public async Task <IActionResult> Borrow(int id)
{
var copy = _context.Copies.FirstOrDefault(c => c.Book.Id == id && c.IsAvailable);
if (copy != null)
{
var borrowing = new Borrowing
{
Copy = copy,
DateOfBorrowing = DateTime.Today,
ApplicationUser = await _userManager.GetUserAsync(User)
};
await _context.Borrowings.AddAsync(borrowing);
copy.IsAvailable = false;
await _context.SaveChangesAsync();
}
return(RedirectToAction(nameof(Index)));
}