#include <renderer/rhi/opengl/gl_pipeline.h>
#include <renderer/rhi/opengl/gl_utils.h>

namespace extra2d {

GLPipeline::GLPipeline(const PipelineDesc &desc) : desc_(desc), vao_(0) {}

GLPipeline::~GLPipeline() { destroy(); }

bool GLPipeline::create() {
  // 创建 VAO
  glGenVertexArrays(1, &vao_);
  if (vao_ == 0) {
    return false;
  }

  glBindVertexArray(vao_);

  // 配置顶点属性
  const auto &layout = desc_.vertexLayout;
  for (const auto &attr : layout.attributes) {
    glEnableVertexAttribArray(attr.location);

    GLenum type = GL_FLOAT;
    GLint size = 1;
    GLboolean normalized = GL_FALSE;

    switch (attr.format) {
    case VertexFormat::Float1:
      size = 1;
      break;
    case VertexFormat::Float2:
      size = 2;
      break;
    case VertexFormat::Float3:
      size = 3;
      break;
    case VertexFormat::Float4:
      size = 4;
      break;
    default:
      break;
    }

    glVertexAttribPointer(attr.location, size, type, normalized, layout.stride,
                          reinterpret_cast<const void *>(attr.offset));
  }

  glBindVertexArray(0);
  return true;
}

void GLPipeline::destroy() {
  if (vao_ != 0) {
    glDeleteVertexArrays(1, &vao_);
    vao_ = 0;
  }
}

void GLPipeline::bind() {
  // 绑定着色器程序
  if (shaderProgram_ != 0) {
    glUseProgram(shaderProgram_);
  }

  // 注意：VAO 需要与具体的顶点缓冲区绑定才能工作
  // 所以我们不在此处绑定 VAO，而是在渲染时动态配置顶点属性
  // 这样可以支持不同的 Mesh 使用相同的 Pipeline

  // 应用混合状态
  if (desc_.blendState.enabled) {
    glEnable(GL_BLEND);
    glBlendFunc(blendFactorToGL(desc_.blendState.srcFactor),
                blendFactorToGL(desc_.blendState.dstFactor));
  } else {
    glDisable(GL_BLEND);
  }

  // 应用深度状态
  if (desc_.depthStencilState.depthTestEnabled) {
    glEnable(GL_DEPTH_TEST);
    glDepthFunc(compareFuncToGL(desc_.depthStencilState.depthCompare));
    glDepthMask(desc_.depthStencilState.depthWriteEnabled ? GL_TRUE : GL_FALSE);
  } else {
    glDisable(GL_DEPTH_TEST);
  }

  // 应用光栅化状态
  if (desc_.rasterizerState.cullEnabled) {
    glEnable(GL_CULL_FACE);
    glCullFace(desc_.rasterizerState.cullFrontFace ? GL_FRONT : GL_BACK);
    glFrontFace(desc_.rasterizerState.frontCCW ? GL_CCW : GL_CW);
  } else {
    glDisable(GL_CULL_FACE);
  }
}

void GLPipeline::unbind() { glBindVertexArray(0); }

ShaderHandle GLPipeline::getVertexShader() const {
  return desc_.vertexShader;
}

ShaderHandle GLPipeline::getFragmentShader() const {
  return desc_.fragmentShader;
}

const VertexLayout& GLPipeline::getVertexLayout() const {
  return desc_.vertexLayout;
}

bool GLPipeline::isValid() const {
  return vao_ != 0;
}

} // namespace extra2d