using System.Collections.Generic;
using UnityEngine;

public class CollisionDetection: MonoBehaviour

{
    static private List<KeyValuePair<GameObject, GameObject>> collisionList =new List<KeyValuePair<GameObject, GameObject>>();

    void OnTriggerEnter(Collider other)
    {
        //Debug.Log("Trigger Entered");
        //Get the two Objects involved in the collision
        GameObject col1 = Get.o1(SceneModeManager.SelectedName);//this.gameObject;
        GameObject col2 = other.gameObject;

        //Add to the collison List
        RegisterTouchedItems(collisionList, col1, col2);
    }

    void OnTriggerExit(Collider other)
    {
        //Debug.Log("Trigger Exit");

        //Get the two Objects involved in the collision
        GameObject col1 = this.gameObject;
        GameObject col2 = other.gameObject;

        //Remove from the collison List
        UnRegisterTouchedItems(collisionList, col1, col2);
    }

    public static bool IsTouching(GameObject obj1, GameObject obj2)
    {
        int matchIndex = 0;
        return _itemExist(collisionList, obj1, obj2, ref matchIndex);
    }

    private void UnRegisterTouchedItems(List<KeyValuePair<GameObject, GameObject>> existingObj, GameObject col1, GameObject col2)
    {
        int matchIndex = 0;

        //Remove if it exist
        if (_itemExist(existingObj, col1, col2, ref matchIndex))

        {
            existingObj.RemoveAt(matchIndex);
        }
    }

    private void RegisterTouchedItems(List<KeyValuePair<GameObject, GameObject>> existingObj, GameObject col1, GameObject col2)
    {
        int matchIndex = 0;

        //Add if it doesn't exist
        if (!_itemExist(existingObj, col1, col2, ref matchIndex))

        {
            KeyValuePair<GameObject, GameObject> item = new KeyValuePair<GameObject, GameObject>(col1, col2);
            existingObj.Add(item);
        }
    }

    private static bool _itemExist(List<KeyValuePair<GameObject, GameObject>> existingObj, GameObject col1,
    GameObject col2, ref int matchIndex)
    {
        bool existInList = false;
        for (int i = 0; i < existingObj.Count; i++)
        {
            //Check if key and value exist and vice versa
            if ((existingObj[i].Key == col1 && existingObj[i].Value == col2) ||
                    (existingObj[i].Key == col2 && existingObj[i].Value == col1))
            {
                existInList = true;
                matchIndex = i;
                break;
            }
        }
        return existInList;
    }

}