInfo{};
    viewportInfo.sType = VK_STRUCTURE_TYPE_PIPELINE_VIEWPORT_STATE_CREATE_INFO;
    viewportInfo.viewportCount = 1;
    viewportInfo.pViewports = &configInfo.viewport;
    viewportInfo.scissorCount = 1;
    viewportInfo.pScissors = &configInfo.scissor;

    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 = &viewportInfo;
    pipelineInfo.pRasterizationState = &configInfo.rasterizationInfo;
    pipelineInfo.pMultisampleState = &configInfo.multisampleInfo;
    pipelineInfo.pColorBlendState = &configInfo.colorBlendInfo;
    pipelineInfo.pDepthStencilState = &configInfo.depthStencilInfo;
    pipelineInfo.pDynamicState = nullptr;

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

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

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

  void CvePipeline::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(cveDevice.device(), &createInfo, nullptr, shaderModule) != VK_SUCCESS) {
      throw std::runtime_error("Failed to create shader module.");
    }
  }

  PipelineConfigInfo CvePipeline::defaultPipelineConfigInfo(uint32_t width, uint32_t height) {
    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.viewport.x = 0.0f;
    configInfo.viewport.y = 0.0f;
    configInfo.viewport.width = static_cast<float>(width);
    configInfo.viewport.height = static_cast<float>(height);
    configInfo.viewport.minDepth = 0.0f;
    configInfo.viewport.maxDepth = 1.0f;

    configInfo.scissor.offset = {0, 0};
    configInfo.scissor.extent = {width, height};

    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;           // Optional
    configInfo.multisampleInfo.pSampleMask = nullptr;             // Optional
    configInfo.multisampleInfo.alphaToCoverageEnable = VK_FALSE;  // Optional
    configInfo.multisampleInfo.alphaToOneEnable = VK_FALSE;       // Optional

    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;   // Optional
    configInfo.colorBlendAttachment.dstColorBlendFactor = VK_BLEND_FACTOR_ZERO;  // Optional
    configInfo.colorBlendAttachment.colorBlendOp = VK_BLEND_OP_ADD;              // Optional
    configInfo.colorBlendAttachment.srcAlphaBlendFactor = VK_BLEND_FACTOR_ONE;   // Optional
    configInfo.colorBlendAttachment.dstAlphaBlendFactor = VK_BLEND_FACTOR_ZERO;  // Optional
    configInfo.colorBlendAttachment.alphaBlendOp = VK_BLEND_OP_ADD;              // Optional

    configInfo.colorBlendInfo.sType = VK_STRUCTURE_TYPE_PIPELINE_COLOR_BLEND_STATE_CREATE_INFO;
    configInfo.colorBlendInfo.logicOpEnable = VK_FALSE;
    configInfo.colorBlendInfo.logicOp = VK_LOGIC_OP_COPY;  // Optional
    configInfo.colorBlendInfo.attachmentCount = 1;
    configInfo.colorBlendInfo.pAttachments = &configInfo.colorBlendAttachment;
    configInfo.colorBlendInfo.blendConstants[0] = 0.0f;  // Optional
    configInfo.colorBlendInfo.blendConstants[1] = 0.0f;  // Optional
    configInfo.colorBlendInfo.blendConstants[2] = 0.0f;  // Optional
    configInfo.colorBlendInfo.blendConstants[3] = 0.0f;  // Optional

    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;  // Optional
    configInfo.depthStencilInfo.maxDepthBounds = 1.0f;  // Optional
    configInfo.depthStencilInfo.stencilTestEnable = VK_FALSE;
    configInfo.depthStencilInfo.front = {};  // Optional
    configInfo.depthStencilInfo.back = {};   // Optional

    return configInfo;
  }
}