using UnityEngine;
using System.Collections;

//Attach this to a prefab or gameobject that you would like to disable based on distance to another object. Like main camera or player.

public class UnluckDistanceDisabler : MonoBehaviour {
	public int _distanceDisable = 1000;
	public Transform _distanceFrom;
	public bool _distanceFromMainCam;	
	#if UNITY_4_5
	[Tooltip("The amount of time in seconds between checks")]
	#endif
	public float _disableCheckInterval = 10.0f;
	#if UNITY_4_5
	[Tooltip("The amount of time in seconds between checks")]
	#endif
	public float _enableCheckInterval = 1.0f;
	public bool _disableOnStart;
	public bool _useDistanceFade = false;
	public float _fadeRange = 5f;
	int m_fadeDistanceID = Shader.PropertyToID("_FarFadeDistance");
	private int m_invFadeDistanceRangeID = Shader.PropertyToID("_InverseFarFadeRange");
	Material[] m_materials;

	void SetupMaterials()
	{
		int matNum = 0;
		var	meshes = transform.GetComponentsInChildren<Renderer>();
		
		for (int i = 0; i < meshes.Length; i++)
		{
			matNum += meshes[i].materials.Length;
		}

		m_materials = new Material[matNum];
		int cnt = 0;
		for (int i = 0; i < m_materials.Length; i++)
		{
			for (int j=0; j<meshes[i].materials.Length; j++) 
				m_materials[cnt++] = meshes[i].materials[j];
		}

		float invDist = 1f / _fadeRange;
		foreach (var m in m_materials)
		{
			m.SetFloat(m_fadeDistanceID, _distanceDisable);
			m.SetFloat(m_invFadeDistanceRangeID, invDist);
		}
	}
	public void Start()
	{
		if (_distanceFromMainCam){
			_distanceFrom = Camera.main.transform;
		}	
		InvokeRepeating("CheckDisable", _disableCheckInterval + (Random.value * _disableCheckInterval), _disableCheckInterval);
		InvokeRepeating("CheckEnable", _enableCheckInterval + (Random.value * _enableCheckInterval), _enableCheckInterval);	
		Invoke("DisableOnStart", 0.01f);
		if (_useDistanceFade)
			SetupMaterials();
	}
	
	public void DisableOnStart(){
		if (_disableOnStart){
			gameObject.SetActive(false);
		}
	}

	public void CheckDisable(){
		if (gameObject.activeInHierarchy && (transform.position - _distanceFrom.position).sqrMagnitude > _distanceDisable * _distanceDisable){
			gameObject.SetActive(false);			
		}
	}

	public void CheckEnable(){
		if (!gameObject.activeInHierarchy && (transform.position - _distanceFrom.position).sqrMagnitude < _distanceDisable * _distanceDisable){
			gameObject.SetActive(true);	
		}
	}
}