/* minimalistic telnet/network interface it might turn into a wire interface */
/* (C) 2009 by Holger Hans Peter Freyther <zecke@selfish.org>
 * 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 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 <sys/socket.h>
#include <netinet/in.h>
#include <malloc.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>

#include <openbsc/telnet_interface.h>
#include <openbsc/gsm_subscriber.h>
#include <openbsc/chan_alloc.h>
#include <openbsc/gsm_04_08.h>

extern void telnet_parse(struct telnet_connection *connection, char *line);

#define WRITE_CONNECTION(fd, msg...) \
	int ret; \
	char buf[4096]; \
	snprintf(buf, sizeof(buf), msg); \
	ret = write(fd, buf, strlen(buf));


/* per connection data */
LLIST_HEAD(active_connections);

/* per network data */
static int telnet_new_connection(struct bsc_fd *fd, unsigned int what);
static struct bsc_fd server_socket = {
	.when	    = BSC_FD_READ,
	.cb	    = telnet_new_connection,
	.priv_nr    = 0,
};

void telnet_init(struct gsm_network *network, int port) {
	struct sockaddr_in sock_addr;
	int fd;

	fd = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);

	if (fd < 0) {
		perror("Telnet interface socket creation failed");
		return;
	}

	memset(&sock_addr, 0, sizeof(sock_addr));
	sock_addr.sin_family = AF_INET;
	sock_addr.sin_port = htons(port);
	sock_addr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);

	if (bind(fd, (struct sockaddr*)&sock_addr, sizeof(sock_addr)) < 0) {
		perror("Telnet interface failed to bind");
		return;
	}

	if (listen(fd, 0) < 0) {
		perror("Telnet interface failed to listen");
		return;
	}

	server_socket.data = network;
	server_socket.fd = fd;
	bsc_register_fd(&server_socket);
}

void telnet_write_help(int fd) {
	int ret;
	static char *msg =
		"Help for the ad-hoc telnet command line interface\n"
		"The generic pattern is CMD LEN DATA\\n or just CMD\n"
		"where CMD is one of the following:\n"
		"help\n"
		"page IMSI (type)\n"
		"call IMSI (number)\n"
		"get_channel IMSI Add use count on an active channel\n"
		"put_channel IMSI Remove use count on an active channel\n"
		"show  This will show the channel allocation\n"
		"48 IMSI 0xAB 0xEF...Send GSM 04.08\n"
		"11 IMSI 0xAB 0xEF...Send GSM 04.11\n";

	ret = write(fd, msg, strlen(msg));
}

static void print_welcome(int fd) {
	int ret;
	static char *msg =
		"Welcome to the OpenBSC Control interface\n"
		"Copyright (C) 2008, 2009 Harald Welte\n"
		"Contributions by Daniel Willmann, Jan Lübbe, "
		"Stefan Schmidt, Holger Freyther\n\n"
		"License GPLv2+: GNU GPL version 2 or later "
		"<http://gnu.org/licenses/gpl.html>\n"
		"This is free software: you are free to change "
		"and redistribute it.\n"
		"There is NO WARRANTY, to the extent permitted "
		"by law.\nType \"help\" to get a short introduction.\n";

	ret = write(fd, msg, strlen(msg));
}

int telnet_close_client(struct bsc_fd *fd) {
	struct telnet_connection *conn = (struct telnet_connection*)fd->data;

	close(fd->fd);
	bsc_unregister_fd(fd);
	llist_del(&conn->entry);
	free(conn);
	return 0;
}

void telnet_error_client(int fd) {
	int ret;
	static char *msg = "Something went wrong. Please try again.\n";

	printf("Error\n");
	ret = write(fd, msg, strlen(msg));
}

void telnet_page(struct telnet_connection *connection, const char *imsi, int page) {
	printf("going to page: '%s' %d\n", imsi, page);
}

static struct gsm_lchan* find_channel(struct gsm_bts *bts, const char *imsi,
			    const char **error, int fd) {
	int ret;
	struct gsm_lchan *lchan;
	struct gsm_subscriber *subscr;

	subscr = subscr_get_by_imsi(imsi);
	if (!subscr) {
		ret = write(fd, error[0], strlen(error[0]));
		return NULL;
	}

	lchan = lchan_find(bts, subscr);
	if (!lchan)
		ret = write(fd, error[1], strlen(error[1]));

	subscr_put(subscr);
	return lchan;
}

void telnet_put_channel(struct telnet_connection *connection, const char *imsi) {
	static const char* error[] = {
		"put_channel: IMSI not found\n",
		"put_channel: No channel allocated for IMSI\n" };
	struct gsm_bts *bts = &connection->network->bts[connection->bts];
	struct gsm_lchan *lchan = find_channel(bts, imsi, error, connection->fd.fd);

	if (!lchan)
		return;

	put_lchan(lchan);
}

void telnet_get_channel(struct telnet_connection *connection, const char *imsi) {
	static const char* error[] = {
		"get_channel: IMSI not found\n",
		"get_channel: No channel allocated for IMSI\n" };
	struct gsm_bts *bts = &connection->network->bts[connection->bts];
	struct gsm_lchan *lchan = find_channel(bts, imsi, error, connection->fd.fd);

	if (!lchan)
		return;

	use_lchan(lchan);
}

void telnet_call(struct telnet_connection *connection, const char* imsi,
		const char *origin) {
	static const char* error[] = {
		"call: IMSI not found\n",
		"call: No channel allocated for IMSI\n" };
	struct gsm_bts *bts = &connection->network->bts[connection->bts];
	struct gsm_lchan *lchan = find_channel(bts, imsi, error, connection->fd.fd);

	if (!lchan)
		return;

	/* TODO: add the origin */
	gsm48_cc_tx_setup(lchan);
}

void telnet_send_gsm_48(struct telnet_connection *connection) {
	printf("sending gsm04.08 message\n");
}

void telnet_send_gsm_11(struct telnet_connection *connection) {
	printf("sending gsm04.11 message\n");
}

static void show_bts(int fd, struct gsm_bts *bts) {
	WRITE_CONNECTION(fd,
		 "BTS #%u on link %u  LOC: %u TRX: %d CCCH0: arfcn:%u,#%u\n",
		 bts->nr, bts->bts_nr, bts->location_area_code,
		 bts->num_trx, bts->c0->arfcn, bts->c0->nr)
}

static void show_trx(int fd, struct gsm_bts_trx *trx) {
	WRITE_CONNECTION(fd,
		 "  TRX: %u ARFCN: %u\n",
		trx->nr, trx->arfcn)
}

static void show_ts(int fd, struct gsm_bts_trx_ts *ts) {
	WRITE_CONNECTION(fd,
		"     TS: #%u pchan: %d flags: %u\n",
		ts->nr, ts->pchan, ts->flags);
}

static void show_lchan(int fd, struct gsm_lchan *lchan) {
	struct gsm_subscriber *subscr = lchan->subscr;
	WRITE_CONNECTION(fd,
		"       LCHAN: #%u type: %d  subscriber: %s/%s/%s use: %d loc: %p\n",
		lchan->nr, lchan->type,
		subscr ? subscr->imsi : "na",
		subscr ? subscr->tmsi : "na",
		subscr ? subscr->name : "na",
		lchan->use_count, lchan->loc_operation);
}

void telnet_list_channels(struct telnet_connection *connection) {
	int bts_no, trx, lchan_no, ts_no;
	struct gsm_network *network = connection->network;

	for (bts_no = 0; bts_no < network->num_bts; ++bts_no) {
		struct gsm_bts *bts = &network->bts[bts_no];
		show_bts(connection->fd.fd, bts);

		for (trx = 0; trx < bts->num_trx; ++trx) {
			show_trx(connection->fd.fd, &bts->trx[trx]);
			for (ts_no = 0; ts_no < 8; ++ts_no) {
				show_ts(connection->fd.fd, &bts->trx[trx].ts[ts_no]);
				for (lchan_no = 0; lchan_no < TS_MAX_LCHAN; ++lchan_no) {
					struct gsm_lchan *lchan =
						&bts->trx[trx].ts[ts_no].lchan[lchan_no];
					show_lchan(connection->fd.fd, lchan);
				}
			}
		}
	}
}

static int client_data(struct bsc_fd *fd, unsigned int what) {
	char buf[4096];
	int ret;

	ret = read(fd->fd, buf, sizeof(buf)-1);
	buf[ret] = '\0';

	/* connection is gone */
	if (ret <= 0)
		return telnet_close_client(fd);

	/* time to parse. This code assumes that the input is line based */
	telnet_parse((struct telnet_connection*)fd->data, buf);

	return 0;
}

static int telnet_new_connection(struct bsc_fd *fd, unsigned int what) {
	struct telnet_connection *connection;
	struct sockaddr_in sockaddr;
	socklen_t len = sizeof(sockaddr);
	int new_connection = accept(fd->fd, (struct sockaddr*)&sockaddr, &len);

	if (new_connection < 0) {
		perror("telnet accept failed");
		return -1;
	}


	connection = (struct telnet_connection*)malloc(sizeof(*connection));
	memset(connection, 0, sizeof(*connection));
	connection->network = (struct gsm_network*)fd->data;
	connection->fd.data = connection;
	connection->fd.fd = new_connection;
	connection->fd.when = BSC_FD_READ;
	connection->fd.cb = client_data;
	connection->bts = 0;
	bsc_register_fd(&connection->fd);
	llist_add_tail(&connection->entry, &active_connections);

	print_welcome(new_connection);

	return 0;
}