#include "unp.h"
#include <limits.h> // for OPEN_MAX

#ifndef OPEN_MAX
#define OPEN_MAX _SC_OPEN_MAX
#endif


int main(int argc, char *argv[])
{
    int     listenfd, confd, sockfd, maxi, i;
    int     nready;
    ssize_t n;
    char    buf[MAXLINE];
    socklen_t clilen;
    struct pollfd client[OPEN_MAX];
    struct sockaddr_in cliaddr, servaddr;

    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);

    Bind(listenfd, (SA *)&servaddr, sizeof(servaddr));

    Listen(listenfd, LISTENQ);

    client[0].fd = listenfd;
    client[0].events = POLLIN;
    for(i = 1; i < OPEN_MAX; i++)
        client[i].fd = -1;
    maxi = 0;



    for(;;) {
        nready = Poll(client, maxi + 1, INFTIM);

        if(client[0].revents & POLLIN) { // new client connection 
            clilen = sizeof(cliaddr);
            confd = Accept(listenfd, (SA *) &cliaddr, &clilen);
        
            for ( i = 0; i < OPEN_MAX; i++)
                if(client[i].fd < 0) {
                    client[i].fd = confd; // save descriptor
                    break;
                }
            if( i == OPEN_MAX)
                err_quit("too many clients");

            client[i].events = POLLIN;
 
            if( i > maxi) 
                maxi = i;       // max index in client[] array

            if(--nready <= 0)
                continue;       // no more readable descriptor
        }

        for(i = 0; i <= maxi; i++) { // check all clients for data 
            if((sockfd = client[i].fd) < 0)
                continue;
            if(client[i].revents & (POLLIN | POLLERR)) {
                if( (n = Read(sockfd, buf, MAXLINE)) < 0) { 
                    if( errno == ECONNRESET) {
                        // connection closed by client
                        Close(sockfd);
                        client[i].fd = -1;
                    } else {
                        err_sys("read error");
                    }
                } else if(n == 0) {
                    // connection closed by client
                    Close(sockfd);
                    client[i].fd = -1;
                } else {
                    Writen(sockfd, buf, n);
                }

                if(--nready <= 0) 
                    break; // no more readable descriptors
            }
        }
    }

}