#ifndef RENDERER_H
#define RENDERER_H

#include <array>
#include <memory>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>

#define THREADED_RENDERING

#ifdef THREADED_RENDERING
#include <condition_variable>
#include <deque>
#include <future>
#include <mutex>
#include <thread>
#endif  // THREADED_RENDERING

#include "opengl.h"
#if defined(__linux__) && !defined(__ANDROID__)
#include <X11/Xlib.h>
#include "../../third_party/glew/glxew.h"
#endif

#include "../../base/closure.h"
#ifdef THREADED_RENDERING
#include "../../base/task_runner.h"
#endif  // THREADED_RENDERING
#include "render_resource.h"
#include "renderer_types.h"

#if defined(__ANDROID__)
struct ANativeWindow;
#endif

namespace eng {

struct RenderCommand;
class Image;

class Renderer {
 public:
  Renderer();
  ~Renderer();

  void SetContextLostCB(base::Closure cb);

#if defined(__ANDROID__)
  bool Initialize(ANativeWindow* window);
#elif defined(__linux__)
  bool Initialize();
#endif

  void Shutdown();

  void Update();

  void ContextLost();

  std::unique_ptr<RenderResource> CreateResource(
      RenderResourceFactoryBase& factory);
  void ReleaseResource(unsigned resource_id);

  void EnqueueCommand(std::unique_ptr<RenderCommand> cmd);

  bool SupportsETC1() const { return texture_compression_.etc1; }
  bool SupportsDXT1() const {
    return texture_compression_.dxt1 || texture_compression_.s3tc;
  }
  bool SupportsDXT5() const { return texture_compression_.s3tc; }
  bool SupportsATC() const { return texture_compression_.atc; }

  bool SupportsVAO() const { return vertex_array_objects_; }

  int screen_width() const { return screen_width_; }
  int screen_height() const { return screen_height_; }

  size_t GetAndResetFPS();

  size_t global_queue_size() { return global_queue_size_; }
  size_t render_queue_size() { return render_queue_size_; }

#if defined(__linux__) && !defined(__ANDROID__)
  Display* display() { return display_; }
  Window window() { return window_; }
#endif

 private:
  struct TextureCompression {
    unsigned etc1 : 1;
    unsigned dxt1 : 1;
    unsigned latc : 1;
    unsigned s3tc : 1;
    unsigned pvrtc : 1;
    unsigned atc : 1;

    TextureCompression()
        : etc1(false),
          dxt1(false),
          latc(false),
          s3tc(false),
          pvrtc(false),
          atc(false) {}
  };

  struct GeometryOpenGL {
    struct Element {
      GLsizei num_elements;
      GLenum type;
      size_t vertex_offset;
    };

    GLsizei num_vertices = 0;
    GLsizei num_indices = 0;
    GLenum primitive = 0;
    GLenum index_type = 0;
    std::vector<Element> vertex_layout;
    GLuint vertex_size = 0;
    GLuint vertex_array_id = 0;
    GLuint vertex_buffer_id = 0;
    GLuint index_buffer_id = 0;
  };

  struct ShaderOpenGL {
    GLuint id = 0;
    std::unordered_map<std::string, GLuint> uniforms;
  };

  struct TextureOpenGL {
    GLuint id = 0;
  };

  base::Closure context_lost_cb_;

  TextureCompression texture_compression_;
  bool vertex_array_objects_ = false;
  bool npot_ = false;

  int screen_width_ = 0;
  int screen_height_ = 0;

  std::unordered_map<unsigned, RenderResource*> resources_;

#ifdef THREADED_RENDERING
  // Global commands are independent from frames and guaranteed to be processed.
  std::deque<std::unique_ptr<RenderCommand>> global_commands_;
  // Draw commands are fame specific and can be discarded if the renderer deems
  // frame drop.
  std::deque<std::unique_ptr<RenderCommand>> draw_commands_[2];

  std::condition_variable cv_;
  std::mutex mutex_;
  std::thread worker_thread_;
  bool terminate_worker_ = false;

  base::TaskRunner task_runner_;
#endif  // THREADED_RENDERING

  // Stats.
  size_t fps_ = 0;
  size_t global_queue_size_ = 0;
  size_t render_queue_size_ = 0;

#if defined(__ANDROID__)
  ANativeWindow* window_;
#elif defined(__linux__)
  Display* display_ = NULL;
  Window window_ = 0;
  XVisualInfo* visual_info_;
  GLXContext glx_context_ = NULL;
#endif

  bool InitInternal();
  bool InitCommon();
  void ShutdownInternal();

  void InvalidateAllResources();

  bool StartWorker();
  void TerminateWorker();

#ifdef THREADED_RENDERING
  void WorkerMain(std::promise<bool> promise);
#endif  // THREADED_RENDERING

  void ProcessCommand(RenderCommand* cmd);

  void HandleCmdEnableBlend(RenderCommand* cmd);
  void HandleCmdClear(RenderCommand* cmd);
  void HandleCmdPresent(RenderCommand* cmd);
  void HandleCmdUpdateTexture(RenderCommand* cmd);
  void HandleCmdDestoryTexture(RenderCommand* cmd);
  void HandleCmdActivateTexture(RenderCommand* cmd);
  void HandleCmdCreateGeometry(RenderCommand* cmd);
  void HandleCmdDestroyGeometry(RenderCommand* cmd);
  void HandleCmdDrawGeometry(RenderCommand* cmd);
  void HandleCmdCreateShader(RenderCommand* cmd);
  void HandleCmdDestroyShader(RenderCommand* cmd);
  void HandleCmdActivateShader(RenderCommand* cmd);
  void HandleCmdSetUniformVec2(RenderCommand* cmd);
  void HandleCmdSetUniformVec3(RenderCommand* cmd);
  void HandleCmdSetUniformVec4(RenderCommand* cmd);
  void HandleCmdSetUniformMat4(RenderCommand* cmd);
  void HandleCmdSetUniformFloat(RenderCommand* cmd);
  void HandleCmdSetUniformInt(RenderCommand* cmd);

  bool SetupVertexLayout(const VertexDescripton& vd,
                         GLuint vertex_size,
                         bool use_vao,
                         std::vector<GeometryOpenGL::Element>& vertex_layout);
  GLuint CreateShader(const char* source, GLenum type);
  bool BindAttributeLocation(GLuint id, const VertexDescripton& vd);
  GLint GetUniformLocation(GLuint id,
                           const std::string& name,
                           std::unordered_map<std::string, GLuint>& uniforms);

#if defined(__linux__) && !defined(__ANDROID__)
  bool CreateWindow();
  void DestroyWindow();
#endif

  Renderer(const Renderer&) = delete;
  Renderer& operator=(const Renderer&) = delete;
};

}  // namespace eng

#endif  // RENDERER_H