/*
// Multiperson chat server using select
// Server part
*/

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

//#define PORT 9034   // port we're listening on
fd_set master;   // master file descriptor list
fd_set read_fds; // temp file descriptor list for select()
struct sockaddr_in myaddr;     // server address
struct sockaddr_in remoteaddr; // client address
int fdmax;        // maximum file descriptor number
int listener;     // listening socket descriptor
int newfd;        // newly accept()ed socket descriptor
char buf[256], tmpbuf[256];    // buffer for client data
int nbytes, ret;
int yes=1;        // for setsockopt() SO_REUSEADDR, below
int addrlen;
int i, j, crt, int_port,client_count=0;


struct sockaddr_in getSocketName(int s, bool local_or_remote) {
  struct sockaddr_in addr;
  int addrlen = sizeof(addr);
  int ret;

  memset(&addr, 0, sizeof(addr));
  ret = (local_or_remote==true?getsockname(s,(struct sockaddr *)&addr,(socklen_t*)&addrlen):
	 getpeername(s,(struct sockaddr *)&addr, (socklen_t*)&addrlen) );
  if (ret < 0)
    perror("getsock(peer)name");
  return addr;
}

char * getIPAddress(int s, bool local_or_remote) {
  struct sockaddr_in addr;
  addr = getSocketName(s, local_or_remote);
  return inet_ntoa(addr.sin_addr);
}

int getPort(int s, bool local_or_remote) {
  struct sockaddr_in addr;
  addr = getSocketName(s, local_or_remote);
  return addr.sin_port;
}

// send to everyone
void sendToALL(char * buf, int nbytes) {
  int j, ret;
  for(j = 0; j <= fdmax; j++) {
    if (FD_ISSET(j, &master))
      // except the listener and ourselves
      if (j != listener && j != crt)
	if ( send(j, buf, nbytes, 0) == -1)
	  perror("send");
  }
  return;
}


int main(int argc, char **argv)
{
   
    if (argc < 2 ) {
      printf("Usage:\n%s <portno>\n",argv[0]);
      exit(1);
    }
   
    int_port = atoi(argv[1]);
   
    FD_ZERO(&master);    // clear the master and temp sets
    FD_ZERO(&read_fds);

    // get the listener
    if ((listener = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
        perror("socket");
        exit(1);
    }

    // lose the pesky "address already in use" error message
    if (setsockopt(listener, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(int) ) == -1) {
        perror("setsockopt:");
        exit(1);
    }

    // bind
    memset(&myaddr, 0, sizeof(myaddr));
    myaddr.sin_family = AF_INET;
    myaddr.sin_addr.s_addr = INADDR_ANY;
    myaddr.sin_port = htons(int_port);
    //    memset(&(myaddr.sin_zero), '\0', 8);
    if (bind(listener, (struct sockaddr *)&myaddr, sizeof(myaddr)) == -1) {
        perror("bind:");
        exit(1);
    }
    // listen
    if (listen(listener, 10) == -1) {
        perror("listen");
        exit(1);
    }
    // add the listener to the master set
    FD_SET(listener, &master);
    // keep track of the biggest file descriptor
    fdmax = listener; // so far, it's this one
    // main loop
    for(;;) {
        read_fds = master; // copy it
        if (select(fdmax+1, &read_fds, NULL, NULL, NULL) == -1) {
            perror("select");
            exit(1);
        }
	
        // run through the existing connections looking for data to read
        for(i = 0; i <= fdmax; i++) {
	  if (FD_ISSET(i, &read_fds)) { // we got one!!
	    crt = i;
	    if (i == listener) {
	      // handle new connections
	      addrlen = sizeof(remoteaddr);
		  if ((newfd = accept(listener, (struct sockaddr *)&remoteaddr,(socklen_t*)&addrlen)) == -1) {
		    perror("accept");
		  } else {
		    FD_SET(newfd, &master); // add to master set
		    if (newfd > fdmax) {    // keep track of the maximum
		      fdmax = newfd;
		    }
		    printf("selectserver: new connection from %s on "
			   "socket %d\n", getIPAddress(newfd, false),newfd);
		   
		    client_count++;
		    sprintf(buf,"Hi-you are client :[%d] (%s:%d) connected to server %s\nThere
are %d clients connected\n",
			    newfd, getIPAddress(newfd,false), getPort(newfd, false),
			    getIPAddress(listener, true), client_count);
		    send(newfd,buf,strlen(buf)+1,0);
		  }
	    } else {
	      // handle data from a client
	      if ((nbytes = recv(i, buf, sizeof(buf), 0)) <= 0) {
		// got error or connection closed by client
		if (nbytes == 0) {
		  // connection closed
		  printf("<selectserver>: client %d forcibly hung up\n", i);
		}
		else
		  perror("recv");
		client_count--;
		close(i); // bye!
		FD_CLR(i, &master); // remove from master set
	      }
	      else {
		// we got some data from a client
		// check for connection close request
		buf[nbytes]=0;
		//printf("%s\n",buf);
		if ( (strncasecmp("QUIT\n",buf,4) == 0)) {
		  sprintf(buf,"Request granted [%d] - %s. Disconnecting...\n",i,getIPAddress(i,false));
		  send(i,buf, strlen(buf)+1,0);
		  nbytes = sprintf(tmpbuf,"<%s - [%d]> disconnected\n",getIPAddress(i,false), i);
		  sendToALL(tmpbuf,nbytes);
		  client_count--;
		  close(i);
		  FD_CLR(i,&master);
		}
		else {
		  nbytes = sprintf(tmpbuf, "<%s - [%d]> %s",getIPAddress(crt, false),crt, buf);
		  sendToALL(tmpbuf, nbytes);
		}
	      }
	    }
	  }
	}
    }
    return 0;
}