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

public class TPSCamera : MonoBehaviour {

    public Transform pivot;
    public float minRadius = 5;
    public float maxRadius = 15;
    public float minAzimuth = 0;
    public float maxAzimuth = 360;
    public float minElevation = 5;
    public float maxElevation = 180;
    public float resetTime = 5;

    public float radius = 0;
    public float azimuth = 180;
    public float elevation = 60;

    float defoAzimuth, defoElevation;
    bool isMove;
    float timer;

    // Use this for initialization
    void Start () {
        defoAzimuth = azimuth;
        defoElevation = elevation;
        radius = (minRadius + maxRadius) / 2;
        updatePosition();
	}

	// Update is called once per frame
	void Update () {
        var horizon = -Input.GetAxis("Mouse X");
        var vertical = Input.GetAxis("Mouse Y");

        if (timer > resetTime) {
            azimuth = Mathf.Lerp(azimuth, defoAzimuth, Time.deltaTime);
            elevation = Mathf.Lerp(elevation, defoElevation, Time.deltaTime);
        } else {
            azimuth += horizon;
            elevation += vertical;
        }

        azimuth = Mathf.Clamp(azimuth, minAzimuth, maxAzimuth);
        elevation = Mathf.Clamp(elevation, minElevation, maxElevation);

        var wheel = Input.GetAxis("Mouse ScrollWheel");
        radius += wheel;
        radius = Mathf.Clamp(radius, minRadius, maxRadius);

        if (Mathf.Abs(horizon) > 0 || Mathf.Abs(vertical) > 0 || Mathf.Abs(wheel) > 0) {
            isMove = true;
        } else {
            isMove = false;
        }

        if (!isMove) {
            timer += Time.deltaTime;
        } else {
            timer = 0;
        }
    }

    void LateUpdate() {
        transform.position = updatePosition();
        transform.LookAt(pivot);
    }

    Vector3 updatePosition() {
        var offs = 90;
        var sinA = Mathf.Sin((azimuth + offs) * Mathf.Deg2Rad);
        var cosA = Mathf.Cos((azimuth + offs) * Mathf.Deg2Rad);
        var sinE = Mathf.Sin(elevation * Mathf.Deg2Rad);
        var cosE = Mathf.Cos(elevation * Mathf.Deg2Rad);
        return pivot.position + new Vector3(sinE * cosA, cosE, sinE * sinA) * radius;
    }
}