#include <memory>
#include <cstdio>
#include <string>
#include <GL/glew.h>
#include <SDL3/SDL.h>
#include <SDL3/SDL_keyboard.h>
#include <SDL3/SDL_timer.h>

#include "db/db.h"

#include "gfx/shape_renderer.h"
#include "gfx/txt_renderer.h"
#include "game_state.h"
#include "ui/ui_renderer.h"
#include "gfx/types.h"
#include "ui/cursor_manager.h"
#include "debug/debug_stats.h"

const int SCREEN_WIDTH  = 1280;
const int SCREEN_HEIGHT = 720;
int main(int argc, char** argv) {
  /* Init SDL. */
  if(!SDL_Init(SDL_INIT_VIDEO)) {
    printf("SDL could not initialise! SDL_ERROR: %s\n", SDL_GetError());
    return 1;
  }

  /* Set OpenGL attributes. */
  SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
  SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 3);
  SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);

  /* Create a window. */
  SDL_Window* window = SDL_CreateWindow(
    "Bettola Client",
    SCREEN_WIDTH,
    SCREEN_HEIGHT,
    SDL_WINDOW_OPENGL
  );

  if(window == NULL) {
    printf("Unable to create window! SDL_ERROR: %s\n", SDL_GetError());
    return 1;
  }

  /* Create OpenGL context. */
  SDL_GLContext context = SDL_GL_CreateContext(window);
  if(context == NULL) {
    printf("OpenGL context could not be created! SDL_ERROR: %s\n", SDL_GetError());
    return 1;
  }

  /* Initialise GLEW. */
  glewExperimental = GL_TRUE;
  GLenum glewError = glewInit();
  if (glewError != GLEW_OK) {
    /* NOTE:
     * Dear future self, or other intrepid developer:
     * In some environments (like the Fedora VM I tested),
     * glewInit() returns an error here even when the context is valid.
     * This is a known quirk. We print the error but continue anyway,
     * because it's not fatal. Don't "fix" this by making it exit. Thank you.
     * It's GLEW, not you.
     */
    fprintf(stderr, "Warning: glewInit failed with error code %u: %s. Attempting to continue anyway.\n",
            glewError, glewGetErrorString(glewError));
  }

  /* Configure OpenGL. */
  glEnable(GL_BLEND);
  glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

  /* Listen for text input. */
  SDL_StartTextInput(window);

  /* Init cursor manager. */
  CursorManager::init();

  /* Init text renderer. */
  TextRenderer* txt_render_instance = new TextRenderer(SCREEN_WIDTH, SCREEN_HEIGHT);
  txt_render_instance->load_font("assets/fonts/hack/Hack-Regular.ttf", 14);

  /* Init shape renderer. */
  ShapeRenderer* shape_renderer_instance = new ShapeRenderer(SCREEN_WIDTH, SCREEN_HEIGHT);

  /* Init UI renderer. */
  UIRenderer* ui_renderer_instance = new UIRenderer(shape_renderer_instance,
                                                    txt_render_instance, SCREEN_HEIGHT);

  auto game_state = std::make_unique<GameState>();
  if(argc > 1 && std::string(argv[1]) == "-sp") {
    game_state->start_single_player_now(SCREEN_WIDTH, SCREEN_HEIGHT);
  } else {
    game_state->init(SCREEN_WIDTH, SCREEN_HEIGHT);
  }

  /* timer for cursor blink. */
  Uint32 last_blink_time = 0;
  bool show_cursor = true;

  /* Timestep. */
  Uint64 last_frame_time = SDL_GetPerformanceCounter();
  float dt = 0.0f;

  bool running = true;
  while(running) {
    /* Reset per-frame stats. */
    DebugStats::reset();

    /* Event handling. */
    SDL_Event event;
    while(SDL_PollEvent(&event)) {
      if(event.type == SDL_EVENT_QUIT) { running = false; }
      game_state->handle_event(&event, SCREEN_WIDTH, SCREEN_HEIGHT);
    }

    /* Calculate delta time. */
    Uint64 current_frame_time = SDL_GetPerformanceCounter();
    dt = (current_frame_time - last_frame_time) / (float)SDL_GetPerformanceFrequency();
    last_frame_time = current_frame_time;

    /* Clamp dt to avoid large jumps. */
    if(dt > 0.1f) dt = 0.1f;

    Uint32 current_time = SDL_GetTicks();
    if(current_time - last_blink_time > 500) { /* Every 500ms. */
      show_cursor = !show_cursor;
      last_blink_time = current_time;
    }

    /* Clear screen. */
    glClearColor(0.04f, 0.05f, 0.06, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT);

    RenderContext context = {
      ui_renderer_instance,
      SCREEN_HEIGHT,
      show_cursor
    };
    game_state->render(context);

    /* Update game state after rendering so stats are for the frame just rendered.
     * I know this is unusual, but given the text based nature of the game
     * we won't see a negative impact, and this is better than a large refactor ;)
     */
    game_state->update(dt, DebugStats::draw_calls, DebugStats::shape_vertices,
                       DebugStats::text_vertices);

    /* It's really odd to call it SwapWindow now, rather than SwapBuffer. */
    SDL_GL_SwapWindow(window);
  }

  /* Cleanup. */
  game_state.reset();
  delete ui_renderer_instance;
  delete shape_renderer_instance;
  delete txt_render_instance;
  SDL_GL_DestroyContext(context);
  CursorManager::quit();
  SDL_DestroyWindow(window);
  SDL_Quit();

  return 0;
}