#include <stdio.h>
#include <stdlib.h>
#include <sys/shm.h>
#include <sys/stat.h>
#include <sys/ipc.h>
#include <sys/sem.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <time.h>
#include <math.h>
#include "sem.h"
#include "keys.h"

int main(int argc, char* argv[]){
  int buff_id, sem_buff_id, sem_full_id, sem_free_id, sem_data;
  int sem_readers_id, readers_id, readA_id;
  int seg_size;
  char *buff;
  int loop;
  char letter;
  char alphabet[ALPHABET_SIZE]={'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','r','s','t','u'};

  seg_size=(1+MAX_BUFF)*sizeof(char);

  buff_id=shmget(buff_key, seg_size, 0666| IPC_CREAT);

  if(buff_id<0){
	printf("shmget error");
	exit(1);
  }
  buff=(char*)shmat(buff_id, 0, 0);
  if( (buff_id = mutex_allocate(sem_buff_key, 0666 | IPC_CREAT)) < 0) exit(1);

  if( (sem_data = sem_allocate(sem_data_key, 0666 | IPC_CREAT)) < 0) exit(1);

  if( (sem_free_id = sem_allocate(free_key, 0666 | IPC_CREAT)) < 0) exit(1);

  if( (sem_full_id = sem_allocate(full_key, 0666 | IPC_CREAT)) < 0) exit(1);

  mutex_init(buff_id);
  sem_init(sem_data, 1);
  sem_init(sem_free_id, MAX_BUFF);
  sem_init(sem_full_id, 0);

  buff[0] = 0;   // w kolejce 0 procesow

  for(loop=0; loop<REP; ++loop){

	if(sem_getVal(sem_data)<=0){
		break;
	}
	letter = alphabet[rand() % ALPHABET_SIZE];
        if(sem_getVal(sem_free_id)>0){
		mutex_wait(buff_id);

        	bufferInsert(buff, letter);
		printf("have written: %d to buffer\n", letter);
       		sem_change(sem_free_id, -1);
        	sem_change(sem_full_id, 1);
        	mutex_post(buff_id);
		printf("producent zwalnia\n");
	}
        randSleep1();
}

  union semun arg;
  arg.val = 0;
  semctl(sem_data, 0, SETVAL, arg);

  // wyłączamy segment pamięci wspólnej
  shmdt(buff);

   mutex_deallocate(buff_id);
   sem_deallocate(sem_free_id);
   sem_deallocate(sem_full_id);


  return 0;
}