/* osmo-cc-misdn-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 <sched.h>
#include <math.h>
#include "../liblogging/logging.h"
#include "../liboptions/options.h"
#include <osmocom/cc/g711.h>
#include <mISDN/mbuffer.h>
#include "isdn.h"
#include "dss1.h"
#include "bridge.h"
#include "../libmisdn/core.h"
#include "ph_driver.h"

isdn_t *isdn_ep = NULL;
int num_kanal = 1;

static char law = 'a';
static const char *portname = NULL;
static int misdn_kernel = 0, misdn_user = 0;
static int ntmode = 0;
static int ptp = 0;
static int layer1hold = 0;
static int layer2hold = 0;
static int aocd = 0;
static int aocs = 0;
static int time_no_sec = 0;
static const char *channel_out = NULL;
static const char *channel_in = NULL;
static const char *timeouts = NULL;
static int tx_delay = 0;
static int local_tones = 0;
static int debug_mISDN = 0;
static int serving_location = 1; /* private network serving local user */
static int use_hfc_bridging = 1;
static int bridging_server_only = 0;
static int pcm_slots = 32;
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 [--port <misdn port>] [--nt] [<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");
	logging_print_help();
	printf(" --ulaw\n");
	printf(" 	Use U-LAW for b-channel coding instead of alaw.\n");
	printf(" -p --port <portnr> | <portname>\n");
	printf("        Number or name of misdn port (see misdn_info).\n");
	printf(" -s --socket <path>\n");
	printf("        Path to UNIX socket that provides layer 1 connection to an ISDN\n");
	printf("        interface.\n");
	printf(" -n --nt\n");
	printf("        The given port is configured as NT-mode, instead of TE-mode.\n");
	printf(" -0 --ptp\n");
	printf("        The given port is configured as point-to-point. PRI-Ports are always\n");
	printf("        configured as point-to-point.\n");
	printf(" -M --msn <msn1> [--msn <msn2> ...]\n");
	printf("        Give one or multiple MSN numbers. If MSN numbers are defined, only\n");
	printf("        MSN numbers that are defined are allowed. If a different MSN number\n");
	printf("        is received from a phone, it is replaced by the first MSN number.\n");
	printf("        This is only useful for NT-mode with point-to-mulipoint configuration.\n");
	printf("        (Any MSN is accepted and forwarded by default.).\n");
	printf(" -1 --layer-1-hold 0 | 1\n");
	printf("        Keep layer 1 always active. (Default for point-to-point)\n");
	printf(" -2 --layer-2-hold 0 | 1\n");
	printf("        Keep layer 2 always active. (Default for point-to-point)\n");
	printf(" --channel-out [force,][<number>][,...][,free][,any][,no]\n");
	printf("        Channel selection list for all outgoing calls to the interface.\n");
	printf("        A free channels is searched in order of appearance.\n");
	printf("         force - Forces the selected port with no acceptable alternative.\n");
	printf("          -> this must be used for multipoint NT-mode ports\n");
	printf("         <number>[,...] - List of channels to search.\n");
	printf("         free - Select any free channel\n");
	printf("         any - On outgoing calls, signal 'any channel acceptable'. (see DSS1)\n");
	printf("         no - Signal 'no channel available' aka 'call waiting'. (see DSS1)\n");
	printf("         Default for multipoint NT-Mode: 'force,free,no'\n");
	printf("         Default for point-to-point NT-Mode: 'force,free'\n");
	printf("         Default for TE-Mode: 'any'\n");
	printf(" --channel-in [<number>][,...][,free]\n");
	printf("        Give list of channels to select for calls from ISDN\n");
	printf("        Channel selection list for all incoming calls from the interface.\n");
	printf("        A free channels is accepted if in the list.\n");
	printf("        If any channel was requested, the first free channel found is selected.\n");
	printf("         <number>[,...] - List of channels to accept.\n");
	printf("         free - Accept any free channel\n");
	printf("         Default: 'free'\n");

	printf(" --timeouts <setup>,<overlap>,<proceeding>,<alerting>,<disconnect>\n");
	printf("        Alter ISDN protocol times.\n");
	printf("        The default is 120 seconds for all states. Use 0 to disable.\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(" --aocd\n");
	printf("        Send AOC-D charging information\n");
	printf(" --aocs\n");
	printf("        Send AOC-S charging information\n");
	printf(" --time-no-seconds\n");
	printf("        Send date/time IE without seconds\n");
	printf(" -T --local-tones german | oldgerman | american\n");
	printf("        Send locally generated tones, if not provided by remote interface.\n");
	printf(" -D --debug-misdn\n");
	printf("        Enables mISDN stack debugging.\n");
	printf(" --serving-location (see Q.931)\n");
	printf("        0 = user, 1 = private network serving local user (default=%d)\n", serving_location);
	printf(" -B --bridging 0 | 1\n");
	printf("        Enable or disable hardware bridging with HFC cards. (default = %d)\n", use_hfc_bridging);
	printf(" --pcm-slots 32 | 64 | 128\n");
	printf("        The number of slots must match the configured PCM bus size.\n");
	printf("        (default = %d)\n", pcm_slots);
	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");
}

#define OPT_ULAW	256
#define OPT_CHANNEL_OUT	257
#define OPT_CHANNEL_IN	258
#define OPT_TIMEOUTS	259
#define OPT_TX_DELAY	260
#define OPT_TX_GAIN	261
#define OPT_RX_GAIN	262
#define OPT_PIPELINE	263
#define OPT_DTMF	264
#define OPT_SERVING	265
#define OPT_PCM_SLOTS	266
#define OPT_BR_ONLY	267
#define OPT_AOCD	268
#define OPT_AOCS	269
#define OPT_TIME_NO_SEC	270

static void add_options(void)
{
	option_add('h', "help", 0);
	option_add('v', "verbose", 1);
	option_add(OPT_ULAW, "ulaw", 0);
	option_add('p', "port", 1);
	option_add('s', "socket", 1);
	option_add('n', "nt", 0);
	option_add('0', "ptp", 0);
	option_add('M', "msn", 1);
	option_add('1', "layer-1-hold", 1);
	option_add('2', "layer-2-hold", 1);
	option_add(OPT_CHANNEL_OUT, "channel-out", 1);
	option_add(OPT_CHANNEL_IN, "channel-in", 1);
	option_add(OPT_TIMEOUTS, "timeouts", 1);
	option_add(OPT_TX_DELAY, "tx-delay", 1);
	option_add('T', "local-tones", 1);
	option_add(OPT_AOCD, "aocd", 0);
	option_add(OPT_AOCS, "aocs", 0);
	option_add(OPT_TIME_NO_SEC, "time-no-seconds", 0);
	option_add('D', "debug-misdn", 0);
	option_add(OPT_SERVING, "serving-location", 1);
	option_add('B', "bridging", 1);
	option_add(OPT_PCM_SLOTS, "pcm-slots", 1);
	option_add(OPT_BR_ONLY, "bridging-server-only", 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':
		rc = parse_logging_opt(argv[argi]);
		if (rc > 0)
			return 0;
		if (rc < 0) {
			fprintf(stderr, "Failed to parse debug option, please use -h for help.\n");
			return rc;
		}
		break;
	case OPT_ULAW:
		law = 'u';
		break;
	case 'p':
		portname = options_strdup(argv[argi]);
		misdn_kernel = 1;
		break;
	case 's':
		portname = options_strdup(argv[argi]);
		misdn_user = 1;
		break;
	case 'n':
		ntmode = 1;
		break;
	case '0':
		ptp = 1;
		break;
	case 'M':
		isdn_add_msn(isdn_ep, argv[argi]);
		break;
	case '1':
		layer1hold = atoi(argv[argi]);
		break;
	case '2':
		layer2hold = atoi(argv[argi]);
		break;
	case OPT_CHANNEL_OUT:
		channel_out = options_strdup(argv[argi]);
		break;
	case OPT_CHANNEL_IN:
		channel_in = options_strdup(argv[argi]);
		break;
	case OPT_TIMEOUTS:
		timeouts = options_strdup(argv[argi]);
		break;
	case OPT_TX_DELAY:
		tx_delay = atoi(argv[argi]);
		break;
	case OPT_AOCD:
		aocd = 1;
		break;
	case OPT_AOCS:
		aocs = 1;
		break;
	case OPT_TIME_NO_SEC:
		time_no_sec = 1;
		break;
	case 'T':
		if (!strcasecmp(argv[argi], "american"))
			local_tones = TONES_TYPE_AMERICAN;
		else if (!strcasecmp(argv[argi], "german"))
			local_tones = TONES_TYPE_GERMAN;
		else if (!strcasecmp(argv[argi], "oldgerman"))
			local_tones = TONES_TYPE_OLDGERMAN;
		else {
			fprintf(stderr, "Invalid tones type given!\n");
			return -EINVAL;
		}
		break;
	case 'D':
		debug_mISDN = 1;
		break;
	case OPT_SERVING:
		serving_location = atoi(argv[argi]);
		break;
	case 'B':
		use_hfc_bridging = atoi(argv[argi]);
		break;
	case OPT_PCM_SLOTS:
		pcm_slots = strtoul(argv[argi], NULL, 10);
		break;
	case OPT_BR_ONLY:
		bridging_server_only = 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;
}

static struct mi_ext_fn_s mi_fn;

static int mISDNlib_debug(const char *file, int line, const char __attribute__((unused)) *func, int __attribute__((unused)) level, const char *fmt, va_list va)
{
	LOGPSRC(DMISDN, LOGL_NOTICE, file, line, fmt, va);

	return 0;
}

int main(int argc, char *argv[])
{
	int argi, rc;
	int misdn_initialized = 0;
	int ph_drv_initialized = 0;
	int layer3_initialized = 0;
	struct ph_socket_driver ph_drv;
	const char *p;
	struct osmo_timer_list mISDN_timer;

	logging_init();

	g711_init();

	isdn_ep = isdn_create();
	if (!isdn_ep)
		goto error;

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

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

	if (bridging_server_only) {
		bridge_socket_server_child(pcm_slots, 1);
		return 0;
	}

	/* start bridge server */
	if (use_hfc_bridging) {
		bridge_socket_server(pcm_slots);
		bridge_socket_client(isdn_ep);
	}

	if (!misdn_kernel && !misdn_user) {
		fprintf(stderr, "You defined no mISDN port or layer 1 socket. You must define either one of them! Use '-h' for help.\n");
		goto error;
	}
	if (misdn_kernel && misdn_user) {
		fprintf(stderr, "You defined mISDN port and layer 1 socket. You must define either one of them!\n");
		goto error;
	}

	/* init user space mISDN */
	if (misdn_user) {
		rc = mISDNInit((debug_mISDN) ? 0xffffffff : 0);
		if (rc)
			goto error;
		misdn_initialized = 1;
		rc = init_ph_socket_driver(&ph_drv, isdn_ep, portname, 0, ntmode, (debug_mISDN) ? 0xffffffff : 0);
		if (rc)
			goto error;
		ph_drv_initialized = 1;
	}

	/* mISDNuser init and debug */
	mi_fn.prt_debug = mISDNlib_debug;
	init_layer3(4, &mi_fn, (misdn_user) ? 1 : 0);
	layer3_initialized = 1;
	mISDN_set_debug_level((debug_mISDN) ? 0xfffffeff : 0);

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

	/* init instance */
	rc = isdn_initialize(isdn_ep, (misdn_user) ? &ph_drv.ph_socket : NULL, law, portname, ntmode, ptp, layer1hold, layer2hold, channel_out, channel_in, timeouts, tx_delay, local_tones, serving_location, aocd, aocs, time_no_sec);
	if (rc) {
		LOGP(DISDN, LOGL_ERROR, "mISDN initializing failed!\n");
		goto error;
	}

	rc = isdn_open(isdn_ep);
	if (rc) {
		LOGP(DISDN, LOGL_ERROR, "mISDN open failed!\n");
		goto error;
	}

	while ((p = strchr(portname, '/')))
		portname = p + 1;

	rc = osmo_cc_new(&isdn_ep->cc_ep, OSMO_CC_VERSION, isdn_ep->portname, serving_location, cc_message, NULL, isdn_ep, cc_argc, cc_argv);
	if (rc < 0)
		goto error;

	/* Dummy timer to interrupt osmo_select_main when mISDN timer fires before anything else. */
	osmo_timer_setup(&mISDN_timer, NULL, NULL);

	/* 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);
	}

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

	while (!quit) {
		int work;
		double misdn_timeout = 0.0;

		do {
			work = 0;
			work |= osmo_cc_handle();
			if (misdn_user) {
				/* run workers of mISDN stacks in user space */
				work |= mISDN_work();
				work |= work_layer3(isdn_ep->ml3, &misdn_timeout);
			}
		} while (work);
		/* wait for event or stop, if mISDN_timer fires */
		if (misdn_timeout)
			osmo_timer_schedule(&mISDN_timer, floor(misdn_timeout), (misdn_timeout - floor(misdn_timeout)) * 1000000);
		osmo_select_main(0);
		osmo_timer_del(&mISDN_timer);
	}

	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 (isdn_ep) {
		osmo_cc_delete(&isdn_ep->cc_ep);
		isdn_destroy(isdn_ep);
	}

	if (layer3_initialized)
		cleanup_layer3();

	if (ph_drv_initialized)
		exit_ph_socket_driver(&ph_drv);

	if (misdn_initialized)
		mISDN_cleanup();

	options_free();

	return 0;
}