using Godot;
using System;
using BITKit.Selection;

namespace BITKit
{
	public partial class CameraSelector : EntityBehaviour,ISelector
	{
		[Export] private Node3D node3D;
		[Export] private Control control;
		[Export] private float distance;
		
		private ISelectable _currentSelectable;

		private readonly ValidHandle _isEnabled = new();
		public override void _EnterTree()
		{
			base._EnterTree();
			DI.Register<ISelector>(this);
		}

		public override void _Ready()
		{
			base._Ready();
			if (control is not null)
			{
				control.MouseEntered += () => _isEnabled.RemoveDisableElements(control);
				control.MouseExited += () => _isEnabled.AddDisableElements(control);
			}
			_isEnabled.AddElement(this);
		}

		public override void _Input(InputEvent @event)
		{
			base._Input(@event);
			switch (@event)
			{
				case InputEventMouseButton { Pressed: true}:
					if (_currentSelectable is not null)
					{
						_currentSelectable.SetSelectionState(SelectionState.Selected);
						OnSelected?.Invoke(_currentSelectable);
					}
					break;
			}
		}

		public override void _Process(double delta)
		{
			base._Process(delta);
			if (!_isEnabled)
			{
				if (_currentSelectable is not null)
				{
					_currentSelectable.SetSelectionState(SelectionState.None);
					OnNone?.Invoke(_currentSelectable);
					_currentSelectable = null;
				}
			}
			
			var mousePosition = GetViewport().GetMousePosition();
			var origin = CameraService.Singleton.ProjectRayOrigin(mousePosition);
			var normal = CameraService.Singleton.ProjectRayNormal(mousePosition);
			var end = origin + normal * distance;
			var query = PhysicsRayQueryParameters3D.Create(origin, end);
			query.CollideWithAreas = true;

			var spaceState =node3D.GetWorld3D().DirectSpaceState;
			var result = spaceState.IntersectRay(query);

			ISelectable currentSelected=null;
			if (result.TryGetValue("collider", out var collider))
			{
				var node = (Node3D)collider;
				//var pos = (Vector3)result["position"];

				MathNode.TryGetNodeInParent<ISelectable>(node, out currentSelected);
			}
			
			//BIT4Log.Log($"currentSelected:{currentSelected}");

			switch (currentSelected,_currentSelectable)
			{
				case (not null,not null) when currentSelected != _currentSelectable:
					OnNone?.Invoke(_currentSelectable);
					_currentSelectable.SetSelectionState(SelectionState.None);
					_currentSelectable = currentSelected;
					_currentSelectable.SetSelectionState(SelectionState.Hover);
					OnHover?.Invoke(_currentSelectable);
					break;
				case (null,null): break;
				case (null,not null): 
					_currentSelectable.SetSelectionState(SelectionState.None);
					OnNone?.Invoke(_currentSelectable);
					_currentSelectable = null;
					break;
				case (not null,null):
					_currentSelectable = currentSelected;
					_currentSelectable.SetSelectionState(SelectionState.Hover);
					OnHover?.Invoke(_currentSelectable);
					break;
			}
		}

		public bool TryGetCurrentSelectable(out ISelectable selectable)
		{
			selectable = _currentSelectable;
			return selectable is not null;
		}

		public event Action<ISelectable> OnNone;
		public event Action<ISelectable> OnHover;
		public event Action<ISelectable> OnActive;
		public event Action<ISelectable> OnInactive;
		public event Action<ISelectable> OnFocus;
		public event Action<ISelectable> OnSelected;
		public event Action<ISelectable> OnEnabled;
		public event Action<ISelectable> OnChecked;
		public event Action<ISelectable> OnRoot;
	}

}