using System.Collections;
using System.Collections.Generic;
using System.Linq;
using UnityEngine;

using Assets.Scripts.Touch;
using DigitalRubyShared;

public class TouchController : MonoBehaviour
{
	private readonly Dictionary<int, Vector2> _recordedTouches = new Dictionary<int, Vector2>();
    private readonly Dictionary<int, GestureTouch> _virtualTouches = new Dictionary<int, GestureTouch>();
    private readonly List<int> idsToRemove = new List<int>();

	private void Awake()
	{
		TouchManager.OnStart += OnTouchStarted;
		TouchManager.OnEnd += OnTouchStopped;

		CreateGestures();

		FingersScript.Instance.VirtualTouchCountHandler = GetVirtualTouchCount;
		FingersScript.Instance.VirtualTouchObjectHandler = id => _virtualTouches.ElementAt(id).Value;
		FingersScript.Instance.VirtualTouchUpdateHandler = RemoveExpiredTouches;
		FingersScript.Instance.VirtualTouchResetHandler = () =>
		{
			_recordedTouches.Clear();
			_virtualTouches.Clear();
		};
	}

	private void OnTouchStarted(int touchId)
	{
		Vector2 touchPos = TouchManager.GetPosition(touchId);
		if (touchPos == Vector2.zero) return;

		_recordedTouches[touchId] = touchPos;

		AddTouch(touchId, touchPos, UnityEngine.TouchPhase.Began);
	}

	private void OnTouchStopped(int touchId)
	{
		Vector2 touchPos = TouchManager.GetPosition(touchId);

		AddTouch(touchId, touchPos, UnityEngine.TouchPhase.Ended);

		_recordedTouches.Remove(touchId);
	}

    private int GetVirtualTouchCount()
    {
	    ProcessVirtualTouches();

	    return _virtualTouches.Count;
    }

    private void ProcessVirtualTouches()
    {
	    for (int i = _recordedTouches.Count - 1; i >= 0; i--)
	    {
		    KeyValuePair<int, Vector2> current = _recordedTouches.ElementAt(i);
		    Vector2 pos = TouchManager.GetPosition(current.Key);

		    UnityEngine.TouchPhase phase = Mathf.Approximately(Vector2.Distance(pos, current.Value), 0.01f)
			    ? UnityEngine.TouchPhase.Stationary
			    : UnityEngine.TouchPhase.Moved;

		    AddTouch(current.Key, pos, phase);
	    }
    }

    private void AddTouch(int id, Vector2 position, UnityEngine.TouchPhase phase, float pressure = 1.0f)
    {
	    GestureTouch touch = FingersScript.Instance.GestureTouchFromVirtualTouch(id, position, phase, pressure);
	    _virtualTouches[id] = touch;
    }

    private void CreateGestures()
    {
	    TapGestureRecognizer tap = new TapGestureRecognizer();
	    tap.StateUpdated += gesture =>
	    {
		    Debug.Log($"State updated: {gesture.State}");

		    if (gesture.State == GestureRecognizerState.Ended)
		    {
			    Debug.Log($"Tap detected at {gesture.FocusX}, {gesture.FocusY}");
		    }
	    };
	    FingersScript.Instance.AddGesture(tap);
    }

    private void RemoveExpiredTouches()
    {
	    foreach (GestureTouch touch in _virtualTouches.Values)
	    {
		    if (touch.TouchPhase == DigitalRubyShared.TouchPhase.Ended ||
		        touch.TouchPhase == DigitalRubyShared.TouchPhase.Cancelled ||
		        touch.TouchPhase == DigitalRubyShared.TouchPhase.Unknown)
		    {
			    idsToRemove.Add(touch.Id);
		    }
	    }

	    foreach (int id in idsToRemove)
	    {
		    _recordedTouches.Remove(id);
		    _virtualTouches.Remove(id);
	    }

	    idsToRemove.Clear();
    }
}