Add CronCraft dependency injection registration

CronCraft.Test/CronCraft.Test.csproj

@@ -9,6 +9,7 @@
   </PropertyGroup>
 
   <ItemGroup>
+    <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="9.0.6" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.12.0" />
     <PackageReference Include="MSTest" Version="3.6.4" />
   </ItemGroup>

CronCraft.Test/ServiceCollectionExtensionsTest.cs

@@ -0,0 +1,53 @@
+using CronCraft.Extensions;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Options;
+
+namespace CronCraft.Test;
+
+[TestClass]
+public sealed class ServiceCollectionExtensionsTest
+{
+    [TestMethod]
+    public void AddCronCraft_RegistersServiceAsSingleton()
+    {
+        var services = new ServiceCollection();
+        services.AddCronCraft();
+
+        using var provider = services.BuildServiceProvider();
+
+        var first = provider.GetRequiredService<CronCraftService>();
+        var second = provider.GetRequiredService<CronCraftService>();
+
+        Assert.AreSame(first, second);
+    }
+
+    [TestMethod]
+    public void AddCronCraft_AppliesConfiguration()
+    {
+        var services = new ServiceCollection();
+        services.AddCronCraft(settings =>
+        {
+            settings.Language = "en";
+            settings.DayNameFormat = "full";
+        });
+
+        using var provider = services.BuildServiceProvider();
+
+        var options = provider.GetRequiredService<IOptions<Models.CronSettings>>();
+        var cronCraft = provider.GetRequiredService<CronCraftService>();
+
+        Assert.AreEqual("en", options.Value.Language);
+        Assert.AreEqual("full", options.Value.DayNameFormat);
+        Assert.AreEqual("Every Monday at 09:00 AM", cronCraft.Convert("0 9 * * 1"));
+    }
+
+    [TestMethod]
+    public void AddCronCraft_ReturnsServiceCollectionForChaining()
+    {
+        var services = new ServiceCollection();
+
+        var result = services.AddCronCraft();
+
+        Assert.AreSame(services, result);
+    }
+}

CronCraft/CronCraft.csproj

@@ -17,6 +17,7 @@
   </PropertyGroup>
 
   <ItemGroup>
+    <PackageReference Include="Microsoft.Extensions.DependencyInjection.Abstractions" Version="9.0.6" />
     <PackageReference Include="Microsoft.Extensions.Options" Version="9.0.6" />
   </ItemGroup>
 

CronCraft/Extensions/ServiceCollectionExtensions.cs

@@ -0,0 +1,31 @@
+using CronCraft.Models;
+using Microsoft.Extensions.DependencyInjection;
+
+namespace CronCraft.Extensions;
+
+public static class ServiceCollectionExtensions
+{
+    /// <summary>
+    /// Adds CronCraft and its configuration options to the service collection.
+    /// </summary>
+    /// <param name="services">The service collection to add CronCraft to.</param>
+    /// <param name="configure">
+    /// An optional delegate used to configure <see cref="CronSettings"/>.
+    /// </param>
+    /// <returns>The service collection so that additional calls can be chained.</returns>
+    public static IServiceCollection AddCronCraft(
+        this IServiceCollection services,
+        Action<CronSettings>? configure = null)
+    {
+        ArgumentNullException.ThrowIfNull(services);
+
+        services.AddOptions<CronSettings>();
+
+        if (configure is not null)
+            services.Configure(configure);
+
+        services.AddSingleton<CronCraftService>();
+
+        return services;
+    }
+}

CronCraft/README.md

@@ -11,7 +11,7 @@ CronCraft is designed for **clarity, speed, and minimal setup**.
 
 Whether you're building a **web app**, a **CLI tool**, a **Windows Service**, or a **background worker** — just create a `CronSettings` object, and you're good to go.
 
-> ❝ No dependency injection. No appsettings. Just clean, functional cron parsing. ❞
+> ❝ No dependency injection required. No appsettings. Just clean, functional cron parsing. ❞
 
 ---
 
@@ -21,6 +21,7 @@ Whether you're building a **web app**, a **CLI tool**, a **Windows Service**, or
 - 🌍 Localized day-of-week formatting (`short`, `full`, `single`, or custom)
 - 🕘 Time zone adjustment (optional)
 - 🔧 Fully configurable via `CronSettings` object
+- 💉 Optional dependency injection registration with `AddCronCraft`
 - 📦 Lightweight, zero-dependency core logic
 
 ---
@@ -64,6 +65,30 @@ Console.WriteLine($"📖 Human Readable (Local TZ): {humanReadable}");
 Console.ReadLine();
 ```
 
+### Dependency Injection
+
+For ASP.NET Core and generic host applications, register CronCraft through
+`IServiceCollection`:
+
+```csharp
+using CronCraft.Extensions;
+
+builder.Services.AddCronCraft(settings =>
+{
+    settings.Language = "en";
+    settings.DayNameFormat = "short";
+});
+```
+
+Then inject `CronCraftService` where it is needed:
+
+```csharp
+public class MyScheduler(CronCraftService cronCraft)
+{
+    public string Describe(string expression) => cronCraft.Convert(expression);
+}
+```
+
 **Expected Output:**
 
 ```

README.md

@@ -11,7 +11,7 @@ CronCraft is designed for **clarity, speed, and minimal setup**.
 
 Whether you're building a **web app**, a **CLI tool**, a **Windows Service**, or a **background worker** — just create a `CronSettings` object, and you're good to go.
 
-> ❝ No dependency injection. No appsettings. Just clean, functional cron parsing. ❞
+> ❝ No dependency injection required. No appsettings. Just clean, functional cron parsing. ❞
 
 ---
 
@@ -21,6 +21,7 @@ Whether you're building a **web app**, a **CLI tool**, a **Windows Service**, or
 - 🌍 Localized day-of-week formatting (`short`, `full`, `single`, or custom)
 - 🕘 Time zone adjustment (optional)
 - 🔧 Fully configurable via `CronSettings` object
+- 💉 Optional dependency injection registration with `AddCronCraft`
 - 📦 Lightweight, zero-dependency core logic
 
 ---
@@ -64,6 +65,30 @@ Console.WriteLine($"📖 Human Readable (Local TZ): {humanReadable}");
 Console.ReadLine();
 ```
 
+### Dependency Injection
+
+For ASP.NET Core and generic host applications, register CronCraft through
+`IServiceCollection`:
+
+```csharp
+using CronCraft.Extensions;
+
+builder.Services.AddCronCraft(settings =>
+{
+    settings.Language = "en";
+    settings.DayNameFormat = "short";
+});
+```
+
+Then inject `CronCraftService` where it is needed:
+
+```csharp
+public class MyScheduler(CronCraftService cronCraft)
+{
+    public string Describe(string expression) => cronCraft.Convert(expression);
+}
+```
+
 **Expected Output:**
 
 ```