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

public class GameObjectPiaker : MonoBehaviour
{
    private IPicked currentPickedGO;//当前拾起的物体

    // Start is called before the first frame update
    void Start()
    {
      
    }
    //注入一个待放置的物体  无法重复注入 即当前正持有物体时 不在捡起新的物体
    public void InjectGO(IPicked picked)
    {
        if (currentPickedGO != null)
        {
            Debug.Log("当前持有物体，无法捡起新的物体");
            return;
        }
        CameraCtrl.Instance.rightButtonEvent += TryStopPick;
        currentPickedGO = picked;
        picked.PickUp();//捡起该物体
    }

    public GameObject GetCurrentPickGO()
    {
        return currentPickedGO?.GetGameObject();
    }

    //移动物体
    public void MoveGO(Vector3 vector)
    {
        if (currentPickedGO==null) return;
        currentPickedGO.GetGameObject().transform.position = vector;
    }

    //尝试放置物体在地面上
    private void TrySetGOOnFloor(Vector3 pos)
    {
        if (currentPickedGO == null) return;
        if (!currentPickedGO.CanPickDown())
        {
            Debug.Log(currentPickedGO.GetGameObject().name + "不能放置在当前位置");
            return;
        }
        currentPickedGO.PickDown();
        currentPickedGO = null;
    }

    //尝试放弃物体
    void TryStopPick()
    {
        if (currentPickedGO == null) return;
        if (!currentPickedGO.CanStopPick())//尝试停止
        { 
            currentPickedGO.StopPick();
            currentPickedGO = null;//删除当前控制的物体时 移除移动/右键空白地面/点击地面事件
            CameraCtrl.Instance.rightButtonEvent -= TryStopPick;
        }
    }

    float doubleClickTime;

    //射线检测捡起或删除物体
    private void Update()
    {
        if (EventSystem.current != null && EventSystem.current.IsPointerOverGameObject()) return; //相机控制时屏蔽UI部分

        if (currentPickedGO == null)//当前物体未放下时 不允许拾取新的物体
        {
            if (Input.GetKey(KeyCode.LeftControl) && Input.GetMouseButtonDown(0))//左Ctrl+左键点击物体时 拾取指定层级的物体
            {
                GameObject hitGo = GetMouseRayHitGO("Flag");
                if (hitGo)
                {
                    IPicked pciked = hitGo.GetComponent<IPicked>();
                    if (pciked != null && pciked.CanPickUpByRay())
                        InjectGO(pciked);
                }
            }
        }
        else//不为空时 实时检测射线位置 在射线检测点击到的地面 尝试放置物体
        {
            RaycastHit hit;//鼠标射线检测
            Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
            if (Physics.Raycast(ray, out hit, 2000, LayerMask.GetMask("Floor")))
            {
                MoveGO(hit.point);
                if (Input.GetMouseButtonDown(0))//左键 点击到地面时 放置该物体
                {
                    TrySetGOOnFloor(hit.point);
                }
            }
        }
    }

    //获取射线检测到的当前物体
    GameObject GetMouseRayHitGO(string layer)
    {
        RaycastHit hit;//鼠标射线检测
        Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
        if (Physics.Raycast(ray, out hit, 2000, LayerMask.GetMask(layer)))//点到指定层级的物体
        {
            return hit.collider.gameObject;
        }
        return null;
    }

}