#include <stdio.h>
#include <string.h>
#include <strings.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>    /* Internet domain header */
#include "wrapsock.h"

#define MAXLINE 1024
#define SERV_PORT 31000
#define LISTENQ 10

ssize_t Readline(int fd, void *ptr, size_t maxlen);
void Writen(int fd, void *ptr, size_t nbytes);

int
main(int argc, char **argv)
{
    int i, maxi, maxfd, listenfd, connfd, sockfd;
    int nready, client[FD_SETSIZE];
    ssize_t	n;
    fd_set	rset, allset;
    char	line[MAXLINE];
    socklen_t clilen;
    struct sockaddr_in cliaddr, servaddr;
    int yes = 1;
    
    listenfd = Socket(AF_INET, SOCK_STREAM, 0);

    bzero(&servaddr, sizeof(servaddr));
    servaddr.sin_family      = AF_INET;
    servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
    servaddr.sin_port        = htons(SERV_PORT);

    if((setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(int)))
       == -1) {
        perror("setsockopt");
    }

    Bind(listenfd, (struct sockaddr *) &servaddr, sizeof(servaddr));

    Listen(listenfd, LISTENQ);

    maxfd = listenfd;	/* initialize */
    maxi = -1;		/* index into client[] array */
    for (i = 0; i < FD_SETSIZE; i++)
	client[i] = -1;	/* -1 indicates available entry */
    FD_ZERO(&allset);
    FD_SET(listenfd, &allset);
    
    for ( ; ; ) {
	rset = allset;		/* structure assignment */
	nready = Select(maxfd+1, &rset, NULL, NULL, NULL);
	
	if (FD_ISSET(listenfd, &rset)) {	/* new client connection */
	    clilen = sizeof(cliaddr);
	    connfd = Accept(listenfd, (struct sockaddr *) &cliaddr, &clilen);
	    printf("accepted a new client\n");

	    for (i = 0; i < FD_SETSIZE; i++)
		if (client[i] < 0) {
		    client[i] = connfd;	/* save descriptor */
		    break;
		}
	    if (i == FD_SETSIZE) {
		printf("too many clients");
	    }
	    
	    FD_SET(connfd, &allset);	/* add new descriptor to set */
	    if (connfd > maxfd)
		maxfd = connfd;	/* for select */
	    if (i > maxi)
		maxi = i;	/* max index in client[] array */
	    
	    if (--nready <= 0)
		continue;	/* no more readable descriptors */
	}
	
	for (i = 0; i <= maxi; i++) {	/* check all clients for data */
	    if ( (sockfd = client[i]) < 0)
		continue;
	    if (FD_ISSET(sockfd, &rset)) {
		if ( (n = Readline(sockfd, line, MAXLINE)) <= 0) {
		    /*4connection closed by client */
		    Close(sockfd);
		    FD_CLR(sockfd, &allset);
		    client[i] = -1;
		} else
		    printf("Got %s from client, echoing it to client\n", line);
		    Writen(sockfd, line, n);
		
		if (--nready <= 0)
		    break;	/* no more readable descriptors */
	    }
	}
    }
}