feat: Create product catalog and order system

- Added migrations for `Product`, `ProductCategory`, `Order`, and `OrderItem` entities.
- Introduced relationships, indexes, and constraints to support the product catalog and order management.
- Removed obsolete `CompanyIsNullException` as it is no longer required.

Author: samuelzedec

src/SnackFlow.Application/Events/Handlers/CompanyWelcomeEmailRequestedEventHandler.cs

@@ -7,7 +7,7 @@
 
 namespace SnackFlow.Application.Events.Handlers;
 
-public sealed class CompanyWelcomeEmailRequestedEventHandler(
+internal sealed class CompanyWelcomeEmailRequestedEventHandler(
     IEmailScheduler emailScheduler)
     : IDomainEventHandler<CompanyWelcomeEmailRequestedEvent>
 {

src/SnackFlow.Application/Features/Auths/Commands/Logout/LogoutCommandHandler.cs

@@ -18,7 +18,7 @@ public async ValueTask<Result> Handle(LogoutCommand command, CancellationToken c
         try
         {
             var userId = currentUserService.GetUserId()?.ToString()
-                ?? throw new BadRequestException(ErrorMessage.Invalid.IdIsNull);
+                ?? throw new BadRequestException(ErrorMessage.Invalid.UserId);
 
             await authService.UpdateSecurityStampAndGetUserAsync(userId);
             return Result.Success();

src/SnackFlow.Application/Features/Companies/Queries/GetCompanyById/GetCompanyByIdQueryValidator.cs

@@ -9,6 +9,6 @@ public GetCompanyByIdQueryValidator()
     {
         RuleFor(x => x.CompanyId)
             .NotEmpty()
-            .WithMessage(ErrorMessage.Invalid.IdIsNull);
+            .WithMessage(ErrorMessage.Invalid.CompanyId);
     }
 }

src/SnackFlow.Application/Features/Users/Commands/CreateUser/CreateUserCommandValidator.cs

@@ -27,7 +27,7 @@ public CreateUserCommandValidator()
         {
             RuleFor(x => x.CompanyId)
                 .NotEqual(Guid.Empty)
-                .WithMessage(ErrorMessage.Invalid.IdIsNull);
+                .WithMessage(ErrorMessage.Invalid.CompanyId);
         });
 
         RuleFor(x => x.UserName)

src/SnackFlow.Domain/Entities/Order.cs

@@ -0,0 +1,55 @@
+using SnackFlow.Domain.Abstractions;
+using SnackFlow.Domain.Abstractions.ValueObjects;
+using SnackFlow.Domain.ValueObjects.RandomToken;
+
+namespace SnackFlow.Domain.Entities;
+
+public sealed class Order 
+    : BaseEntity, IAggregateRoot, IHasRandomToken
+{
+    #region Properties
+
+    public RandomToken Token { get; private set; }
+    public Guid CompanyId { get; private set; }
+    public Guid AttendantId { get; private set; }
+    private readonly List<OrderItem> _items = [];
+    public decimal SubTotal => _items.Sum(x => x.SubTotal);
+    public decimal TotalDiscounts => _items.Sum(x => x.DiscountAmount);
+    public decimal TotalAmount => SubTotal - TotalDiscounts;
+    
+    #endregion
+    
+    #region Navigation Properties
+    
+    public Company Company { get; private set; } = null!;
+    public User Attendant { get; private set; } = null!;
+    public IReadOnlyCollection<OrderItem> ItemsReadOnly => _items.AsReadOnly();
+    
+    #endregion
+    
+    #region Constructors
+
+    private Order() : base(Guid.Empty)
+    {
+        Token = null!;
+        CompanyId = Guid.Empty;
+        AttendantId = Guid.Empty;
+    }
+
+    private Order(Guid companyId, Guid attendantId) 
+        : base(Guid.CreateVersion7())
+    {
+        CompanyId = companyId;
+        AttendantId = attendantId;
+        Token = RandomToken.Create();
+    }
+
+    #endregion
+    
+    #region Factories
+
+    public static Order Create(Guid companyId, Guid attendantId)
+        => new(companyId, attendantId);
+    
+    #endregion
+}

src/SnackFlow.Domain/Entities/OrderItem.cs

@@ -0,0 +1,97 @@
+using SnackFlow.Domain.Abstractions.ValueObjects;
+using SnackFlow.Domain.Constants;
+using SnackFlow.Domain.ValueObjects.Discount;
+using SnackFlow.Domain.ValueObjects.Discount.Exceptions;
+using SnackFlow.Domain.ValueObjects.Money;
+using SnackFlow.Domain.ValueObjects.Quantity;
+
+namespace SnackFlow.Domain.Entities;
+
+public sealed class OrderItem 
+    : BaseEntity, IHasDiscount, IHasQuantity, IHasUnitPrice
+{
+    #region Properties
+
+    public Guid OrderId { get; private set; }
+    public Guid ProductId { get; private set; }
+    public string ProductName { get; private set; }
+    public Money UnitPrice { get;  private set; }
+    public Quantity Quantity { get; private set; }
+    public Discount? ItemDiscount { get; private set; }
+    public decimal SubTotal => UnitPrice.Multiply(Quantity);
+    public decimal DiscountAmount => ItemDiscount?.CalculateDiscount(SubTotal) ?? 0;
+    public decimal TotalPrice => SubTotal - DiscountAmount;
+
+    #endregion
+    
+    #region Navigation Properties
+    
+    public Order Order { get; private set; } = null!;
+    public Product Product { get; private set; } = null!;
+    
+    #endregion
+    
+    #region Constructors
+    
+    private OrderItem() : base(Guid.Empty)
+    {
+        OrderId = Guid.Empty;
+        ProductId = Guid.Empty;
+        ProductName = string.Empty;
+        UnitPrice = Money.Zero();
+        Quantity = Quantity.Zero();
+    }
+    
+    private OrderItem(
+        Guid orderId,
+        Guid productId, 
+        string productName,
+        decimal unitPrice,
+        int quantity
+    ) : base(Guid.CreateVersion7())
+    {
+        OrderId = orderId;
+        ProductId = productId;
+        ProductName = productName;
+        UnitPrice = Money.Create(unitPrice);
+        Quantity = Quantity.Create(quantity);
+    }
+    
+    #endregion
+
+    #region Factories
+
+    public static OrderItem Create(
+        Guid orderId,
+        Guid productId,
+        string productName,
+        decimal unitPrice,
+        int quantity
+    ) => new(orderId, productId, productName, unitPrice, quantity);
+
+    #endregion
+    
+    #region Methods
+    
+    public void ApplyDiscount(Discount discount)
+    {
+        if (!discount.HasDiscount())
+            throw new InvalidDiscountException(ErrorMessage.Discount.LessThanOrEqualToZero);
+
+        var calculatedDiscount = discount.CalculateDiscount(SubTotal);
+        if (calculatedDiscount > SubTotal)
+            throw new InvalidDiscountException(ErrorMessage.Discount.GreaterThanSubtotal);
+
+        ItemDiscount = discount;
+    }
+
+    public void RemoveDiscount()
+    {
+        if (ItemDiscount != null)
+            ItemDiscount = null;
+    }
+
+    public bool HasDiscount() => ItemDiscount?.HasDiscount() == true;
+    
+    #endregion
+}

src/SnackFlow.Domain/Entities/Product.cs

@@ -0,0 +1,117 @@
+using SnackFlow.Domain.Abstractions;
+using SnackFlow.Domain.Abstractions.ValueObjects;
+using SnackFlow.Domain.Constants;
+using SnackFlow.Domain.Exceptions;
+using SnackFlow.Domain.ValueObjects.Money;
+
+namespace SnackFlow.Domain.Entities;
+
+public sealed class Product 
+    : BaseEntity, IAggregateRoot, IHasUnitPrice
+{
+    #region Properties
+
+    public string Name { get; private set; }
+    public string Description { get; private set; }
+    public Money UnitPrice { get; private set; }
+    public Guid CategoryId { get; private set; }
+    public Guid CompanyId { get; private set; }
+    public bool IsActive { get; private set; }
+    public string? ImageUrl { get; private set; }
+
+    #endregion
+
+    #region Navigation Properties
+
+    public Company Company { get; private set; } = null!;
+    public ProductCategory Category { get; private set; } = null!;
+
+    #endregion
+
+    #region Constructors
+
+    private Product() : base(Guid.Empty)
+    {
+        Name = string.Empty;
+        Description = string.Empty;
+        UnitPrice = null!;
+        CategoryId = Guid.Empty;
+        IsActive = false;
+        CompanyId = Guid.Empty;
+    }
+
+    private Product(
+        string name,
+        string description,
+        decimal price,
+        Guid categoryId,
+        Guid companyId,
+        string? imageUrl = null) : base(Guid.CreateVersion7())
+    {
+        Name = name;
+        Description = description;
+        UnitPrice = Money.CreatePrice(price);
+        CategoryId = categoryId;
+        CompanyId = companyId;
+        ImageUrl = imageUrl;
+        IsActive = true;
+    }
+
+    #endregion
+
+    #region Factories
+
+    public static Product Create(
+        string name,
+        string description,
+        decimal price,
+        Guid categoryId,
+        Guid companyId,
+        string? imageUrl = null)
+    {
+        if (string.IsNullOrWhiteSpace(name))
+            throw new ProductNameNullException(ErrorMessage.Product.NameIsNull);
+        
+        if (string.IsNullOrWhiteSpace(description))
+            throw new ProductDescriptionNullException(ErrorMessage.Product.DescriptionIsNull);
+        
+        if (categoryId == Guid.Empty)
+            throw new IdentifierNullException(ErrorMessage.Invalid.CategoryId);
+        
+        if (companyId == Guid.Empty)
+            throw new IdentifierNullException(ErrorMessage.Invalid.CompanyId);
+        
+        return new Product(name, description, price, categoryId, companyId, imageUrl);
+    }
+
+    #endregion
+
+    #region Business Methods
+
+    public void UpdateDetails(string name, string description, decimal price)
+    {
+        if (string.IsNullOrWhiteSpace(name))
+            throw new ProductNameNullException(ErrorMessage.Product.NameIsNull);
+        
+        if (string.IsNullOrWhiteSpace(description))
+            throw new ProductDescriptionNullException(ErrorMessage.Product.DescriptionIsNull);
+        
+        Name = name;
+        Description = description;
+        UnitPrice = Money.CreatePrice(price);
+    }
+
+    public void ChangeCategory(Guid categoryId)
+    {
+        if (categoryId == Guid.Empty)
+            throw new IdentifierNullException(ErrorMessage.Invalid.CategoryId);
+        
+        CategoryId = categoryId;
+    }
+
+    public void UpdateImage(string? imageUrl) => ImageUrl = imageUrl;
+    public void Activate() => IsActive = true;
+    public void Deactivate() => IsActive = false;
+
+    #endregion
+}