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

#define BUFSIZE 42000

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

// GLOBALS
int					server_fd;
int					id;
int					max_fd;
socklen_t		addr_len;
fd_set			fdset;
t_client		clients[FD_SETSIZE];

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

void broadcast(char *buf, fd_set *set, int max_fd, int server_fd, int sender_fd) {
	for(int i = 0; i <= max_fd; ++i) {
		if (i == server_fd)
			continue;
		if (i == sender_fd)
			continue;
		if (FD_ISSET(i, set))
			send(i, buf, strlen(buf), 0);
	}
}

void handle_socket(struct sockaddr *addr) {
	fd_set		rdset;
	int				client_fd;
	int				ret;
	t_client	client;
	char			buf[BUFSIZE];
	char			msg[BUFSIZE];

	rdset = fdset;
	select(max_fd + 1, &rdset, NULL, NULL, NULL);

	if (FD_ISSET(server_fd, &rdset)) {
		client_fd = accept(server_fd, addr, &addr_len);
		FD_SET(client_fd, &fdset);
		if (client_fd > max_fd)
			max_fd = client_fd;
		client = clients[client_fd];
		client.id = id;
		bzero(client.msg, strlen(client.msg));
		sprintf(buf, "server: client %d arrived\n", id);
	}

	client_fd = 0;
	while(client_fd < max_fd) {
		if (FD_ISSET(client_fd, &rdset)) {
			bzero(buf, BUFSIZE);
			ret = recv(client_fd, buf, BUFSIZE, 0);
			if (ret == 0) {
				sprintf(msg, "server: client %d just left\n", clients[client_fd].id);
				broadcast(msg, &fdset, max_fd, server_fd, client_fd);
				FD_CLR(client_fd, &fdset);
			}
			else if (ret > 0) {

				client = clients[client_fd];
				for(int i = 0, j = strlen(client.msg); i < ret; ++i, ++j) {
					client.msg[j] = buf[i];
					if (buf[i] == '\n') {
						client.msg[j] = '\0';
						sprintf(msg, "client %d: %s\n", client.id, client.msg);
						broadcast(msg, &fdset, max_fd, server_fd, client_fd);
						bzero(client.msg, strlen(client.msg));
						j = -1;
					}
				}

			}
		}
		client_fd++;
	}
}

int main(int ac, char **av) {
	struct sockaddr_in	addr;
	int									port;

	if (ac != 2)
		error("Fatal error\n");
	port = atoi(av[1]);
	addr_len = sizeof(addr);

	// socket create and verification 
	if ( (server_fd = socket(AF_INET, SOCK_STREAM, 0)) == -1)
		error("Fatal error\n");
	bzero(&addr, addr_len);

	// assign IP, PORT 
	addr.sin_family = AF_INET; 
	addr.sin_addr.s_addr = htonl(2130706433); //127.0.0.1
	addr.sin_port = htons(port); 

	// Binding newly created socket to given IP and verification 
	if (bind(server_fd, (const struct sockaddr *)&addr, addr_len) == -1)
		error("Fatal error\n");
	if (listen(server_fd, 10) == -1)
		error("Fatal error\n");

	FD_ZERO(&fdset);
	FD_SET(server_fd, &fdset);
	max_fd = server_fd;

	while(1)
		handle_socket((struct sockaddr *)&addr);

	return (0);
}