using UnityEngine;
using System.Collections;

public enum ScanType {
	ROTATING,
	RANDOM
}

public class TurretController : MonoBehaviour {

	public float rotateSpeed = 20;
	public float lookDistance = 3;
	public float FOV = 90;
	public ScanType ScanMode;	
	float delayTime = 2;
	float elapsedTime = 0;
	
	Vector3 target = Vector3.forward;
	GameObject player;
	
	void Start () {
		player = GameObject.FindGameObjectWithTag("Player");	
	}
	
	void Update () 
	{	
		if( CanSeePlayer() && IsWithinFOV() )
			CenterOnPlayer();
		else
			ScanForPlayer();
	}
	
	void ScanForPlayer()
	{
		switch( ScanMode )
		{
		case ScanType.ROTATING:
			RotatingScan();
			break;
			
		case ScanType.RANDOM:
			RandomScan();			
			break;
			
		default:
			RotatingScan();
			break;
		}
	}
	
	void RotatingScan()
	{
		Debug.DrawRay( transform.position, transform.forward * lookDistance, Color.green );
		transform.Rotate( Vector3.up * rotateSpeed * Time.deltaTime );
	}
	
	void RandomScan()
	{
		elapsedTime += Time.deltaTime;
		
		if( elapsedTime > delayTime ) {
			elapsedTime = 0;
			
			float x = Random.Range( -10, 10);
			float y = Random.Range( -10, 10 );
			
			this.target = new Vector3( x, 0, y );
		
			Debug.Log( string.Format("Getting new scan location, {0} {1}", x, y) );
		}
		
		CenterOnTarget( this.target );
	}

	private bool IsWithinFOV() 
	{
		Vector3 playerLookAtVector = player.transform.position - transform.position;
		float angleBetween = Vector3.Angle( transform.forward, playerLookAtVector );
		
		var distance = Vector3.Distance( transform.position, player.transform.position );
		
		return (angleBetween < FOV && distance < lookDistance);
	}
	
	private void CenterOnPlayer()
	{
		Debug.DrawRay( transform.position, transform.forward * lookDistance, Color.red );
		
		var rotate = Quaternion.LookRotation( player.transform.position - transform.position );
		transform.rotation = Quaternion.Slerp( transform.rotation, rotate, 5 * Time.deltaTime );
	}
	
	private void CenterOnTarget( Vector3 target )
	{
		Debug.DrawRay( transform.position, transform.forward * lookDistance, Color.red );
		
		var rotate = Quaternion.LookRotation( target - transform.position );
		transform.rotation = Quaternion.Slerp( transform.rotation, rotate, 5 * Time.deltaTime );
	}
	
	private bool CanSeePlayer()
	{
		Vector3 playerLookAtVector = player.transform.position - transform.position;
		RaycastHit hit = new RaycastHit();
		
		if( Physics.Raycast( transform.position, playerLookAtVector, out hit, lookDistance ) )
			return hit.collider.gameObject.tag == "Player";
		
		return false;
	}
}