/* 
 Chatroom server using select
 Copyright (C) 2004-2006, Li Suke, School of Software and Microelectronics,
 Peking University
 This  is free software; you can redistribute it and/or
 modify it freely.

 This software  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. 
*/


#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/time.h>
#include <sys/select.h>
#include <string.h>
#include <errno.h>
#define  BACK_LOG 10
#define BUF_SIZE 1024
int main(int argc, char *argv[]){
   int sockfd;
   int connfd;
   int clifd;
   int clifd2;
   struct sockaddr_in servaddr,cliaddr;
   int clilen;
   int port;
   int client[FD_SETSIZE];
   fd_set allset,rdset;
   int max_fd;
   int i;
   int nready;
   int max_index;
   char buffer[BUF_SIZE];
   int j;
   int len;
   if(argc != 2){
      printf("Usage chatsrv port\n");
      exit(0);
   }
   port = atoi(argv[1]);
   bzero(&servaddr,sizeof(struct sockaddr_in));
   servaddr.sin_family = AF_INET;
   servaddr.sin_addr.s_addr = INADDR_ANY;
   servaddr.sin_port = htons(port);
   
   if((sockfd = socket(AF_INET,SOCK_STREAM,0))==-1){
      perror("socket");
      exit(1);
   }	 
   if(bind(sockfd,(struct sockaddr *)&servaddr,sizeof(struct sockaddr))==-1){
      perror("bind");
      exit(1);
   }
   if(listen(sockfd,BACK_LOG)==-1){
      perror("listen");
      exit(1);
   }  
   max_fd = sockfd;
   FD_ZERO(&allset);
   FD_ZERO(&rdset);
   FD_SET(sockfd,&allset);
   for(i=0;i< FD_SETSIZE;i++)
     client[i] = -1;
   max_index = -1;
   for(;;){
     rdset = allset;
     nready = select(max_fd+1,&rdset,NULL,NULL,NULL);
     if(FD_ISSET(sockfd,&rdset)){
        clilen = sizeof(cliaddr);
        connfd = accept(sockfd,(struct sockaddr *)&cliaddr,&clilen);
        if(connfd ==-1){
           perror("accept");
           continue;
        }
        for(i=0;i<FD_SETSIZE;i++){
           if(client[i]==-1){
              client[i] = connfd;
              break;
           }
        }
        
        if(i==FD_SETSIZE){
           printf("Too many client here!\n");
           exit(1);
        }
        if(i > max_index)
           max_index = i;
        if(connfd > max_fd)
           max_fd = connfd;
        FD_SET(connfd,&allset);

        if(--nready <=0)
          continue;        
     }
     for (i=0;i<=max_index;i++){
        if((clifd=client[i])< 0)
          continue;
        if(FD_ISSET(clifd,&rdset)){
           len = BUF_SIZE;
           if((len = recv(clifd,buffer,len,0))<=0){
              close(clifd);
              FD_CLR(clifd,&allset);
              client[i] = -1;
           }else{ 
              printf("buffer is %s",buffer);           
              for(j=0;j<=max_index;j++){
                clifd2 = client[j];
                if(clifd2>0 && clifd2!=sockfd)
                   send(clifd2,buffer,len,0);
               
             } //for
             if(--nready <=0) 
                break;
           }//else
        }//if
     
     }//for   
   }//for 
}