Implement customer overdue orders query feature

Modules/Contracts/Sales/CustomerWithOverdueOrdersData.cs

@@ -0,0 +1,22 @@
+namespace Contracts.Sales;
+
+/// <summary>
+/// Customer information with overdue order statistics
+/// </summary>
+public sealed class CustomerWithOverdueOrdersData
+{
+    /// <summary>
+    /// Customer display name (CompanyName if available, otherwise FirstName + LastName)
+    /// </summary>
+    public required string CustomerName { get; init; }
+
+    /// <summary>
+    /// Total count of overdue orders for this customer
+    /// </summary>
+    public int OverdueOrdersCount { get; init; }
+
+    /// <summary>
+    /// Due date of the oldest overdue order
+    /// </summary>
+    public DateTime OldestDueDate { get; init; }
+}

Modules/Contracts/Sales/ICustomerService.cs

@@ -7,4 +7,14 @@ public interface ICustomerService
     CustomerData[] GetCustomersWithOrdersStartingWith(string prefix);
 
     CustomerData[] GetCustomersWithOrdersContaining(string fragment);
+
+    /// <summary>
+    /// Retrieves customers that have at least one overdue order.
+    /// An order is overdue when DueDate &lt; Today and Status is not Shipped or Cancelled.
+    /// </summary>
+    /// <returns>
+    /// Array of customers with overdue order information, ordered by oldest overdue date ascending.
+    /// Returns empty array if no customers with overdue orders exist.
+    /// </returns>
+    CustomerWithOverdueOrdersData[] GetCustomersWithOverdueOrders();
 }

Modules/Sales/Sales.ConsoleCommands/CustomersWithOverdueOrdersConsoleCommand.cs

@@ -0,0 +1,31 @@
+using AppBoot.DependencyInjection;
+using Contracts.ConsoleUi;
+using Contracts.Sales;
+
+namespace Sales.ConsoleCommands;
+
+[Service(typeof(IConsoleCommand))]
+internal sealed class CustomersWithOverdueOrdersConsoleCommand(IConsole console, ICustomerService customerService) : IConsoleCommand
+{
+    public string MenuLabel => "Show customers with overdue orders";
+
+    public void Execute()
+    {
+        console.WriteLine("Retrieving customers with overdue orders...");
+
+        var customers = customerService.GetCustomersWithOverdueOrders();
+
+        if (customers.Length == 0)
+        {
+            console.WriteLine("No customers with overdue orders found.");
+            return;
+        }
+
+        console.WriteLine($"Found {customers.Length} customer(s) with overdue orders:\n");
+
+        foreach (var customer in customers)
+        {
+            console.WriteEntity(customer);
+        }
+    }
+}

Modules/Sales/Sales.Services.UnitTests/CustomerServiceTests.cs

@@ -0,0 +1,212 @@
+using Contracts.Sales;
+using Sales.DataModel.SalesLT;
+using Sales.DataModel.Values;
+using Sales.Services.UnitTests.Fakes;
+
+namespace Sales.Services.UnitTests;
+
+public class CustomerServiceTests
+{
+    [Fact]
+    public void GetCustomersWithOverdueOrders_WithNoCustomers_ReturnsEmptyArray()
+    {
+        var target = GetTarget(new Customer[0]);
+
+        var result = target.GetCustomersWithOverdueOrders();
+
+        Assert.Empty(result);
+    }
+
+    [Fact]
+    public void GetCustomersWithOverdueOrders_WithNoOverdueOrders_ReturnsEmptyArray()
+    {
+        var customer = CreateCustomer(1, "Acme", "John", "Doe",
+            CreateOrder(1, DateTime.Today.AddDays(10), SalesOrderHeaderStatusValues.InProcess));
+        var target = GetTarget(new[] { customer });
+
+        var result = target.GetCustomersWithOverdueOrders();
+
+        Assert.Empty(result);
+    }
+
+    [Fact]
+    public void GetCustomersWithOverdueOrders_WithOneCustomerOneOverdueOrder_ReturnsCustomer()
+    {
+        var dueDate = DateTime.Today.AddDays(-5);
+        var customer = CreateCustomer(1, "Acme Corp", "John", "Doe",
+            CreateOrder(1, dueDate, SalesOrderHeaderStatusValues.InProcess));
+        var target = GetTarget(new[] { customer });
+
+        var result = target.GetCustomersWithOverdueOrders();
+
+        Assert.Single(result);
+        Assert.Equal("Acme Corp", result[0].CustomerName);
+        Assert.Equal(1, result[0].OverdueOrdersCount);
+        Assert.Equal(dueDate, result[0].OldestDueDate);
+    }
+
+    [Fact]
+    public void GetCustomersWithOverdueOrders_WithMultipleCustomers_ReturnsSortedByOldestDueDate()
+    {
+        var customer1 = CreateCustomer(1, "Beta Inc", "Jane", "Smith",
+            CreateOrder(1, DateTime.Today.AddDays(-3), SalesOrderHeaderStatusValues.InProcess));
+        var customer2 = CreateCustomer(2, "Alpha Corp", "Bob", "Jones",
+            CreateOrder(2, DateTime.Today.AddDays(-10), SalesOrderHeaderStatusValues.Approved));
+        var customer3 = CreateCustomer(3, "Gamma LLC", "Alice", "Brown",
+            CreateOrder(3, DateTime.Today.AddDays(-5), SalesOrderHeaderStatusValues.Backordered));
+        var target = GetTarget(new[] { customer1, customer2, customer3 });
+
+        var result = target.GetCustomersWithOverdueOrders();
+
+        Assert.Equal(3, result.Length);
+        Assert.Equal("Alpha Corp", result[0].CustomerName);
+        Assert.Equal("Gamma LLC", result[1].CustomerName);
+        Assert.Equal("Beta Inc", result[2].CustomerName);
+    }
+
+    [Fact]
+    public void GetCustomersWithOverdueOrders_ExcludesShippedOrders_WhenDueDatePassed()
+    {
+        var customer = CreateCustomer(1, "Test Co", "John", "Doe",
+            CreateOrder(1, DateTime.Today.AddDays(-5), SalesOrderHeaderStatusValues.Shipped));
+        var target = GetTarget(new[] { customer });
+
+        var result = target.GetCustomersWithOverdueOrders();
+
+        Assert.Empty(result);
+    }
+
+    [Fact]
+    public void GetCustomersWithOverdueOrders_ExcludesCancelledOrders_WhenDueDatePassed()
+    {
+        var customer = CreateCustomer(1, "Test Co", "John", "Doe",
+            CreateOrder(1, DateTime.Today.AddDays(-5), SalesOrderHeaderStatusValues.Cancelled));
+        var target = GetTarget(new[] { customer });
+
+        var result = target.GetCustomersWithOverdueOrders();
+
+        Assert.Empty(result);
+    }
+
+    [Fact]
+    public void GetCustomersWithOverdueOrders_IncludesInProcessOrders_WhenDueDatePassed()
+    {
+        var customer = CreateCustomer(1, "Test Co", "John", "Doe",
+            CreateOrder(1, DateTime.Today.AddDays(-5), SalesOrderHeaderStatusValues.InProcess));
+        var target = GetTarget(new[] { customer });
+
+        var result = target.GetCustomersWithOverdueOrders();
+
+        Assert.Single(result);
+    }
+
+    [Fact]
+    public void GetCustomersWithOverdueOrders_ExcludesOrdersNotYetDue_EvenIfNotClosed()
+    {
+        var customer = CreateCustomer(1, "Test Co", "John", "Doe",
+            CreateOrder(1, DateTime.Today.AddDays(5), SalesOrderHeaderStatusValues.InProcess));
+        var target = GetTarget(new[] { customer });
+
+        var result = target.GetCustomersWithOverdueOrders();
+
+        Assert.Empty(result);
+    }
+
+    [Fact]
+    public void GetCustomersWithOverdueOrders_CalculatesCountCorrectly_ForMultipleOverdueOrders()
+    {
+        var oldestDueDate = DateTime.Today.AddDays(-10);
+        var customer = CreateCustomer(1, "Test Co", "John", "Doe",
+            CreateOrder(1, oldestDueDate, SalesOrderHeaderStatusValues.InProcess),
+            CreateOrder(2, DateTime.Today.AddDays(-5), SalesOrderHeaderStatusValues.Approved),
+            CreateOrder(3, DateTime.Today.AddDays(-2), SalesOrderHeaderStatusValues.Backordered));
+        var target = GetTarget(new[] { customer });
+
+        var result = target.GetCustomersWithOverdueOrders();
+
+        Assert.Single(result);
+        Assert.Equal(3, result[0].OverdueOrdersCount);
+        Assert.Equal(oldestDueDate, result[0].OldestDueDate);
+    }
+
+    [Fact]
+    public void GetCustomersWithOverdueOrders_UsesCompanyName_WhenAvailable()
+    {
+        var customer = CreateCustomer(1, "Acme Corporation", "John", "Doe",
+            CreateOrder(1, DateTime.Today.AddDays(-5), SalesOrderHeaderStatusValues.InProcess));
+        var target = GetTarget(new[] { customer });
+
+        var result = target.GetCustomersWithOverdueOrders();
+
+        Assert.Single(result);
+        Assert.Equal("Acme Corporation", result[0].CustomerName);
+    }
+
+    [Fact]
+    public void GetCustomersWithOverdueOrders_CombinesFirstAndLastName_WhenCompanyNameNull()
+    {
+        var customer = CreateCustomer(1, null, "Jane", "Smith",
+            CreateOrder(1, DateTime.Today.AddDays(-5), SalesOrderHeaderStatusValues.InProcess));
+        var target = GetTarget(new[] { customer });
+
+        var result = target.GetCustomersWithOverdueOrders();
+
+        Assert.Single(result);
+        Assert.Equal("Jane Smith", result[0].CustomerName);
+    }
+
+    [Fact]
+    public void GetCustomersWithOverdueOrders_MixedOrderStatuses_ReturnsOnlyOverdue()
+    {
+        var oldestOverdue = DateTime.Today.AddDays(-8);
+        var customer = CreateCustomer(1, "Test Co", "John", "Doe",
+            CreateOrder(1, oldestOverdue, SalesOrderHeaderStatusValues.InProcess),
+            CreateOrder(2, DateTime.Today.AddDays(-5), SalesOrderHeaderStatusValues.Shipped),
+            CreateOrder(3, DateTime.Today.AddDays(-3), SalesOrderHeaderStatusValues.Approved),
+            CreateOrder(4, DateTime.Today.AddDays(5), SalesOrderHeaderStatusValues.InProcess));
+        var target = GetTarget(new[] { customer });
+
+        var result = target.GetCustomersWithOverdueOrders();
+
+        Assert.Single(result);
+        Assert.Equal(2, result[0].OverdueOrdersCount);
+        Assert.Equal(oldestOverdue, result[0].OldestDueDate);
+    }
+
+    private static CustomerService GetTarget(Customer[] customers)
+    {
+        var repositoryStub = new FakeRepository(customers);
+        return new CustomerService(repositoryStub);
+    }
+
+    private static Customer CreateCustomer(int id, string? companyName, string firstName, string lastName, params SalesOrderHeader[] orders)
+    {
+        var customer = new Customer
+        {
+            CustomerID = id,
+            CompanyName = companyName,
+            FirstName = firstName,
+            LastName = lastName
+        };
+
+        foreach (var order in orders)
+        {
+            customer.SalesOrderHeaders.Add(order);
+            order.Customer = customer;
+            order.CustomerID = id;
+        }
+
+        return customer;
+    }
+
+    private static SalesOrderHeader CreateOrder(int id, DateTime dueDate, byte status)
+    {
+        return new SalesOrderHeader
+        {
+            SalesOrderID = id,
+            DueDate = dueDate,
+            Status = status,
+            OrderDate = DateTime.Today.AddDays(-30)
+        };
+    }
+}

Modules/Sales/Sales.Services.UnitTests/Fakes/FakeRepository.cs

@@ -0,0 +1,28 @@
+using Sales.DataModel.SalesLT;
+
+namespace Sales.Services.UnitTests.Fakes;
+
+internal class FakeRepository : DataAccess.IRepository
+{
+    private readonly List<Customer> _customers = new();
+
+    public FakeRepository(Customer[] customers)
+    {
+        _customers.AddRange(customers);
+    }
+
+    public IQueryable<TEntity> GetEntities<TEntity>() where TEntity : class
+    {
+        if (typeof(TEntity) == typeof(Customer))
+        {
+            return (IQueryable<TEntity>)_customers.AsQueryable();
+        }
+
+        throw new NotImplementedException($"Entity type {typeof(TEntity).Name} not supported in FakeRepository");
+    }
+
+    public DataAccess.IUnitOfWork CreateUnitOfWork()
+    {
+        throw new NotImplementedException("CreateUnitOfWork not needed for read-only tests");
+    }
+}

Modules/Sales/Sales.Services.UnitTests/Sales.Services.UnitTests.csproj

@@ -0,0 +1,31 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net10.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+    <OutputType>Exe</OutputType>
+    <IsPackable>false</IsPackable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.0.1" />
+    <PackageReference Include="NSubstitute" Version="5.3.0" />
+    <PackageReference Include="xunit.v3" Version="3.2.0" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="3.1.5">
+      <PrivateAssets>all</PrivateAssets>
+      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+    </PackageReference>
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\Sales.Services\Sales.Services.csproj" />
+    <ProjectReference Include="..\Sales.DataModel\Sales.DataModel.csproj" />
+    <ProjectReference Include="..\..\..\Infra\DataAccess\DataAccess.csproj" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <Using Include="Xunit" />
+  </ItemGroup>
+
+</Project>

Modules/Sales/Sales.Services/CustomerService.cs

@@ -4,6 +4,7 @@
 using Contracts.Sales;
 using DataAccess;
 using Sales.DataModel.SalesLT;
+using Sales.DataModel.Values;
 
 namespace Sales.Services;
 
@@ -52,4 +53,27 @@ public CustomerData[] GetCustomersWithOrdersContaining(string fragment)
 
         return GetCustomersWithOrdersFilteredBy(filter);
     }
+
+    public CustomerWithOverdueOrdersData[] GetCustomersWithOverdueOrders()
+    {
+        var today = DateTime.Today;
+        var closedStatuses = new[] { SalesOrderHeaderStatusValues.Shipped, SalesOrderHeaderStatusValues.Cancelled };
+
+        return repository.GetEntities<Customer>()
+            .Where(c => c.SalesOrderHeaders.Any(o =>
+                o.DueDate < today &&
+                !closedStatuses.Contains(o.Status)))
+            .Select(c => new CustomerWithOverdueOrdersData
+            {
+                CustomerName = c.CompanyName ?? $"{c.FirstName} {c.LastName}",
+                OverdueOrdersCount = c.SalesOrderHeaders
+                    .Where(o => o.DueDate < today && !closedStatuses.Contains(o.Status))
+                    .Count(),
+                OldestDueDate = c.SalesOrderHeaders
+                    .Where(o => o.DueDate < today && !closedStatuses.Contains(o.Status))
+                    .Min(o => o.DueDate)
+            })
+            .OrderBy(x => x.OldestDueDate)
+            .ToArray();
+    }
 }

Modules/Sales/Sales.Services/Sales.Services.csproj

@@ -7,6 +7,10 @@
     <EnableDynamicLoading>true</EnableDynamicLoading>
   </PropertyGroup>
 
+  <ItemGroup>
+    <InternalsVisibleTo Include="Sales.Services.UnitTests" />
+  </ItemGroup>
+
   <ItemGroup>
     <ProjectReference Include="..\..\..\Infra\AppBoot\AppBoot.csproj" />
     <ProjectReference Include="..\..\..\Infra\DataAccess\DataAccess.csproj" />