/*
   telnetchat.c

   This is a telnet chat server.
   Copyright (C) 2008 Kenny1987.
   Contact me : kenny1987 at users dot sourceforge dot net

   Telnetchat is free software; you can redistribute it and/or modify it
   under the terms of the GNU General Public License as published by the
   Free Software Foundation; either version 3 of the License, or (at your
   option) any later version.

   Telnetchat is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License along
   with Telnetchat.  If not, see <http://www.gnu.org/licenses/>.
*/


#include <sys/types.h> 
#include <sys/socket.h> 
#include <netinet/in.h> 
#include <netdb.h> 
#include <pthread.h>
#include <unistd.h>
#include <stdio.h> 
#include <fcntl.h>
#define PORT 23                 
#define MAX_QUEUE 3 
#define BUF_SIZE 1024 
#define BOX_NAME "Insert Boxname here"

int sock_listen, sock_comm;
char outputbuf[BUF_SIZE];
struct sockaddr_in server;
unsigned int usernr;

void* handle_communication(void * arg)	{
	int priv_sock_comm = sock_comm; // copy current socket info
	char username[BUF_SIZE];
	char outputbufcp[BUF_SIZE];
	char linebuf[BUF_SIZE];
	char buffer[BUF_SIZE];
	unsigned int my_usernr = usernr++;
	int i=0;
		
	sprintf(buffer, "Welcome to %s . Please enter a username\r\n", BOX_NAME);
	if (send(priv_sock_comm, buffer, strlen(buffer), 0) < 0) perror("Error when sending.");
	
	for (i=0; i < BUF_SIZE; i++) buffer[i] = 0;	
	for (i=0; i < BUF_SIZE; i++) linebuf[i] = '\0';
	int bytes = 0;
	
	// "login"
	for (;;)  {
		int bytes = recv(priv_sock_comm, buffer, sizeof(buffer) -1, 0);
		//buffer[bytes - 2] = '\0'; //remove \n and \r
		buffer[bytes] = '\0';
		if (bytes > 0) {
			strcat(linebuf, buffer);
			if (strchr(linebuf, '\n')!=NULL) {
				linebuf[strlen(linebuf) - 2] = '\0';
				strcpy(&username, &linebuf);
				for (i=0; i < BUF_SIZE; i++) linebuf[i] = '\0';
				break;
			}
		}
		
	}

	sprintf(outputbuf, "%s joined us. His user-id is %d. Have fun %s! \r\n", &username, my_usernr, &username);
	
	// chat
	for (;;) {	
		int bytes = recv(priv_sock_comm, buffer, sizeof(buffer) -1, 0);
		buffer[bytes] = '\0';
		if (bytes > 0) {
			// Input from user – build chatstring
			strcat(linebuf, buffer);			
			if (strchr(linebuf, '\n')!=NULL) {
				linebuf[strlen(linebuf) - 2] = '\0';				
				if (strcmp(linebuf, "!QUIT")==0) break;
				sprintf(outputbuf, "'%s' says %s \r\n", &linebuf, &username);
				for (i=0; i < BUF_SIZE; i++) linebuf[i] = '\0';
			}
		}
		
		if (strcmp(outputbuf, outputbufcp)!=0) {
			// Send outputbuffer
			if (outputbuf[1]=='@') { // 0 is \t
				char temp[BUF_SIZE];
				strcpy(&temp, &outputbuf);			
				temp[0] = '0';
				temp[1] = '0';
				char *space;
				space = strchr(&temp, ' ');
				*space = '\0'; // now @15 is 0015 and we can use atoi
				unsigned int recipent = atoi(&temp);
				if (recipent == my_usernr) {
					if (send(priv_sock_comm, outputbuf, strlen(outputbuf), 0) < 0) perror("Error when sending. (3)");
				}
			}
			else {
				if (send(priv_sock_comm, outputbuf, strlen(outputbuf), 0) < 0) perror("Error when sending. (3)");			
			}
			strcpy(&outputbufcp, &outputbuf);
		}
	}
	
	sprintf(outputbuf, "%s left us \r\n", &username);
	close(priv_sock_comm);
	pthread_exit(NULL);
	}

int main() {
	usernr = 0;
	
	// Create Server
	sock_listen = socket(AF_INET, SOCK_STREAM, 0);
	if (sock_listen < 0) {
		perror("Error when trying to listen.");
		return(1);
	}
	
	server.sin_family 		= AF_INET;
	server.sin_addr.s_addr	= INADDR_ANY;
	server.sin_port			= htons(PORT);
	
	//Binding socket
	int yes = 1;
	setsockopt(sock_listen, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(int));
	if (bind(sock_listen, &server, sizeof(server))) {
		perror("Error when binding socket.");
		return(1);
	}
	
	for (;;) {
		listen(sock_listen, MAX_QUEUE);
		sock_comm = accept(sock_listen, 0, 0);
		fcntl(sock_comm, F_SETFL, O_NONBLOCK);
		
		pthread_t t;
		if (pthread_create(&t,NULL,handle_communication,NULL) != 0)  perror("Could not create thread");
		

		if (sock_comm < 0) {
			perror("Error when trying to accept.");
			return(1);
		}
	}
	close(sock_listen);
}