/*
 * audio.c
 *
 * Moo like a cow
 *
 * (c) 2008-2009 Thomas White <taw@bitwiz.org.uk>
 *
 * This file is part of OpenMooCow - accelerometer moobox simulator
 *
 * OpenMooCow is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * OpenMooCow is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with OpenMooCow.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

/* SDL's headers don't like this. Grr. */
//#ifdef HAVE_CONFIG_H
//#include <config.h>
//#endif

#include <stdlib.h>
#include <stdarg.h>
#include <stdio.h>
#include <SDL.h>
#include <SDL_audio.h>
#include <math.h>
#include <sys/types.h>
#include <unistd.h>
#include <sys/wait.h>
#include <assert.h>

#include "types.h"
#include "audio.h"

static AudioContext *audio_context = NULL;

static void audio_mix(void *data, Uint8 *stream8, int len)
{
	AudioContext *a = data;
	int j;
	Sint16 *stream = (Sint16 *)stream8;
	Sint16 samp;

	len /= 2;	/* Number of samples to write */

	for ( j=0; j<len; j++ ) {

		stream[j] = 0;

		if ( a->moo_pos < a->moo_len ) {
			samp = a->moo_buf[a->moo_pos++];
			stream[j] += samp;
		} else {
			a->mootex = 0;
		}

	}
}

void audio_trigger_moo()
{
	AudioContext *a = audio_context;

	if ( a == NULL ) {
		/* Try to open the audio again */
		printf("Trying to open the audio again...\n");
		audio_setup();
		a = audio_context;
		if ( a == NULL ) return;
	}
	if ( a->mootex != 0 ) {
		printf("Mootex says 'no'\n");
		return;
	}

	printf("Moo!\n");
	a->mootex = 1;

	if ( a->moo_pos == a->moo_len ) {
		a->moo_pos = 0;
	}
}

/* SDL audio initial setup */
void audio_setup()
{
	AudioContext *a;
	SDL_AudioSpec fmt;
	SDL_AudioSpec wave;
	Uint8 *data;
	Uint32 dlen;
	SDL_AudioCVT cvt;

	/* Create audio context */
	a = malloc(sizeof(AudioContext));
	assert(a != NULL);
	a->mootex = 0;

	/* 16-bit mono audio at 44.1 kHz */
	fmt.freq = 44100;
	fmt.format = AUDIO_S16;
	fmt.channels = 1;
	fmt.samples = 512;
	fmt.callback = audio_mix;
	fmt.userdata = a;
	fmt.silence = 0;

	if ( SDL_OpenAudio(&fmt, NULL) < 0 ) {
		fprintf(stderr, "Unable to open audio: %s\n", SDL_GetError());
		free(a);
		return;
	}

	if ( SDL_LoadWAV(DATADIR"/openmoocow/moo.wav", &wave, &data, &dlen)
								== NULL ) {
		fprintf(stderr, "Couldn't load moo sound: %s\n",
				SDL_GetError());
		free(a);
		return;
	}
	SDL_BuildAudioCVT(&cvt, wave.format, wave.channels, wave.freq,
				AUDIO_S16, 1, 44100);
	cvt.buf = malloc(dlen*cvt.len_mult);
	if ( cvt.buf == NULL ) {
		fprintf(stderr, "Not enough memory to convert audio \n");
		free(a);
		return;
	}
	memcpy(cvt.buf, data, dlen);
	cvt.len = dlen;
	SDL_ConvertAudio(&cvt);
	SDL_FreeWAV(data);

	a->moo_len = cvt.len_cvt/2 - 2;	/* Convert bytes to samples */
	a->moo_pos = a->moo_len;	/* Play nothing to start with */
	a->moo_buf = (Sint16 *)cvt.buf;

	audio_context = a;

	SDL_PauseAudio(0);
}

void audio_shutdown()
{
	AudioContext *a = audio_context;

	if ( a == NULL ) return;

	SDL_CloseAudio();

	/* Now this can be freed */
	free(a);
}