/**
 * Copyright (c) 2022 Dominic Masters
 * 
 * This software is released under the MIT License.
 * https://opensource.org/licenses/MIT
 */

#include "DawnGLFWHost.hpp"
#include "game/DawnGame.hpp"
#include "dawnopengl.hpp"
#include "display/BackBufferRenderTarget.hpp"

#include <AL/al.h>
#include <AL/alc.h>
#include "AudioFile.h"

using namespace Dawn;

// Static declaration of the host, needed due to GLFW events being C-like
DawnHost *DAWN_HOST = nullptr;

// Host
DawnHost::DawnHost() {
  this->data = new DawnHostData();
  this->data->window = nullptr;
}

int32_t DawnHost::init(DawnGame *game) {
  AudioFile<double> audioFile;
  audioFile.load ("C:\\sample.wav");
  audioFile.printSummary();

  ALCdevice* device = alcOpenDevice(nullptr);
  if(!device) assertUnreachable();
  
  ALCcontext *context;
  context = alcCreateContext(device, NULL);
  if(!alcMakeContextCurrent(context)) assertUnreachable();

  ALfloat listenerOri[] = { 0.0f, 0.0f, 1.0f, 0.0f, 1.0f, 0.0f };
  alListener3f(AL_POSITION, 0, 0, 1.0f);
  alListener3f(AL_VELOCITY, 0, 0, 0);
  alListenerfv(AL_ORIENTATION, listenerOri);

  ALuint source;
  alGenSources((ALuint)1, &source);
  alSourcef(source, AL_PITCH, 1);
  alSourcef(source, AL_GAIN, 1);
  alSource3f(source, AL_POSITION, 0, 0, 0);
  alSource3f(source, AL_VELOCITY, 0, 0, 0);
  alSourcei(source, AL_LOOPING, AL_FALSE);

  ALuint buffer;
  alGenBuffers((ALuint)1, &buffer);

  ALenum format;
  switch(audioFile.getBitDepth()) {
    case 16:
      switch(audioFile.getNumChannels()) {
        case 2:
          format = AL_FORMAT_STEREO16;
          break;
        case 1:
          format = AL_FORMAT_MONO16;
          break;
        default:
          assertUnreachable();
      }
      break;

    case 8:
      switch(audioFile.getNumChannels()) {
        case 2:
          format = AL_FORMAT_STEREO8;
          break;
        case 1:
          format = AL_FORMAT_MONO8;
          break;
        default:
          assertUnreachable();
      }
      break;
    
    default:
      assertUnreachable();
  }

  std::vector<uint8_t> data;
  for (int i = 0; i < audioFile.getNumSamplesPerChannel(); i++) {
    for(int y = 0; y < audioFile.getNumChannels(); y++) {
      double sample = audioFile.samples[y][i];
      sample = mathClamp(sample, -1., 1.);
      auto q = static_cast<int16_t> (sample * 32767.);
      
      uint8_t bytes[2];
      bytes[0] = (q >> 8) & 0xFF;
      bytes[1] = q & 0xFF;
      data.push_back(bytes[1]);
      data.push_back(bytes[0]);
    }
  }
  alBufferData(buffer, format, &data[0], data.size(), audioFile.getSampleRate());

	ALint source_state;
  alSourcei(source, AL_BUFFER, buffer);
	alSourcePlay(source);
	alGetSourcei(source, AL_SOURCE_STATE, &source_state);
	while (source_state == AL_PLAYING) {
		alGetSourcei(source, AL_SOURCE_STATE, &source_state);
	}

  return DAWN_HOST_INIT_RESULT_SUCCESS;


  // Update values
  this->game = game;
  DAWN_HOST = this;

  // Init GLFW
  if(!glfwInit()) return DAWN_GLFW_INIT_RESULT_INIT_FAILED;

  glfwSetErrorCallback(&glfwOnError);
  
  // Setup window hints 
  glfwWindowHint(GLFW_OPENGL_DEBUG_CONTEXT, false);
  
  // Create Window
  this->data->window = glfwCreateWindow(
    DAWN_GLFW_WINDOW_WIDTH_DEFAULT,
    DAWN_GLFW_WINDOW_HEIGHT_DEFAULT,
    "Dawn", NULL, NULL
  );
  if(this->data->window == nullptr) {
    glfwTerminate();
    return DAWN_GLFW_INIT_RESULT_WINDOW_CREATE_FAILED;
  }

  // Load GLAD
  glfwMakeContextCurrent(this->data->window);
  glfwSwapInterval(0);
  gladLoadGLLoader((GLADloadproc)glfwGetProcAddress);

  // Override the defaults
  game->renderManager.backBuffer.setSize(
    DAWN_GLFW_WINDOW_WIDTH_DEFAULT,
    DAWN_GLFW_WINDOW_HEIGHT_DEFAULT
  );

  // Default keybinds
  game->inputManager.bind(INPUT_BIND_ACCEPT, GLFW_KEY_ENTER);
  game->inputManager.bind(INPUT_BIND_ACCEPT, GLFW_KEY_E);
  game->inputManager.bind(INPUT_BIND_ACCEPT, GLFW_KEY_SPACE);
  // game->inputManager.bind(INPUT_BIND_NEGATIVE_X, GLFW_KEY_A);
  // game->inputManager.bind(INPUT_BIND_POSITIVE_X, GLFW_KEY_D);
  // game->inputManager.bind(INPUT_BIND_NEGATIVE_Y, GLFW_KEY_S);
  // game->inputManager.bind(INPUT_BIND_POSITIVE_Y, GLFW_KEY_W);

  // Initialize the game
  auto result = game->init();
  if(result != DAWN_GAME_INIT_RESULT_SUCCESS) return result;

  // Hard-Load the first scene assets.
  if(game->scene != nullptr) {
    auto assets = game->scene->getRequiredAssets();
    game->assetManager.queueLoad(assets);
    game->assetManager.syncLoad();
    game->scene->stage();
  }

  // Set up event listeners
  glfwSetFramebufferSizeCallback(this->data->window, &glfwOnResize);
  glfwSetKeyCallback(this->data->window, &glfwOnKey);

  return DAWN_HOST_INIT_RESULT_SUCCESS;
}

int32_t DawnHost::start(DawnGame *game) {
  double_t time, newTime;
  float_t fDelta;
  int32_t updateResult;

  // Main Render Loop 
  time = 0.0f;
  while(!glfwWindowShouldClose(this->data->window)) {
    // Determine the delta.
    newTime = glfwGetTime();
    fDelta = (float_t)(newTime - time);
    time = newTime;

    // Perform update
    updateResult = this->update(game, fDelta);

    // Did the update complete successfully?
    if(updateResult == DAWN_HOST_UPDATE_RESULT_EXIT) {
      break;
    } else if(updateResult != DAWN_HOST_UPDATE_RESULT_SUCCESS) {
      return DAWN_GLFW_START_RESULT_UPDATE_FAILED;
    }
    
    // Tick the engine.
    glfwSwapBuffers(this->data->window);
    
    // Update events
    glfwPollEvents();
  }

  return DAWN_HOST_START_RESULT_EXIT_SUCCESS;
}

int32_t DawnHost::update(DawnGame *game, float_t delta) {
  // Tick game.
  auto ret = game->update(delta);
  switch(ret) {
    case DAWN_GAME_UPDATE_RESULT_SUCCESS:
      return DAWN_HOST_UPDATE_RESULT_SUCCESS;
    
    case DAWN_GAME_UPDATE_RESULT_EXIT:
      return DAWN_HOST_UPDATE_RESULT_EXIT;

    default:
      return ret;
  }
}

void DawnHost::unload(DawnGame *game) {
  glfwDestroyWindow(this->data->window);
  this->data->window = nullptr;
  glfwTerminate();
}

DawnHost::~DawnHost() {
  delete this->data;
  DAWN_HOST = nullptr;
}


// GLFW Callbacks
void glfwOnError(int error, const char* description) {
  fputs(description, stderr);
}

void glfwOnResize(GLFWwindow *window, int32_t w, int32_t h) {
  if(DAWN_HOST == nullptr) return;

  // TODO: I may throttle this, it calls for every frame the window's resized.
  DAWN_HOST->game->renderManager.backBuffer.setSize((float_t)w, (float_t)h);
}

void glfwOnKey(
  GLFWwindow *window,
  int32_t key,
  int32_t scancode,
  int32_t action,
  int32_t mods
) {
  if(DAWN_HOST == nullptr) return;

  // Determine Value
  float_t value;
  if(action == GLFW_PRESS) {
    value = 1.0f;
  } else if(action == GLFW_RELEASE) {
    value = 0.0f;
  } else {
    return;
  }

  // Determine the input axis
  DAWN_HOST->game->inputManager.rawInputValues[key] = value;
}