/* osmo-cc-pstn-endpoint main
 *
 * (C) 2020 by Andreas Eversberg <jolly@eversberg.eu>
 * All Rights Reserved
 *
 * 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 3 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, see <http://www.gnu.org/licenses/>.
 */

#include <stdio.h>
#include <unistd.h>
#include <errno.h>
#include <signal.h>
#include <string.h>
#include <stdint.h>
#include <stdlib.h>
#include <termios.h>
#include <sched.h>
#include "../libdebug/debug.h"
#include "../liboptions/options.h"
#include "../libg711/g711.h"
#include "pstn.h"

pstn_t *pstn_ep = NULL;
int num_kanal = 1;

#define SUBSCRIBER_MAX 16
static char law = 'a';
static int sweden = 0;
static int serving_location = 1; /* private network serving local user */
static const char *socketname = NULL;
static const char *name = "pstn";
static const char *subscribers[SUBSCRIBER_MAX] = { "" };
static int subscriber_num = 0;
static int tx_delay = 0;
static enum pstn_cid_method clip = CID_METHOD_NONE;
static int cid_bell = 0;
static int cid_dtmf = 0;
static int clip_date = 0;
static int enblock = 4;
static int recall = 0;
static int ringing_types_incoming[SUBSCRIBER_MAX] = { 0 };
static int ringing_type_incoming_num = 0;
static int ringing_type_hold = 0;
static enum tones_type tones_type = TONES_TYPE_GERMAN;
static int rt_prio = 1;
#define MAX_CC_ARGS 1024
static int cc_argc = 0;
static const char *cc_argv[MAX_CC_ARGS];

static void print_usage(const char *app)
{
	printf("Usage: %s -s <socketname> [--clip --clip-date] [--recall] [<options>]\n", app);
}

static void print_help()
{
	/*      -                                                                             - */
	printf(" -h --help\n");
	printf("        This help\n");
	printf(" --config [~/]<path to config file>\n");
	printf("        Give a config file to use. If it starts with '~/', path is at home dir.\n");
	printf("        Each line in config file is one option, '-' or '--' must not be given!\n");
	debug_print_help();
	printf(" -s --socket <name>\n");
	printf("        Abstract UNIX socket that provides layer 1 connection to a PSTN device\n");
	printf(" -n --name <interface name>\n");
	printf("        Give name of this interface. It will be sent in each call towards\n");
	printf(" -I --subscriber <subscriber id>\n");
	printf("        What caller ID to send on calls made from terminal. (default = '%s')\n", subscribers[0]);
	printf(" -I <subscriber id 1> -R <ringing type 1> -I <subscriber id 2> -R <ringing type 2> ...\n");
	printf("        You may specify multiple subscriber IDs and as much ringing types.\n");
	printf("        Calls to a subscriber's ID will then ring as specified. Calls to an\n");
	printf("        unspecified subscriber ID will ring as specified for first subscriber.\n");
	printf(" --tx-delay <ms>\n");
	printf("        Give a delay in milliseconds. This is required for modem/fax. Audio\n");
	printf("        toward ISDN interface is buffered with the given delay.\n");
	printf("        This feature alters dejittering strategy.\n");
	printf(" --clip pulse | stop | dtas | dtas-lr [--clip-date]\n");
	printf("        Enable caller ID, optionally with date info. (disabled by default)\n");
	printf("        Use 'pulse' to send first ringing via pulse signal and CLIP afterwards.\n");
	printf("        Use 'stop' to stop after first ring, send CLIP and continue ringing.\n");
	printf("        Use 'dtas' to send CLIP with DT-AS before first ring.\n");
	printf("        Use 'dtas-lr' to send CLIP as above, but with reversed polarity.\n");
	printf(" --clip-date\n");
	printf("        Send date+time with caller ID.\n");
	printf(" --cid-bell\n");
	printf("        Use Bell 202 to modulate caller ID, rather than V.23 (default).\n");
	printf("        Note that both systems are so similar (and have same center frequency),\n");
	printf("        so that it does not matter which one is used. (my oppinion!)\n");
	printf(" --cid-dtmf D\n");
	printf("        Use DTMF with given start digit 'D' for default, rather than FSK.\n");
	printf("        'D' is used in Taiwan, 'A' in Brazil...\n");
	printf(" --enblock off | <seconds>\n");
	printf("        Enable en-block dialing, to collect number before setup. The value\n");
	printf("        given is the number of seconds to wait for more digits to be dialed.\n");
	printf("        (default = %d)\n", enblock);
	printf(" -D --dial-hint xxxx | xxxx-yyyy\n");
	printf("        The given one or multpiple hits for numbers with a fixed length. This\n");
	printf("        can be a single number or a range of number. If a range is given, xxxx\n");
	printf("        and yyyy must have equal length. If one of the given numbers are dialed,\n");
	printf("        the en-block dialing is complete and there is no need to wait for the\n");
	printf("        timeout.\n");
	printf(" --recall\n");
	printf("        Enable recall / call waiting. (disabled by default)\n");
	printf(" -R --ringing-type-incoming <type>\n");
	printf("        Cadenced ringing for incoming call. (default = %d)\n", ringing_types_incoming[0]);
	printf(" --ringing-type-hold <type>\n");
	printf("        Cadenced ringing for call on hold. (default = %d)\n", ringing_type_hold);
	printf(" -T --local-tones german | oldgerman | american\n");
	printf("        Send locally generated tones, if not provided by remote interface.\n");
	printf("        DTMF may not work with old German tones, because they might interfer!\n");
	printf(" --ulaw\n");
	printf("        Use U-LAW for b-channel coding instead of alaw.\n");
	printf(" --serving-location (see Q.931)\n");
	printf("        0 = user, 1 = private network serving local user (default=%d)\n", serving_location);
	printf(" --sweden\n");
	printf("        Translate pulses from Swedish rotary phone into digits. One pulse is\n");
	printf("        digit '0', two pulses are digit '1', and so on.\n");
	printf(" -r --realtime <prio>\n");
	printf("        Set prio: 0 to disable, 99 for maximum (default = %d)\n", rt_prio);
	printf(" -C --cc \"<osmo-cc arg>\" [--cc ...]\n");
	printf("        Pass arguments to Osmo-CC endpoint. Use '-cc help' for description.\n");
}

static void print_recall()
{
	/*      -                                                                             - */
	printf("\n");
	printf("Recall:\n");
	printf("To enable recall, use --recall option. Then you can place or receive a second\n");
	printf("call and switch between them.\n");
	printf("If you have an active call, press hook-flash to hold the active call and make\n");
	printf("a second call.\n");
	printf("If you have two connected calls, press hook-flash to switch between these\n");
	printf("calls.\n");
	printf("If an incoming call is waiting, you will hear CW singal. Press hook-flash to\n");
	printf("switch between these calls.\n");
	printf("If you want to release the active call and retrieve the call on hold, hang up\n");
	printf("and the phone will ring. Answer it.\n");
	printf("\n");
}

#define OPT_TX_DELAY		256
#define OPT_TX_CLIP		257
#define OPT_TX_CLIP_DATE	258
#define OPT_TX_CID_BELL		259
#define OPT_TX_CID_DTMF		260
#define OPT_TX_ENBLOCK		261
#define OPT_TX_RECALL		262
#define OPT_TX_RING_I		'R'
#define OPT_TX_RING_H		264
#define OPT_ULAW		265
#define OPT_SERVING		266
#define OPT_SWEDEN		267

static void add_options(void)
{
	option_add('h', "help", 0);
	option_add('v', "verbose", 1);
	option_add('s', "socket", 1);
	option_add('n', "name", 1);
	option_add('I', "subscriber", 1);
	option_add(OPT_TX_DELAY, "tx-delay", 1);
	option_add(OPT_TX_CLIP, "clip", 1);
	option_add(OPT_TX_CLIP_DATE, "clip-date", 0);
	option_add(OPT_TX_CID_BELL, "cid-bell", 0);
	option_add(OPT_TX_CID_DTMF, "cid-dtmf", 1);
	option_add(OPT_TX_ENBLOCK, "enblock", 1);
	option_add('D', "dial-hint", 1);
	option_add(OPT_TX_RECALL, "recall", 0);
	option_add(OPT_TX_RING_I, "ringing-type-incoming", 1);
	option_add(OPT_TX_RING_H, "ringing-type-hold", 1);
	option_add('T', "local-tones", 0);
	option_add(OPT_ULAW, "ulaw", 0);
	option_add(OPT_SERVING, "serving-location", 1);
	option_add(OPT_SWEDEN, "sweden", 0);
	option_add('r', "realtime", 1);
	option_add('C', "cc", 1);
}

static int handle_options(int short_option, int argi, char **argv)
{
	int rc;

	switch (short_option) {
	case 'h':
		print_usage(argv[0]);
		print_help();
		return 0;
	case 'v':
		if (!strcasecmp(argv[argi], "list")) {
	                debug_list_cat();
			return 0;
		}
		rc = parse_debug_opt(argv[argi]);
		if (rc < 0) {
			fprintf(stderr, "Failed to parse debug option, please use -h for help.\n");
			return rc;
		}
		break;
	case 's':
		socketname = options_strdup(argv[argi]);
		break;
	case 'n':
		name = options_strdup(argv[argi]);
		break;
	case 'I':
		if (subscriber_num == SUBSCRIBER_MAX) {
			fprintf(stderr, "Cannot define more than %d subscriber Ids.\n", SUBSCRIBER_MAX);
			return -EINVAL;
		}
		subscribers[subscriber_num++] = options_strdup(argv[argi]);
		break;
	case OPT_TX_DELAY:
		tx_delay = atoi(argv[argi]);
		break;
	case OPT_TX_CLIP:
		if (!strcasecmp(argv[argi], "pulse"))
			clip = CID_METHOD_PULSE;
		else if (!strcasecmp(argv[argi], "stop"))
			clip = CID_METHOD_STOP;
		else if (!strcasecmp(argv[argi], "dtas"))
			clip = CID_METHOD_DTAS;
		else if (!strcasecmp(argv[argi], "dtas-lr"))
			clip = CID_METHOD_DTAS_LR;
		else {
			fprintf(stderr, "Invalid clip method!\n");
			return -EINVAL;
		}
		break;
	case OPT_TX_CLIP_DATE:
		clip_date = 1;
		break;
	case OPT_TX_CID_BELL:
		cid_bell = 1;
		break;
	case OPT_TX_CID_DTMF:
		if (strlen(argv[argi]) != 1 || argv[argi][0] < 'A' || argv[argi][0] > 'D') {
			fprintf(stderr, "Only DTMF start digits 'A', 'B', 'C', 'D' are allowed.\n");
			return -EINVAL;
		}
		cid_dtmf = argv[argi][0];
		break;
	case OPT_TX_ENBLOCK:
		enblock = atoi(argv[argi]);
		break;
	case OPT_TX_RECALL:
		recall = 1;
		break;
	case 'D':
		rc = add_dial_hint(argv[argi]);
		if (rc < 0) {
			fprintf(stderr, "Given dial hint '%s' is not valid, please use -h for help.\n", argv[argi]);
			return rc;
		}
		break;
	case OPT_TX_RING_I:
		if (ringing_type_incoming_num == SUBSCRIBER_MAX) {
			fprintf(stderr, "Cannot define more than %d ringing types.\n", SUBSCRIBER_MAX);
			return -EINVAL;
		}
		ringing_types_incoming[ringing_type_incoming_num++] = atoi(argv[argi]);
		break;
	case OPT_TX_RING_H:
		ringing_type_hold = atoi(argv[argi]);
		break;
	case 'T':
		if (!strcasecmp(argv[argi], "american"))
			tones_type = TONES_TYPE_AMERICAN;
		else if (!strcasecmp(argv[argi], "german"))
			tones_type = TONES_TYPE_GERMAN;
		else if (!strcasecmp(argv[argi], "oldgerman"))
			tones_type = TONES_TYPE_OLDGERMAN;
		else {
			fprintf(stderr, "Invalid tones type given!\n");
			return -EINVAL;
		}
		break;
	case OPT_ULAW:
		law = 'u';
		break;
	case OPT_SERVING:
		serving_location = atoi(argv[argi]);;
		break;
	case OPT_SWEDEN:
		sweden = 1;
		break;
	case 'r':
		rt_prio = atoi(argv[argi]);
		break;
	case 'C':
		if (!strcasecmp(argv[argi], "help")) {
			osmo_cc_help();
			return 0;
		}
		if (cc_argc == MAX_CC_ARGS) {
			fprintf(stderr, "Too many osmo-cc args!\n");
			break;
		}
		cc_argv[cc_argc++] = options_strdup(argv[argi]);
		break;
	default:
		return -EINVAL;
	}
	return 1;
}

static int quit = 0;
void sighandler(int sigset)
{
	if (sigset == SIGHUP || sigset == SIGPIPE)
		return;

	fprintf(stderr, "\nSignal %d received.\n", sigset);

	quit = 1;
}

int main(int argc, char *argv[])
{
	int argi, rc;

	/* init codecs */
	g711_init();

	cc_argv[cc_argc++] = options_strdup("remote auto");

        /* handle options / config file */
	add_options();
	rc = options_config_file(argc, argv, "~/.osmocom/pstn/pstn.conf", handle_options);
	if (rc < 0)
		return 0;
	argi = options_command_line(argc, argv, handle_options);
	if (argi <= 0)
		return argi;

	/* init fm */
        fm_init(0);

	if (!socketname) {
		fprintf(stderr, "No socket name given, use '-h' for help.\n");
		goto error;
	}

	/* change tones to ulaw */
	if (law == 'u')
		isdn_tone_generate_ulaw_samples();

	/* check subscribers and their ringing types */
	if (subscriber_num == 0)
		subscriber_num = 1;
	if (ringing_type_incoming_num == 0)
		ringing_type_incoming_num = 1;
	if (subscriber_num !=  ringing_type_incoming_num) {
		fprintf(stderr, "You need to specify as many ringing types as you specified subscriber IDs, use '-h' for help.\n");
		goto error;
	}

	pstn_ep = pstn_create();
	if (!pstn_ep)
		goto error;

	rc = pstn_init(pstn_ep, name, socketname, subscribers, subscriber_num, serving_location, tx_delay, clip, cid_bell, cid_dtmf, clip_date, enblock, recall, ringing_types_incoming, ringing_type_hold, tones_type, law, sweden);
	if (rc) {
		PDEBUG(DTEL, DEBUG_ERROR, "Endpoint initializing failed!\n");
		goto error;
	}

	rc = osmo_cc_new(&pstn_ep->cc_ep, OSMO_CC_VERSION, name, OSMO_CC_LOCATION_USER, cc_message, NULL, pstn_ep, cc_argc, cc_argv);
	if (rc < 0)
		goto error;

	/* real time priority */
	if (rt_prio > 0) {
		struct sched_param schedp;
		int rc;

		memset(&schedp, 0, sizeof(schedp));
		schedp.sched_priority = rt_prio;
		rc = sched_setscheduler(0, SCHED_RR, &schedp);
		if (rc)
			fprintf(stderr, "Error setting SCHED_RR with prio %d\n", rt_prio);
	}

	printf("PSTN endpoint ready, waiting for V5 application to connect...\n");

	print_recall();

	if (tones_type == TONES_TYPE_OLDGERMAN) {
		printf("********************\n");
		printf("DTMF may not work with old German dial tone, because it disturbs the DTMF tones!\n");
		printf("********************\n");
	}

	signal(SIGINT, sighandler);
	signal(SIGHUP, sighandler);
	signal(SIGTERM, sighandler);
	signal(SIGPIPE, sighandler);

	while (!quit) {
		int work;
		double timeout;
		/* handle all handlers until done */
		do {
			work = 0;
			work |= osmo_cc_handle();
		} while (work);
		/* handle all timers
		 * timeout is 0, if there was an event
		 * -> handle FDs without waiting, continue this loop
		 * timeout is not 0, if there was no event
		 * -> wait until FD or timeout
		*/
		timeout = process_timer();
		/* wait for FD event until given timeout */
		work = osmo_fd_select(timeout);
	}

	signal(SIGINT, SIG_DFL);
	signal(SIGTSTP, SIG_DFL);
	signal(SIGHUP, SIG_DFL);
	signal(SIGTERM, SIG_DFL);
	signal(SIGPIPE, SIG_DFL);

	/* reset real time prio */
	if (rt_prio > 0) {
		struct sched_param schedp;

		memset(&schedp, 0, sizeof(schedp));
		schedp.sched_priority = 0;
		sched_setscheduler(0, SCHED_OTHER, &schedp);
	}

error:
	if (pstn_ep) {
		osmo_cc_delete(&pstn_ep->cc_ep);
		pstn_destroy(pstn_ep);
	}

	purge_dial_hints();

	options_free();

	/* exit fm */
        fm_exit();

	return 0;
}