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;

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

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

		if (isBlocked)
		{
			wantedHeight = target.position.y + altHeight;
			wantedDistance = target.position.z + altDistance;
		}

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

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

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