/* La un InternetCafe exista 8 calculatoare si vin 20 de clienti. Initial
 * se stabileste ( arbitrar ) de cati bani dispune fiecare client. In functie
 * de cati bani are, respectiv cate ore poate inchiria un calculator, clientii
 * vor fi repartizati la cate un calculator. Dar un client nu poate inchiria
 * mai mult de 1 ora odata chiar daca dispune de suficienti bani, deci dupa o
 * ora este scos de la calculator si trece la coada ( daca mai are bani ). Cand 
 * nu mai sunt clienti cu bani, proprietarul isi face bilantul ( afiseaza cati 
 * bani a castigat ).
 * Obs: Evident fiecare client e 'simulat' de catre un thread.
 */


#include <stdlib.h>
#include <pthread.h>
#include <errno.h>
#define nrCalc 8
#define nrCl 20 

   pthread_mutex_t semm[nrCalc];
   pthread_mutex_t mutex=PTHREAD_MUTEX_INITIALIZER;
   pthread_mutex_t mutexc=PTHREAD_MUTEX_INITIALIZER;
   pthread_cond_t condElm=PTHREAD_COND_INITIALIZER;
   int poz[nrCl];
   pthread_t tid[nrCl];
   int money[nrCl];
   int semmutex_lock() {
      int i;
      while (1) {
         for (i=0;i<nrCalc;i++)
            if (pthread_mutex_trylock(&semm[i])!=EBUSY)
               return i;
         pthread_mutex_lock(&mutexc);
         pthread_cond_wait(&condElm,&mutexc);
         pthread_mutex_unlock(&mutexc);
      }
   }

   int semmutex_unlock(int i) {
      pthread_mutex_unlock(&semm[i]);
      pthread_cond_signal(&condElm);
   }

//afisare trenuri care intra in gara
   void afisare() {
      int i;
      pthread_mutex_lock(&mutex);
      printf("Clients at stations: ");
      for (i=0;i<nrCl;i++)
         if (poz[i]==1)
            printf(" %d",i);
      printf("\n");
      pthread_mutex_unlock(&mutex);
   }

//rutina unui thread
   void* client(char* sind){
      int sl,ind,indm;
      ind=atoi((char*)sind);
      free(sind);
      
      do 
      { indm=semmutex_lock();
        if (money[ind]>=60)
  	   {	printf("Client %d  ->  IN\n",ind);
		money[ind] -= 60;
	        sleep(60);
	   }
	else
	   {    printf("Client %d  ->  IN\n",ind);
		sleep(money[ind]);
		money[ind]=0;
	   }

	if (money[ind]==0)
	   {	printf("Client %d  <-  OUT (no money left)\n",ind);
	   }
 	else
           {    printf("Client %d  <-  OUT (money left: %d)\n",ind,money[ind]);
	   }

//        poz[ind]=1;
//        afisare();
        
//        sl=1+(int) (3.0*rand()/(RAND_MAX+1.0));
//        sleep(sl);
//        poz[ind]=2;
        semmutex_unlock(indm);
       }  
       while ( money[ind]>0 );

    }

//main
  int main() {
      char* sind;
      int i;
      for (i=0;i<nrCalc;i++)
      //semm[i]=PTHREAD_MUTEX_INITIALIZER;
         pthread_mutex_init(&semm[i],NULL);
//    srand();
      for (i=0; i<nrCl; i++)
         money[i]=11+rand()%110;
      for (i=0; i<nrCl; i++)
         printf("client: %d; money: %d\n",i,money[i]);


      for (i=0;i<nrCl;i++) {
         sind=(char*) malloc(5*sizeof(char));
         sprintf(sind,"%d",i);
         pthread_create(&(tid[i]),NULL,client,sind);
      }
      for (i=0;i<nrCl; i++)
         pthread_join(tid[i],NULL);
   }