#define _POSIX_C_SOURCE 200112L

#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/types.h>

#include <errno.h>
#include <limits.h>
#include <netdb.h>
#include <poll.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "log.h"

#ifndef OPEN_MAX
#define OPEN_MAX 1024
#endif

#define PORT "3000"
#define BUFSIZE 1024

static int
create_server(const char *port)
{
	int fd, yes = 1;
	struct addrinfo *res, *p, hints;

	memset(&hints, 0, sizeof hints);
	hints.ai_family = AF_UNSPEC;
	hints.ai_socktype = SOCK_STREAM;
	hints.ai_flags = AI_PASSIVE;

	if (getaddrinfo(NULL, port, &hints, &res) != 0) {
		perror("getaddrinfo");
		return -1;
	}
	for (p = res; p != NULL; p = p->ai_next) {
		if ((fd = socket(p->ai_family, p->ai_socktype, p->ai_protocol))
		    == -1) {
			perror("socket");
			continue;
		}
		if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &yes,
			       sizeof(int)) == -1) {
			perror("setsockopt");
			close(fd);
			return -1;
		}
		if (ioctl(fd, FIONBIO, &yes) == -1) {
			perror("ioctl");
			close(fd);
			return -1;
		}
		if (bind(fd, p->ai_addr, p->ai_addrlen) == -1) {
			perror("bind");
			continue;
		}
		break;
	}

	freeaddrinfo(res);

	if (p == NULL) {
		fprintf(stderr, "failed to bind\n");
		return -1;
	}
	if (listen(fd, 32) == -1) {
		perror("listen");
		return -1;
	}
	logmsg(LOG_INFO, "listening on %s", port);
	return fd;
}

static int
accept_connection(int s_fd)
{
	int c_fd;

	if ((c_fd = accept(s_fd, NULL, NULL)) == -1) {
		if (errno != EWOULDBLOCK || errno != EAGAIN) {
			perror("accept");
			exit(1);
		}
		return -1;
	}
	logmsg(LOG_INFO, "connection accepted");

	return c_fd;
}

static void
handle_client(int c_fd)
{
	int n;
	char buf[BUFSIZE];

	n = recv(c_fd, &buf, BUFSIZE - 1, 0);
	switch (n) {
	case -1:
		if (errno != EWOULDBLOCK || errno != EAGAIN) {
			perror("recv");
		}
	case 0:
		logmsg(LOG_INFO, "connection closed by client");
	default:
		buf[n] = '\0';
		if (send(c_fd, buf, n, 0) == -1) {
			perror("send");
		}
	}
	close(c_fd);
}

static void
main_loop(int s_fd)
{
	int i, rc, end_server = 0;
	int c_fd, nfds = 1, curr_size = 0;
	struct pollfd pfds[OPEN_MAX];

	memset(pfds, 0, sizeof(pfds));
	pfds[0].fd = s_fd;
	pfds[0].events = POLLIN;

	do {
		rc = poll(pfds, nfds, -1);
		if (rc == -1) {
			perror("poll");
			break;
		}
		if (rc == 0) {
			fprintf(stderr, "poll timeout\n");
			break;
		}
		curr_size = nfds;
		for (i = 0; i < curr_size; i++) {
			if (pfds[i].revents == 0)
				continue;

			if (pfds[i].revents != POLLIN) {
				logmsg(LOG_INFO, "revents not POLLIN\n");
				end_server = 1;
				break;
			}
			if (pfds[i].fd == s_fd) {
				do {
					c_fd = accept_connection(s_fd);
					if (c_fd != -1) {
						pfds[nfds].fd = c_fd;
						pfds[nfds].events = POLLIN;
						nfds++;
					}
				} while (c_fd != -1);
			} else {
				handle_client(pfds[i].fd);
				pfds[i].fd = -1;
			}
		}
	} while (end_server == 0);
}

int
main()
{
	int s_fd;

	s_fd = create_server(PORT);
	if (s_fd == -1) {
		fprintf(stderr, "failed to create server\n");
		exit(0);
	}
	main_loop(s_fd);

	return 0;
}