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

#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/sem.h>

#include <sys/stat.h>

#define SEM_ACCESS 0
#define SEM_EMPTY 1
#define SEM_FILLED 2

#define SIZE 3
#define OP_DOWN -1
#define OP_UP 1
#define nb_prod 4
#define nb_cons 4

void die(const char *s)
{
  perror(s);
  exit(EXIT_FAILURE);
}

void produce(int semid)
{

  struct sembuf operations[1];
  operations[0].sem_flg=0;


  operations[0].sem_num=SEM_EMPTY;
  operations[0].sem_op=OP_DOWN;
  if (semop(semid,operations,1) == -1)
  {
     perror("MAIN.c op_up a foiré dans sem_access");
     return EXIT_FAILURE;
  }

  operations[0].sem_num=SEM_ACCESS;
  operations[0].sem_op=OP_DOWN;
  if (semop(semid,operations,1) == -1)
  {
     perror("MAIN.c op_up a foiré dans sem_access");
     return EXIT_FAILURE;
  }

  struct storage {
    int pos_prod, pos_cons;
    int store[SIZE];
  };

  struct storage storage;

  FILE* stream=fopen("entrepot.txt","r");
  fscanf(stream, "%d %d", &storage.pos_prod, &storage.pos_cons);
  int loop_i;
  for(loop_i = 0; loop_i < SIZE; loop_i++)
  {
    fscanf(stream, "%d", &storage.store[loop_i]);
  }
  fclose(stream);

  storage.store[storage.pos_prod] = getpid();
  storage.pos_prod++;
  stream=fopen("entrepot.txt","w");
  if(stream == NULL)
  {
    die("produce:fopen");
  }

  fprintf(stream, "%d %d\n", storage.pos_prod, storage.pos_cons);
  for(loop_i=0;loop_i<SIZE;loop_i++)
  {
    fprintf(stream, "%d ",storage.store[loop_i]);
  }

  operations[0].sem_num=SEM_ACCESS;
  operations[0].sem_op=OP_UP;
  if (semop(semid,operations,1) == -1)
  {
     perror("MAIN.c op_up a foiré dans sem_access");
     return EXIT_FAILURE;
  }

  operations[0].sem_num=SEM_FILLED;
  operations[0].sem_op=OP_UP;
  if (semop(semid,operations,1) == -1)
  {
     perror("MAIN.c op_up a foiré dans sem_filled");
     return EXIT_FAILURE;
  }

}

void consume(int semid)
{

}

int main() {

  // synchronisation
 int semid = 0;
 if((semid=semget(IPC_PRIVATE,3 /*nb de sempahore*/ ,IPC_CREAT
   |S_IRUSR/*user read*/
   |S_IWUSR/*user write*/))==-1)
 {
   die("ERROR creation semaphore");
 }

 if(semctl(semid,SEM_ACCESS,SETVAL,1) == -1)
 {
    die("ERROR control semaphore access");
 } //binaire ou mutux ---> un seul processus


 if(semctl(semid,SEM_EMPTY,SETVAL,SIZE) == -1)
 {
    die("ERROR control semaphore empty");
 }

 if(semctl(semid,SEM_FILLED,SETVAL,0) == -1)
 {
    die("ERROR control semaphore filled");
 }

 FILE* stream=fopen("entrepot.txt","w+");
 fprintf(stream, "0 0\n");

 int loop_i = 0;
 for(loop_i = 0; loop_i < SIZE; loop_i++)
 {
   fprintf(stream, "0 ");
 }


 // Processus management
 char father = 1;

 pid_t PIDs[nb_cons + nb_prod];
 for(loop_i = 0; loop_i < nb_cons; loop_i++)
 {
   PIDs[loop_i] = fork();
   if(PIDs[loop_i] == -1 )
   {
     die("ERROR Creation");
   }

   if(PIDs[loop_i] == 0)
   {
     father = 0;
     consume(semid);
     break;
   }
 }

   if(father)
   {
      for(loop_i = 0; loop_i < nb_cons; loop_i++)
      {
	PIDs[loop_i] = fork();
	if(PIDs[loop_i] == -1 )
	{
	  die("ERROR Creation processus");
	}

	if(PIDs[loop_i] == 0)
	{
	  father = 0;
	  produce(semid);
	  break;
	}
      }

      if(father)
      {
	for(loop_i = 0; loop_i < nb_cons; loop_i++)
	{
	  if(waitpid(PIDs[loop_i], NULL, 0) == -1)
	  {
	    die("ERROR attente processus");
	  }
	}

	if (semctl(semid, SEM_ACCESS, IPC_RMID) == -1)
	{
	  die("ERROR semaphore détruite");
	}
      }
   }

   return EXIT_SUCCESS;
}