#include <stdio.h>
#include <stdlib.h>
#include "SDL.h"
#include "SDL_mixer.h"
#include "SDL_thread.h"

Mix_Chunk *phaser = NULL;
Mix_Music *music = NULL;

int phaserChannel = -1;

void handleKey(SDL_KeyboardEvent key);
void musicDone();

/*This function polls every 20 ms for new SDL_Events.
If it finds such events, it determines type and has a behaviour for different 
SDL_Keys. It can be called by SDL_Quit or other events.*/

int main(void) {
  SDL_Surface *screen;
  SDL_Event event;
  int done = 0, bits = 0, audio_rate = 44100, audio_channels = 2, 
  audio_buffers = 4096, volume = SDL_MIX_MAXVOLUME;
  Uint16 audio_format = AUDIO_S16; 

  // Opening the sound and graphic card
  SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO);
  if(Mix_OpenAudio(audio_rate, audio_format, audio_channels, audio_buffers)) {
    printf("Unable to open audio!\n");
    exit(1);
  }

  // Print out some info on the audio device and stream
  Mix_QuerySpec(&audio_rate, &audio_format, &audio_channels);
  bits=audio_format&0xFF;
  printf("Opened audio at %d Hz %d bit %s, %d bytes audio buffer\n", audio_rate, bits, audio_channels>1?"stereo":"mono", audio_buffers );

  // 
  phaser = Mix_LoadWAV("phaser.wav");
  screen = SDL_SetVideoMode(1024,768,0,SDL_FULLSCREEN|SDL_ANYFORMAT|SDL_HWSURFACE|SDL_DOUBLEBUF);
  SDL_WM_SetCaption("mixer4 - SDL_mixer demo","mixer4");
  SDL_ShowCursor(SDL_DISABLE);  
  
  while(!done) {
    while(SDL_PollEvent(&event)) {
      switch(event.type) {
      case SDL_QUIT:
	done = 1;
	break;
      case SDL_KEYDOWN:
	switch(event.key.keysym.sym){

	  // Escape and q exit the loop
	case SDLK_ESCAPE:
	  done = 1;
	  break;
	case SDLK_q:
	  done = 1;
	  break;

	  // Restart the music 
	case SDLK_r:
	  Mix_RewindMusic();
	  break;

	  // For future implementation with a mp3 -> fast forward and backwards
	case SDLK_LEFT:
	  switch(Mix_GetMusicType(NULL))
	    {
	    case MUS_MP3:
	      Mix_SetMusicPosition(-5);
	      break;
	    default:
	      printf("Cannot turn back this type of music\n");
	      break;
	    }
	  break;
	case SDLK_RIGHT:
	  switch(Mix_GetMusicType(NULL))
	    {
	    case MUS_MP3:
	      Mix_SetMusicPosition(+5);
	      break;
	      default:
		printf("cannot forward this type of music\n");
		break;
	    }
	  break;

	  // Up and down serve as volume control
	case SDLK_UP:
	  volume=(volume+1)<<1;
	  if(volume>SDL_MIX_MAXVOLUME)
	    volume=SDL_MIX_MAXVOLUME;
	    Mix_VolumeMusic(volume);
	    break;
	case SDLK_DOWN:
	  volume>>=1;
	  Mix_VolumeMusic(volume);
	  break;

	  // Stops the music and continues the music
	case SDLK_SPACE:
	  if(Mix_PausedMusic())
	    Mix_ResumeMusic();
	  else
	    Mix_PauseMusic();
	  break;

	  // Phaser
	case SDLK_p:
	  if(event.key.type == SDL_KEYDOWN) {
	    if(phaserChannel < 0) {
	      phaserChannel = Mix_PlayChannel(-1, phaser, -1);
	    }
	    else {
	      Mix_HaltChannel(phaserChannel);
	      phaserChannel = -1;
	    }
	  }
	  break;

	  // Music
	case SDLK_m:
	  if(event.key.state == SDL_PRESSED) {
	    if(music == NULL) {
	      music = Mix_LoadMUS("music.ogg");	
	      Mix_PlayMusic(music, 0);
	      Mix_HookMusicFinished(musicDone);
	    } else {
	      Mix_HaltMusic();
	      Mix_FreeMusic(music);
	      music = NULL;
	    }
	  }
	  break;
	default:
	  break;
	}
      }
      SDL_Delay(30);
    }
  }
  Mix_CloseAudio();
  SDL_Quit();
}
 
void musicDone() {
  Mix_HaltMusic();
  Mix_FreeMusic(music);
  music = NULL;
}