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

public class Snake : MonoBehaviour {
	//Current movement directions
	//(By default it moves to the right)
	Vector2 dir = Vector2.right;
	List<Transform> tail = new List <Transform>();
	//Did the snake eat something?
	bool ate = false;

	// Tail prefab
	public GameObject tailPrefab;

	void OnTriggerEnter2D(Collider2D coll)
	{
		//Food?
		if (coll.name.StartsWith ("FoodPrefab")) {
			//get longer in next Move call
			ate = true;

			//Remove the food
			Destroy (coll.gameObject);
		}
		//Collided with Tail or Border
		else
		{
			//Todo you lose screen
		}

	}
	// Use this for initialization
	void Start ()
	{
		InvokeRepeating ("Move", 0.3f, 0.3f);
	}

	// Update is called once per frame
	void Update ()
	{
		Vector2 tempVector = new Vector2 (0, -90);
		transform.rotation += tempVector;

		//Move in a new direction?
		if (Input.GetKey (KeyCode.RightArrow))
			dir = Vector2.right;
		else if (Input.GetKey (KeyCode.DownArrow))
			dir = Vector2.down;
		else if (Input.GetKey (KeyCode.LeftArrow))
			dir = Vector2.left;
		else if (Input.GetKey (KeyCode.UpArrow))
			dir = Vector2.up;
	}

	void Move()
	{
		//Save current position (Gap will be here)
		Vector2 v = transform.position;

		//Move head into new direction
		transform.Translate(dir);



		//Ate something?
		if (ate)
		{
			//Load Prefab into the world
			GameObject g = (GameObject)Instantiate(tailPrefab, v, Quaternion.identity);

			//Keep track of it in our tail list
			tail.Insert(0, g.transform);

			//Reset the flag
			ate = false;
		}

		//Do we have a tail?
		else if (tail.Count > 0)
		{
			//move Last tail element to where the head was
			tail.Last().position = v;

			//Add to front of list, remove from back
			tail.Insert (0, tail.Last ());
			tail.RemoveAt(tail.Count-1);
		}
	}

}