using System.Collections;
using System.Collections.Generic;
using UnityEngine;
//Author:ZCG
//CreatTime:12/1/2017
/// <summary>
///物体伸缩（梯子,举臂等）
/// </summary>
public class ObjStretch: MonoBehaviour
{
    private void Start()
    {
        Init();
        initY = objUp[0].localPosition.y;//初始化第一节高度
    }
    private void Update()
    {
        InputControl();
    }
    /// <summary>
    /// 初始化
    /// </summary>
    protected virtual void Init()
    {
       
    }
    /// <summary>
    /// 输入控制
    /// </summary>
    protected virtual void InputControl()
    {
        if (Input.GetKey(KeyCode.LeftShift) && Input.GetKey(KeyCode.W))
            Stretch();
        if (Input.GetKey(KeyCode.LeftShift) && Input.GetKey(KeyCode.S))
            Shorten();
    }
    /// <summary>
    /// 根据物体名字关键字获取可伸展的所有物体
    /// </summary>
    /// <returns></returns>
    protected Transform[] GetObj(string keyword)
    {
        List<Transform> childs = new List<Transform>();
        for (int i = 0; i < transform.childCount; i++)
        {
            var child = transform.GetChild(i);
            if (child.name.Contains(keyword))
            {
                childs.Add(child);
            }
        }
        return childs.ToArray();
    }
    [Tooltip("可以伸展的所有物体（不包括固定的那一节）")]
    /// <summary>
    /// 可以伸展的所有梯子（不包括固定的那一节）
    /// </summary>
    public Transform[] objUp;
    private Vector3 speedVec = new Vector3(0, 1, 0);
    [Tooltip("每一节米数")]
    public float nodeLength;
    [Tooltip("速度")]
    public float speed;
    private float initY;
    //第几节索引
    private int index = 0;
    /// <summary>
    /// 延伸
    /// </summary>
    protected virtual void Stretch()
    {
        //根据高度计算操作的第几节
        if (objUp[index].localPosition.y < (index+1) * nodeLength)
        {
            for (int i = index; i < objUp.Length; i++)//所有节一起移动
                objUp[i].localPosition += speed * Time.deltaTime * speedVec;
        }
        else if(index < objUp.Length - 1)
        {
            index++;
            Stretch();
        }
    }
    /// <summary>
    /// 收回
    /// </summary>
    protected virtual void Shorten()
    {
        //当前节是否已经伸展
        if (objUp[index].localPosition.y > initY)
        {
            for (int i = index; i < objUp.Length; i++)//移动每一节阶梯
                objUp[i].localPosition -= speed * Time.deltaTime * speedVec;
        }
        //如果这一节移动完开始移动下一节
        if (index > 0 && objUp[index].localPosition.y <= objUp[index - 1].localPosition.y)
        {
            index--;
            Shorten();
        }
    }
}