/*
 * Usurpation – server daemon main logic
 *
 * Copyright (C) 2019 Gediminas Jakutis
 * Copyright (C) 2019 Paulius Ratkevičius
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; version 2.1
 * of the License.
 *
 * 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
 */

#include <unistd.h>
#include <time.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include "settings.h"
#include "net.h"
#include "purple.h"
#include "proto_stdio.h"
#include "tlv.h"
#include "utils.h"

static struct _state {
	int nd;
} __progstate;

static void cleanup(void);
static int __main_loop(const struct timespec * const iter_len);
static int does_my_kokoro_go_doki_doki(struct tlv *tlv);

/* the logic is a placeholder right now */
int main(int argc, char **argv)
{
	extern const char * const version;
	static const struct timespec t = {0, 250 * 1000 * 1000}; /* 250ms */
	char *proto;

	printf("Usurpation daemon version %s starting\n", version);

	atexit(cleanup);
	settings_init();
	__progstate.nd = net_init(setting_port());
	proto = setting_im_proto();

	if (strcmp(proto, "null")) {
		if (purple_init() && setting_verbose()) {
			fprintf(stderr, "libpurple initialization failed\n");
		}
	} else {
		if (proto_stdio_init() && setting_verbose()) {
			fprintf(stderr, "stdio interface initialization failed\n");
		}
	}

	free(proto);
	proto = NULL;

	/* by default and if running by as a system service, the init system
	 * needs to keep control of the process and thus only detach if
	 * requested when ran manually by a user.
	 */
	if (setting_detach()) {
		daemon(0, 0);
	}

	return __main_loop(&t);
}

/* TODO: semi-stub */
static int __main_loop(const struct timespec * const iter_len)
{
	struct tlv_packet pack;
	struct tlv field;
	struct timespec t;
	char *buf = NULL;
	size_t recvsize;
	int ret = A_OK;

	t = *iter_len;
	tlv_packet_init(&pack);

	while (ret != ERROR) {
		ret = net_getlastdata(__progstate.nd, &buf, &recvsize);

		if (ret != A_OK) {
			goto skiprecv;
		}
		/* we're only sending one TLV per packet as of now,
		 * so no need to save the pointer for further parsing
		 */
		ret = tlv_get(buf, &field, NULL);

		/* handles discovery */
		if (ret != A_OK || !(does_my_kokoro_go_doki_doki(&field))) {
			goto skiprecv;
		}

		/* handles receiving messages */
		if (field.head.type == TEXT) {
			message_receive(field.data);
		}
/* jumping here if did not receive any data */
skiprecv:
		/* handles sending messages */
		if (message_send(&field)) {
			if (field.head.size) {
				tlv_pack(&pack, &field);
				tlv_packet_finalize(&pack);
				tlv_destroy(&field);
				net_send(__progstate.nd, pack.data, pack.cursor);
				tlv_packet_reset(&pack);
			}
		}

		nanosleep(&t, NULL);
	}

	tlv_packet_destroy(&pack);

	return ret;
}

static int does_my_kokoro_go_doki_doki(struct tlv *tlv)
{
	int ret = ERROR;
	static struct tlv_packet pack;
	static size_t firstrun = 1;

	if (firstrun) {
		struct tlv field;
		tlv_init(&field, HEARTBEAT);
		field.data = strdup(heartbeat_server);
		field.head.size = sizeof(heartbeat_server);
		tlv_packet_init(&pack);
		tlv_pack(&pack, &field);
		tlv_packet_finalize(&pack);
		tlv_destroy(&field);
		firstrun = 0;
	}

	if (tlv->head.type == HEARTBEAT && !(strcmp(tlv->data, heartbeat_device))) {
		if (setting_verbose() >= INFO) {
			fprintf(stderr, "heartbeat.\n");
		}

		ret = net_send(__progstate.nd, pack.data, pack.cursor);
	}

	return ret;
}

static void cleanup(void)
{
	purple_close();
	proto_stdio_close();
	net_close(__progstate.nd);
	__progstate.nd = 0;
	settings_cleanup();
}