initial commit v2

warmup/OrderDomain/Order.cs

@@ -0,0 +1,14 @@
+namespace OrderDomain;
+
+public class Order
+{
+    public List<OrderLine> Lines { get; } = new();
+
+    public decimal Total => Lines.Sum(l => l.Value);
+
+    public void AddLine(decimal unitPrice, int quantity)
+        => Lines.Add(new OrderLine(unitPrice, quantity));
+
+    public void ApplyDiscount(int lineIndex)
+        => Lines[lineIndex].ApplyDiscount();
+}

warmup/OrderDomain/OrderDomain.csproj

@@ -0,0 +1,7 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <TargetFramework>net10.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+</Project>

warmup/OrderDomain/OrderLine.cs

@@ -0,0 +1,19 @@
+namespace OrderDomain;
+
+public class OrderLine
+{
+    public decimal UnitPrice { get; }
+    public int Quantity { get; }
+    public bool HasDiscount { get; private set; }
+
+    public decimal Value =>
+        HasDiscount ? UnitPrice * Quantity * 0.8m : UnitPrice * Quantity;
+
+    public OrderLine(decimal unitPrice, int quantity)
+    {
+        UnitPrice = unitPrice;
+        Quantity = quantity;
+    }
+
+    public void ApplyDiscount() => HasDiscount = true;
+}