using UnityEngine;
using System.Collections;
[ExecuteInEditMode]
public class Follower : MonoBehaviour {
    public Transform leader;

    public bool position = true;
    public bool rotation = true;
    public bool scaling = true;
    public bool useInitRotation = true;

    public float pos_duration = 0.2f;
    public float rot_duration = 0.2f;
    public float scale_duration = 0.2f;

    Quaternion initialRotate = Quaternion.identity;

    Vector3 TargetPosition
    {
        get
        {
            if (leader == null)
                return Vector3.zero;
            if (biasMode == BiasMode.WorldSpace) return leader.position + bias;
            else return leader.TransformPoint(bias);
        }
    }
    public Vector3 bias;
    public enum BiasMode
    {
        TargetLocalSpace,
        WorldSpace
    }
    public BiasMode biasMode = BiasMode.WorldSpace;

    // Use this for initialization
    void Start () {
        //game.hideFlags = HideFlags.DontSave;
        if(useInitRotation)
            initialRotate = transform.rotation;
    }
	
	// Update is called once per frame
	void Update () {
        if (leader == null)
            return;

        float pos_step = Mathf.Clamp01(Time.deltaTime / pos_duration);
        float rot_step = Mathf.Clamp01(Time.deltaTime / rot_duration);
        float scale_step = Mathf.Clamp01(Time.deltaTime / scale_duration);

        if (Application.isPlaying == false)
            pos_step = rot_step = scale_step = 1.0f;

        if (position)
            transform.position = Vector3.Lerp(transform.position, TargetPosition, pos_step);

        if (rotation)
            transform.rotation = Quaternion.Slerp(transform.rotation, leader.rotation * initialRotate, rot_step);

        if(scaling)
            transform.localScale = Vector3.Lerp(transform.localScale, leader.localScale, scale_step);
    }

    private void OnDestroy()
    {
        transform.rotation = initialRotate;
    }

    void OnDrawGizmos()
    {
        Gizmos.color = Color.red;
        Gizmos.DrawLine(transform.position, transform.position + transform.right);
        Gizmos.color = Color.green;
        Gizmos.DrawLine(transform.position, transform.position + transform.up);
        Gizmos.color = Color.blue;
        Gizmos.DrawLine(transform.position, transform.position + transform.forward);
    }
}