SnekController

using System.Collections;
using System.Collections.Generic;
using UnityEngine.UI;
using UnityEngine;

public class SnekController : MonoBehaviour {

    public List<GameObject> Snake = new List<GameObject> ();

    public int sizeOfSnake;

    public float TimeToMove;


    public string dir = "right";
    public Vector3 tempPos;

    private float elapsedTime;
    public Text elTime;

    private Sprite TurnSprite;
    private Sprite BodySprite;
    private Sprite TailSprite;

    void Start () {
        initSNEK ();
        SpriteLoads ();
    }



    void Update () {
        Inputs ();
        updateSnake ();
        ChangingSprites ();
        ShowTime ();
    }



    void appendToSnake()            //function that instantiate clones of Body
    {
        GameObject part = Instantiate (Resources.Load<GameObject> ("Prefabs/Body")) as GameObject;
        if (!Snake.Contains (part)) {
            Snake.Add (part);
        }
    }

    string CheckCurve(int prev, int current, int next)              //func to check which direction snake turned (if it does)
    {
        float prevPartX = Snake [prev].transform.position.x;
        float prevPartY = Snake [prev].transform.position.y;

        float nextPartX = Snake [next].transform.position.x;
        float nextPartY = Snake [next].transform.position.y;

        float currentPartX = Snake [current].transform.position.x;
        float currentPartY = Snake [current].transform.position.y;

        if (((prevPartX > currentPartX) && (nextPartY < currentPartY)) || ((prevPartY < currentPartY) && (nextPartX > currentPartX))) {
            return "down-to-right";
        }
        else if (((prevPartX > currentPartX) && (nextPartY > currentPartY)) || ((prevPartY > currentPartY && nextPartX > currentPartX))) {
            return "up-to-right";
        }
        else if (((prevPartX < currentPartX) && (nextPartY < currentPartY)) || ((prevPartY < currentPartY) && (nextPartX < currentPartX))) {
            return "down-to-left";
        }
        else if (((prevPartX < currentPartX) && (nextPartY > currentPartY)) || ((prevPartY > currentPartY) && (nextPartX < currentPartX))) {
            return "up-to-left";
        }
        return "same";

    }

    void initSNEK(){                            //func to add proper number of snake parts
        for (int i = 0; i < sizeOfSnake; i++) {
            appendToSnake ();
        }
        for (int j = Snake.Count - 1; j > 0; j--) {
            if (j > 0) {
                Snake [j].transform.position = Snake [j - 1].transform.position;
            }
        }
        Snake [0].transform.position = transform.position;

        if (dir == "up") {
            tempPos.y++;
            transform.localEulerAngles = new Vector3 (0, 0, 90);
        } else if (dir == "left") {
            tempPos.x--;
            transform.localEulerAngles = new Vector3 (0, 0, 180);
        } else if (dir == "down") {
            tempPos.y--;
            transform.localEulerAngles = new Vector3 (0, 0, 270);
        } else if (dir == "right") {
            tempPos.x++;
            transform.localEulerAngles = new Vector3 (0, 0, 0);
        }

        transform.position = tempPos;
    }

    void Inputs()       //func that interpret input to direction of snake head
    {

        if (Input.GetAxis ("Vertical") > 0) {
            dir = "up";
        }
        if (Input.GetAxis ("Vertical") < 0) {
            dir = "down";
        }
        if (Input.GetAxis ("Horizontal") < 0) {
            dir = "left";
        }
        if (Input.GetAxis ("Horizontal") > 0) {
            dir = "right";
        }

    }

    bool ItIsTime()     //func to test if it is time to update snake
    {
        if (elapsedTime >= TimeToMove)
        {
            elapsedTime = 0;
            return true;
        }
        else
            return false;
    }


    void SpriteLoads()      //lol, just like in name, it is loading sprites from resources (also changing sprite of last part)
    {
        TurnSprite = Resources.Load<Sprite> ("Graphics/Turn") as Sprite;
        BodySprite = Resources.Load<Sprite> ("Graphics/Body1") as Sprite;
        TailSprite = Resources.Load<Sprite> ("Graphics/Tail") as Sprite;
        Snake [Snake.Count - 1].GetComponent <SpriteRenderer> ().sprite = TailSprite;
    }

    void SetTime()      //Function to calculate how much time elapsed from last update of snake
    {
        elapsedTime += Time.deltaTime;
    }



    void ShowTime()     //func to "draw" time on screen
    {
        elTime.text = "Time :" + elapsedTime.ToString ();
    }



    void updateSnake()      //function that move our lovely animal, also turning head
    {
        SetTime ();
        if (ItIsTime()) {

            for (int j = Snake.Count - 1; j > 0; j--) {
                if (j > 0) {
                    Snake [j].transform.position = Snake [j - 1].transform.position;
                }
            }


            Snake [0].transform.position = transform.position;


                if (dir == "up") {
                    tempPos.y++;
                    transform.localEulerAngles = new Vector3 (0, 0, 90);
                } else if (dir == "left") {
                    tempPos.x--;
                    transform.localEulerAngles = new Vector3 (0, 0, 180);
                } else if (dir == "down") {
                    tempPos.y--;
                    transform.localEulerAngles = new Vector3 (0, 0, 270);
                } else if (dir == "right") {
                    tempPos.x++;
                    transform.localEulerAngles = new Vector3 (0, 0, 0);
                }
            }

        transform.position = tempPos;
    }

    void ChangingSprites(){         //messy func to set right sprites to right parts of snek :)     I dunno how to improve that part.

        string curve = "";

        for (int j = Snake.Count - 1; j > 0; j--) {
            if (j > 0) {
                if (j < Snake.Count - 1) {
                    curve = CheckCurve (j - 1, j, j + 1);
                    if (curve == "same") {
                        Snake [j].GetComponent <SpriteRenderer> ().sprite = BodySprite;
                    }
                    else if (curve == "up-to-left") {
                        Snake [j].GetComponent <SpriteRenderer> ().sprite = TurnSprite;
                        Snake [j].transform.localEulerAngles = new Vector3 (0, 0, 0);
                    }
                    else if (curve == "up-to-right") {
                        Snake [j].GetComponent <SpriteRenderer> ().sprite = TurnSprite;
                        Snake [j].transform.localEulerAngles = new Vector3 (0, 0, 270);
                    }
                    else if (curve == "down-to-right") {
                        Snake [j].GetComponent <SpriteRenderer> ().sprite = TurnSprite;
                        Snake [j].transform.localEulerAngles = new Vector3 (0, 0, 180);
                    }
                    else if (curve == "down-to-left") {
                        Snake [j].GetComponent <SpriteRenderer> ().sprite = TurnSprite;
                        Snake [j].transform.localEulerAngles = new Vector3 (0, 0, 90);
                    }
                }
            }
        }

        float prevPartX = transform.position.x;
        float prevPartY = transform.position.y;

        float nextPartX = Snake [1].transform.position.x;
        float nextPartY = Snake [1].transform.position.y;

        float currentPartX = Snake [0].transform.position.x;
        float currentPartY = Snake [0].transform.position.y;

        if (((prevPartX > currentPartX) && (nextPartY < currentPartY)) || ((prevPartY < currentPartY) && (nextPartX > currentPartX))) {
            Snake [0].GetComponent <SpriteRenderer> ().sprite = TurnSprite;
            Snake [0].transform.localEulerAngles = new Vector3 (0, 0, 180);
        }
        else if (((prevPartX > currentPartX) && (nextPartY > currentPartY)) || ((prevPartY > currentPartY && nextPartX > currentPartX))) {
            Snake [0].GetComponent <SpriteRenderer> ().sprite = TurnSprite;
            Snake [0].transform.localEulerAngles = new Vector3 (0, 0, 270);
        }
        else if (((prevPartX < currentPartX) && (nextPartY < currentPartY)) || ((prevPartY < currentPartY) && (nextPartX < currentPartX))) {
            Snake [0].GetComponent <SpriteRenderer> ().sprite = TurnSprite;
            Snake [0].transform.localEulerAngles = new Vector3 (0, 0, 90);
        }
        else if (((prevPartX < currentPartX) && (nextPartY > currentPartY)) || ((prevPartY > currentPartY) && (nextPartX < currentPartX))) {
            Snake [0].GetComponent <SpriteRenderer> ().sprite = TurnSprite;
            Snake [0].transform.localEulerAngles = new Vector3 (0, 0, 0);
        }
        else Snake [0].GetComponent <SpriteRenderer> ().sprite = BodySprite;

        float tailY = Snake [Snake.Count - 1].transform.position.y;
        float tailX = Snake [Snake.Count - 1].transform.position.x;

        float nextToTailX = Snake [Snake.Count - 2].transform.position.x;
        float nextToTailY = Snake [Snake.Count - 2].transform.position.y;


        if (nextToTailY > tailY)
            Snake [Snake.Count - 1].transform.localEulerAngles = new Vector3 (0, 0, 0);
        if (nextToTailY < tailY)
            Snake [Snake.Count - 1].transform.localEulerAngles = new Vector3 (0, 0, 180);
        if (nextToTailX > tailX)
            Snake [Snake.Count - 1].transform.localEulerAngles = new Vector3 (0, 0, 270);
        if (nextToTailX < tailX)
            Snake [Snake.Count - 1].transform.localEulerAngles = new Vector3 (0, 0, 90);

    }

}