using UnityEngine.UIElements;
using UIComponents;

[UxmlName("Counter")] // A UxmlFactory implementation is generated.
[Layout("CounterComponent/CounterComponent")]
[Stylesheet("CounterComponent/CounterComponent.style")]
[Stylesheet("Common")]
[Dependency(typeof(ICounterService), provide: typeof(CounterService))]
public partial class CounterComponent : UIComponent, IOnAttachToPanel
{
    // The layout and stylesheets are loaded automatically.
    // They are retrieved from Resources by default,
    // hence the lack of file extensions.
    
    // An UxmlTraits implementation is generated automatically for this class.
    [UxmlTrait]
    public string IncrementText = "Increment";
    
    // Queries are made after all assets have loaded.
    // The query calls are generated automatically for you.
    [Query("count-label")]
    public Label CountLabel;
    
    [Query("increment-button")]
    public Button IncrementButton;
    
    // An instance of CounterService is injected into this field
    // in the inherited constructor.
    [Provide]
    private ICounterService _counterService;
    
    // The OnInit method is called after all assets have loaded.
    // Any operations related to the DOM and stylesheets should
    // be done here.
    public override void OnInit()
    {
        CountLabel.text = _counterService.Count.ToString();
        IncrementButton.text = IncrementText;
    }
    
    // Event handlers are registered after all assets have loaded.
    // To listen for events, all you need to do is implement
    // a supported interface.
    public void OnAttachToPanel(AttachToPanelEvent evt)
    {
        CountLabel.text = _counterService.Count.ToString();
    }
}

var container = new VisualElement();
container.Add(new CounterComponent() { IncrementText = "+1" });

using UIComponents;
using UIComponents.Testing;
using NUnit.Framework;
using UnityEngine.TestTools;

[TestFixture]
public class CounterComponentTests
{
    private TestBed<CounterComponent> _testBed;
    private ICounterService _counterService;
    
    [SetUp]
    public void SetUp()
    {
        // A mocking framework like NSubstitute is recommended.
        // Here we don't use a mock at all.
        _counterService = new CounterService();
        _testBed = new TestBed<CounterComponent>()
            .WithSingleton<ICounterService>(_counterService);
    }
    
    [UnityTest]
    public IEnumerator It_Initializes_Count_Label_On_Init()
    {
        _counterService.Count = 42;

        var component = _testBed.CreateComponent();
        // UIComponents start their initialization when they are first attached to a panel.
        // We can force the initialization by calling Initialize() manually.
        component.Initialize();
        // Wait until the component's assets have been loaded.
        yield return component.WaitForInitializationEnumerator();
        Assert.That(component.CountLabel.text, Is.EqualTo("42"));
    }
}