public string AssignBook(int bookId, int studentId)
{
var isValid = ValidateBookAndStudent(bookId, studentId);
if (!isValid)
{
return("Either student or book does not exist!");
}
var isBookAlreadyIssued = _context.BookAssignToStudents.Any(a => a.Book.Id == bookId && a.Book.IsIssued == true);
if (isBookAlreadyIssued)
{
return("Book is already issued to the student.");
}
var book = _context.Books.First(a => a.Id == bookId);
book.IsIssued = true;
_context.Update(book);
var now = DateTime.Now;
var student = _context.Students.FirstOrDefault(a => a.Id == studentId);
var bookAssignToStudent = new BookAssignToStudent
{
BookId = bookId,
Book = book,
StudentId = studentId,
Student = student,
IssueDate = now,
DueDate = now.AddDays(7)
};
_context.Add(bookAssignToStudent);
_context.SaveChanges();
return("Success");
}
