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

struct Student {
   char  nazwa[50];
   char  indeks[7];
};

void childend(int signo){
    wait(NULL);
}

int main (int argc, char *argv[])
{
    struct Student PCH;
    strcpy( PCH.nazwa, "PCH");
    strcpy( PCH.indeks, "116658");

    struct Student ja2;
    strcpy( ja2.nazwa, "hubert");
    strcpy( ja2.indeks, "132285");

    signal(SIGCHLD, childend);
    int sfd,cfd,on=1;
    char indeks_in[7];
    struct sockaddr_in saddr,caddr;
    socklen_t sl;
    saddr.sin_family = AF_INET;
    //zapisanie adresu ip, konwenterowanego do bitow ta funkcja
    saddr.sin_addr.s_addr = INADDR_ANY;
    saddr.sin_port = htons(1234);
    sfd = socket(PF_INET, SOCK_STREAM, 0);
    setsockopt(sfd, SOL_SOCKET, SO_REUSEADDR, (char*) &on, sizeof(on));
    bind(sfd, (struct sockaddr*) &saddr, sizeof(saddr));
    listen(sfd,5);
    int i = 1;
    while(i>0){
        sl = sizeof(caddr);
        cfd = accept(sfd, (struct sockaddr*) &caddr, &sl);
        i = fork();
        if(i==0){
            close(sfd);
            printf("new connection %s: %d\n",inet_ntoa(caddr.sin_addr), ntohs(caddr.sin_port));
            read(cfd, &indeks_in, 7);
            if( strncmp(indeks_in, PCH.indeks, 6) == 0)
            {
                write(cfd,PCH.nazwa,3);
            }else if ( strncmp(indeks_in, ja2.indeks, 6) == 0)
            {
                write(cfd,ja2.nazwa,6);
            }else{
                write(cfd,"nieznany",8);
            }
            close(cfd);
            exit(EXIT_SUCCESS);
        }
        close(cfd);
    }
    close(sfd);
    return 0;
}