Add invoice print and finalize flow

Distribution/Features/Invoice/InvoiceService.cs

@@ -30,4 +30,61 @@ public class InvoiceService(
         var items = await repo.GetAllAsync(agentId, routeId, shopId, status, page, pageSize);
         return new PagedResponse<InvoiceResponse>(page, pageSize, total, items.Select(ToResponse).ToList());
     }
+
+    public async Task<InvoiceResponse> PrintAsync(Guid id, Guid printedBy, CancellationToken ct = default)
+    {
+        var invoice = await repo.GetByIdAsync(id)
+            ?? throw new KeyNotFoundException("Invoice not found");
+
+        if (invoice.Status != InvoiceStatus.Draft)
+            throw new InvalidOperationException($"Cannot print an invoice in {invoice.Status} status");
+
+        invoice.Status = InvoiceStatus.Printed;
+        invoice.PrintedAt = DateTime.Now;
+        invoice.PrintedBy = printedBy;
+
+        await uow.BeginAsync(ct);
+        try { repo.Update(invoice); await uow.CommitAsync(ct); }
+        catch { await uow.RollbackAsync(ct); throw; }
+
+        return ToResponse(invoice);
+    }
+
+    public async Task<InvoiceResponse> FinalizeAsync(Guid id, FinalizeInvoiceRequest request, Guid finalizedBy, CancellationToken ct = default)
+    {
+        var invoice = await repo.GetByIdAsync(id)
+            ?? throw new KeyNotFoundException("Invoice not found");
+
+        if (invoice.Status != InvoiceStatus.Printed)
+            throw new InvalidOperationException($"Cannot finalize an invoice in {invoice.Status} status");
+
+        var adjustments = request.Adjustments ?? [];
+        if (adjustments.Count > 0)
+        {
+            var poItems = invoice.ShopPO.Items.Where(i => i.IsActive).ToList();
+            decimal total = 0;
+            foreach (var item in poItems)
+            {
+                var adjustment = adjustments.FirstOrDefault(a => a.ShopPOItemId == item.Id);
+                var billedQuantity = adjustment is not null ? adjustment.AdjustedQuantity : item.Quantity;
+
+                if (billedQuantity < 0 || billedQuantity > item.Quantity)
+                    throw new InvalidOperationException(
+                        $"Adjusted quantity for item {item.Id} must be between 0 and {item.Quantity}");
+
+                total += billedQuantity * item.UnitPrice;
+            }
+            invoice.TotalAmount = total;
+        }
+
+        invoice.Status = InvoiceStatus.Finalized;
+        invoice.FinalizedAt = DateTime.Now;
+        invoice.FinalizedBy = finalizedBy;
+
+        await uow.BeginAsync(ct);
+        try { repo.Update(invoice); await uow.CommitAsync(ct); }
+        catch { await uow.RollbackAsync(ct); throw; }
+
+        return ToResponse(invoice);
+    }
 }