/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 1999 - 2005, Digium, Inc.
 *
 * Mark Spencer <markster@digium.com>
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */

/*! \file
 *
 * \brief Work with WAV in the proprietary Microsoft format.
 * Microsoft WAV format (8000hz Signed Linear)
 * \arg File name extension: wav (lower case)
 * \ingroup formats
 */

/*** MODULEINFO
	<support_level>core</support_level>
 ***/

#include "asterisk.h"

#include "asterisk/mod_format.h"
#include "asterisk/module.h"
#include "asterisk/endian.h"
#include "asterisk/format_cache.h"
#include "asterisk/format.h"
#include "asterisk/codec.h"

/* Some Ideas for this code came from makewave.c by Jeffrey Chilton */

/* Portions of the conversion code are by guido@sienanet.it */

#define	WAV_BUF_SIZE	320

#define WAV_HEADER_SIZE 44

struct wav_desc {	/* format-specific parameters */
	int hz;
	int bytes;
	int lasttimeout;
	int maxlen;
	struct timeval last;
};

#define BLOCKSIZE 160

#if __BYTE_ORDER == __LITTLE_ENDIAN
#define htoll(b) (b)
#define htols(b) (b)
#define ltohl(b) (b)
#define ltohs(b) (b)
#else
#if __BYTE_ORDER == __BIG_ENDIAN
#define htoll(b) \
	(((((b)      ) & 0xFF) << 24) | \
	((( (b) >>  8) & 0xFF) << 16) | \
	((( (b) >> 16) & 0xFF) <<  8) | \
	((( (b) >> 24) & 0xFF)      ))
#define htols(b) \
	(((((b)      ) & 0xFF) <<  8) | \
	((( (b) >>  8) & 0xFF)      ))
#define ltohl(b) htoll(b)
#define ltohs(b) htols(b)
#else
#error "Endianess not defined"
#endif
#endif


static int check_header_fmt(FILE *f, int hsize, int hz)
{
	unsigned short format, chans, bysam, bisam;
	unsigned int freq, bysec;
	if (hsize < 16) {
		ast_log(LOG_WARNING, "Unexpected header size %d\n", hsize);
		return -1;
	}
	if (fread(&format, 1, 2, f) != 2) {
		ast_log(LOG_WARNING, "Read failed (format)\n");
		return -1;
	}
	if (ltohs(format) != 1) {
		ast_log(LOG_WARNING, "Not a supported wav file format (%d). Only PCM encoded, 16 bit, mono, 8kHz/16kHz files are supported with a lowercase '.wav' extension.\n", ltohs(format));
		return -1;
	}
	if (fread(&chans, 1, 2, f) != 2) {
		ast_log(LOG_WARNING, "Read failed (format)\n");
		return -1;
	}
	if (ltohs(chans) != 1) {
		ast_log(LOG_WARNING, "Not in mono %d\n", ltohs(chans));
		return -1;
	}
	if (fread(&freq, 1, 4, f) != 4) {
		ast_log(LOG_WARNING, "Read failed (freq)\n");
		return -1;
	}
	freq = ltohl(freq);
	if ((freq != 8000 && freq != 16000) || freq != hz) {
		ast_log(LOG_WARNING, "Unexpected frequency mismatch %d (expecting %d)\n", freq, hz);
		return -1;
	}
	/* Ignore the byte frequency */
	if (fread(&bysec, 1, 4, f) != 4) {
		ast_log(LOG_WARNING, "Read failed (BYTES_PER_SECOND)\n");
		return -1;
	}
	/* Check bytes per sample */
	if (fread(&bysam, 1, 2, f) != 2) {
		ast_log(LOG_WARNING, "Read failed (BYTES_PER_SAMPLE)\n");
		return -1;
	}
	if (ltohs(bysam) != 2) {
		ast_log(LOG_WARNING, "Can only handle 16bits per sample: %d\n", ltohs(bysam));
		return -1;
	}
	if (fread(&bisam, 1, 2, f) != 2) {
		ast_log(LOG_WARNING, "Read failed (Bits Per Sample): %d\n", ltohs(bisam));
		return -1;
	}
	/* Skip any additional header */
	if (fseek(f,hsize-16,SEEK_CUR) == -1 ) {
		ast_log(LOG_WARNING, "Failed to skip remaining header bytes: %d\n", hsize-16 );
		return -1;
	}
	return 0;
}

static int check_header(FILE *f, int hz)
{
	int type, size, formtype;
	int data;
	if (fread(&type, 1, 4, f) != 4) {
		ast_log(LOG_WARNING, "Read failed (type)\n");
		return -1;
	}
	if (fread(&size, 1, 4, f) != 4) {
		ast_log(LOG_WARNING, "Read failed (size)\n");
		return -1;
	}
#if __BYTE_ORDER == __BIG_ENDIAN
	size = ltohl(size);
#endif
	if (fread(&formtype, 1, 4, f) != 4) {
		ast_log(LOG_WARNING, "Read failed (formtype)\n");
		return -1;
	}
	if (memcmp(&type, "RIFF", 4)) {
		ast_log(LOG_WARNING, "Does not begin with RIFF\n");
		return -1;
	}
	if (memcmp(&formtype, "WAVE", 4)) {
		ast_log(LOG_WARNING, "Does not contain WAVE\n");
		return -1;
	}
	/* Skip any facts and get the first data block */
	for(;;)
	{
		char buf[4];

		/* Begin data chunk */
		if (fread(&buf, 1, 4, f) != 4) {
			ast_log(LOG_WARNING, "Read failed (block header format)\n");
			return -1;
		}
		/* Data has the actual length of data in it */
		if (fread(&data, 1, 4, f) != 4) {
			ast_log(LOG_WARNING, "Read failed (block '%.4s' header length)\n", buf);
			return -1;
		}
#if __BYTE_ORDER == __BIG_ENDIAN
		data = ltohl(data);
#endif
		if (memcmp(&buf, "fmt ", 4) == 0) {
			if (check_header_fmt(f, data, hz))
				return -1;
			continue;
		}
		if(memcmp(buf, "data", 4) == 0 )
			break;
		ast_log(LOG_DEBUG, "Skipping unknown block '%.4s'\n", buf);
		if (fseek(f,data,SEEK_CUR) == -1 ) {
			ast_log(LOG_WARNING, "Failed to skip '%.4s' block: %d\n", buf, data);
			return -1;
		}
	}
#if 0
	curpos = lseek(fd, 0, SEEK_CUR);
	truelength = lseek(fd, 0, SEEK_END);
	lseek(fd, curpos, SEEK_SET);
	truelength -= curpos;
#endif
	return data;
}

static int update_header(FILE *f)
{
	off_t cur,end;
	int datalen,filelen,bytes;

	cur = ftello(f);
	fseek(f, 0, SEEK_END);
	end = ftello(f);
	/* data starts 44 bytes in */
	bytes = end - 44;
	datalen = htoll(bytes);
	/* chunk size is bytes of data plus 36 bytes of header */
	filelen = htoll(36 + bytes);

	if (cur < 0) {
		ast_log(LOG_WARNING, "Unable to find our position\n");
		return -1;
	}
	if (fseek(f, 4, SEEK_SET)) {
		ast_log(LOG_WARNING, "Unable to set our position\n");
		return -1;
	}
	if (fwrite(&filelen, 1, 4, f) != 4) {
		ast_log(LOG_WARNING, "Unable to set write file size\n");
		return -1;
	}
	if (fseek(f, 40, SEEK_SET)) {
		ast_log(LOG_WARNING, "Unable to set our position\n");
		return -1;
	}
	if (fwrite(&datalen, 1, 4, f) != 4) {
		ast_log(LOG_WARNING, "Unable to set write datalen\n");
		return -1;
	}
	if (fseeko(f, cur, SEEK_SET)) {
		ast_log(LOG_WARNING, "Unable to return to position\n");
		return -1;
	}
	return 0;
}

static int write_header(FILE *f, int writehz)
{
	unsigned int hz;
	unsigned int bhz;
	unsigned int hs = htoll(16);
	unsigned short fmt = htols(1);
	unsigned short chans = htols(1);
	unsigned short bysam = htols(2);
	unsigned short bisam = htols(16);
	unsigned int size = htoll(0);

	if (writehz == 16000) {
		hz = htoll(16000);
		bhz = htoll(32000);
	} else {
		hz = htoll(8000);
		bhz = htoll(16000);
	}
	/* Write a wav header, ignoring sizes which will be filled in later */
	fseek(f,0,SEEK_SET);
	if (fwrite("RIFF", 1, 4, f) != 4) {
		ast_log(LOG_WARNING, "Unable to write header\n");
		return -1;
	}
	if (fwrite(&size, 1, 4, f) != 4) {
		ast_log(LOG_WARNING, "Unable to write header\n");
		return -1;
	}
	if (fwrite("WAVEfmt ", 1, 8, f) != 8) {
		ast_log(LOG_WARNING, "Unable to write header\n");
		return -1;
	}
	if (fwrite(&hs, 1, 4, f) != 4) {
		ast_log(LOG_WARNING, "Unable to write header\n");
		return -1;
	}
	if (fwrite(&fmt, 1, 2, f) != 2) {
		ast_log(LOG_WARNING, "Unable to write header\n");
		return -1;
	}
	if (fwrite(&chans, 1, 2, f) != 2) {
		ast_log(LOG_WARNING, "Unable to write header\n");
		return -1;
	}
	if (fwrite(&hz, 1, 4, f) != 4) {
		ast_log(LOG_WARNING, "Unable to write header\n");
		return -1;
	}
	if (fwrite(&bhz, 1, 4, f) != 4) {
		ast_log(LOG_WARNING, "Unable to write header\n");
		return -1;
	}
	if (fwrite(&bysam, 1, 2, f) != 2) {
		ast_log(LOG_WARNING, "Unable to write header\n");
		return -1;
	}
	if (fwrite(&bisam, 1, 2, f) != 2) {
		ast_log(LOG_WARNING, "Unable to write header\n");
		return -1;
	}
	if (fwrite("data", 1, 4, f) != 4) {
		ast_log(LOG_WARNING, "Unable to write header\n");
		return -1;
	}
	if (fwrite(&size, 1, 4, f) != 4) {
		ast_log(LOG_WARNING, "Unable to write header\n");
		return -1;
	}
	return 0;
}

static int wav_open(struct ast_filestream *s)
{
	/* We don't have any header to read or anything really, but
	   if we did, it would go here.  We also might want to check
	   and be sure it's a valid file.  */
	struct wav_desc *tmp = s->_private;
	unsigned int sample_rate = ast_format_get_sample_rate(s->fmt->format);

	tmp->maxlen = check_header(s->f, sample_rate);
	if (tmp->maxlen < 0) {
		return -1;
	}

	tmp->hz = sample_rate;
	return 0;
}

static int wav_rewrite(struct ast_filestream *s, const char *comment)
{
	/* We don't have any header to read or anything really, but
	   if we did, it would go here.  We also might want to check
	   and be sure it's a valid file.  */

	struct wav_desc *tmp = (struct wav_desc *)s->_private;
	tmp->hz = ast_format_get_sample_rate(s->fmt->format);
	if (write_header(s->f,tmp->hz))
		return -1;
	return 0;
}

static void wav_close(struct ast_filestream *s)
{
	char zero = 0;
	struct wav_desc *fs = (struct wav_desc *)s->_private;

	if (s->mode == O_RDONLY) {
		return;
	}

	if (s->filename) {
		update_header(s->f);
	}

	/* Pad to even length */
	if (fs->bytes & 0x1) {
		if (fwrite(&zero, 1, 1, s->f) != 1) {
			ast_log(LOG_WARNING, "fwrite() failed: %s\n", strerror(errno));
		}
	}
}

static struct ast_frame *wav_read(struct ast_filestream *s, int *whennext)
{
	size_t res;
	int samples;	/* actual samples read */
#if __BYTE_ORDER == __BIG_ENDIAN
	int x;
	short *tmp;
#endif
	int bytes;
	off_t here;
	/* Send a frame from the file to the appropriate channel */
	struct wav_desc *fs = (struct wav_desc *)s->_private;

	bytes = (fs->hz == 16000 ? (WAV_BUF_SIZE * 2) : WAV_BUF_SIZE);

	here = ftello(s->f);
	if (fs->maxlen - here < bytes)		/* truncate if necessary */
		bytes = fs->maxlen - here;
	if (bytes <= 0) {
		return NULL;
	}
/* 	ast_debug(1, "here: %d, maxlen: %d, bytes: %d\n", here, s->maxlen, bytes); */
	AST_FRAME_SET_BUFFER(&s->fr, s->buf, AST_FRIENDLY_OFFSET, bytes);

	if ((res = fread(s->fr.data.ptr, 1, s->fr.datalen, s->f)) == 0) {
		if (res) {
			ast_log(LOG_WARNING, "Short read of %s data (expected %d bytes, read %zu): %s\n",
					ast_format_get_name(s->fr.subclass.format), s->fr.datalen, res,
					strerror(errno));
		}
		return NULL;
	}
	s->fr.datalen = res;
	s->fr.samples = samples = res / 2;

#if __BYTE_ORDER == __BIG_ENDIAN
	tmp = (short *)(s->fr.data.ptr);
	/* file format is little endian so we need to swap */
	for( x = 0; x < samples; x++)
		tmp[x] = (tmp[x] << 8) | ((tmp[x] & 0xff00) >> 8);
#endif

	*whennext = samples;
	return &s->fr;
}

static int wav_write(struct ast_filestream *fs, struct ast_frame *f)
{
#if __BYTE_ORDER == __BIG_ENDIAN
	int x;
	short tmp[16000], *tmpi;
#endif
	struct wav_desc *s = (struct wav_desc *)fs->_private;
	int res;

	if (!f->datalen)
		return -1;

#if __BYTE_ORDER == __BIG_ENDIAN
	/* swap and write */
	if (f->datalen > sizeof(tmp)) {
		ast_log(LOG_WARNING, "Data length is too long\n");
		return -1;
	}
	tmpi = f->data.ptr;
	for (x=0; x < f->datalen/2; x++)
		tmp[x] = (tmpi[x] << 8) | ((tmpi[x] & 0xff00) >> 8);

	if ((res = fwrite(tmp, 1, f->datalen, fs->f)) != f->datalen ) {
#else
	/* just write */
	if ((res = fwrite(f->data.ptr, 1, f->datalen, fs->f)) != f->datalen ) {
#endif
		ast_log(LOG_WARNING, "Bad write (%d): %s\n", res, strerror(errno));
		return -1;
	}

	s->bytes += f->datalen;

	return 0;

}

static int wav_seek(struct ast_filestream *fs, off_t sample_offset, int whence)
{
	off_t min = WAV_HEADER_SIZE, max, cur, offset = 0, samples;

	samples = sample_offset * 2; /* SLINEAR is 16 bits mono, so sample_offset * 2 = bytes */

	if ((cur = ftello(fs->f)) < 0) {
		ast_log(AST_LOG_WARNING, "Unable to determine current position in wav filestream %p: %s\n", fs, strerror(errno));
		return -1;
	}

	if (fseeko(fs->f, 0, SEEK_END) < 0) {
		ast_log(AST_LOG_WARNING, "Unable to seek to end of wav filestream %p: %s\n", fs, strerror(errno));
		return -1;
	}

	if ((max = ftello(fs->f)) < 0) {
		ast_log(AST_LOG_WARNING, "Unable to determine max position in wav filestream %p: %s\n", fs, strerror(errno));
		return -1;
	}

	if (whence == SEEK_SET) {
		offset = samples + min;
	} else if (whence == SEEK_CUR || whence == SEEK_FORCECUR) {
		offset = samples + cur;
	} else if (whence == SEEK_END) {
		offset = max - samples;
	}
	if (whence != SEEK_FORCECUR) {
		offset = (offset > max)?max:offset;
	}
	/* always protect the header space. */
	offset = (offset < min)?min:offset;
	return fseeko(fs->f, offset, SEEK_SET);
}

static int wav_trunc(struct ast_filestream *fs)
{
	int fd;
	off_t cur;

	if ((fd = fileno(fs->f)) < 0) {
		ast_log(AST_LOG_WARNING, "Unable to determine file descriptor for wav filestream %p: %s\n", fs, strerror(errno));
		return -1;
	}
	if ((cur = ftello(fs->f)) < 0) {
		ast_log(AST_LOG_WARNING, "Unable to determine current position in wav filestream %p: %s\n", fs, strerror(errno));
		return -1;
	}
	/* Truncate file to current length */
	if (ftruncate(fd, cur)) {
		return -1;
	}
	return update_header(fs->f);
}

static off_t wav_tell(struct ast_filestream *fs)
{
	off_t offset;
	offset = ftello(fs->f);
	/* subtract header size to get samples, then divide by 2 for 16 bit samples */
	return (offset - 44)/2;
}

static struct ast_format_def wav16_f = {
	.name = "wav16",
	.exts = "wav16",
	.open =	wav_open,
	.rewrite = wav_rewrite,
	.write = wav_write,
	.seek = wav_seek,
	.trunc = wav_trunc,
	.tell =	wav_tell,
	.read = wav_read,
	.close = wav_close,
	.buf_size = (WAV_BUF_SIZE * 2) + AST_FRIENDLY_OFFSET,
	.desc_size = sizeof(struct wav_desc),
};

static struct ast_format_def wav_f = {
	.name = "wav",
	.exts = "wav",
	.open =	wav_open,
	.rewrite = wav_rewrite,
	.write = wav_write,
	.seek = wav_seek,
	.trunc = wav_trunc,
	.tell =	wav_tell,
	.read = wav_read,
	.close = wav_close,
	.buf_size = WAV_BUF_SIZE + AST_FRIENDLY_OFFSET,
	.desc_size = sizeof(struct wav_desc),
};

static int unload_module(void)
{
	return ast_format_def_unregister(wav_f.name)
		|| ast_format_def_unregister(wav16_f.name);
}

static int load_module(void)
{
	wav_f.format = ast_format_slin;
	wav16_f.format = ast_format_slin16;
	if (ast_format_def_register(&wav_f)
		|| ast_format_def_register(&wav16_f)) {
		unload_module();
		return AST_MODULE_LOAD_DECLINE;
	}
	return AST_MODULE_LOAD_SUCCESS;
}

AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_LOAD_ORDER, "Microsoft WAV/WAV16 format (8kHz/16kHz Signed Linear)",
	.support_level = AST_MODULE_SUPPORT_CORE,
	.load = load_module,
	.unload = unload_module,
	.load_pri = AST_MODPRI_APP_DEPEND
);