/*-
 * 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>

#ifndef BTASKTD_QUEUE_LEN
#	define QUEUE_LEN 16
#endif

enum flag_val_res {
	fvr_not_found = -1,
	fvr_min = fvr_not_found,
	fvr_ok = 0,
	fvr_invalid,
	fvr_max = fvr_invalid
};

struct str_flag_val {
	enum flag_val_res code;
	char *data;
};

struct int_flag_val {
	enum flag_val_res code;
	int data;
};

/* -f the_str */
static struct str_flag_val
extract_str_flag(char flagletter, int argc, char **argv)
{
	struct str_flag_val res = {0};
	char flagstr[3] = { '-', ' ', '\0' };
	int i;
	flagstr[1] = flagletter;
	for (i = 1; i < argc; i++)
		if (0 == strcmp(flagstr, argv[i]))
			break;
	if (i >= argc) {
		res.code = fvr_not_found;
	} else if (i == argc-1) {
		res.code = fvr_invalid;
	} else {
		res.code = fvr_ok;
		res.data = argv[i+1];
	}
	return res;
}

/* -f number */
static struct int_flag_val
extract_int_flag(char flagletter, int argc, char **argv)
{
	struct int_flag_val res;
	struct str_flag_val strres =
		extract_str_flag(flagletter, argc, argv);
	char *endptr;
	res.code = strres.code;
	if (res.code != fvr_ok) {
		return res;
	}
	res.data = strtol(strres.data, &endptr, 10);
	if (*endptr != '\0')
		res.code = fvr_invalid;
	return res;
}

int
main(int argc, char **argv)
{
	int server_fd, opt = 1, res, flags, port;
	struct sockaddr_in addr = {0};
	struct int_flag_val port_res =
		extract_int_flag('p', argc, argv);
	switch (port_res.code) {
	case fvr_not_found:
#		ifdef BTASKTD_DEFAULT_PORT
			port = BTASKTD_DEFAULT_PORT;
#		else
			fputs("No port specified!\n", stderr);
			return 1;
#		endif
		break;
	case fvr_invalid:
		fputs("Invalid port!\n", stderr);
		return 1;
	case fvr_ok:
		port = port_res.data;
	}

	server_fd = socket(AF_INET, SOCK_STREAM, 0);
	if (server_fd < 0) {
		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);
		perror("bind");
		return 1;
	}
	res = listen(server_fd, QUEUE_LEN);
	if (0 != res) {
		close(server_fd);
		perror("listen");
		return 1;
	}
	res = setsockopt(server_fd, SOL_SOCKET, SO_REUSEADDR,
		&opt, sizeof(opt));
	if (0 != res) {
		close(server_fd);
		perror("setsockopt");
		return 1;
	}
	flags = fcntl(server_fd, F_GETFL);
	fcntl(server_fd, F_SETFL, flags|O_NONBLOCK);

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

	/* main loop here */

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