#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <mqueue.h>
#include <sys/stat.h>
#include <sys/wait.h>

#define MESSAGE_COUNT 5
#define TEXT_SIZE 50

char text_message[TEXT_SIZE];

struct message {
  char mtext[TEXT_SIZE];
};

struct mq_attr message_attr = {
  .mq_maxmsg = MESSAGE_COUNT,
  .mq_msgsize = sizeof(struct message)
};

const char *queue_name = "/gotowe";

int main(int argc, char *argv[]){
  printf("start %d\n");

  mqd_t mqid = mq_open(queue_name,  O_CREAT | O_RDWR, 0666, &message_attr);

    if (mqid == (mqd_t) -1) {
        perror("mq_open"); exit(1);
    }

    pid_t child_a, child_b;

    child_a = fork();

    if (child_a == 0) {
      printf("proces wpisujacy priorytet 1\n");
      int i;
      for (i=0; i<MESSAGE_COUNT; i++) {
        sprintf(text_message, "Message id = %d with priority %d", i, 1);
        int result = mq_send(mqid, text_message, strlen(text_message) + 1, 1);
        if (result == -1) {
          perror("mq_send");
        }
        sleep(1);
      }
    } else {
        child_b = fork();

        if (child_b == 0) {
            printf("proces wpisujacy priorytet 2\n");
            int i;
            for (i=0; i<MESSAGE_COUNT; i++) {
                sprintf(text_message, "Message id = %d with priority %d", i+10, 2);
                int result = mq_send(mqid, text_message, strlen(text_message) + 1, 2);
                if (result == -1) {
                  perror("mq_send");
                }
                sleep(1);
          }

        } else {
            sleep(2);
            printf("proces wypisujacy\n");
            do {
              unsigned int priority;
              struct message msg;
              int len = mq_receive(mqid, (char *) &msg,sizeof(msg), &priority);
              if (len == -1) {
                perror("mq_receive");
                break;
              }
              printf("Otrzymalem wiadomosc (priorytet = %d): '%s'\n", priority, msg.mtext);
              int r = mq_getattr(mqid, &message_attr);
              if (r == -1) {
                perror("mq_getattr");
                break;
                }
               sleep(1);
          } while (message_attr.mq_curmsgs);
        }
    }

  /*

  //tworzenie
  int i;
  for (i=0; i<MESSAGE_COUNT; i++) {
    printf("Obrot numer: %d ", i);
    sprintf(text_message, "Message id = %d with priority %d", i, 1);
    int result = mq_send(mqid, text_message, strlen(text_message) + 1, 1);
    if (result == -1) {
      perror("mq_send");
    }
    printf("stop\n");
    sleep(1);
  }


  //czytanie
  do {
      unsigned int priority;
      struct message msg;
      int len = mq_receive(mqid, (char *) &msg,sizeof(msg), &priority);
      if (len == -1) {
        perror("mq_receive");
        break;
      }
      printf("Otrzymalem wiadomosc (priorytet = %d): '%s'\n", priority, msg.mtext);
      int r = mq_getattr(mqid, &message_attr);
      if (r == -1) {
        perror("mq_getattr");
        break;
        }
  } while (message_attr.mq_curmsgs);
  */
  mq_close(mqid);

  return 0;
}