#include "kernel/types.h"
#include "user/user.h"

void pipeline(int leftfd) {
    int pipefd[2];
    int p; read(leftfd, &p, sizeof(p));
    printf("prime %d\n", p);
    int n; 
    int has_right = 0;
    while (read(leftfd, &n, sizeof(n)) > 0) {
        if (n % p != 0) {
            if (!has_right) {
                has_right = 1;
                pipe(pipefd);
                if (fork() == 0) {
                    close(pipefd[1]);
                    pipeline(pipefd[0]);
                } else {
                    close(pipefd[0]);
                }
            }
            write(pipefd[1], &n, sizeof(n));
        }
    }
    close(leftfd);
    if (has_right) {
        close(pipefd[1]);
        while(wait(0) != -1);
    }
    exit(0);
}

int main(int argc, char** argv) {
    int pipefd[2];
    pipe(pipefd);
    int pid = fork();
    if (pid != 0) {
        close(pipefd[0]); // no need to read in the feeding proc
        for (int i = 2; i <= 35; ++ i) {
            write(pipefd[1], &i, sizeof(i));
        }
        close(pipefd[1]);
        while(wait(0) != -1);
        exit(0);
    }
    else {
        close(pipefd[1]);  // pipeline proc will have its own write pipe
        pipeline(pipefd[0]);
    }
    exit(0);
}