#include <bitset>
#include <iostream>

#include "platform.hpp"

#define SAMPLE_RATE 44100
#define PI 3.14159265358979323846
#define FREQUENCY 440.0
#define TIMEPERIOD 200

Platform::Platform(const char* title, int windowWidth, int windowHeight, int textureWidth, int textureHeight) {
  if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO) != 0) {
      std::cerr << "SDL initialization error: " << SDL_GetError() << std::endl;
  }
  
  window = SDL_CreateWindow(title, SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, windowWidth, windowHeight, SDL_WINDOW_SHOWN);
  renderer = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED);

  audioSpec.freq = SAMPLE_RATE;
  audioSpec.format = AUDIO_S16SYS;
  audioSpec.channels = 1;
  audioSpec.samples = 4096;
  audioSpec.userdata = this;
  beepRequested = false;
  audioSpec.callback = AudioCallback;

  audioDevice = SDL_OpenAudioDevice(nullptr, 0, &audioSpec, nullptr, 0);
  if (audioDevice == 0) {
      std::cerr << "Audio device opening error: " << SDL_GetError() << std::endl;
  }
  SDL_PauseAudioDevice(audioDevice, 0);
}

Platform::~Platform() {
  SDL_CloseAudioDevice(audioDevice);
  SDL_DestroyRenderer(renderer);
  SDL_DestroyWindow(window);
  SDL_Quit();
}

void Platform::Update(const std::bitset<2048> bitset, int videoScale) {
  SDL_SetRenderDrawColor(renderer, 0, 0, 0, 255);
  SDL_RenderClear(renderer);

  for (int y = 0; y < 32; ++y) {
    for (int x = 0; x < 64; ++x) {
        SDL_Rect pixelRect = {x * videoScale, y * videoScale, videoScale, videoScale};
      if (bitset[y * 64 + x]) {
        SDL_SetRenderDrawColor(renderer, 255, 255, 255, 255);
      } else {
        SDL_SetRenderDrawColor(renderer, 0, 0, 0, 255);
      }
      SDL_RenderFillRect(renderer, &pixelRect);
    }
  }
  SDL_RenderPresent(renderer);
}

bool Platform::ProcessInput(std::bitset<16>* keys) {
  bool quit = false;

  SDL_Event event;

  while (SDL_PollEvent(&event)) {
    switch (event.type) {
      case SDL_QUIT:
        quit = true;
        break;

      case SDL_KEYDOWN:
        switch (event.key.keysym.sym) {
          case SDLK_ESCAPE: quit = true;
          case SDLK_x: (*keys)[0x0] = 1; break;
          case SDLK_1: (*keys)[0x1] = 1; break;
          case SDLK_2: (*keys)[0x2] = 1; break;
          case SDLK_3: (*keys)[0x3] = 1; break;
          case SDLK_q: (*keys)[0x4] = 1; break;
          case SDLK_w: (*keys)[0x5] = 1; break;
          case SDLK_e: (*keys)[0x6] = 1; break;
          case SDLK_a: (*keys)[0x7] = 1; break;
          case SDLK_s: (*keys)[0x8] = 1; break;
          case SDLK_d: (*keys)[0x9] = 1; break;
          case SDLK_z: (*keys)[0xA] = 1; break;
          case SDLK_c: (*keys)[0xB] = 1; break;
          case SDLK_4: (*keys)[0xC] = 1; break;
          case SDLK_r: (*keys)[0xD] = 1; break;
          case SDLK_f: (*keys)[0xE] = 1; break;
          case SDLK_v: (*keys)[0xF] = 1; break;
        } break;

      case SDL_KEYUP:
        switch (event.key.keysym.sym) {
          case SDLK_x: (*keys)[0x0] = 0; break;
          case SDLK_1: (*keys)[0x1] = 0; break;
          case SDLK_2: (*keys)[0x2] = 0; break;
          case SDLK_3: (*keys)[0x3] = 0; break;
          case SDLK_q: (*keys)[0x4] = 0; break;
          case SDLK_w: (*keys)[0x5] = 0; break;
          case SDLK_e: (*keys)[0x6] = 0; break;
          case SDLK_a: (*keys)[0x7] = 0; break;
          case SDLK_s: (*keys)[0x8] = 0; break;
          case SDLK_d: (*keys)[0x9] = 0; break;
          case SDLK_z: (*keys)[0xA] = 0; break;
          case SDLK_c: (*keys)[0xB] = 0; break;
          case SDLK_4: (*keys)[0xC] = 0; break;
          case SDLK_r: (*keys)[0xD] = 0; break;
          case SDLK_f: (*keys)[0xE] = 0; break;
          case SDLK_v: (*keys)[0xF] = 0; break;
        }
    }
  }

  return quit;
}

void Platform::AudioCallback(void* userdata, uint8_t* stream, int len) {
  Platform* platform = static_cast<Platform*>(userdata);
  if (platform->beepRequested) {
      static double time = 0.0;

      int16_t* sample = reinterpret_cast<int16_t*>(stream);
      for (int i = 0; i < len / 2; i++) {
          int16_t value = static_cast<int16_t>(32767.0 * sin(2.0 * PI * FREQUENCY * time));
          sample[i] = value;
          time += 1.0 / SAMPLE_RATE;
      }
  } else {
      memset(stream, 0, len);
  }
}

void Platform::StartBeep() { beepRequested = true; }

void Platform::StopBeep(){ beepRequested = false; }