#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>

// accept
// atoi
// bind
// bzero
// calloc
// close
// exit
// free
// listen
// malloc
// memset
// realloc
// recv
// select
// send
// socket
// sprintf
// strcat
// strcpy
// strlen
// strstr
// write

#define BUFSIZE 100

typedef struct s_client {
	int							fd;
	int							id;
	char						*msg;
	struct s_client	*next;
} t_client;

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

int extract_message(char **buf, char **msg)
{
	char	*newbuf;
	int	i;

	*msg = 0;
	if (*buf == 0)
		return (0);
	i = 0;
	while ((*buf)[i])
	{
		if ((*buf)[i] == '\n')
		{
			newbuf = calloc(1, sizeof(*newbuf) * (strlen(*buf + i + 1) + 1));
			if (newbuf == 0)
				return (-1);
			strcpy(newbuf, *buf + i + 1);
			*msg = *buf;
			(*msg)[i + 1] = 0;
			*buf = newbuf;
			return (1);
		}
		i++;
	}
	return (0);
}

char *str_join(char *buf, char *add)
{
	char	*newbuf;
	int		len;

	if (buf == 0)
		len = 0;
	else
		len = strlen(buf);
	newbuf = malloc(sizeof(*newbuf) * (len + strlen(add) + 1));
	if (newbuf == 0)
		return (0);
	newbuf[0] = 0;
	if (buf != 0)
		strcat(newbuf, buf);
	free(buf);
	strcat(newbuf, add);
	return (newbuf);
}

void add_client(t_client **first_client, int fd, int id) {
	t_client	*new_client;
	t_client	*client;

	new_client = calloc(1, sizeof(*new_client));
	if (!new_client)
		error("Fatal error\n");
	new_client->fd = fd;
	new_client->id = id;
	new_client->next = NULL;
	if (!(*first_client))
		*first_client = new_client;
	else {
		client = *first_client;
		while (client->next)
			client = client->next;
		client->next = new_client;
	}
}

void broadcast(char *buf, fd_set *set, int maxfd, int client_fd) {
	for(int fd = 0; fd <= maxfd; ++fd) {
		if (fd == client_fd)
			continue;
		if (FD_ISSET(fd, set))
			send(fd, buf, strlen(buf), 0);
	}
}

// debug
void print_clients(t_client *client) {
	printf("clients:");
	while(client) {
		printf("[%i - %i]", client->id, client->fd);
		client = client->next;
	}
	printf("\n");
}

int main(int ac, char **av) {
	int									sockfd;
	int									client_fd;
	int									maxfd;
	int									id;
	struct sockaddr_in	servaddr;
	fd_set							read_set;
	fd_set							write_set;
	t_client						*client;
	t_client						*first_client;
	char								buf[BUFSIZE];

	if (ac != 2)
		error("Wrong number of arguments\n");
	client = NULL;
	id = 0;
	first_client = client;

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

	// assign IP, PORT 
	servaddr.sin_family = AF_INET; 
	servaddr.sin_addr.s_addr = htonl(2130706433); //127.0.0.1
	servaddr.sin_port = htons(atoi(av[1])); 

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

	while(1) {
//print_clients(first_client);
		maxfd = sockfd;
		FD_ZERO(&read_set);
		FD_ZERO(&write_set);
		FD_SET(sockfd, &read_set);
		client = first_client;
		while(client) {
			FD_SET(client->fd, &read_set);
			FD_SET(client->fd, &write_set);
			if (client->fd > maxfd)
				maxfd = client_fd;
			client = client->next;
		}

		select(maxfd + 1, &read_set, NULL, NULL, NULL);

		if (FD_ISSET(sockfd, &read_set)) {
			client_fd = accept(sockfd, NULL, NULL);
			add_client(&first_client, client_fd, id);
			sprintf(buf, "server: client %d just arrived\n", id);
			broadcast(buf, &write_set, maxfd, client_fd) {
			id++;
		}
	}
	return (0);
}