Add DeliveryTask, Payment, and Sale features

Implemented DeliveryTask, Payment, and Sale entities with full CRUD, business logic, and API endpoints. Updated Order/OrderItem for sale linkage and fulfillment tracking. Registered new DbSets and DI services. Revised documentation for delivery, sale, and payment workflows.

Distribution/Features/Payment/IPaymentRepository.cs

@@ -0,0 +1,9 @@
+using Distribution.Models;
+
+namespace Distribution.Features.Payment;
+
+public interface IPaymentRepository
+{
+    Task<List<Models.Payment>> GetBySaleIdAsync(Guid saleId);
+    Task AddAsync(Models.Payment payment);
+}

Distribution/Features/Payment/PaymentController.cs

@@ -0,0 +1,28 @@
+using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Mvc;
+
+namespace Distribution.Features.Payment;
+
+[ApiController]
+[Authorize]
+[Route("api/sales/{saleId:guid}/payments")]
+public class PaymentController(PaymentService service) : ControllerBase
+{
+    [HttpGet]
+    public async Task<IActionResult> GetBySale(Guid saleId)
+    {
+        var result = await service.GetBySaleIdAsync(saleId);
+        return result is null ? NotFound() : Ok(result);
+    }
+
+    [HttpPost]
+    public async Task<IActionResult> Create(Guid saleId, CreatePaymentRequest request, CancellationToken ct)
+    {
+        try
+        {
+            var result = await service.CreateAsync(saleId, request, ct);
+            return result is null ? NotFound() : Ok(result);
+        }
+        catch (InvalidOperationException ex) { return BadRequest(new { error = ex.Message }); }
+    }
+}

Distribution/Features/Payment/PaymentDTOs.cs

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+using Distribution.Models;
+
+namespace Distribution.Features.Payment;
+
+public record CreatePaymentRequest(decimal Amount, PaymentMethod Method);
+
+public record PaymentResponse(
+    Guid Id,
+    Guid SaleId,
+    Guid StoreId,
+    decimal Amount,
+    PaymentMethod Method,
+    DateTime CollectedAt,
+    Guid CollectedBy,
+    DateTime CreatedAt);

Distribution/Features/Payment/PaymentRepository.cs

@@ -0,0 +1,17 @@
+using Distribution.Data;
+using Distribution.Models;
+using Microsoft.EntityFrameworkCore;
+
+namespace Distribution.Features.Payment;
+
+public class PaymentRepository(AppDBContext context) : IPaymentRepository
+{
+    public async Task<List<Models.Payment>> GetBySaleIdAsync(Guid saleId) =>
+        await context.Payments
+            .Where(p => p.FK_SaleId == saleId && p.IsActive)
+            .OrderBy(p => p.CollectedAt)
+            .ToListAsync();
+
+    public async Task AddAsync(Models.Payment payment) =>
+        await context.Payments.AddAsync(payment);
+}

Distribution/Features/Payment/PaymentService.cs

@@ -0,0 +1,67 @@
+using Distribution.Features.Sale;
+using Distribution.Infra.Authorization;
+using Distribution.Infra.UoW;
+using Distribution.Models;
+
+namespace Distribution.Features.Payment;
+
+public class PaymentService(
+    IPaymentRepository repo,
+    ISaleRepository saleRepo,
+    IUnitOfWork uow,
+    ICurrentUserService currentUser)
+{
+    private static PaymentResponse ToResponse(Models.Payment p) =>
+        new(p.Id, p.FK_SaleId, p.FK_StoreId, p.Amount, p.Method, p.CollectedAt, p.CollectedBy, p.CreatedAt);
+
+    public async Task<List<PaymentResponse>?> GetBySaleIdAsync(Guid saleId)
+    {
+        var sale = await saleRepo.GetByIdAsync(saleId);
+        if (sale is null || !sale.IsActive) return null;
+
+        var payments = await repo.GetBySaleIdAsync(saleId);
+        return payments.Select(ToResponse).ToList();
+    }
+
+    public async Task<PaymentResponse?> CreateAsync(Guid saleId, CreatePaymentRequest request, CancellationToken ct = default)
+    {
+        var sale = await saleRepo.GetByIdAsync(saleId);
+        if (sale is null || !sale.IsActive) return null;
+        if (sale.Status == SaleStatus.Cancelled)
+            throw new InvalidOperationException("Cannot record a payment against a cancelled sale");
+
+        var userId = currentUser.UserId ?? throw new UnauthorizedAccessException();
+
+        var payment = new Models.Payment
+        {
+            FK_SaleId = saleId,
+            FK_StoreId = sale.FK_StoreId,
+            Amount = request.Amount,
+            Method = request.Method,
+            CollectedAt = DateTime.Now,
+            CollectedBy = userId
+        };
+
+        await uow.BeginAsync(ct);
+        try
+        {
+            await repo.AddAsync(payment);
+
+            var allPayments = await repo.GetBySaleIdAsync(saleId);
+            var total = allPayments.Sum(p => p.Amount) + request.Amount;
+
+            sale.PaymentStatus = total == 0
+                ? PaymentStatus.Pending
+                : total < sale.TotalAmount
+                    ? PaymentStatus.PartiallyPaid
+                    : PaymentStatus.Paid;
+
+            saleRepo.Update(sale);
+
+            await uow.CommitAsync(ct);
+        }
+        catch { await uow.RollbackAsync(ct); throw; }
+
+        return ToResponse(payment);
+    }
+}