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

public class CustomSmoothFollow : MonoBehaviour
{
	public Transform target;
	public float distance = -200.0f;
	public float height = 200.0f;
	public float altDistance = -100.0f;
	public float altHeight = 250.0f;
	public Vector3 damping;
	public string layerToMask = "CameraObstruct";
	private int layerMask;
    [Range (0,360)]
    public float offsetAngle = 90;
	public float shakeStrength = 5f;

	private float shakeCurrent;

	// Use this for initialization
	void Start()
	{
		layerMask = LayerMask.NameToLayer(layerToMask);

		NotificationServer.register("shake camera", shake);
	}

	// Update is called once per frame
	void LateUpdate()
	{
		// Early out if we don't have a target
		if (!target)
			return;

		// Calculate the current and wanted height / XZ pos
		float wantedHeight = target.position.y + height;
		float wantedDistance = target.position.z + distance;
		float wantedSide = target.position.x;

		bool isBlocked = false;
		Vector3 wantedPos = new Vector3(wantedSide, wantedHeight, wantedDistance);

        wantedPos = RotatePointAroundPivot(wantedPos, target.transform.position, offsetAngle);


		RaycastHit hitInfo;
		if (Physics.Raycast(wantedPos, target.position-wantedPos, out hitInfo, (target.position-wantedPos).magnitude * 2f))
		{
//			Debug.LogWarning (hitInfo.collider.name + " -- " + hitInfo.collider.gameObject.layer + " -- " + layerMask);
			if (hitInfo.collider.gameObject.layer == layerMask)
				isBlocked = true;
		}

		if (isBlocked)
		{
			wantedPos.y = target.position.y + altHeight;
			wantedPos.z = target.position.z + altDistance;
			wantedPos.x = target.position.x;
			wantedPos = RotatePointAroundPivot(wantedPos, target.transform.position, offsetAngle);
		}

		float currentHeight = transform.position.y;
		float currentDistance = transform.position.z;
		float currentSide = transform.position.x;



		// Damp the height
		currentHeight = Mathf.Lerp(currentHeight, wantedPos.y, damping.y * Time.deltaTime);
		currentDistance = Mathf.Lerp(currentDistance, wantedPos.z, damping.z * Time.deltaTime);
		currentSide = Mathf.Lerp(currentSide, wantedPos.x, damping.x * Time.deltaTime);

		// Set the position of the camera on the x-z plane to:
		// distance meters behind the target
		transform.position = target.position;



		// Set the height of the camera
		transform.position = new Vector3(currentSide, currentHeight, currentDistance);
		if (shakeCurrent > 0f)
		{
			transform.position +=  Random.insideUnitSphere * shakeStrength;
			shakeCurrent -= Time.deltaTime * shakeStrength;
		}

		// Always look at the target
		Vector3 lookTarget = target.position;
		lookTarget.z = transform.position.z;
		transform.LookAt(lookTarget);
	}

	public void shake()
	{
		shakeCurrent = shakeStrength;
	}

   private Vector3 RotatePointAroundPivot(Vector3 point,Vector3 pivot,float angles ){
   Vector3 dir = point - pivot; // get point direction relative to pivot
   dir = Quaternion.Euler(angles * Vector3.up) * dir; // rotate it
   point = dir + pivot; // calculate rotated point
   return point; // return it
 }
}