snakes_mp/Assets/Scripts/SnakeController.cs

using System.Collections;
using System.Collections.Generic;
using Photon.Pun;
using UnityEngine;
using UnityEngine.UIElements;

public class SnakeController : MonoBehaviourPunCallbacks
{  
    public GameManager gameManager;
    public Vector2 startOffset = new Vector3(-10,-10);
    public float movingInterval = 0.2f;
    public Vector2 curDirection = Vector3.right;
    public List<SnakePiece> snakePieces = new List<SnakePiece>();
    public List<BendData> bends = new List<BendData>();
    public GameObject snakePiecePrefab;
    public int startingLength = 3;

    public Vector2 fieldSize= new Vector2(160,90);
    float moveTimer;

    public float topEdge =>   transform.position.y + fieldSize.y /2f;
    public float botEdge =>   transform.position.y - fieldSize.y /2f;
    public float leftEdge =>  transform.position.x - fieldSize.x /2f;
    public float rightEdge => transform.position.x + fieldSize.x /2f;

    void Start(){
        snakePieces = new List<SnakePiece>();
        for(int i=0; i < startingLength; i++){
            Vector3 pos = ((Vector2)transform.position - startOffset)-(Vector2.right * i); 
            GameObject newPiece = PhotonNetwork.Instantiate(snakePiecePrefab.name,pos, Quaternion.identity );
            snakePieces.Add(newPiece.GetComponent<SnakePiece>());
        }

        ButtonSet.OnUp   +=OnUp;
        ButtonSet.OnDown +=OnDown;
        ButtonSet.OnLeft +=OnLeft;
        ButtonSet.OnRight+=OnRight;

    }

    private void OnDestroy() {
        ButtonSet.OnUp   -=OnUp;
        ButtonSet.OnDown -=OnDown;
        ButtonSet.OnLeft -=OnLeft;
        ButtonSet.OnRight-=OnRight;
    }

    bool kickstarted = false;

    void Update()
    {
        CheckHead();
        if(isDead){return;}

        Move();
        ProcessInput();
    }


    void ProcessInput(){
        if(Input.GetKeyDown(KeyCode.RightArrow)){            
            OnRight();
        }else if(Input.GetKeyDown(KeyCode.LeftArrow)){
            OnLeft();
        }else if(Input.GetKeyDown(KeyCode.UpArrow)){
            OnUp();
        }else if(Input.GetKeyDown(KeyCode.DownArrow)){
            OnDown();
        }
    }

    void OnRight(){
        ChangeDir(Vector2.right);
    }

    void OnLeft(){
        ChangeDir(-Vector2.right);
    }

    void OnUp(){
        ChangeDir(Vector2.up);
    }

    void OnDown(){
        ChangeDir(-Vector2.up);
    }


    public int Score;
    public void AddScore(int amount = 1){
        Score+=amount;
        if(PhotonNetwork.LocalPlayer.CustomProperties.ContainsKey("score")){
            PhotonNetwork.LocalPlayer.CustomProperties["score"]=Score;
        }else{
            PhotonNetwork.LocalPlayer.CustomProperties.Add("score",Score);
        }
        PhotonNetwork.LocalPlayer.SetCustomProperties(PhotonNetwork.LocalPlayer.CustomProperties);
    }

    List<Vector2> moveInputQueue =new List<Vector2>();
    void ChangeDir(Vector2 newDir){
        if(curDirection == -newDir){
            return;
        }
        moveInputQueue.Add(newDir);
    }

    bool queueNewPiece = false;
    void Move(){
        if(moveTimer > 0){
            moveTimer-=Time.deltaTime;
        }else{
            moveTimer = movingInterval;
            if(moveInputQueue.Count >0){
                Vector2 dir = Vector2.zero;
                if(curDirection.x != 0){
                    dir = new Vector2(-curDirection.x, moveInputQueue[0].y);
                }else{
                    dir = new Vector2(moveInputQueue[0].x, -curDirection.y);
                }
                curDirection = moveInputQueue[0];
                moveInputQueue.RemoveAt(0);

                bends.Add(new BendData(){
                    position = snakePieces[0].transform.position,
                    direction = dir
                });
            }
            Vector2 curPosition = snakePieces[0].transform.position;
            Vector2 lastPosition = snakePieces[snakePieces.Count-1].transform.position;

            for(int i=snakePieces.Count-1; i>0; i--){
                Vector3 dir = (snakePieces[i-1].transform.position - snakePieces[i].transform.position).normalized;

                snakePieces[i].direction = dir;
                
                snakePieces[i].isHead=false;
                snakePieces[i].transform.position = snakePieces[i-1].transform.position;
                snakePieces[i].transform.position = snakePieces[i].transform.position;
                BendData bendToRemove = null;
                foreach(BendData bend in bends){
                    if(bend.position == snakePieces[i].transform.position){
                        snakePieces[i].direction = bend.direction;
                        if(i == snakePieces.Count-1){
                            bendToRemove = bend;
                        }
                        break;
                    }
                }

                if(bendToRemove!=null){
                    bends.Remove(bendToRemove);
                }
            }

            if(queueNewPiece){
                GameObject newPiece = PhotonNetwork.Instantiate(snakePiecePrefab.name,lastPosition, Quaternion.identity );
                snakePieces.Add(newPiece.GetComponent<SnakePiece>());
                AddScore();

                queueNewPiece=false;
            }

            snakePieces[0].transform.position = curPosition + curDirection;
            snakePieces[0].direction = curDirection;
            snakePieces[0].isHead=true;
            
            if(snakePieces[0].transform.position.x > rightEdge){
                snakePieces[0].transform.position= new Vector2(leftEdge,snakePieces[0].transform.position.y);
            }else if(snakePieces[0].transform.position.x <leftEdge){
                snakePieces[0].transform.position= new Vector2(rightEdge,snakePieces[0].transform.position.y);
            }

            if(snakePieces[0].transform.position.y > topEdge){
                snakePieces[0].transform.position = new Vector2(snakePieces[0].transform.position.x, botEdge);
            }else if(snakePieces[0].transform.position.y < botEdge){
                snakePieces[0].transform.position = new Vector2(snakePieces[0].transform.position.x, topEdge);
            }
        }
    }
    bool isDead = false;
    void CheckHead(){
        Collider2D[] obstacles = Physics2D.OverlapCircleAll(snakePieces[0].transform.position, 0.25f);
        foreach(Collider2D obstacle in obstacles){
            if(obstacle.GetComponent<SnakePiece>()!=null){
                if(obstacle.transform == snakePieces[0].transform){

                }else{
                    Debug.Log($"Crashed into {obstacle.name}", gameObject);
                    isDead = true;
                    gameManager.OnGameOver();  
                }
            }

            if(obstacle.GetComponent<Fruit>()!=null){
                queueNewPiece=true;
                gameManager.DestroyFruit(obstacle.transform.position);
            }

        }
    }

    private void OnDrawGizmos() {
        Gizmos.DrawWireCube(transform.position, new Vector3(fieldSize.x,fieldSize.y));
        if(snakePieces.Count > 0){
            Gizmos.DrawWireSphere(snakePieces[0].transform.position, 0.25f);
        }
    }

}

[System.Serializable]
public class BendData{
    public Vector3 position;
    public Vector2 direction;
}