// // // // // // // // // // // // // // // // // // // // // // // // 
//
//   CS270 Class Example
//
//   Author: Robert Heckendorn
//           University of Idaho
//
#include <stdio.h>
#include <stdlib.h>  // for system
#include <fcntl.h>   // for open and open flags
#include <errno.h>   // for errno
#include <string.h>  // for strerror
#include <unistd.h>  // for unlink

int main()
{
    pid_t pid;
    int pipefds[2];
    char *whoAmI;

    printf("\nBEGINNING TESTS\n");
    fflush(stdout);

    // open a pipe
    if (pipe(pipefds)==-1) {
        printf("ERROR: pipe failure\n");
        fflush(stdout);
    }
    else {

        // pipe is up and running so... fork
        pid = fork();
        switch (pid) {
        case -1:
            perror("ERROR: Fork failed");
            exit(1);

            // CHILD
        case 0:
        {
            // local data
            int data3size=1024;
            char data3[data3size];
            int len;

            whoAmI = (char *)"Child";

            sleep(3);
            printf("%s: Start reading from %d\n", whoAmI, pipefds[0]);
            fflush(stdout);
            
            // read from fds[0]
            if ((len = read(pipefds[0], data3, data3size))==-1) {
                printf("ERROR: receiver trying to read from fd: %d\n", pipefds[0]);
            }
            else {
                printf("%s read %d bytes\n", whoAmI, len);
                printf("%s: DATA:", whoAmI);
//                fflush(stdout);
                write(1, data3, len);   // use printf.
                printf("\n");
            }
        }
        break;
        
        default:
        {
            // local variables
            char *data = (char *)"Now is the winter of our discontent made glorious summer by this sun of York";
            char *data2 = (char *)"Cry havoc and let slip the dogs of war.";
            whoAmI = (char *)"Parent";

//            sleep(2);

            // write to fds[1]
            write(pipefds[1], data, strlen(data));
            printf("%s: writes %d bytes of data to fd: %d\n", whoAmI, (int)strlen(data), pipefds[1]);
            fflush(stdout);

            write(pipefds[1], data2, strlen(data2));
            printf("%s: writes %d bytes of data to fd: %d\n", whoAmI, (int)strlen(data2), pipefds[1]);
            fflush(stdout);
            printf("%s: done writing\n", whoAmI);
            fflush(stdout);
//            sleep(5);

            {
                int stat_val;
                printf("Parent waiting on child!\n");
  
                wait(&stat_val);  // note pass in the address of stat_val
                if (WIFEXITED(stat_val)) {
                    printf("Parent reports child (PID: %d) exited with return code %d\n", pid, WEXITSTATUS(stat_val));
                }
                else {
                    printf("Parent reports child (PID: %d) terminated abnormally\n", pid);
                }
            }


            break;
        }
        }


        printf("%s: terminates\n", whoAmI);
        fflush(stdout);

        return(0);
    }
}