#include <sys/types.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>

/*
//ce bloc de code vient d'un exercice de tp que j'ai recuperer
int set_signal_handler(int signo, void (*handler)(int)) {
    struct sigaction sa;
    sa.sa_handler = handler;    // call `handler` on signal
    sigemptyset(&sa.sa_mask);   // don't block other signals in handler
    sa.sa_flags = SA_RESTART;            //  restart system calls
    return sigaction(signo, &sa, NULL);
}

void sig_hand(int sig) {
}*/

void commander_une_pizza(int* p){
    int i;
    
    printf("pizza ordered!\n");
    for (i=1; i<=8; i++){
        write(p[1],&i,sizeof(int));
    }
    printf("pizza delivered!\n");
    //kill(getppid(), SIGUSR1);
}


void prendre_une_part_de_pizza(int numEtudiant, int* p){
    int numPartPizza;
    read(p[0],&numPartPizza,sizeof(int));
    printf("student %d takes piece %d\n",numEtudiant, numPartPizza);
    //rendre atomique cette partie (mais je n'y arrive pas)
    if (numPartPizza == 8){
        commander_une_pizza(p);
    }
    else{
        //kill(getppid(), SIGUSR1);
    }
}

void reviser_et_manger_la_part_de_pizza(void){
    sleep(3);
}


int main(int argc, char ** argv){
    int Nbetudiant;
    int i;
    int pid;
    int p[2];

    if (argc != 2) {
		printf("Usage: %s <NbEtudiants>\n",argv[0]);
		exit(1);
	}

    Nbetudiant = strtol(argv[1],NULL,0);
    //set_signal_handler(SIGUSR1,sig_hand);

    pipe(p);
    commander_une_pizza(p);

    for (i=0; i<Nbetudiant; i++){
        pid = fork();
        if (pid == 0){
            while (1){
                prendre_une_part_de_pizza(i, p);
	            reviser_et_manger_la_part_de_pizza();
            }
        }
    }
    while (1){
        // le professeur dort pendant que les eleves revises
        sleep(1);
    }
}