#include <fstream>
#include <renderer/rhi_module.h>
#include <renderer/shader.h>
#include <sstream>
#include <utils/logger.h>

namespace extra2d {

Shader::Shader() = default;

Shader::~Shader() {
  // RHIHandle 是轻量级句柄，不需要显式释放
  // 实际的资源由 RHI 设备管理
  pipeline_ = PipelineHandle();
  handle_ = ShaderHandle();
}

bool Shader::loadFromFile(const std::string &vsPath,
                          const std::string &fsPath) {
  // 读取顶点着色器
  std::ifstream vsFile(vsPath);
  if (!vsFile.is_open()) {
    E2D_LOG_ERROR("Failed to open vertex shader: {}", vsPath);
    return false;
  }
  std::stringstream vsStream;
  vsStream << vsFile.rdbuf();
  std::string vsSource = vsStream.str();

  // 读取片段着色器
  std::ifstream fsFile(fsPath);
  if (!fsFile.is_open()) {
    E2D_LOG_ERROR("Failed to open fragment shader: {}", fsPath);
    return false;
  }
  std::stringstream fsStream;
  fsStream << fsFile.rdbuf();
  std::string fsSource = fsStream.str();

  return loadFromSource(vsSource, fsSource);
}

bool Shader::loadFromSource(const std::string &vsSource,
                            const std::string &fsSource) {
  // 释放旧资源
  pipeline_ = PipelineHandle();
  handle_ = ShaderHandle();

  // 获取 RHI 设备
  auto *rhiModule = RHIModule::get();
  if (!rhiModule) {
    E2D_LOG_ERROR("RHIModule not available");
    return false;
  }

  auto *device = rhiModule->getDevice();
  if (!device) {
    E2D_LOG_ERROR("RHIDevice not available");
    return false;
  }

  // 处理源码（添加版本声明）
  std::string processedVS = addVersionIfNeeded(vsSource, true);
  std::string processedFS = addVersionIfNeeded(fsSource, false);

  // 创建着色器描述
  ShaderDesc shaderDesc;
  shaderDesc.vertexSource = processedVS;
  shaderDesc.fragmentSource = processedFS;

  // 创建着色器
  auto shader = device->createShader(shaderDesc);
  if (!shader) {
    E2D_LOG_ERROR("Failed to create shader");
    return false;
  }

  // 获取着色器句柄
  handle_ = ShaderHandle(shader.release());

  // 创建顶点布局（2D 标准布局：位置 + 纹理坐标 + 颜色）
  VertexLayout vertexLayout;
  vertexLayout.stride = sizeof(float) * 8; // 2 (pos) + 2 (uv) + 4 (color)
  vertexLayout.addAttribute(0, VertexFormat::Float2, 0);  // 位置
  vertexLayout.addAttribute(1, VertexFormat::Float2, 8);  // 纹理坐标
  vertexLayout.addAttribute(2, VertexFormat::Float4, 16); // 颜色

  // 创建管线描述
  PipelineDesc pipelineDesc;
  pipelineDesc.vertexShader = handle_;
  pipelineDesc.fragmentShader = handle_;
  pipelineDesc.vertexLayout = vertexLayout;
  pipelineDesc.blendState = BlendState::alphaBlend();
  pipelineDesc.depthStencilState = DepthStencilState::noDepthTest();
  pipelineDesc.rasterizerState = RasterizerState::noCull();

  // 创建管线
  auto pipeline = device->createPipeline(pipelineDesc);
  if (!pipeline) {
    E2D_LOG_ERROR("Failed to create pipeline");
    handle_ = ShaderHandle();
    return false;
  }

  // 获取管线句柄
  pipeline_ = PipelineHandle(pipeline.release());

  E2D_LOG_INFO("Shader created successfully");
  return true;
}

void Shader::setUniformBlock(const std::string &name, uint32_t binding) {
  // 存储 uniform block 绑定信息
  uniformBlockBindings_[name] = binding;

  // 注意：实际的 uniform block 绑定需要在渲染时通过 RHI 命令列表设置
  // 这里仅存储绑定信息，供后续渲染使用
  // 例如：commandList->setUniformBlock(binding, buffer);
}

uint32_t Shader::getUniformBlockBinding(const std::string &name) const {
  auto it = uniformBlockBindings_.find(name);
  if (it != uniformBlockBindings_.end()) {
    return it->second;
  }
  return UINT32_MAX; // 未找到
}

std::string Shader::addVersionIfNeeded(const std::string &source,
                                       bool isVertex) {
  // 如果已经包含版本声明，直接返回
  if (source.find("#version") != std::string::npos) {
    return source;
  }

  // 添加 OpenGL ES 3.2 版本声明
  std::string result = "#version 320 es\n";

  // 片段着色器需要添加精度声明
  if (!isVertex) {
    result += "precision mediump float;\n";
  }

  result += source;
  return result;
}

} // namespace extra2d