/*
 * Ogg/Vorbis streaming music support, loosely based on several open source
 * Quake engine based projects with many modifications.
 *
 * Copyright (C) 2010-2012 O.Sezer <sezero@users.sourceforge.net>
 *
 * 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.,
 * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 */

#include "q_defs.h"

#if USE_CODEC_VORBIS
#include "snd_codec.h"
#include "snd_codeci.h"

#define OV_EXCLUDE_STATIC_CALLBACKS
#include <vorbis/vorbisfile.h>

/* Vorbis codec can return the samples in a number of different
 * formats, we use the standard int16_t format. */
#define VORBIS_SAMPLEBITS 16
#define VORBIS_SAMPLEWIDTH 2
#define VORBIS_SIGNED_DATA 1

/* CALLBACK FUNCTIONS: */
static size_t ovc_fread(void *ptr, size_t size, size_t nmemb, void *fh)
{
	return FS_fread(ptr, size, nmemb, fh);
}

static int32_t ovc_fseek(void *f, ogg_int64_t off, int32_t whence)
{
	if(f == NULL) return -1;
	return FS_fseek(f, (long)off, whence);
}

static long ovc_ftell(void *f)
{
	return (long)FS_ftell(f);
}

static int32_t ovc_fclose(void *f)
{
	(void)f;
	return 0; /* we fclose() elsewhere. */
}

static ov_callbacks ovc_qfs =
{
	.read_func  = ovc_fread,
	.seek_func  = ovc_fseek,
	.tell_func  = ovc_ftell,
	.close_func = ovc_fclose,
};

static bool S_VORBIS_CodecInitialize(void)
{
	return true;
}

static void S_VORBIS_CodecShutdown(void)
{
}

static bool S_VORBIS_CodecOpenStream(snd_stream_t *stream)
{
	OggVorbis_File *ovFile;
	vorbis_info *ovf_info;
	long numstreams;
	int32_t res;

	ovFile = (OggVorbis_File *) Z_Malloc(sizeof(OggVorbis_File));
	stream->priv = ovFile;
	res = ov_open_callbacks(&stream->fh, ovFile, NULL, 0, ovc_qfs);
	if(res != 0)
	{
		Con_Printf("%s is not a valid Ogg Vorbis file (error %" PRIi32 ").\n",
		           stream->name, res);
		goto fail;
	}

	if(!ov_seekable(ovFile))
	{
		Con_Printf("Stream %s not seekable.\n", stream->name);
		goto fail;
	}

	ovf_info = ov_info(ovFile, 0);
	if(!ovf_info)
	{
		Con_Printf("Unable to get stream info for %s.\n", stream->name);
		goto fail;
	}

	/* FIXME: handle section changes */
	numstreams = ov_streams(ovFile);
	if(numstreams != 1)
	{
		Con_Printf("More than one (%li) stream in %s.\n",
		           numstreams, stream->name);
		goto fail;
	}

	if(ovf_info->channels != 1 && ovf_info->channels != 2)
	{
		Con_Printf("Unsupported number of channels %" PRIi32 " in %s\n",
		           ovf_info->channels, stream->name);
		goto fail;
	}

	stream->info.rate = ovf_info->rate;
	stream->info.channels = ovf_info->channels;
	stream->info.bits = VORBIS_SAMPLEBITS;
	stream->info.width = VORBIS_SAMPLEWIDTH;

	return true;
fail:
	if(res == 0)
		ov_clear(ovFile);
	Z_Free(ovFile);
	return false;
}

static int32_t S_VORBIS_CodecReadStream(snd_stream_t *stream, int32_t bytes, void *buffer)
{
	int32_t section;        /* FIXME: handle section changes */
	int32_t cnt, res, rem;
	char *  ptr;

	cnt = 0;
	rem = bytes;
	ptr = (char *) buffer;
	while(1)
	{
		/* # ov_read() from libvorbisfile returns the decoded PCM audio
		 *   in requested endianness, signedness and word size.
		 * # ov_read() from Tremor (libvorbisidec) returns decoded audio
		 *   always in host-endian, signed 16 bit PCM format.
		 * # For both of the libraries, if the audio is multichannel,
		 *   the channels are interleaved in the output buffer.
		 */
		res = ov_read((OggVorbis_File *)stream->priv, ptr, rem,
		              HOST_BIGENDIAN,
		              VORBIS_SAMPLEWIDTH,
		              VORBIS_SIGNED_DATA,
		              & section);
		if(res <= 0)
			break;
		rem -= res;
		cnt += res;
		if(rem <= 0)
			break;
		ptr += res;
	}

	if(res < 0)
		return res;
	return cnt;
}

static void S_VORBIS_CodecCloseStream(snd_stream_t *stream)
{
	ov_clear((OggVorbis_File *)stream->priv);
	Z_Free(stream->priv);
	S_CodecUtilClose(&stream);
}

static int32_t S_VORBIS_CodecRewindStream(snd_stream_t *stream)
{
	/* for libvorbisfile, the ov_time_seek() position argument
	 * is seconds as doubles, whereas for Tremor libvorbisidec
	 * it is milliseconds as 64 bit integers.
	 */
	return ov_time_seek((OggVorbis_File *)stream->priv, 0);
}

snd_codec_t vorbis_codec =
{
	CODECTYPE_VORBIS,
	true,   /* always available. */
	"ogg",
	S_VORBIS_CodecInitialize,
	S_VORBIS_CodecShutdown,
	S_VORBIS_CodecOpenStream,
	S_VORBIS_CodecReadStream,
	S_VORBIS_CodecRewindStream,
	S_VORBIS_CodecCloseStream,
};

#endif /* USE_CODEC_VORBIS */