Add FluentValidation

src/Imprink.Application/Validation/Models/Auth0UserValidator.cs

@@ -0,0 +1,23 @@
+using FluentValidation;
+using Imprink.Domain.Models;
+
+namespace Imprink.Application.Validation.Models;
+
+public class Auth0UserValidator : AbstractValidator<Auth0User>
+{
+    public Auth0UserValidator()
+    {
+        RuleFor(x => x.Sub)
+            .NotEmpty();
+        
+        RuleFor(x => x.Name)
+            .NotEmpty();
+        
+        RuleFor(x => x.Nickname)
+            .NotEmpty();
+        
+        RuleFor(x => x.Email)
+            .NotEmpty()
+            .EmailAddress();
+    }
+}

src/Imprink.Application/Validation/Models/ProductFilterParametersValidator.cs

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+using FluentValidation;
+using Imprink.Domain.Models;
+
+namespace Imprink.Application.Validation.Models;
+
+public class ProductFilterParametersValidator : AbstractValidator<ProductFilterParameters>
+{
+    public ProductFilterParametersValidator()
+    {
+        RuleFor(x => x.PageNumber)
+            .GreaterThan(0).WithMessage("PageNumber must be greater than 0.");
+
+        RuleFor(x => x.PageSize)
+            .InclusiveBetween(1, 100).WithMessage("PageSize must be between 1 and 100.");
+        
+        RuleFor(x => x.SearchTerm)
+            .Length(1, 100).WithMessage("Length must be between 1 and 100.")
+            .When(x => !string.IsNullOrWhiteSpace(x.SearchTerm));
+
+        RuleFor(x => x.MinPrice)
+            .GreaterThanOrEqualTo(0).When(x => x.MinPrice.HasValue)
+            .WithMessage("MinPrice cannot be negative.");
+
+        RuleFor(x => x.MaxPrice)
+            .GreaterThanOrEqualTo(0).When(x => x.MaxPrice.HasValue)
+            .WithMessage("MaxPrice cannot be negative.");
+
+        RuleFor(x => x)
+            .Must(x => !x.MinPrice.HasValue || !x.MaxPrice.HasValue || x.MinPrice <= x.MaxPrice)
+            .WithMessage("MinPrice cannot be greater than MaxPrice.");
+
+        RuleFor(x => x.SortBy)
+            .NotEmpty().WithMessage("SortBy is required.")
+            .Must(value => AllowedSortColumns.Contains(value, StringComparer.OrdinalIgnoreCase))
+            .WithMessage("SortBy must be one of: Name, Price, CreatedDate.");
+
+        RuleFor(x => x.SortDirection)
+            .NotEmpty().WithMessage("SortDirection is required.")
+            .Must(value => value.Equals("ASC", StringComparison.OrdinalIgnoreCase) 
+                           || value.Equals("DESC", StringComparison.OrdinalIgnoreCase))
+            .WithMessage("SortDirection must be 'ASC' or 'DESC'.");
+    }
+
+    private static readonly string[] AllowedSortColumns = ["Name", "Price", "CreatedDate"];
+}

src/Imprink.Application/Validation/Products/GetProductsQueryValidator.cs

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+using FluentValidation;
+using Imprink.Application.Products;
+using Imprink.Application.Validation.Models;
+
+namespace Imprink.Application.Validation.Products;
+
+public class GetProductsQueryValidator : AbstractValidator<GetProductsQuery>
+{
+    public GetProductsQueryValidator()
+    {
+        RuleFor(x => x.FilterParameters)
+            .NotNull()
+            .SetValidator(new ProductFilterParametersValidator());
+    }
+}