/*
    MACLIB:  A companion library to SDL for working with Macintosh (tm) data
    Copyright (C) 1997-2021 Sam Lantinga <slouken@libsdl.org>

    This program 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 2 of the License, or
    (at your option) any later version.

    This program 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 this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

#include <signal.h>

#include "Mac_Sound.h"
#include "Mac_Compat.h"

static int bogus_running = 0;

extern "C" {
static int BogusAudioThread(void *data)
{
	SDL_AudioSpec *spec;
	void (*fill)(void *userdata, Uint8 *stream, int len);
	Uint32 then;
	Uint32 playticks;
	Sint32 ticksleft;
	Uint8 *stream;

#ifdef NSIG
	/* Clear out any signal handlers */
	for ( int i = 0; i<NSIG; ++i )
		signal(i, SIG_DFL);
#else
	signal(SIGINT, SIG_DFL);
	signal(SIGSEGV, SIG_DFL);
	signal(SIGTERM, SIG_DFL);
#endif

	/* Get ready to roll.. */
	spec = (SDL_AudioSpec *)data;
	if ( spec->callback == NULL ) {
		for ( ; ; )
			Delay(60*60*60);	/* Delay 1 hour */
	}
	fill = spec->callback;
	playticks = ((Uint32)spec->samples*1000)/spec->freq;
	/* Fill in the spec */
	spec->size = (spec->format&0xFF)/8;
	spec->size *= spec->channels;
	spec->size *= spec->samples;
	stream = new Uint8[spec->size];

	while ( bogus_running ) {
		then = SDL_GetTicks();

		/* Fill buffer */
		if ( fill )
			(*fill)(spec->userdata, stream, spec->size);

		/* Calculate time left, and sleep */
		ticksleft = playticks-(SDL_GetTicks()-then);
		if ( ticksleft > 0 )
			SDL_Delay(ticksleft);
	}
	delete[] stream;

	return(0);
}

static void FillAudio(void *udata, Uint8 *stream, int len)
{
	Sound *sound = (Sound *)udata;
	
	Sound::FillAudioU8(sound, stream, len);
}
/* extern "C" */
};

Sound:: Sound(const char *soundfile, Uint8 vol)
{
	Wave         *wave;
	Mac_Resource *soundres;
	int           i, p;
	Uint16       *ids;
	Mac_ResData  *snd;

	/* Initialize variables */
	volume  = 0;
	playing = 0;
	bogus_audio = NULL;
	InitHash();
	errstr = NULL;

	/* Load the sounds from the resource files */
	soundres = new Mac_Resource(soundfile);
	if ( soundres->Error() ) {
		error("%s", soundres->Error());
		return;
	}
	if ( soundres->NumResources("snd ") == 0 ) {
		error("No sound resources in '%s'", soundfile);
		return;
	}
	ids = soundres->ResourceIDs("snd ");
	wave = NULL;
	for ( i=0; ids[i] != 0xFFFF; ++i ) {
		snd = soundres->Resource("snd ", ids[i]);
		if ( snd == NULL ) {
			error("%s", soundres->Error());
			delete soundres;
			return;
		}
		wave = new Wave(snd, DSP_FREQUENCY);
		if ( wave->Error() ) {
			error("%s", wave->Error());
			delete wave;
			delete soundres;
			return;
		}
		Hash(ids[i], wave);
	}
	delete soundres;
	spec = wave->Spec();
	/* Allow ~ 1/30 second time-lag in audio buffer -- samples is x^2  */
	spec->samples = (wave->Frequency()*wave->SampleSize())/30;
	for ( p = 0; spec->samples > 1; ++p )
		spec->samples /= 2;
	++p;
	for ( i = 0; i < p; ++i )
		spec->samples *= 2;
	spec->callback = FillAudio;
	spec->userdata = (void *)this;

	/* Empty the channels and start the music :-) */
	HaltSound();
	if ( vol == 0 ) {
		bogus_running = 1;
		bogus_audio = SDL_CreateThread(BogusAudioThread, "Maelstrom Audio", spec);
	} else {
		Volume(vol);
	}
}

Sound:: ~Sound()
{
	if ( playing )
		SDL_CloseAudio();
	else
	if ( bogus_audio ) {
		bogus_running = 0;
		SDL_WaitThread(bogus_audio, NULL);
		bogus_audio = NULL;
	}
	FreeHash();
}

Uint8
Sound:: Volume(Uint8 vol)
{
	Uint8 active;

	active = playing;
	if ( (volume == 0) && (vol > 0) ) {
		/* Kill bogus sound thread */
		if ( bogus_audio ) {
			bogus_running = 0;
			SDL_WaitThread(bogus_audio, NULL);
			bogus_audio = NULL;
		}

		/* Try to open the audio */
		if ( SDL_OpenAudio(spec, NULL) < 0 )
			vol = 0;		/* Fake sound */
		active = 1;
		SDL_PauseAudio(0);		/* Go! */
	}
	if ( vol > MAX_VOLUME )
		vol = MAX_VOLUME;
	volume = vol;

	if ( active && (volume == 0) ) {
		if ( playing )
			SDL_CloseAudio();
		active = 0;

		/* Run bogus sound thread */
		bogus_running = 1;
		bogus_audio = SDL_CreateThread(BogusAudioThread, "Maelstrom Audio", spec);
		if ( bogus_audio == NULL ) {
			/* Oh well... :-) */
		}
	}
	playing = active;
	return(volume);
}

int
Sound:: PlaySound(Uint16 sndID, Uint8 priority, Uint8 channel,
					void (*callback)(Uint8 channel))
{
	Wave *wave;

	if ( priority <= Priority(channel) )
		return(-1);

	wave = Hash(sndID);
	if ( wave == NULL )
		return(-1);

	channels[channel].ID = sndID;
	channels[channel].priority = priority;
	channels[channel].len = wave->DataLeft();
	channels[channel].src = wave->Data();
	channels[channel].callback = callback;
#ifdef DEBUG_SOUND
printf("Playing sound %hu on channel %d\n", sndID, channel);
#endif
	return(0);
}

/* This has to be a very fast routine, otherwise sound will lag and crackle */
void
Sound:: FillAudioU8(Sound *sound, Uint8 *stream, int len)
{
	int i, s;

	/* Mix in each of the channels, assuming 8-bit unsigned audio data */
	while ( len-- ) {
		s = 0;
		for ( i=0; i<NUM_CHANNELS; ++i ) {
			if ( sound->channels[i].len > 0 ) {
				/*
				  Possible race condition:
				  If the channel is halted here,
					len = 0 then we do '--len'
				  len = -1, but that's okay.
				*/
				--sound->channels[i].len;
				s += *(sound->channels[i].src)-0x80;
				++sound->channels[i].src;
				/*
				  Possible race condition:
				  If a sound is played here,
					len > 0, then we do 'if len <= 0'
				  We never call back on channel.. bad.
				*/
				if ( sound->channels[i].len <= 0 ) {
#ifdef DEBUG_SOUND
printf("Channel %d finished\n", i);
#endif
					/* This is critical */
					void (*callback)(Uint8);
					callback = sound->channels[i].callback;
					if ( callback )
						(*callback)(i);
				}
			}
		}
		/* handle volume */
		s = (s*sound->volume)/MAX_VOLUME;

		/* convert to 8-bit unsigned */
		s += 0x80;

		/* clip */
		if ( s > 0xFE )	/* 0xFF causes static on some audio systems */
			*stream++ = 0xFE;
		else
		if ( s < 0x00 )
			*stream++ = 0x00;
		else
			*stream++ = (Uint8)s;
	}
}