using System;
using UnityEngine;
using UnityEngine.EventSystems;


public class Bar : MonoBehaviour, IPointerEnterHandler, IPointerDownHandler, IPointerExitHandler, IPointerUpHandler {

    private Transform m_transform;

    private SnapPoint m_eastSnapPos;
    private SnapPoint m_westSnapPos;

    private PointerEventData m_pointerEvData;

    // ===========working vars============
    Vector3 offset;
    private Vector3 touchPos;


    internal void Initialize(PointerEventData _eventData) {
        SnapPoint[] snapPoints = GetComponentsInChildren<SnapPoint>();
        foreach (SnapPoint point in snapPoints) {
            if (point.snapDir == SnapPoint.SnapDir.E) {
                if (m_eastSnapPos == null) {
                    m_eastSnapPos = point;
                }
            } else if (point.snapDir == SnapPoint.SnapDir.W) {
                if (m_westSnapPos == null) {
                    m_westSnapPos = point;
                }
            }
        }
        m_transform = this.transform;

        Vector3 screenPos = Input.mousePosition;
        screenPos.z = Grid.instance.transform.position.z - Camera.main.transform.position.z;
        touchPos = Camera.main.ScreenToWorldPoint(screenPos);
        m_transform.localPosition = touchPos;

        var pointer = new PointerEventData(EventSystem.current);
        ExecuteEvents.Execute(this.gameObject, pointer, ExecuteEvents.pointerEnterHandler);
        ExecuteEvents.Execute(this.gameObject, pointer, ExecuteEvents.pointerDownHandler);
    }

    public void OnPointerEnter(PointerEventData eventData) {
        print("Bar::OnPointerEnter()");
    }

    public void OnPointerDown(PointerEventData _eventData) {
        print("Bar::OnPointerDown()");

        m_pointerEvData = _eventData;
        offset = m_transform.localPosition - touchPos;

    }

    public void OnPointerExit(PointerEventData eventData) {
        print("Bar::OnPointerExit()");
    }

    public void OnPointerUp(PointerEventData eventData) {
        print("Bar::OnPointerUp()");
    }


    private void Update() {

        if (m_pointerEvData != null) {

            if (Input.GetMouseButtonUp(0)) { // BETTER FIND A WAY TO USE: public void OnPointerUp(PointerEventData eventData) {m_pointerEvData = null;}
                print("Bar::Update::GetMouseButtonUp()");
                //var pointer = new PointerEventData(EventSystem.current);
                //ExecuteEvents.Execute(this.gameObject, pointer, ExecuteEvents.pointerEnterHandler);
                //ExecuteEvents.Execute(this.gameObject, pointer, ExecuteEvents.pointerDownHandler);
                m_pointerEvData = null;
                return;
            }

            Vector3 screenPos = Input.mousePosition;
            screenPos.z = Grid.instance.transform.position.z - Camera.main.transform.position.z;
            Vector3 newTouchPos = Camera.main.ScreenToWorldPoint(screenPos);

            Vector3 newPos = Vector3.zero;
            newPos.x = newTouchPos.x + offset.x;
            newPos.y = newTouchPos.y + offset.y;


            if (m_transform != null) { // if the object was Initialized at runtime - it can be moved
                m_transform.localPosition = newPos;
            }
        }
    }


}