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

public class ArrowTraceDebug : MonoBehaviour
{
    [SerializeField] Transform cameraTF;
    [SerializeField] Transform tracePoints;
    [SerializeField] Button btnTap;
    [SerializeField] ButtonListener btnL;
    [SerializeField] ButtonListener btnR;
    bool isBtnLDown = false;
    bool isBtnRDown = false;
    bool isValid = false;

    public static ArrowTraceDebug ins;

    void Awake() {
        ins = this;
    }

    void OnDestroy() {
        if (ins == this) ins = null;
    }

    void Start()
    {
        btnTap.onClick.AddListener(() => {
            isValid = !isValid;
            CheckValidAndUpdateUI();
        });
        btnL.onPointerDown += (e) => {
            isBtnLDown = true;
        };
        btnL.onPointerUp += (e) => {
            isBtnLDown = false;
        };
        btnR.onPointerDown += (e) => {
            isBtnRDown = true;
        };
        btnR.onPointerUp += (e) => {
            isBtnRDown = false;
        };
        CheckValidAndUpdateUI();
    }

    void Update() {
        if (isValid) {
            if (isBtnLDown) {
                MoveCamera(Time.deltaTime * -20f);
            }
            if (isBtnRDown) {
                MoveCamera(Time.deltaTime * 20f);
            }
        }
    }

    void CheckValidAndUpdateUI() {
        btnTap.GetComponentInChildren<Text>().text = isValid ? "退出查看" : "查看轨迹"; 
        btnL.gameObject.SetActive(isValid);
        btnR.gameObject.SetActive(isValid);
        cameraTF.gameObject.SetActive(isValid);
        tracePoints.gameObject.SetActive(isValid);
    }

    void MoveCamera(float dz) {
        Vector3 pos = cameraTF.transform.localPosition;
        pos.z += dz;
        cameraTF.transform.localPosition = pos;
    }

    Arrow arrow;
    public void OnArrowUpdate(Arrow arrow) {
        if (arrow != this.arrow) {
            this.arrow = arrow;
            ClearTracePoints();
        }
        GameObject.Instantiate(
            this.tracePoints.GetChild(0).gameObject, 
            arrow.transform.position, 
            Quaternion.identity, 
            this.tracePoints
        ).SetActive(true);
    }

    void ClearTracePoints() {
        for (int i = 1; i < this.tracePoints.childCount; i++) {
            Transform t = this.tracePoints.GetChild(i);
            if (t && t.gameObject) Destroy(t.gameObject);
        }
    }
}