/*
 * (C) 2022 by Harald Welte <laforge@osmocom.org>
 * All Rights Reserved
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Affero 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 Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <limits.h>
#include <unistd.h>
#include <errno.h>
#include <osmocom/core/msgb.h>
#include <osmocom/abis/e1_input.h>

#include <osmocom/core/application.h>
#include <osmocom/core/msgb.h>
#include <osmocom/core/talloc.h>
#include <osmocom/core/select.h>
#include <osmocom/core/stats.h>
#include <osmocom/core/rate_ctr.h>
#include <osmocom/core/socket.h>
#include <osmocom/core/gsmtap.h>
#include <osmocom/core/gsmtap_util.h>

#include <osmocom/ctrl/control_vty.h>

#include <osmocom/vty/telnet_interface.h>
#include <osmocom/vty/logging.h>
#include <osmocom/vty/ports.h>
#include <osmocom/vty/command.h>
#include <osmocom/vty/stats.h>
#include <osmocom/vty/misc.h>
#include <osmocom/vty/cpu_sched_vty.h>

#include <osmocom/abis/abis.h>

#include "logging.h"
#include "v5x_internal.h"
#include "v5x_protocol.h"
#include "v51_le_ctrl.h"
#include "v52_le_user_port_fsm.h"
#include "v5x_le_pstn_fsm.h"
#include "v5x_l2_mgmt.h"
#include "v51_le_provisioning.h"
#include "lapv5.h"

#define _GNU_SOURCE
#include <getopt.h>

/* can be changed once libosmocore 1.4.0 is released */
#ifndef OSMO_CTRL_PORT_MGW
#define OSMO_CTRL_PORT_MGW 4267
#endif

/* only temporarily until this is in libosmocore gsmtap.h */
#ifndef GSMTAP_E1T1_V5EF
#define GSMTAP_E1T1_V5EF	0x06
#endif

void *tall_v5le_ctx = NULL;
struct v5x_instance *v5i = NULL;
static struct gsmtap_inst *g_gti;

struct v5le_config {
};

struct v5le_config *v5le_config_alloc(void *ctx)
{
	struct v5le_config *cfg = talloc_zero(ctx, struct v5le_config);
	OSMO_ASSERT(cfg);

	return cfg;
}

static int v5le_rx_sign(struct msgb *msg)
{
	LOGP(DLMI, LOGL_NOTICE, "Rx: %s\n", msgb_hexdump(msg));

	msgb_free(msg);

	return 0;
}

static const struct e1inp_line_ops v5le_e1_line_ops = {
	.sign_link_up = NULL,
	.sign_link_down = NULL,
	.sign_link = v5le_rx_sign,
};

#include "v5x_protocol.h"
/* data L1 -> L2 */
static void hdlc_rx_cb(struct e1inp_ts *ts, struct msgb *msg)
{
#warning HACKING
		struct v5x_interface *v5if = (struct v5x_interface *)v5i->interfaces.next;

	LOGP(DLINP, LOGL_DEBUG, "L1->L2: %s\n", msgb_hexdump(msg));

	/* send V5 data via gsmtap so wireshark can receive + decode it */
	gsmtap_send_ex(g_gti, GSMTAP_TYPE_E1T1, 0, ts->num, GSMTAP_E1T1_V5EF,
			0, 0, 0, 0, msgb_data(msg), msgb_length(msg));

	lapv5ef_rx(v5if->primary_link, msg);
}

static void raw_rx_cb(struct e1inp_ts *ts, struct msgb *msg)
{
#warning HACKING
		struct v5x_interface *v5if = (struct v5x_interface *)v5i->interfaces.next;
		struct v5x_user_port *v5up = v5if->links[0].ts[ts->num].v5up;

	/* not used by any user port */
	if (!v5up) {
		msgb_free(msg);
		return;
	}

	if (v5up->ts_nr[0] == ts->num && v5up->ts_activated[0])
		ph_socket_tx_msg(&v5up->ph_socket, 1, PH_PRIM_DATA_IND, msg->data, msg->len);
	if (v5up->ts_nr[1] == ts->num && v5up->ts_activated[1])
		ph_socket_tx_msg(&v5up->ph_socket, 2, PH_PRIM_DATA_IND, msg->data, msg->len);
	msgb_free(msg);
}

/* l2 -> L1 */
int ph_data_req(struct msgb *msg, void *cbdata)
{
	msg->l2h = msgb_push(msg, 2);
	msg->l2h[0] = msg->l2h[2] & 0xfd;
	msg->l2h[1] = msg->l2h[3];
	LOGP(DLINP, LOGL_DEBUG, "L2->L1: %s\n", msgb_hexdump(msg));

#warning hacking
		struct e1inp_line *e1_line = e1inp_line_find(0);
		struct e1inp_ts *ts = &e1_line->ts[16-1];

	/* send V5 data via gsmtap so wireshark can receive + decode it */
	gsmtap_send_ex(g_gti, GSMTAP_TYPE_E1T1, GSMTAP_ARFCN_F_UPLINK, ts->num, GSMTAP_E1T1_V5EF,
			0, 0, 0, 0, msgb_data(msg), msgb_length(msg));

	return e1inp_ts_send_hdlc(ts, msg);
}

#warning hacking
int ph_data_req_hack(struct msgb *msg)
{
	LOGP(DLINP, LOGL_DEBUG, "L2->L1: %s\n", msgb_hexdump(msg));

#warning hacking
		struct e1inp_line *e1_line = e1inp_line_find(0);
		struct e1inp_ts *ts = &e1_line->ts[16-1];

	/* send V5 data via gsmtap so wireshark can receive + decode it */
	gsmtap_send_ex(g_gti, GSMTAP_TYPE_E1T1, GSMTAP_ARFCN_F_UPLINK, ts->num, GSMTAP_E1T1_V5EF,
			0, 0, 0, 0, msgb_data(msg), msgb_length(msg));

	return e1inp_ts_send_hdlc(ts, msg);
}

#warning hacking
int ph_data_req_raw(struct msgb *msg, int ts_nr)
{
#warning hacking
		struct e1inp_line *e1_line = e1inp_line_find(0);
		struct e1inp_ts *ts = &e1_line->ts[ts_nr-1];

	return e1inp_ts_send_raw(ts, msg);
}

static int e1_init(void)
{
	int line_nr = 1, ts;
	struct e1inp_line *e1_line;

	e1_line = e1inp_line_find(0);
	OSMO_ASSERT(e1_line);

	e1inp_line_bind_ops(e1_line, &v5le_e1_line_ops);

	for (ts = 1; ts <= 31; ts++) {
		struct e1inp_ts *e1_ts = &e1_line->ts[ts-1];
		if (ts == 16) { // FIXME: make this depending on c_channel
			//e1inp_ts_config_sign(e1_ts, e1_line);
			//e1inp_sign_link_create(e1_ts, E1INP_SIGN_NONE, NULL, 115/*TEI*/, 0/*SAPI*/);
			e1inp_ts_config_hdlc(e1_ts, e1_line, hdlc_rx_cb);
		} else
			e1inp_ts_config_raw(e1_ts, e1_line, raw_rx_cb);
	}

	return e1inp_line_update(e1_line);
}

static struct v5le_config *g_cfg;
static int daemonize = 0;

const char *v5le_copyright =
	"Copyright (C) 2022 by Harald Welte\r\n"
	"License AGPLv3+: GNU AGPL version 3 or later <http://gnu.org/licenses/agpl-3.0.html>\r\n"
	"This is free software: you are free to change and redistribute it.\r\n"
	"There is NO WARRANTY, to the extent permitted by law.\r\n";

static char *config_file = "osmo-v5le.cfg";

static void print_help()
{
	printf("Some useful options:\n");
	printf(" -h --help is printing this text.\n");
	printf(" -c --config-file filename The config file to use.\n");
	printf(" -s --disable-color\n");
	printf(" -D --daemonize Fork the process into a background daemon\n");
	printf(" -V --version Print the version number\n");

	printf("\nVTY reference generation:\n");
	printf("    --vty-ref-mode MODE		VTY reference generation mode (e.g. 'expert').\n");
	printf("    --vty-ref-xml		Generate the VTY reference XML output and exit.\n");
}

static void handle_long_options(const char *prog_name, const int long_option)
{
	static int vty_ref_mode = VTY_REF_GEN_MODE_DEFAULT;

	switch (long_option) {
	case 1:
		vty_ref_mode = get_string_value(vty_ref_gen_mode_names, optarg);
		if (vty_ref_mode < 0) {
			fprintf(stderr, "%s: Unknown VTY reference generation "
				"mode '%s'\n", prog_name, optarg);
			exit(2);
		}
		break;
	case 2:
		fprintf(stderr, "Generating the VTY reference in mode '%s' (%s)\n",
			get_value_string(vty_ref_gen_mode_names, vty_ref_mode),
			get_value_string(vty_ref_gen_mode_desc, vty_ref_mode));
		vty_dump_xml_ref_mode(stdout, (enum vty_ref_gen_mode) vty_ref_mode);
		exit(0);
	default:
		fprintf(stderr, "%s: error parsing cmdline options\n", prog_name);
		exit(2);
	}
}

static void handle_options(int argc, char **argv)
{
	while (1) {
		int option_index = 0, c;
		static int long_option = 0;
		static struct option long_options[] = {
			{"help", 0, 0, 'h'},
			{"config-file", 1, 0, 'c'},
			{"daemonize", 0, 0, 'D'},
			{"version", 0, 0, 'V'},
			{"disable-color", 0, 0, 's'},
			{"vty-ref-mode", 1, &long_option, 1},
			{"vty-ref-xml", 0, &long_option, 2},
			{0, 0, 0, 0},
		};

		c = getopt_long(argc, argv, "hc:sVD", long_options, &option_index);

		if (c == -1)
			break;

		switch(c) {
		case 'h':
			print_help();
			exit(0);
			break;
		case 0:
			handle_long_options(argv[0], long_option);
			break;
		case 'c':
			config_file = talloc_strdup(tall_v5le_ctx, optarg);
			break;
		case 's':
			log_set_use_color(osmo_stderr_target, 0);
			break;
		case 'V':
			print_version(1);
			exit(0);
			break;
		case 'D':
			daemonize = 1;
			break;
		default:
			/* ignore */
			break;
		};
	}
	if (argc > optind) {
		fprintf(stderr, "Unsupported positional arguments on command line\n");
		exit(2);
	}
}

int v5le_vty_is_config_node(struct vty *vty, int node)
{
	switch (node) {
	case CONFIG_NODE:
		return 0;
	default:
		return 1;
	}
}

int v5le_vty_go_parent(struct vty *vty)
{
	switch (vty->node) {
	default:
		if (v5le_vty_is_config_node(vty, vty->node))
			vty->node = CONFIG_NODE;
		else
			vty->node = ENABLE_NODE;

		vty->index = NULL;
	}

	return vty->node;
}


static struct vty_app_info vty_info = {
	.name 		= "OsmoV5LE",
	.version	= PACKAGE_VERSION,
	.go_parent_cb	= v5le_vty_go_parent,
	.is_config_node	= v5le_vty_is_config_node,
};

int main(int argc, char **argv)
{
	unsigned int flags;
	int rc;

	tall_v5le_ctx = talloc_named_const(NULL, 1, "v5le");
	vty_info.tall_ctx = tall_v5le_ctx;

	msgb_talloc_ctx_init(tall_v5le_ctx, 0);

	osmo_init_ignore_signals();
	osmo_init_logging2(tall_v5le_ctx, &log_info);
	libosmo_abis_init(tall_v5le_ctx);

	g_cfg = v5le_config_alloc(tall_v5le_ctx);
	if (!g_cfg)
		return -1;

	vty_info.copyright = v5le_copyright;

	vty_init(&vty_info);
	logging_vty_add_cmds();
	osmo_talloc_vty_add_cmds();
	osmo_stats_vty_add_cmds();
	v5x_vty_init();
	ctrl_vty_init(g_cfg);
	e1inp_vty_init();
	osmo_cpu_sched_vty_init(tall_v5le_ctx);

	handle_options(argc, argv);

	rate_ctr_init(tall_v5le_ctx);
	osmo_stats_init(tall_v5le_ctx);

	/* global inits of protocols */
	v51_ctrl_init();
	v51_port_ctrl_init();
	v51_pstn_init();
	v51_provisioning_init();
	v51_mgmt_init();

	/* create v5x instance */
	v5i = v5x_instance_alloc(tall_v5le_ctx);
	if (!v5i)
		return -ENOMEM;

	// FIXME: move this to VTY code
	/* create v5x interface */
	struct v5x_interface *v5if;
//	struct v5x_user_port *v5up;
	uint32_t interface_id = 1;
	uint8_t interface_variant = 1;
	v5if = v5x_interface_alloc(v5i, V5X_DIALECT_V51, interface_id, interface_variant, ph_data_req);
	if (!v5if)
		return -ENOMEM;
//	v5up = v5x_user_port_create(v5if, 1001, V5X_USER_TYPE_ISDN, 1, 2);
//	v5up = v5x_user_port_create(v5if, 1002, V5X_USER_TYPE_PSTN, 3, 0);
//	if (!v5up)
//		return -ENOMEM;

	rc = vty_read_config_file(config_file, NULL);
	if (rc < 0)
		return rc;

	g_gti = gsmtap_source_init("224.0.0.1", GSMTAP_UDP_PORT, 0);
	OSMO_ASSERT(g_gti);
	gsmtap_source_add_sink(g_gti);

	rc = e1_init();
	OSMO_ASSERT(rc == 0);

	/* start telnet after reading config for vty_get_bind_addr() */
	rc = telnet_init_dynif(tall_v5le_ctx, NULL,
			       vty_get_bind_addr(), OSMO_VTY_PORT_MGW);
	if (rc < 0)
		return rc;

#if 0
	cfg->ctrl = v5le_ctrl_interface_setup(cfg, ctrl_vty_get_bind_addr(), OSMO_CTRL_PORT_MGW);
	if (!cfg->ctrl) {
		fprintf(stderr, "Failed to init the control interface on %s:%u. Exiting\n",
			ctrl_vty_get_bind_addr(), OSMO_CTRL_PORT_MGW);
	}

	/* Set the reset callback function. This functions is called when the
	 * mgcp-command "RSIP" (Reset in Progress) is received */
	cfg->reset_cb = mgcp_rsip_cb;

	/* we need to bind a socket */
	flags = OSMO_SOCK_F_BIND;
	if (strlen(cfg->call_agent_addr))
		flags |= OSMO_SOCK_F_CONNECT;

	rc = osmo_sock_init2_ofd(&cfg->gw_fd.bfd, AF_UNSPEC, SOCK_DGRAM, IPPROTO_UDP,
				cfg->source_addr, cfg->source_port,
				cfg->call_agent_addr, strlen(cfg->call_agent_addr) ? 2727 : 0, flags);
	if (rc < 0) {
		perror("Gateway failed to bind");
		return -1;
	}

	cfg->gw_fd.bfd.cb = read_call_agent;
	cfg->gw_fd.bfd.data = msgb_alloc(4096, "mgcp-msg");
	if (!cfg->gw_fd.bfd.data) {
		fprintf(stderr, "Gateway memory error.\n");
		return -1;
	}

	LOGP(DLMGCP, LOGL_NOTICE, "Configured for MGCP, listen on %s:%u\n",
	     cfg->source_addr, cfg->source_port);
#endif

	/* initialisation */
	srand(time(NULL));



	if (daemonize) {
		rc = osmo_daemonize();
		if (rc < 0) {
			perror("Error during daemonize");
			exit(1);
		}
	}

	/* main loop */
	while (1) {
		osmo_select_main(0);
	}


	return 0;
}