/* 
 * Programme simulant la gestion d'une imprimante
 */

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

#define MAXNBIMPRESSIONS 5
#define MAXNBTHREADS 3

char nomFic[MAXNBIMPRESSIONS][80];
int i_depot=0;
int i_extrait = 0;

struct monitor{
  int value;
  pthread_mutex_t mutex;
  pthread_cond_t cond;
};

void init_monitor(struct monitor *m, int value) {
  m->value = value;
  pthread_mutex_init(&m->mutex, NULL);
  pthread_cond_init(&m->cond, NULL);
}

struct monitor places_dispo;
struct monitor info_prete;

pthread_mutex_t mutex;
void impression(char *nomFic){
  pthread_mutex_lock(&mutex);
  printf("Debut d'impression de \"%s\"...\n", nomFic);
  sleep(5); /* Simule la lenteur de l'impression */
  printf("...Fin d'impression de \"%s\"...\n", nomFic);
  pthread_mutex_unlock(&mutex);
}



void* thread_function(void* arg) {
  char nomFic_local[80];
  while(1) {

    pthread_mutex_lock(&info_prete.mutex);
    while(info_prete.value == 0) {
      pthread_cond_wait(&info_prete.cond, &info_prete.mutex);
    }
    info_prete.value--;
    strncpy(nomFic_local, nomFic[i_extrait], 80);
    i_extrait = (i_extrait+1) % MAXNBIMPRESSIONS;
    pthread_mutex_unlock(&info_prete.mutex);

    if(strcmp(nomFic_local, "0") == 0)
      return NULL;
    impression(nomFic_local);

    pthread_mutex_lock(&places_dispo.mutex);
    places_dispo.value ++;
    pthread_cond_signal(&places_dispo.cond);
    pthread_mutex_unlock(&places_dispo.mutex);   
  }
  return NULL;
}

void attenteImpression(){
  do {
    pthread_mutex_lock(&places_dispo.mutex);
    while(places_dispo.value == 0) {
      pthread_cond_wait(&places_dispo.cond, &places_dispo.mutex);
    }
    places_dispo.value--;
    int cur_indice = i_depot++;
    i_depot = i_depot % MAXNBIMPRESSIONS;

    pthread_mutex_unlock(&places_dispo.mutex);

    
    printf("Nom du fichier a imprimer (taper '0' pour terminer) ? ");
    scanf("%s", nomFic[cur_indice]);
    if (strcmp(nomFic[cur_indice], "0") == 0) {
      break;
    }
    
    pthread_mutex_lock(&info_prete.mutex);
    info_prete.value ++;
    pthread_cond_signal(&info_prete.cond);
    pthread_mutex_unlock(&info_prete.mutex);

  }while (1);

  for(int i=0; i<MAXNBTHREADS; i++) {
    pthread_mutex_lock(&places_dispo.mutex);
    while(places_dispo.value == 0) {
      pthread_cond_wait(&places_dispo.cond, &places_dispo.mutex);
    }
    places_dispo.value--;
    int cur_indice = i_depot++;
    i_depot = i_depot % MAXNBIMPRESSIONS;

    pthread_mutex_unlock(&places_dispo.mutex);

    strcpy(nomFic[cur_indice], "0");

    pthread_mutex_lock(&info_prete.mutex);
    info_prete.value ++;
    pthread_cond_signal(&info_prete.cond);
    pthread_mutex_unlock(&info_prete.mutex);

  }
  printf("Au revoir\n");
}

int main(){
  pthread_t tid[MAXNBTHREADS];
  init_monitor(&places_dispo, MAXNBIMPRESSIONS);
  init_monitor(&info_prete, 0);
  i_depot = 0;
  i_extrait = 0;

  
  pthread_mutex_init(&mutex, NULL);
  for(int i=0; i< MAXNBTHREADS; i++) {
    int ret = pthread_create(&tid[i], NULL, thread_function, NULL);
    if(ret) {
      perror("pthread_create failed");
      abort();
    }
  }

  attenteImpression();

  for(int i=0; i< MAXNBTHREADS; i++) {
    int ret = pthread_join(tid[i], NULL);
    if(ret) {
      perror("pthread_join failed");
      abort();
    }
  }
  
  return EXIT_SUCCESS;
}