/*-
 * Copyright (c) 2026, Mr. Goblin
 *
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following
 * disclaimer in the documentation and/or other materials provided
 * with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT
 * NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
 * THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
 * OF SUCH DAMAGE.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/socket.h>
#include <sys/select.h>
#include <netinet/in.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include "cliflags.h"

#define BTASKTD_HELP_STR \
	"Copyright (c) 2026, Mr. Goblin\n" \
	"btasktd - task tracking TCP-server\n" \
	"Usage: btasktd [-Vh] [-p port] [-u users]\n" \
	"For more info read program's man page\n"

#define BTASKTD_VERSION_STR \
	"0.0.0"

#ifndef BTASKTD_QUEUE_LEN
#	define BTASKTD_QUEUE_LEN 16
#endif

static void
fprint_help(FILE *f)
{
	fputs(BTASKTD_HELP_STR, f);
}

static void
set_nonblock(int fd)
{
	int fflags = fcntl(fd, F_GETFL);
	fcntl(fd, F_SETFL, fflags|O_NONBLOCK);
}

int
main(int argc, char **argv)
{
	int server_fd, opt = 1, res, port, passed_flags = 1, users_cnt;
	int *users = NULL;
	struct sockaddr_in addr = {0};
	struct int_flag_val int_res;
	struct bool_flag_val show_ver, show_help;

	show_ver = extract_bool_flag('V', argc, argv);
	if (fvr_ok == show_ver.code && show_ver.data) {
		printf("btasktd version %s\n", BTASKTD_VERSION_STR);
		return 0;
	}

	show_help = extract_bool_flag('h', argc, argv);
	if (show_help.code == fvr_ok && show_help.data) {
		fprint_help(stdout);
		return 0;
	}

	int_res = extract_int_flag('p', argc, argv);
	switch (int_res.code) {
	case fvr_not_found:
#		ifdef BTASKTD_DEFAULT_PORT
			port = BTASKTD_DEFAULT_PORT;
#		else
			fputs("No port specified!\n", stderr);
			passed_flags = 0;
#		endif
		break;
	case fvr_ok:
		port = int_res.data;
		if (port > 0)
			break;
		/* fallthrough */
	case fvr_invalid:
		fputs("Invalid port!\n", stderr);
		return 1;
		break;
	}

	int_res = extract_int_flag('u', argc, argv);
	switch (int_res.code) {
	case fvr_not_found:
#		ifdef BTASKTD_DEFAULT_USERS_CNT
			users_cnt = BTASKTD_DEFAULT_USERS_CNT;
#		else
			fputs("No users count specified!\n", stderr);
			passed_flags = 0;
#		endif
		break;
	case fvr_ok:
		users_cnt = int_res.data;
		if (users_cnt > 0)
			break;
		/* fallthrough */
	case fvr_invalid:
		fputs("Invalid users count!\n", stderr);
		return 1;
		break;
	}

	if (!passed_flags) {
		fputs("-\n", stderr);
		fprint_help(stderr);
		return 1;
	}

	users = (int*)malloc(users_cnt * sizeof(int));
	if (NULL == users) {
		fputs("No memory!\n", stderr);
		return 1;
	}

	server_fd = socket(AF_INET, SOCK_STREAM, 0);
	if (server_fd < 0) {
		free(users);
		perror("socket");
		return 1;
	}
	addr.sin_family = AF_INET;
	addr.sin_port = htons(port);
	addr.sin_addr.s_addr = htonl(INADDR_ANY);
	res = bind(server_fd, (struct sockaddr*)&addr, sizeof(addr));
	if (0 != res) {
		close(server_fd);
		free(users);
		perror("bind");
		return 1;
	}
	res = listen(server_fd, BTASKTD_QUEUE_LEN);
	if (0 != res) {
		close(server_fd);
		free(users);
		perror("listen");
		return 1;
	}
	res = setsockopt(server_fd, SOL_SOCKET, SO_REUSEADDR,
		&opt, sizeof(opt));
	if (0 != res) {
		close(server_fd);
		free(users);
		perror("setsockopt");
		return 1;
	}

	set_nonblock(server_fd);
	printf("btaskt server btasktd started on port %d\n", port);

	/* main loop here */

	printf("btaskt server btasktd stopped\n");
	close(server_fd);
	free(users);
	return 0;
}