using UnityEngine.UI;
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.EventSystems;
using UnityEngine.Events;

public class WorldItemSelector : MonoBehaviour
{
    public float moveThreshold = 1;
    public LayerMask layerMask;

    public void SelectScreenPoint(Vector2 screenPoint){
        Ray ray = Camera.main.ScreenPointToRay(screenPoint);
        RaycastHit hit = new RaycastHit();

        if(Physics.Raycast(ray,out hit, Mathf.Infinity, layerMask)){
            Building selectedB = hit.collider.GetComponent<Building>();
            if(selectedB!=null){
                Debug.Log("Selected building : " + selectedB.buildingData.buildingName);
                Selector.selectBuilding(selectedB);
            }else{
                Debug.Log("No target here, Unselecting");
                Selector.selectBuilding(null);
            }
        }else{
            Selector.selectBuilding(null);
        }
    }



    private Vector2 startedPos= Vector2.zero;
    public void OnPointerDown(BaseEventData e){
        PointerEventData ped = (PointerEventData) e as PointerEventData;
        startedPos = ped.position;
    }

    public void OnPointerUp(BaseEventData e){
        PointerEventData ped = (PointerEventData) e as PointerEventData;
        float pointerDiff = Mathf.Abs(ped.position.magnitude - startedPos.magnitude);
        if(pointerDiff < moveThreshold){
            SelectScreenPoint(ped.position);
        }else{
            Debug.Log("Pointer moved (" + pointerDiff+ "), Not gonna select item");
        }
    }
}

public static class Selector{
    public static Building selectedBuilding;
    public static BuildingData selectedData => selectedBuilding.buildingData;
    public static UnityEvent OnSelectedChanged = new UnityEvent();

    public static void selectBuilding(Building e){
        selectedBuilding = e;
        OnSelectedChanged.Invoke();
    }
}