using UnityEngine;
using System.Collections;

public class GameManager : MonoBehaviour 
{
	public static GameManager Instance;
	public Transform[] spaceShipPrefebs;

	public Transform explosionEffect;

	public static string HERO_TAG = "Player";
	public static string ENEMY_TAG = "Enemy";
	public static string ALLY_TAG = "Ally";

	void Awake()
	{
		Instance = this;

		int heroShipType = 0;
		if (GlobalObject.Instance) {
			heroShipType = GlobalObject.Instance.shipType;
		} else {
			Debug.LogError("GlobalObject.Instance is NULL!");
		}

		CreateHero(spaceShipPrefebs[heroShipType]);
	}

	public static Transform CreateHero(Transform template)
	{
		Transform tp = Instantiate(template, Vector3.zero, Quaternion.identity) as Transform;
		//tp.tag = HERO_NAME;

		return tp;
	}

	public static Transform CreateEnemy(Transform template)
	{
		Transform tp = Instantiate(template, Vector3.zero, Quaternion.identity) as Transform;
		// Defined in prefabs
		// tp.tag = ENEMY_NAME;
		
		return tp;
	}

	public static Transform CreateAlly(Transform template)
	{
		Transform tp = Instantiate(template, Vector3.zero, Quaternion.identity) as Transform;
		// Defined in prefabs
		// tp.tag = ALLY_NAME;
		
		return tp;
	}

	public static Transform GetHero()
	{
		GameObject heroGameObject = GameObject.FindGameObjectWithTag(HERO_TAG);
		if (heroGameObject != null) {
			return heroGameObject.transform;
		}
		return null;
	}

	private static float evaluateShip(GameObject observer, GameObject enemy)
	{
		Vector3 relativePosition = enemy.transform.position - observer.transform.position;
		float distance = relativePosition.magnitude;
		relativePosition.Normalize();
		
		// -1 0 +1 -> 3 2 1
		float penalty = (2.0f - Vector3.Dot(observer.transform.forward, relativePosition)) / 3.0f;
		float score = distance * penalty * penalty * penalty;

		return score;
	}

	public static GameObject GetClosestShip(string tag, GameObject observer)
	{
		GameObject[] entities = GameObject.FindGameObjectsWithTag(tag);

		GameObject closest = null;
		float bestScore = Mathf.Infinity;

		foreach(GameObject entity in entities) 
		{
			float score = GameManager.evaluateShip(observer, entity);

			if (score < bestScore) {
				bestScore = score;
				closest = entity;
			}
		}

		if (tag == GameManager.ALLY_TAG)
		{
			// Include Hero in Ally list
			GameObject entity = GameObject.FindGameObjectWithTag(HERO_TAG);
			if (entity != null)
			{
				float score = GameManager.evaluateShip(observer, entity);
				
				if (score < bestScore) {
					bestScore = score;
					closest = entity;
				}
			}
		}
		/*
		if (closest) 
		{
			Debug.Log("Found: " + closest.transform.position.ToString());
		} else {
			Debug.Log("Nothing FOUND!!");
		}*/
		return closest;
	}

	public static void HandleWeaponHit(RaycastHit _hit, float hitPower, Transform firedBy, Transform explosionEffect, Quaternion _rotation)
	{
		if(_hit.transform.tag==HERO_TAG && firedBy.tag!=HERO_TAG)
		{
			Life l = _hit.transform.GetComponent<Life>();
			if(l!=null)
				l.getHitted(hitPower);
			CommunicationCenter.Instance.ShowSmallCamera2(true);
		}
		else if(_hit.transform.tag==ENEMY_TAG)
		{
			EnemyShip es = _hit.transform.GetComponent<EnemyShip>();
			if(es!=null)
				es.getHitted(hitPower);
		}
		else if(_hit.transform.tag==ALLY_TAG)
		{
			AllyShip a = _hit.transform.GetComponent<AllyShip>();
			if(a !=null)
				a.getHitted(hitPower);
		}
		else if (_hit.transform.tag!=HERO_TAG && Random.Range(0,20) < 2) 
		{ 
			if(StartGameUI.currentLanguage == 0)
			MessageWindow.Instance.NewMessage ("An asteroid has been destroyed");
			if(StartGameUI.currentLanguage == 1)
			MessageWindow.Instance.NewMessage ("Un asteroide e' stato distrutto");
			
			// Instantiate the explosion effect at the point of impact
			Instantiate(explosionEffect, _hit.transform.position, _rotation);
			// Destroy the game object that we just hit
			Destroy(_hit.transform.gameObject);
		}
	}

	void Start()
	{

	}
	
	// Update is called once per frame
	void Update () 
	{
		if (Input.GetKey (KeyCode.Escape))					
		{
			Application.Quit();
		}

		if (Input.GetKey (KeyCode.Z))
		{
			CommunicationCenter.Instance.ShowSmallCamera1(true);
		}
	}
}