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87c9973 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 | using Database.Models;
using Microsoft.EntityFrameworkCore;
namespace LibraryManagement.Backend.Features.Borrowings
{
public interface IBorrowingService
{
Task<BorrowingDto> BorrowBookAsync(int userId, int bookId);
Task<BorrowingDto> ReturnBookAsync(int borrowingId);
Task<IEnumerable<BorrowingDto>> GetUserBorrowingsAsync(int userId);
Task<IEnumerable<BorrowingDto>> GetAllBorrowingsAsync();
}
public class BorrowingService : IBorrowingService
{
private readonly LibraryManagementContext _context;
private const decimal FinePerDay = 500;
public BorrowingService(LibraryManagementContext context)
{
_context = context;
}
public async Task<BorrowingDto> BorrowBookAsync(int userId, int bookId)
{
// 1. Check for Active Membership
var subscription = await _context.UserSubscriptions
.Include(s => s.Membership)
.Where(s => s.UserId == userId && s.IsActive && s.ExpiryDate > DateTime.UtcNow)
.FirstOrDefaultAsync();
if (subscription == null)
{
throw new Exception("Active membership required to borrow books.");
}
// 2. Check for Overdue Books or Unpaid Fines
var hasBlockers = await _context.Borrowings
.AnyAsync(b => b.UserId == userId &&
((b.Status == "Borrowed" && b.DueDate < DateTime.UtcNow) || (b.FineAmount > 0 && !b.IsFinePaid)));
if (hasBlockers)
{
throw new Exception("Borrowing blocked: You have overdue books or unpaid fines.");
}
// 3. Check MaxBooks limit
var activeBorrowCount = await _context.Borrowings
.CountAsync(b => b.UserId == userId && b.Status == "Borrowed");
if (activeBorrowCount >= subscription.Membership.MaxBooks)
{
throw new Exception($"Borrowing limit reached: You can only borrow {subscription.Membership.MaxBooks} books at a time.");
}
// 4. Check Book Availability
var book = await _context.Books.FindAsync(bookId);
if (book == null || !book.IsActive || book.AvailableCopies <= 0)
{
throw new Exception("Book is currently unavailable.");
}
// 5. Create Borrowing Record
var borrowing = new Borrowing
{
UserId = userId,
BookId = bookId,
BorrowDate = DateTime.UtcNow,
DueDate = DateTime.UtcNow.AddDays(subscription.Membership.BorrowingDays),
Status = "Borrowed",
FineAmount = 0,
IsFinePaid = false
};
// 6. Update Book Stock
book.AvailableCopies--;
if (book.AvailableCopies == 0)
{
book.Status = "Out Of Stock";
}
_context.Borrowings.Add(borrowing);
await _context.SaveChangesAsync();
// Load relations for mapping
await _context.Entry(borrowing).Reference(b => b.Book).LoadAsync();
await _context.Entry(borrowing).Reference(b => b.User).LoadAsync();
return MapToDto(borrowing);
}
public async Task<BorrowingDto> ReturnBookAsync(int borrowingId)
{
var borrowing = await _context.Borrowings
.Include(b => b.Book)
.Include(b => b.User)
.FirstOrDefaultAsync(b => b.Id == borrowingId);
if (borrowing == null) throw new Exception("Borrowing record not found.");
if (borrowing.Status == "Returned") throw new Exception("Book has already been returned.");
var now = DateTime.UtcNow;
borrowing.ReturnDate = now;
borrowing.Status = "Returned";
// Calculate Fine
if (now > borrowing.DueDate)
{
var overdueDays = (now.Date - borrowing.DueDate.Date).Days;
if (overdueDays > 0)
{
borrowing.FineAmount = overdueDays * FinePerDay;
}
}
// Update Book Stock
var book = borrowing.Book;
book.AvailableCopies++;
book.Status = "Available";
await _context.SaveChangesAsync();
return MapToDto(borrowing);
}
public async Task<IEnumerable<BorrowingDto>> GetUserBorrowingsAsync(int userId)
{
var borrowings = await _context.Borrowings
.Include(b => b.Book)
.Include(b => b.User)
.Where(b => b.UserId == userId)
.OrderByDescending(b => b.BorrowDate)
.ToListAsync();
return borrowings.Select(MapToDto);
}
public async Task<IEnumerable<BorrowingDto>> GetAllBorrowingsAsync()
{
var borrowings = await _context.Borrowings
.Include(b => b.Book)
.Include(b => b.User)
.OrderByDescending(b => b.BorrowDate)
.ToListAsync();
return borrowings.Select(MapToDto);
}
private static BorrowingDto MapToDto(Borrowing b)
{
return new BorrowingDto
{
Id = b.Id,
UserId = b.UserId,
UserEmail = b.User?.Email ?? "Unknown",
BookId = b.BookId,
BookTitle = b.Book?.Title ?? "Unknown",
BorrowDate = b.BorrowDate,
DueDate = b.DueDate,
ReturnDate = b.ReturnDate,
Status = b.Status,
FineAmount = b.FineAmount,
IsFinePaid = b.IsFinePaid
};
}
}
}
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