using UnityEngine;
using UnityEngine.EventSystems;

public class Joystick : MonoBehaviour, IPointerDownHandler, IDragHandler, IPointerUpHandler, IBeginDragHandler, IEndDragHandler, IPointerClickHandler
{
	public float horizontal { get { return (_snapX) ? SnapFloat(_input.x, AxisOptions.Horizontal) : _input.x; } }
	public float vertical { get { return (_snapY) ? SnapFloat(_input.y, AxisOptions.Vertical) : _input.y; } }
	public Vector2 direction { get { return new Vector2(horizontal, vertical); } }

	public float handleRange
	{
		get { return _handleRange; }
		set { _handleRange = Mathf.Abs(value); }
	}

	public float invalidRange
	{
		get { return _invalidRange; }
		set { _invalidRange = Mathf.Abs(value); }
	}

	public AxisOptions axisOptions { get { return _axisOptions; } set { _axisOptions = value; } }
	public bool snapX { get { return _snapX; } set { _snapX = value; } }
	public bool snapY { get { return _snapY; } set { _snapY = value; } }

	[SerializeField] private float _handleRange = 1;
	[SerializeField] private float _invalidRange = 0;
	[SerializeField] private AxisOptions _axisOptions = AxisOptions.Both;
	[SerializeField] private bool _snapX = false;
	[SerializeField] private bool _snapY = false;

	[SerializeField] protected RectTransform background = null;
	[SerializeField] protected RectTransform handle = null;
	[SerializeField] protected RectTransform indicator = null;

	private RectTransform _baseRect = null;

	private Canvas _canvas;
	private Camera _camera;

	private Vector2 _input = Vector2.zero;

	private float _pointTime;
	protected int _dragPointerId = int.MaxValue;
	private float _dragPointTime;
	private Vector2[] _dragPosition = new Vector2[2];
	private bool _dragInvalid;

	private void OnEnable()
	{
#if UNITY_WEBGL
		G.KPlatform.ApplicationFocusEvent += OnApplicationFocusEvent;
#endif
	}

	private void OnDisable()
	{
#if UNITY_WEBGL
		G.KPlatform.ApplicationFocusEvent -= OnApplicationFocusEvent;
#endif
	}

	void OnApplicationFocusEvent(bool focus)
	{
		if (focus)
			_dragPointerId = int.MaxValue;
	}

	protected virtual void Start()
	{
		handleRange = _handleRange;
		invalidRange = _invalidRange;
		_baseRect = GetComponent<RectTransform>();
		_canvas = GetComponentInParent<Canvas>();
		if (_canvas == null)
			Debug.LogError("The Joystick is not placed inside a canvas");

		//cam = null;
		if (_canvas.renderMode == RenderMode.ScreenSpaceCamera)
			_camera = _canvas.worldCamera;

		Vector2 center = new Vector2(0.5f, 0.5f);
		background.pivot = center;
		handle.anchorMin = center;
		handle.anchorMax = center;
		handle.pivot = center;
		handle.anchoredPosition = Vector2.zero;
	}

	public virtual void OnPointerDown(PointerEventData eventData)
	{
		_pointTime = Time.unscaledTime;
		//OnDrag(eventData);
	}

	public virtual void OnPointerUp(PointerEventData eventData)
	{
		var magn = _input.magnitude;

		_input = Vector2.zero;
		handle.anchoredPosition = Vector2.zero;

		indicator.gameObject.SetActive(false);
	}

	public void OnPointerClick(PointerEventData eventData)
	{
		if (_dragPointerId != eventData.pointerId)
		{
			if (Time.unscaledTime - _pointTime < 0.36f)
			{
				OnShortTap();
			}
		}
		//OnShortTap(eventData.position);
	}

	public virtual void OnBeginDrag(PointerEventData eventData)
	{
		if (_dragPointerId == int.MaxValue)
		{
			_dragPointerId = eventData.pointerId;
			_dragPointTime = Time.unscaledTime;
			_dragInvalid = true;
		}
	}

	public virtual void OnEndDrag(PointerEventData eventData)
	{
		if (_dragPointerId == eventData.pointerId)
		{
			_dragPointerId = int.MaxValue;

			if (_dragInvalid)
			{
				OnShortTap();
			}
			else
			{
				var iMagn = (eventData.position - eventData.pressPosition).sqrMagnitude;
				var wMagn = (eventData.position - _dragPosition[0]).sqrMagnitude;
				if ((iMagn > 900f && Time.unscaledTime - _dragPointTime < 0.3f) || wMagn > 450f)
				{
					OnArrowAction();
				}
			}
		}
	}

	public void OnDrag(PointerEventData eventData)
	{
		if (_dragPointerId == eventData.pointerId)
		{
			_dragPosition[0] = _dragPosition[1];
			_dragPosition[1] = eventData.position;

			//Vector2 position = RectTransformUtility.WorldToScreenPoint(_camera, background.position);
			Vector2 radius = background.sizeDelta / 2f;

			_input = (eventData.position - eventData.pressPosition) / (radius * _canvas.scaleFactor);

			FormatInput();
			HandleInput(_input.magnitude, _input.normalized, radius, _camera);
			handle.anchoredPosition = _input * radius * _handleRange;
		}
	}

	protected virtual void HandleInput(float magnitude, Vector2 normalised, Vector2 radius, Camera cam)
	{
		if (magnitude > _invalidRange)
		{
			_dragInvalid = false;

			if (magnitude > 1)
				_input = normalised;
			if (indicator)
			{
				indicator.gameObject.SetActive(true);
				indicator.right = _input;
			}
		}
		else
		{
			_input = Vector2.zero;
			if (indicator)
			{
				indicator.gameObject.SetActive(false);
			}
		}
	}

	private void FormatInput()
	{
		if (_axisOptions == AxisOptions.Horizontal)
			_input = new Vector2(_input.x, 0f);
		else if (_axisOptions == AxisOptions.Vertical)
			_input = new Vector2(0f, _input.y);
	}

	private float SnapFloat(float value, AxisOptions snapAxis)
	{
		if (value == 0)
			return value;

		if (_axisOptions == AxisOptions.Both)
		{
			float angle = Vector2.Angle(_input, Vector2.up);
			if (snapAxis == AxisOptions.Horizontal)
			{
				if (angle < 22.5f || angle > 157.5f)
					return 0;
				else
					return (value > 0) ? 1 : -1;
			}
			else if (snapAxis == AxisOptions.Vertical)
			{
				if (angle > 67.5f && angle < 112.5f)
					return 0;
				else
					return (value > 0) ? 1 : -1;
			}
			return value;
		}
		else
		{
			if (value > 0)
				return 1;
			if (value < 0)
				return -1;
		}
		return 0;
	}

	protected Vector2 ScreenPointToAnchoredPosition(Vector2 screenPosition)
	{
		Vector2 localPoint = Vector2.zero;
		if (RectTransformUtility.ScreenPointToLocalPointInRectangle(_baseRect, screenPosition, _camera, out localPoint))
		{
			Vector2 pivotOffset = _baseRect.pivot * _baseRect.sizeDelta;
			return localPoint - (background.anchorMax * _baseRect.sizeDelta) + pivotOffset;
		}
		return Vector2.zero;
	}

	protected virtual void OnArrowAction()
	{
	}

	protected virtual void OnShortTap()
	{
	}

	protected virtual void OnLongTap()
	{
	}

}

public enum AxisOptions { Both, Horizontal, Vertical }