#pragma once

#include <glad/glad.h>
#include <renderer/rhi/rhi.h>

namespace extra2d {

// 前向声明
class GLPipeline;
class GLBuffer;
class GLTexture;
class GLFramebuffer;

/**
 * @brief OpenGL 命令列表实现
 */
class GLCommandList : public RHICommandList {
public:
  GLCommandList();
  ~GLCommandList() override;

  //===========================================================================
  // 命令列表生命周期
  //===========================================================================

  void begin() override;
  void end() override;
  void submit() override;

  //===========================================================================
  // 渲染通道
  //===========================================================================

  void beginRenderPass(RHIFramebuffer *framebuffer,
                       ClearFlags clearFlags = ClearFlags::Color,
                       const Color &clearColor = Color::Black,
                       float clearDepth = 1.0f,
                       uint8_t clearStencil = 0) override;
  void endRenderPass() override;

  //===========================================================================
  // 状态设置
  //===========================================================================

  void setViewport(const Viewport &viewport) override;
  void setScissor(const ScissorRect &scissor) override;
  void setPipeline(RHIPipeline *pipeline) override;

  //===========================================================================
  // 资源绑定
  //===========================================================================

  void setVertexBuffer(uint32_t slot, RHIBuffer *buffer,
                       uint32_t offset = 0, uint32_t stride = 0) override;
  void setIndexBuffer(RHIBuffer *buffer, IndexType type,
                      uint32_t offset = 0) override;
  void setUniformBuffer(uint32_t slot, RHIBuffer *buffer) override;
  void setUniformBuffer(uint32_t slot, RHIBuffer *buffer, uint32_t offset, uint32_t size = 0) override;
  void setTexture(uint32_t slot, RHITexture *texture) override;
  void setSampler(uint32_t slot, TextureFilter minFilter,
                  TextureFilter magFilter, TextureWrap wrapS,
                  TextureWrap wrapT) override;

  //===========================================================================
  // 绘制命令
  //===========================================================================

  void draw(uint32_t vertexCount, uint32_t firstVertex = 0,
            uint32_t instanceCount = 1, uint32_t firstInstance = 0) override;

  void drawIndexed(uint32_t indexCount, uint32_t firstIndex = 0,
                   int32_t vertexOffset = 0, uint32_t instanceCount = 1,
                   uint32_t firstInstance = 0) override;

  //===========================================================================
  // 工具方法
  //===========================================================================

  void clear(ClearFlags flags, const Color &color = Color::Black,
             float depth = 1.0f, uint8_t stencil = 0) override;

  bool isRecording() const override;

  // 设置 uniform 变量
  void setUniform(const char* name, float value) override;
  void setUniform(const char* name, const Vec2& value) override;
  void setUniform(const char* name, const Vec3& value) override;
  void setUniform(const char* name, const Color& value) override;
  void setUniform(const char* name, const Mat4& value) override;

private:
  // 状态缓存机制 - 避免冗余的 OpenGL 状态切换
  struct StateCache {
    // 管线状态
    GLPipeline* pipeline = nullptr;
    GLuint shaderProgram = 0;

    // 视口状态
    Viewport viewport;
    bool viewportValid = false;

    // 裁剪状态
    ScissorRect scissor{0, 0, 0, 0};
    bool scissorValid = false;
    bool scissorEnabled = false;

    // 缓冲区状态
    GLBuffer* vertexBuffers[4] = {nullptr, nullptr, nullptr, nullptr}; // 支持最多4个顶点缓冲区槽
    uint32_t vertexBufferOffsets[4] = {0, 0, 0, 0};
    GLBuffer* indexBuffer = nullptr;

    // Uniform 缓冲区状态
    struct UBOBinding {
      GLBuffer* buffer = nullptr;
      uint32_t offset = 0;
      uint32_t size = 0;
      bool valid = false;
    };
    UBOBinding uniformBuffers[4]; // 支持最多4个 UBO 槽

    // 纹理状态
    struct TextureBinding {
      GLTexture* texture = nullptr;
      bool valid = false;
    };
    TextureBinding textures[8]; // 支持最多8个纹理槽

    // 帧缓冲状态
    GLFramebuffer* framebuffer = nullptr;

    // 重置所有状态缓存
    void reset() {
      pipeline = nullptr;
      shaderProgram = 0;
      viewportValid = false;
      scissorValid = false;
      scissorEnabled = false;
      for (int i = 0; i < 4; ++i) {
        vertexBuffers[i] = nullptr;
        vertexBufferOffsets[i] = 0;
        uniformBuffers[i] = {};
      }
      indexBuffer = nullptr;
      for (int i = 0; i < 8; ++i) {
        textures[i] = {};
      }
      framebuffer = nullptr;
    }
  };

  bool recording_ = false;
  StateCache stateCache_;

  // 统计信息（调试用）
  struct Stats {
    uint32_t pipelineChanges = 0;
    uint32_t textureChanges = 0;
    uint32_t bufferChanges = 0;
    uint32_t viewportChanges = 0;
    uint32_t redundantPipelineChanges = 0;
    uint32_t redundantTextureChanges = 0;
    uint32_t redundantBufferChanges = 0;

    void reset() {
      pipelineChanges = 0;
      textureChanges = 0;
      bufferChanges = 0;
      viewportChanges = 0;
      redundantPipelineChanges = 0;
      redundantTextureChanges = 0;
      redundantBufferChanges = 0;
    }
  } stats_;
};

} // namespace extra2d