using UnityEngine;
using System.Collections;

public class Suspension : MonoBehaviour {

	public GameObject dispWheel;
	public float supLength;
	public float supStrength;
	public float supDampner;

	public Rigidbody carRigid;

	public RaycastHit supHit;
	public float supcompressionRatio;


	//public GameObject carBody;

	// Use this for initialization
	void Start () {
		carRigid = transform.parent.GetComponent<Rigidbody>();

		if (carRigid == null)
			carRigid = transform.root.GetComponentInChildren<Rigidbody>();
	
	}
	
	// Update is called once per frame
	void FixedUpdate () {
		float compRatio = calcCompRatio ();

		if (compRatio !=0)
			calcForce (compRatio);
	
	}

	void Update(){
		wheelDisplay (supcompressionRatio);
	}

	private float calcCompRatio(){
		float compressionRatio = 0;
		RaycastHit hit;
		Ray ray = new Ray (transform.position, -transform.up);

		Debug.DrawRay (ray.origin, ray.direction*supLength, Color.green);

		if (Physics.Raycast (ray, out hit, supLength)) {
			Debug.DrawRay (ray.origin, ray.direction*hit.distance, Color.red);

			compressionRatio = 1-hit.distance/supLength;
		}
		supHit = hit;
		supcompressionRatio = compressionRatio;

		return compressionRatio;

	}

	private void calcForce(float compRatio){

		Vector3 curVel = carRigid.GetPointVelocity (transform.position);
		Vector3 curForce = Vector3.Project (curVel, transform.up);
		Vector3 newForce = Vector3.up * supStrength * compRatio;

		Vector3 deltaForce = newForce - curForce*supDampner	;

		//Debug.Log (deltaForce);
		carRigid.AddForceAtPosition (deltaForce, transform.position);



	}

	private void wheelDisplay(float compRatio){
		if (dispWheel == null)
			return;

		Vector3 newPos = transform.position;

		newPos.y = transform.position.y - ((1 - compRatio) * supLength)+ (0.25f * dispWheel.transform.lossyScale.y);
		dispWheel.transform.position = newPos;

	}


}