using Shouldly;
using Xunit;
using JdeScoping.SecureStoreManager.ViewModels;

namespace JdeScoping.SecureStoreManager.Tests.ViewModels;

public class RelayCommandTests
{
    [Fact]
    public void Execute_CallsAction()
    {
        // Arrange
        var wasCalled = false;
        var sut = new RelayCommand(() => wasCalled = true);

        // Act
        sut.Execute(null);

        // Assert
        wasCalled.ShouldBeTrue();
    }

    [Fact]
    public void Execute_PassesParameterToAction()
    {
        // Arrange
        object? receivedParameter = null;
        var sut = new RelayCommand(p => receivedParameter = p);

        // Act
        sut.Execute("testParam");

        // Assert
        receivedParameter.ShouldBe("testParam");
    }

    [Fact]
    public void CanExecute_WhenNoPredicate_ReturnsTrue()
    {
        // Arrange
        var sut = new RelayCommand(() => { });

        // Act
        var result = sut.CanExecute(null);

        // Assert
        result.ShouldBeTrue();
    }

    [Fact]
    public void CanExecute_WhenPredicateReturnsTrue_ReturnsTrue()
    {
        // Arrange
        var sut = new RelayCommand(() => { }, () => true);

        // Act
        var result = sut.CanExecute(null);

        // Assert
        result.ShouldBeTrue();
    }

    [Fact]
    public void CanExecute_WhenPredicateReturnsFalse_ReturnsFalse()
    {
        // Arrange
        var sut = new RelayCommand(() => { }, () => false);

        // Act
        var result = sut.CanExecute(null);

        // Assert
        result.ShouldBeFalse();
    }

    [Fact]
    public void CanExecute_WithParameterPredicate_EvaluatesParameter()
    {
        // Arrange
        var sut = new RelayCommand(_ => { }, p => p is string s && s == "valid");

        // Act
        var validResult = sut.CanExecute("valid");
        var invalidResult = sut.CanExecute("invalid");

        // Assert
        validResult.ShouldBeTrue();
        invalidResult.ShouldBeFalse();
    }

    [Fact]
    public void RaiseCanExecuteChanged_FiresCanExecuteChangedEvent()
    {
        // Arrange
        var sut = new RelayCommand(() => { });
        var eventFired = false;
        sut.CanExecuteChanged += (s, e) => eventFired = true;

        // Act
        sut.RaiseCanExecuteChanged();

        // Assert
        eventFired.ShouldBeTrue();
    }

    [Fact]
    public void RaiseCanExecuteChanged_EventSenderIsSut()
    {
        // Arrange
        var sut = new RelayCommand(() => { });
        object? eventSender = null;
        sut.CanExecuteChanged += (s, e) => eventSender = s;

        // Act
        sut.RaiseCanExecuteChanged();

        // Assert
        eventSender.ShouldBe(sut);
    }

    [Fact]
    public void Constructor_WithNullExecute_ThrowsArgumentNullException()
    {
        // Arrange & Act & Assert
        Should.Throw<ArgumentNullException>(() => new RelayCommand((Action<object?>)null!));
    }
}