/*

    SDL - Simple DirectMedia Layer

    Copyright (C) 1997-2006 Sam Lantinga

    This library is free software; you can redistribute it and/or

    modify it under the terms of the GNU Lesser General Public

    License as published by the Free Software Foundation; either

    version 2.1 of the License, or (at your option) any later version.

    This library 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

    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public

    License along with this library; if not, write to the Free Software

    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Sam Lantinga

    slouken@libsdl.org

*/

#include "SDL_config.h"

/* Output dreamcast aica */

#include "SDL_timer.h"

#include "SDL_audio.h"

#include "../SDL_audiomem.h"

#include "../SDL_audio_c.h"

#include "../SDL_audiodev_c.h"

#include "SDL_dcaudio.h"

#include "aica.h"

#include <dc/spu.h>

/* Audio driver functions */

static int DCAUD_OpenAudio(_THIS, SDL_AudioSpec *spec);

static void DCAUD_WaitAudio(_THIS);

static void DCAUD_PlayAudio(_THIS);

static Uint8 *DCAUD_GetAudioBuf(_THIS);

static void DCAUD_CloseAudio(_THIS);

/* Audio driver bootstrap functions */

static int DCAUD_Available(void)

{

	return 1;

}

static void DCAUD_DeleteDevice(SDL_AudioDevice *device)

{

	SDL_free(device->hidden);

	SDL_free(device);

}

static SDL_AudioDevice *DCAUD_CreateDevice(int devindex)

{

	SDL_AudioDevice *this;

	/* Initialize all variables that we clean on shutdown */

	this = (SDL_AudioDevice *)SDL_malloc(sizeof(SDL_AudioDevice));

	if ( this ) {

		SDL_memset(this, 0, (sizeof *this));

		this->hidden = (struct SDL_PrivateAudioData *)

				SDL_malloc((sizeof *this->hidden));

	}

	if ( (this == NULL) || (this->hidden == NULL) ) {

		SDL_OutOfMemory();

		if ( this ) {

			SDL_free(this);

		}

		return(0);

	}

	SDL_memset(this->hidden, 0, (sizeof *this->hidden));

	/* Set the function pointers */

	this->OpenAudio = DCAUD_OpenAudio;

	this->WaitAudio = DCAUD_WaitAudio;

	this->PlayAudio = DCAUD_PlayAudio;

	this->GetAudioBuf = DCAUD_GetAudioBuf;

	this->CloseAudio = DCAUD_CloseAudio;

	this->free = DCAUD_DeleteDevice;

	spu_init();

	return this;

}

AudioBootStrap DCAUD_bootstrap = {

	"dcaudio", "Dreamcast AICA audio",

	DCAUD_Available, DCAUD_CreateDevice

};

/* This function waits until it is possible to write a full sound buffer */

static void DCAUD_WaitAudio(_THIS)

{

	if (this->hidden->playing) {

		/* wait */

		while(aica_get_pos(0)/this->spec.samples == this->hidden->nextbuf) {

			thd_pass();

		}

	}

}

#define	SPU_RAM_BASE	0xa0800000

static void spu_memload_stereo8(int leftpos,int rightpos,void *src0,size_t size)

{

	uint8 *src = src0;

	uint32 *left  = (uint32*)(leftpos +SPU_RAM_BASE);

	uint32 *right = (uint32*)(rightpos+SPU_RAM_BASE);

	size = (size+7)/8;

	while(size--) {

		unsigned lval,rval;

		lval = *src++;

		rval = *src++;

		lval|= (*src++)<<8;

		rval|= (*src++)<<8;

		lval|= (*src++)<<16;

		rval|= (*src++)<<16;

		lval|= (*src++)<<24;

		rval|= (*src++)<<24;

		g2_write_32(left++,lval);

		g2_write_32(right++,rval);

		g2_fifo_wait();

	}

}

static void spu_memload_stereo16(int leftpos,int rightpos,void *src0,size_t size)

{

	uint16 *src = src0;

	uint32 *left  = (uint32*)(leftpos +SPU_RAM_BASE);

	uint32 *right = (uint32*)(rightpos+SPU_RAM_BASE);

	size = (size+7)/8;

	while(size--) {

		unsigned lval,rval;

		lval = *src++;

		rval = *src++;

		lval|= (*src++)<<16;

		rval|= (*src++)<<16;

		g2_write_32(left++,lval);

		g2_write_32(right++,rval);

		g2_fifo_wait();

	}

}

static void DCAUD_PlayAudio(_THIS)

{

	SDL_AudioSpec *spec = &this->spec;

	unsigned int offset;

	if (this->hidden->playing) {

		/* wait */

		while(aica_get_pos(0)/spec->samples == this->hidden->nextbuf) {

			thd_pass();

		}

	}

	offset = this->hidden->nextbuf*spec->size;

	this->hidden->nextbuf^=1;

	/* Write the audio data, checking for EAGAIN on broken audio drivers */

	if (spec->channels==1) {

		spu_memload(this->hidden->leftpos+offset,this->hidden->mixbuf,this->hidden->mixlen);

	} else {

		offset/=2;

		if ((this->spec.format&255)==8) {

			spu_memload_stereo8(this->hidden->leftpos+offset,this->hidden->rightpos+offset,this->hidden->mixbuf,this->hidden->mixlen);

		} else {

			spu_memload_stereo16(this->hidden->leftpos+offset,this->hidden->rightpos+offset,this->hidden->mixbuf,this->hidden->mixlen);

		}

	}

	if (!this->hidden->playing) {

		int mode;

		this->hidden->playing = 1;

		mode = (spec->format==AUDIO_S8)?SM_8BIT:SM_16BIT;

		if (spec->channels==1) {

			aica_play(0,mode,this->hidden->leftpos,0,spec->samples*2,spec->freq,255,128,1);

		} else {

			aica_play(0,mode,this->hidden->leftpos ,0,spec->samples*2,spec->freq,255,0,1);

			aica_play(1,mode,this->hidden->rightpos,0,spec->samples*2,spec->freq,255,255,1);

		}

	}

}

static Uint8 *DCAUD_GetAudioBuf(_THIS)

{

	return(this->hidden->mixbuf);

}

static void DCAUD_CloseAudio(_THIS)

{

	aica_stop(0);

	if (this->spec.channels==2) aica_stop(1);

	if ( this->hidden->mixbuf != NULL ) {

		SDL_FreeAudioMem(this->hidden->mixbuf);

		this->hidden->mixbuf = NULL;

	}

}

static int DCAUD_OpenAudio(_THIS, SDL_AudioSpec *spec)

{

    Uint16 test_format = SDL_FirstAudioFormat(spec->format);

    int valid_datatype = 0;

    while ((!valid_datatype) && (test_format)) {

        spec->format = test_format;

        switch (test_format) {

            /* only formats Dreamcast accepts... */

            case AUDIO_S8:

            case AUDIO_S16LSB:

                valid_datatype = 1;

                break;

            default:

                test_format = SDL_NextAudioFormat();

                break;

        }

    }

    if (!valid_datatype) {  /* shouldn't happen, but just in case... */

        SDL_SetError("Unsupported audio format");

        return (-1);

    }

    if (spec->channels > 2)

        spec->channels = 2;  /* no more than stereo on the Dreamcast. */

	/* Update the fragment size as size in bytes */

	SDL_CalculateAudioSpec(spec);

	/* Allocate mixing buffer */

	this->hidden->mixlen = spec->size;

	this->hidden->mixbuf = (Uint8 *) SDL_AllocAudioMem(this->hidden->mixlen);

	if ( this->hidden->mixbuf == NULL ) {

		return(-1);

	}

	SDL_memset(this->hidden->mixbuf, spec->silence, spec->size);

	this->hidden->leftpos = 0x11000;

	this->hidden->rightpos = 0x11000+spec->size;

	this->hidden->playing = 0;

	this->hidden->nextbuf = 0;

	/* We're ready to rock and roll. :-) */

	return(0);

}