#include <errno.h>
#include <netdb.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <string.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>

typedef struct s_client {
	int		id;
	char	msg[1024];
} t_client;

t_client	clients[1024];
fd_set		readfds, writefds, active;
int				fd_max;
int				id_next;
char			bufread[120000];
char			bufwrite[120000];

void error(char *msg) {
	write(2, msg, strlen(msg));
	exit(1);
}

void broadcast(int not) {
	for(int fd = 0; fd <= fd_max; ++fd) {
		if (fd == not)
			continue;
		if (FD_ISSET(fd, &writefds))
			send(fd, bufwrite, strlen(bufwrite), 0);
	}
}

int main(int ac, char **av) {
	int sockfd, connfd, res;
	struct sockaddr_in servaddr, cli;
	socklen_t len;

	if (ac != 2)
		error("Wrong number of arguments\n");

	sockfd = socket(AF_INET, SOCK_STREAM, 0); 
	if (sockfd == -1)
		error("Fatal error\n");
	bzero(&servaddr, sizeof(servaddr)); 

	servaddr.sin_family = AF_INET; 
	servaddr.sin_addr.s_addr = htonl(2130706433);
	servaddr.sin_port = htons(atoi(av[1])); 

	if ((bind(sockfd, (const struct sockaddr *)&servaddr, sizeof(servaddr))) == -1)
		error("Fatal error\n");
	if (listen(sockfd, 10) == -1)
		error("Fatal error\n");

	len = sizeof(cli);
	FD_ZERO(&active);
	FD_SET(sockfd, &active);
	bzero(&clients, sizeof(clients));
	fd_max = sockfd;

	while(1) {
		readfds = active;
		writefds = active;

		if (select(fd_max + 1, &readfds, &writefds, NULL, NULL) < 0)
			continue;

		for(int fd_i = 0; fd_i <= fd_max; ++fd_i) {
			if (FD_ISSET(fd_i, &readfds) && fd_i == sockfd) {
				connfd = accept(sockfd, (struct sockaddr *)&cli, &len);
				if (connfd < 0)
					continue;
				if (connfd > fd_max)
					fd_max = connfd;
				clients[connfd].id = id_next++;
				FD_SET(connfd, &active);
				sprintf(bufwrite, "server: client %d just arrived\n", clients[connfd].id);
				broadcast(connfd);
				break;
			}
			if (FD_ISSET(fd_i, &readfds) && fd_i != sockfd) {
				res = recv(fd_i, bufread, 65536, 0);
				if (res <= 0) {
					sprintf(bufwrite, "server: client %d just left\n", clients[fd_i].id);
					broadcast(fd_i);
					FD_CLR(fd_i, &active);
					close(fd_i);
					break;
				}
				else {
					for(int i = 0, j = strlen(clients[fd_i].msg); i < res; ++i, ++j) {
						clients[fd_i].msg[j] = bufread[i];
						if (clients[fd_i].msg[j] == '\n') {
							clients[fd_i].msg[j] = '\0';
							sprintf(bufwrite, "client %d: %s\n", clients[fd_i].id, clients[fd_i].msg);
							broadcast(fd_i);
							bzero(clients[fd_i].msg, strlen(clients[fd_i].msg));
							j = -1;
						}
					}
					break;
				}
			}
		}
	}
}