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

public class ChinarSmoothUi3DCamera : MonoBehaviour {

    public Transform point;
    private Vector3 Tras = Vector3.zero;

    public float distance = 10.0f;
    public float minDistance = 2f;
    public float maxDistance = 15f;
    public float zoomSpeed = 1f;
    public float xSpeed = 250.0f;
    public float ySpeed = 250.0f;
    public bool allowYTilt = true;
    public float yMinLimit = -90f;
    public float yMaxLimit = 90f;

    private float x = 0.0f;
    private float y = 0.0f;
    private float targetX = 0f;
    private float targetY = 0f;
    public float targetDistance = 0f;
    private float xVelocity = 1f;
    private float yVelocity = 1f;
    private float zoomVelocity = 1f;
    void Start () {

        Vector3 tange = transform.eulerAngles;
        targetX = x = tange.x;
        //targetY = y = ClampAngle(tange.y, yMinLimit, yMaxLimit);       
        targetDistance = distance;


    }

    // Update is called once per frame
    
    void LateUpdate() {
		if(point==null)
        {
            return;
        }
        if(Input.GetAxis("Mouse ScrollWheel")>0)
        {
            targetDistance -= zoomSpeed;
        }
        if(Input.GetAxis("Mouse ScrollWheel")<0)
        {
            targetDistance += zoomSpeed;
        }
        targetDistance = Mathf.Clamp(targetDistance, minDistance, maxDistance);
        if(Input.GetMouseButton(1))
        {
            
            targetX+= Input.GetAxis("Mouse X") * xSpeed * 0.02f;           
            if (allowYTilt)
            {
                //targetY -= Input.GetAxis("Mouse Y") * xSpeed * 0.02f;
                //targetY= ClampAngle(targetY, yMinLimit, yMaxLimit);
            }
        }
       x = Mathf.SmoothDampAngle(x, targetX, ref xVelocity, 0.3f);
        //y = allowYTilt ? Mathf.SmoothDampAngle(y, targetY, ref yVelocity, 0.3f) : targetY;
        //Quaternion rotation = Quaternion.Euler(y, x, 0);
        Quaternion rotation = Quaternion.Euler(0, x, 0);
        distance = Mathf.SmoothDamp(distance, targetDistance, ref zoomVelocity, 0.5f);
        Vector3 position = rotation * new Vector3(0.0f, 0.0f, -distance) + point.position + Tras;
        transform.rotation = rotation;
        transform.position = position;
        

    }

    public float ClampAngle(float angle,float min,float max)
    {
        if(angle>360)
        {
            angle -= 360;
        }
        if(angle<-360)
        {
            angle += 360;
        }
        return Mathf.Clamp(angle, min, max);
    }
}