using Syntriax.Engine.Core;
using Syntriax.Engine.Core.Exceptions;

namespace Engine.Tests;

public class BehaviourController_Tests
{
    [Fact]
    public void GetRequiredBehaviour()
    {
        IBehaviourController behaviourController = CreateUniverseObject().BehaviourController;

        behaviourController.AddBehaviour<BehaviourX>();
        Assert.NotNull(behaviourController.GetRequiredBehaviour<BehaviourX>());
    }

    [Fact]
    public void GetRequiredBehaviourRaisesExceptionIfNotFound()
    {
        IBehaviourController behaviourController = CreateUniverseObject().BehaviourController;

        Assert.Throws<BehaviourNotFoundException>(behaviourController.GetRequiredBehaviour<BehaviourX>);
    }

    [Fact]
    public void AddSingleBehaviour()
    {
        IBehaviourController behaviourController = CreateUniverseObject().BehaviourController;

        Assert.NotNull(behaviourController.AddBehaviour<BehaviourX>());
        Assert.NotNull(behaviourController.GetBehaviour<BehaviourX>());
    }

    [Fact]
    public void AddMultipleBehaviours()
    {
        IBehaviourController behaviourController = CreateUniverseObject().BehaviourController;

        BehaviourX behaviourX = behaviourController.AddBehaviour<BehaviourX>();
        BehaviourY behaviourY = behaviourController.AddBehaviour<BehaviourY>();

        bool isXFound = false;
        bool isYFound = false;

        foreach (IBehaviour behaviour in behaviourController.GetBehaviours<IBehaviour>())
        {
            if (behaviour == behaviourX) isXFound = true;
            if (behaviour == behaviourY) isYFound = true;
        }

        Assert.True(isXFound && isYFound);
    }

    [Fact]
    public void AddThenRemoveBehaviour()
    {
        IBehaviourController behaviourController = CreateUniverseObject().BehaviourController;

        behaviourController.AddBehaviour<BehaviourX>();
        behaviourController.RemoveBehaviour<BehaviourX>();
        Assert.Null(behaviourController.GetBehaviour<BehaviourX>());
    }

    [Fact]
    public void GetOrAddBehaviourExtension()
    {
        IBehaviourController behaviourController = CreateUniverseObject().BehaviourController;

        Assert.Null(behaviourController.GetBehaviour<BehaviourX>());
        Assert.NotNull(behaviourController.GetOrAddBehaviour<BehaviourX>());
    }

    [Fact]
    public void GetOrAddBehaviourExtensionFallback()
    {
        IBehaviourController behaviourController = CreateUniverseObject().BehaviourController;

        Assert.Null(behaviourController.GetBehaviour<IBehaviour>());
        Assert.NotNull(behaviourController.GetOrAddBehaviour<IBehaviour, BehaviourX>());
    }

    [Fact]
    public void RemoveSpecificBehaviourViaGeneric()
    {
        IBehaviourController behaviourController = CreateUniverseObject().BehaviourController;

        behaviourController.AddBehaviour<BehaviourX>();
        behaviourController.AddBehaviour<BehaviourY>();
        behaviourController.RemoveBehaviour<BehaviourY>();

        Assert.NotNull(behaviourController.GetBehaviour<BehaviourX>());
        Assert.Null(behaviourController.GetBehaviour<BehaviourY>());
    }

    [Fact]
    public void RemoveSpecificBehaviourViaReference()
    {
        IBehaviourController behaviourController = CreateUniverseObject().BehaviourController;

        behaviourController.AddBehaviour<BehaviourX>();

        BehaviourY behaviourYFirst = behaviourController.AddBehaviour<BehaviourY>();
        BehaviourY behaviourYSecond = behaviourController.AddBehaviour<BehaviourY>();

        behaviourController.RemoveBehaviour(behaviourYFirst);

        Assert.Equal(behaviourController.GetBehaviour<BehaviourY>(), behaviourYSecond);
        Assert.NotNull(behaviourController.GetBehaviour<BehaviourX>());
    }

    [Fact]
    public void AddBehaviourSameTypeCreatesSeparateInstances()
    {
        IBehaviourController behaviourController = CreateUniverseObject().BehaviourController;

        BehaviourY first = behaviourController.AddBehaviour<BehaviourY>();
        BehaviourY second = behaviourController.AddBehaviour<BehaviourY>();

        Assert.NotSame(first, second);
    }

    [Fact]
    public void BehaviourAddedEvents()
    {
        IBehaviourController behaviourController = CreateUniverseObject().BehaviourController;

        IBehaviourController? sender = null;
        IBehaviourController.BehaviourAddedArguments? arguments = null;

        behaviourController.OnBehaviourAdded.AddListener((s, a) =>
        {
            sender = s;
            arguments = a;
        });

        behaviourController.AddBehaviour<BehaviourX>();

        Assert.NotNull(sender);
        Assert.NotNull(arguments);
    }

    [Fact]
    public void BehaviourRemovedEvents()
    {
        IBehaviourController behaviourController = CreateUniverseObject().BehaviourController;

        IBehaviourController? sender = null;
        IBehaviourController.BehaviourRemovedArguments? arguments = null;

        behaviourController.OnBehaviourRemoved.AddListener((s, a) =>
        {
            sender = s;
            arguments = a;
        });

        behaviourController.AddBehaviour<BehaviourX>();
        behaviourController.RemoveBehaviour<BehaviourX>();

        Assert.NotNull(sender);
        Assert.NotNull(arguments);
    }

    #region Hierarchy Structure

    private static IUniverseObject CreateUniverseObject()
    {
        UniverseObject universeObject = new();
        BehaviourController behaviourController = new();

        universeObject.Assign(new StateEnable());
        universeObject.StateEnable.Assign(universeObject);

        behaviourController.Assign(new StateEnable());
        behaviourController.StateEnable.Assign(behaviourController);

        behaviourController.Assign(universeObject);
        universeObject.Assign(behaviourController);

        universeObject.Initialize();
        behaviourController.Initialize();

        return universeObject;
    }

    public static IUniverseObject CreateParentChildScenario()
    {
        IUniverseObject parentUO = CreateUniverseObject().SetUniverseObject("Parent");
        IUniverseObject middleUO = CreateUniverseObject().SetUniverseObject("Middle", parentUO);
        IUniverseObject childUO = CreateUniverseObject().SetUniverseObject("Child", middleUO);

        parentUO.BehaviourController.AddBehaviour<BehaviourY>();
        middleUO.BehaviourController.AddBehaviour<BehaviourX>();
        childUO.BehaviourController.AddBehaviour<BehaviourY>();

        return middleUO;
    }

    [Fact]
    public void ParentChildScenarioGetBehaviourInParent()
    {
        IUniverseObject universeObject = CreateParentChildScenario();

        Assert.NotNull(universeObject.BehaviourController.GetBehaviourInParent<BehaviourY>());
    }

    [Fact]
    public void ParentChildScenarioGetBehaviourInChildren()
    {
        IUniverseObject universeObject = CreateParentChildScenario();

        Assert.NotNull(universeObject.BehaviourController.GetBehaviourInChildren<BehaviourY>());
    }

    [Fact]
    public void ParentChildScenarioGetBehaviourInChildrenOnSameObject()
    {
        IUniverseObject universeObject = CreateParentChildScenario();

        Assert.NotNull(universeObject.BehaviourController.GetBehaviourInChildren<BehaviourX>());
    }

    [Fact]
    public void ParentChildScenarioGetBehaviourInParentOnSameObject()
    {
        IUniverseObject universeObject = CreateParentChildScenario();

        Assert.NotNull(universeObject.BehaviourController.GetBehaviourInParent<BehaviourX>());
    }

    [Fact]
    public void ParentChildScenarioGetBehaviourInParentRaisesExceptionIfNotFound()
    {
        IUniverseObject universeObject = CreateParentChildScenario();

        Assert.Throws<BehaviourNotFoundException>(universeObject.BehaviourController.GetRequiredBehaviourInParent<BehaviourZ>);
    }

    [Fact]
    public void ParentChildScenarioGetBehaviourInChildrenRaisesExceptionIfNotFound()
    {
        IUniverseObject universeObject = CreateParentChildScenario();

        Assert.Throws<BehaviourNotFoundException>(universeObject.BehaviourController.GetRequiredBehaviourInChildren<BehaviourZ>);
    }

    [Fact]
    public void ParentChildScenarioGetBehaviourInChildrenOnSameObjectRaisesExceptionIfNotFound()
    {
        IUniverseObject universeObject = CreateParentChildScenario();

        Assert.Throws<BehaviourNotFoundException>(universeObject.BehaviourController.GetRequiredBehaviourInChildren<BehaviourZ>);
    }

    [Fact]
    public void ParentChildScenarioGetBehaviourInParentOnSameObjectRaisesExceptionIfNotFound()
    {
        IUniverseObject universeObject = CreateParentChildScenario();

        Assert.Throws<BehaviourNotFoundException>(universeObject.BehaviourController.GetRequiredBehaviourInParent<BehaviourZ>);
    }

    #endregion

    private class BehaviourX : BehaviourBase;
    private class BehaviourY : BehaviourBase;
    private class BehaviourZ : BehaviourBase;
}