/*
 * Asterisk -- An open source telephony toolkit.
 *
 * DAHDI native transcoding support
 *
 * Copyright (C) 1999 - 2008, Digium, Inc.
 *
 * Mark Spencer <markster@digium.com>
 * Kevin P. Fleming <kpfleming@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 Translate between various formats natively through DAHDI transcoding
 *
 * \ingroup codecs
 */

/*** MODULEINFO
	<depend>dahdi</depend>
 ***/

#include "asterisk.h"

ASTERISK_FILE_VERSION(__FILE__, "$Revision$")

#include <fcntl.h>
#include <netinet/in.h>
#include <sys/ioctl.h>
#include <sys/mman.h>

#include <dahdi/user.h>

#include "asterisk/lock.h"
#include "asterisk/translate.h"
#include "asterisk/config.h"
#include "asterisk/module.h"
#include "asterisk/cli.h"
#include "asterisk/channel.h"
#include "asterisk/utils.h"
#include "asterisk/linkedlists.h"

#define BUFFER_SAMPLES	8000

static unsigned int global_useplc = 0;

static struct channel_usage {
	int total;
	int encoders;
	int decoders;
} channels;

static char *handle_cli_transcoder_show(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a);

static struct ast_cli_entry cli[] = {
	AST_CLI_DEFINE(handle_cli_transcoder_show, "Display DAHDI transcoder utilization.")
};

struct format_map {
	unsigned int map[32][32];
};

static struct format_map global_format_map = { { { 0 } } };

struct translator {
	struct ast_translator t;
	AST_LIST_ENTRY(translator) entry;
};

static AST_LIST_HEAD_STATIC(translators, translator);

struct pvt {
	int fd;
	int fake;
#ifdef DEBUG_TRANSCODE
	int totalms;
	int lasttotalms;
#endif
	struct dahdi_transcoder_formats fmts;
};

static char *handle_cli_transcoder_show(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
{
	struct channel_usage copy;

	switch (cmd) {
	case CLI_INIT:
		e->command = "transcoder show";
		e->usage =
			"Usage: transcoder show\n"
			"       Displays channel utilization of DAHDI transcoder(s).\n";
		return NULL;
	case CLI_GENERATE:
		return NULL;
	}

	if (a->argc != 2)
		return CLI_SHOWUSAGE;

	copy = channels;

	if (copy.total == 0)
		ast_cli(a->fd, "No DAHDI transcoders found.\n");
	else
		ast_cli(a->fd, "%d/%d encoders/decoders of %d channels are in use.\n", copy.encoders, copy.decoders, copy.total);

	return CLI_SUCCESS;
}

static int dahdi_framein(struct ast_trans_pvt *pvt, struct ast_frame *f)
{
	int res;
	struct pvt *dahdip = pvt->pvt;

	if (f->subclass) {
		/* Give the frame to the hardware transcoder... */
		res = write(dahdip->fd, f->data.ptr, f->datalen); 
		if (-1 == res) {
			ast_log(LOG_ERROR, "Failed to write to /dev/dahdi/transcode: %s\n", strerror(errno));
		}
		if (f->datalen != res) {
			ast_log(LOG_ERROR, "Requested write of %d bytes, but only wrote %d bytes.\n", f->datalen, res);
		}
		res = -1;
		pvt->samples += f->samples;
	} else {
		/* Fake a return frame for calculation purposes */
		dahdip->fake = 2;
		pvt->samples = f->samples;
		res = 0;
	}
	return res;
}

static struct ast_frame *dahdi_frameout(struct ast_trans_pvt *pvt)
{
	struct pvt *dahdip = pvt->pvt;

	if (0 == dahdip->fake) {
		int res;
		/* Let's check to see if there is a new frame for us.... */
		res = read(dahdip->fd, pvt->outbuf.uc + pvt->datalen, pvt->t->buf_size - pvt->datalen);
		if (-1 == res) {
			if (EWOULDBLOCK == errno) {
				/* Nothing waiting... */
				return NULL;
			} else {
				ast_log(LOG_ERROR, "Failed to read from /dev/dahdi/transcode: %s\n", strerror(errno));
				return NULL;
			}
		} else {
			pvt->f.samples = res;
			pvt->f.datalen = res;
			pvt->datalen = 0;
			pvt->f.frametype = AST_FRAME_VOICE;
			pvt->f.subclass = 1 <<  (pvt->t->dstfmt);
			pvt->f.mallocd = 0;
			pvt->f.offset = AST_FRIENDLY_OFFSET;
			pvt->f.src = pvt->t->name;
			pvt->f.data.ptr = pvt->outbuf.uc;
			ast_set_flag(&pvt->f, AST_FRFLAG_FROM_TRANSLATOR);

			return &pvt->f;
		}

	} else if (2 == dahdip->fake) {

		dahdip->fake = 1;
		pvt->f.frametype = AST_FRAME_VOICE;
		pvt->f.subclass = 0;
		pvt->f.samples = 160;
		pvt->f.data.ptr = NULL;
		pvt->f.offset = 0;
		pvt->f.datalen = 0;
		pvt->f.mallocd = 0;
		ast_set_flag(&pvt->f, AST_FRFLAG_FROM_TRANSLATOR);
		pvt->samples = 0;

		return &pvt->f;

	} else if (1 == dahdip->fake) {

		return NULL;

	}
	/* Shouldn't get here... */
	return NULL;
}

static void dahdi_destroy(struct ast_trans_pvt *pvt)
{
	struct pvt *dahdip = pvt->pvt;

	switch (dahdip->fmts.dstfmt) {
	case AST_FORMAT_G729A:
	case AST_FORMAT_G723_1:
		ast_atomic_fetchadd_int(&channels.encoders, -1);
		break;
	default:
		ast_atomic_fetchadd_int(&channels.decoders, -1);
		break;
	}

	close(dahdip->fd);
}

static int dahdi_translate(struct ast_trans_pvt *pvt, int dest, int source)
{
	/* Request translation through zap if possible */
	int fd;
	struct pvt *dahdip = pvt->pvt;
	int flags;
	
	if ((fd = open("/dev/dahdi/transcode", O_RDWR)) < 0) {
		ast_log(LOG_ERROR, "Failed to open /dev/dahdi/transcode: %s\n", strerror(errno));
		return -1;
	}
	
	dahdip->fmts.srcfmt = (1 << source);
	dahdip->fmts.dstfmt = (1 << dest);

	ast_log(LOG_VERBOSE, "Opening transcoder channel from %d to %d.\n", source, dest);

	if (ioctl(fd, DAHDI_TC_ALLOCATE, &dahdip->fmts)) {
		ast_log(LOG_ERROR, "Unable to attach to transcoder: %s\n", strerror(errno));
		close(fd);

		return -1;
	}

	flags = fcntl(fd, F_GETFL);
	if (flags > - 1) {
		if (fcntl(fd, F_SETFL, flags | O_NONBLOCK))
			ast_log(LOG_WARNING, "Could not set non-block mode!\n");
	}

	dahdip->fd = fd;

	switch (dahdip->fmts.dstfmt) {
	case AST_FORMAT_G729A:
	case AST_FORMAT_G723_1:
		ast_atomic_fetchadd_int(&channels.encoders, +1);
		break;
	default:
		ast_atomic_fetchadd_int(&channels.decoders, +1);
		break;
	}

	return 0;
}

static int dahdi_new(struct ast_trans_pvt *pvt)
{
	return dahdi_translate(pvt, pvt->t->dstfmt, pvt->t->srcfmt);
}

static struct ast_frame *fakesrc_sample(void)
{
	/* Don't bother really trying to test hardware ones. */
	static struct ast_frame f = {
		.frametype = AST_FRAME_VOICE,
		.samples = 160,
		.src = __PRETTY_FUNCTION__
	};

	return &f;
}

static int register_translator(int dst, int src)
{
	struct translator *dahdi;
	int res;

	if (!(dahdi = ast_calloc(1, sizeof(*dahdi))))
		return -1;

	snprintf((char *) (dahdi->t.name), sizeof(dahdi->t.name), "dahdi%sto%s", 
		 ast_getformatname((1 << src)), ast_getformatname((1 << dst)));
	dahdi->t.srcfmt = (1 << src);
	dahdi->t.dstfmt = (1 << dst);
	dahdi->t.newpvt = dahdi_new;
	dahdi->t.framein = dahdi_framein;
	dahdi->t.frameout = dahdi_frameout;
	dahdi->t.destroy = dahdi_destroy;
	dahdi->t.sample = fakesrc_sample;
	dahdi->t.useplc = global_useplc;
	dahdi->t.buf_size = BUFFER_SAMPLES * 2;
	dahdi->t.desc_size = sizeof(struct pvt);
	if ((res = ast_register_translator(&dahdi->t))) {
		ast_free(dahdi);
		return -1;
	}

	AST_LIST_LOCK(&translators);
	AST_LIST_INSERT_HEAD(&translators, dahdi, entry);
	AST_LIST_UNLOCK(&translators);

	global_format_map.map[dst][src] = 1;

	return res;
}

static void drop_translator(int dst, int src)
{
	struct translator *cur;

	AST_LIST_LOCK(&translators);
	AST_LIST_TRAVERSE_SAFE_BEGIN(&translators, cur, entry) {
		if (cur->t.srcfmt != src)
			continue;

		if (cur->t.dstfmt != dst)
			continue;

		AST_LIST_REMOVE_CURRENT(entry);
		ast_unregister_translator(&cur->t);
		ast_free(cur);
		global_format_map.map[dst][src] = 0;
		break;
	}
	AST_LIST_TRAVERSE_SAFE_END;
	AST_LIST_UNLOCK(&translators);
}

static void unregister_translators(void)
{
	struct translator *current;

	AST_LIST_LOCK(&translators);
	while ((current = AST_LIST_REMOVE_HEAD(&translators, entry))) {
		ast_unregister_translator(&current->t);
		ast_free(current);
	}
	AST_LIST_UNLOCK(&translators);
}

static int parse_config(int reload)
{
	struct ast_variable *var;
	struct ast_flags config_flags = { reload ? CONFIG_FLAG_FILEUNCHANGED : 0 };
	struct ast_config *cfg = ast_config_load("codecs.conf", config_flags);

	if (cfg == NULL)
		return 0;
	if (cfg == CONFIG_STATUS_FILEUNCHANGED)
		return 0;

	for (var = ast_variable_browse(cfg, "plc"); var; var = var->next) {
	       if (!strcasecmp(var->name, "genericplc")) {
		       global_useplc = ast_true(var->value);
			   ast_verb(3, "codec_dahdi: %susing generic PLC\n",
					   global_useplc ? "" : "not ");
	       }
	}
	ast_config_destroy(cfg);
	return 0;
}

static void build_translators(struct format_map *map, unsigned int dstfmts, unsigned int srcfmts)
{
	unsigned int src, dst;

	for (src = 0; src < 32; src++) {
		for (dst = 0; dst < 32; dst++) {
			if (!(srcfmts & (1 << src)))
				continue;

			if (!(dstfmts & (1 << dst)))
				continue;

			if (global_format_map.map[dst][src])
				continue;

			if (!register_translator(dst, src))
				map->map[dst][src] = 1;
		}
	}
}

static int find_transcoders(void)
{
	struct dahdi_transcoder_info info = { 0, };
	struct format_map map = { { { 0 } } };
	int fd, res;
	unsigned int x, y;

	if ((fd = open("/dev/dahdi/transcode", O_RDWR)) < 0) {
		ast_log(LOG_ERROR, "Failed to open /dev/dahdi/transcode: %s\n", strerror(errno));
		return 0;
	}

	for (info.tcnum = 0; !(res = ioctl(fd, DAHDI_TC_GETINFO, &info)); info.tcnum++) {
		if (option_verbose > 1)
			ast_verbose(VERBOSE_PREFIX_2 "Found transcoder '%s'.\n", info.name);
		build_translators(&map, info.dstfmts, info.srcfmts);
		ast_atomic_fetchadd_int(&channels.total, info.numchannels / 2);
	}

	close(fd);

	if (!info.tcnum && (option_verbose > 1))
		ast_verbose(VERBOSE_PREFIX_2 "No hardware transcoders found.\n");

	for (x = 0; x < 32; x++) {
		for (y = 0; y < 32; y++) {
			if (!map.map[x][y] && global_format_map.map[x][y])
				drop_translator(x, y);
		}
	}

	return 0;
}

static int reload(void)
{
	struct translator *cur;

	if (parse_config(1))
		return AST_MODULE_LOAD_DECLINE;

	AST_LIST_LOCK(&translators);
	AST_LIST_TRAVERSE(&translators, cur, entry)
		cur->t.useplc = global_useplc;
	AST_LIST_UNLOCK(&translators);

	return AST_MODULE_LOAD_SUCCESS;
}

static int unload_module(void)
{
	ast_cli_unregister_multiple(cli, ARRAY_LEN(cli));
	unregister_translators();

	return 0;
}

static int load_module(void)
{
	if (parse_config(0))
		return AST_MODULE_LOAD_DECLINE;
	find_transcoders();
	ast_cli_register_multiple(cli, ARRAY_LEN(cli));
	return AST_MODULE_LOAD_SUCCESS;
}

AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_DEFAULT, "Generic DAHDI Transcoder Codec Translator",
		.load = load_module,
		.unload = unload_module,
		.reload = reload,
		);