bool create(const char *file, unsigned initial_size){
    return filesys_create(file, (off_t)initial_size);
}

int open(const char *file){
    struct file* name = filesys_open(file);
    if (name != NULL){
        for (int i = 0; i < 128; i++) {
          if(thread_current()->files[i] == NULL){
            thread_current()->files[i] = name;
            return i + 2;
          }
        }
    }
    return -1;
}

void close(int fd){
    struct file* openFile = thread_current()->files[fd - 2];
    file_close(openFile);
    thread_current()->files[fd - 2] = NULL;
}

int read(int fd, void *buffer, unsigned size){
    if(fd == 0){
        for (int i = 0; i < 10; i++){
            *((char*)buffer + i) = input_getc();
        }
        return size;
    }
    if (fd < 2 || fd > 128){
        return -1;
    }
    else {
        struct file* open_file = thread_current()->files[fd - 2];
        if(open_file){
            return file_read(open_file, buffer, size);
        }
    }
    return -1;
}

int write(int fd, const void *buffer, unsigned size){
    if (fd == 1){
        putbuf(buffer, size);
        return size;
    }
    struct file* target_file = thread_current()->files[fd - 2];
    if (!target_file){
      return -1;
    }
    return file_write (target_file, buffer, size);
}

void exit(int status){
    for (size_t i = 0; i < 128; i++) {
      if(thread_current()->files[i]){
        close(i + 2);
      }
    }
}

void* get_arg_v(void* esp, int argnr){
    return esp + (4 * argnr);
}


static void
syscall_handler (struct intr_frame *f)
{
    int syscall_nr = *((int*)f->esp);
    int* args = (int*)f->esp;
    switch (syscall_nr) {

      case SYS_HALT:
          halt();
          break;

      case SYS_CREATE:
          ; //A label can only be part of a statement and a declaration is not a statement.
          char *file = *(char**)(args + 1);
          unsigned initial_size = *((unsigned*)(args + 2));
          bool success = create(file, initial_size);
          f->eax = success;
          break;

      case SYS_OPEN:
          f->eax = open(*(char**)(args+1));;
          break;

      case SYS_CLOSE:
          close(*(int*)(args + 1));
          break;

      case SYS_READ:
          f->eax = read(*(int*)(args + 1), (void*)(args + 2), *(unsigned*)(args + 3));
          break;

      case SYS_WRITE:
          f->eax = write(*((int*)(args + 1)), *(int*)(args + 2), *((unsigned*)(args + 3)));
          break;

      case SYS_EXIT:
          exit(*(int*)(args + 1));
          break;


    }
  // printf ("system call!\n");
  // thread_exit ();
}