feat random bullshit GO!

LctMonolith/Services/StoreService.cs

@@ -0,0 +1,75 @@
+using LctMonolith.Domain.Entities;
+using LctMonolith.Infrastructure.UnitOfWork;
+using Microsoft.EntityFrameworkCore;
+using Serilog;
+using System.Text.Json;
+
+namespace LctMonolith.Services;
+
+/// <summary>
+/// Store purchase operations and inventory management.
+/// </summary>
+public class StoreService : IStoreService
+{
+    private readonly IUnitOfWork _uow;
+
+    public StoreService(IUnitOfWork uow)
+    {
+        _uow = uow;
+    }
+
+    public async Task<IEnumerable<StoreItem>> GetActiveItemsAsync(CancellationToken ct = default)
+    {
+        return await _uow.StoreItems.Query(i => i.IsActive).ToListAsync(ct);
+    }
+
+    public async Task<UserInventoryItem> PurchaseAsync(Guid userId, Guid itemId, int quantity, CancellationToken ct = default)
+    {
+        if (quantity <= 0) throw new ArgumentOutOfRangeException(nameof(quantity));
+        var user = await _uow.Users.Query(u => u.Id == userId).FirstOrDefaultAsync(ct) ?? throw new KeyNotFoundException("User not found");
+        var item = await _uow.StoreItems.Query(i => i.Id == itemId && i.IsActive).FirstOrDefaultAsync(ct) ?? throw new KeyNotFoundException("Item not found or inactive");
+        var totalPrice = item.Price * quantity;
+        if (user.Mana < totalPrice) throw new InvalidOperationException("Insufficient mana");
+        if (item.Stock.HasValue && item.Stock.Value < quantity) throw new InvalidOperationException("Insufficient stock");
+
+        user.Mana -= totalPrice;
+        if (item.Stock.HasValue) item.Stock -= quantity;
+
+        var inv = await _uow.UserInventoryItems.FindAsync(userId, itemId);
+        if (inv == null)
+        {
+            inv = new UserInventoryItem
+            {
+                UserId = userId,
+                StoreItemId = itemId,
+                Quantity = quantity,
+                AcquiredAt = DateTime.UtcNow
+            };
+            await _uow.UserInventoryItems.AddAsync(inv, ct);
+        }
+        else
+        {
+            inv.Quantity += quantity;
+        }
+
+        await _uow.Transactions.AddAsync(new Transaction
+        {
+            UserId = userId,
+            StoreItemId = itemId,
+            Type = TransactionType.Purchase,
+            ManaAmount = -totalPrice
+        }, ct);
+
+        await _uow.EventLogs.AddAsync(new EventLog
+        {
+            Type = EventType.ItemPurchased,
+            UserId = userId,
+            Data = JsonSerializer.Serialize(new { itemId, quantity, totalPrice })
+        }, ct);
+
+        await _uow.SaveChangesAsync(ct);
+        Log.Information("User {User} purchased {Qty} of {Item}", userId, quantity, itemId);
+        return inv;
+    }
+}
+