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

public class Snake : MonoBehaviour {

    private List<Transform> tail = new List<Transform>();
    private bool ate = false;
    public GameObject tailPrefab;
    public Text scoreText;
    public GameObject gameOverPanel;
    public Button startButton;
    public float speed = 5;
    public Text speedtext;
    private bool gameOver;
    private int score;
    private Vector3 rot;
    private string username = "Ceeyay";
    public Text highscoresUserText;
    public Text highscoresScoreText;

    private Vector3 left = new Vector3(0, 0, 90);
    private Vector3 right = new Vector3(0, 0, -90);
    private Vector3 up = new Vector3(0, 0, 0);
    private Vector3 down = new Vector3(0, 0, 180);

    // Use this for initialization
    void Start() {
        InvokeRepeating("Move", 0.0f, (float)(1 / speed));
        DisplayMenu();
        gameOver = true;
    }
    void Restart() {
        foreach (Transform t in tail) {
            Destroy(t.gameObject);
        }
        tail.Clear();
        ate = false;
        CancelInvoke();
        InvokeRepeating("Move", 0.0f, (float)(1 / speed));
        transform.position = new Vector2(0, 0);
        UpdateScore();
        gameOver = false;
        gameOverPanel.SetActive(false);
        Text startButtonText = startButton.GetComponentInChildren<Text>();
        if (startButtonText.text.Equals("Play")) {
            startButtonText.text = "Restart";
        }
    }

    void GameOver() {
        gameOver = true;
        gameOverPanel.SetActive(true);
        HighScoreManager.SaveHighscore(score, username);
        HighScoreManager.ShowHighscores();
        SpawnFood.DestroyAllFood();
        highscoresUserText.text = username.ToString();
        highscoresScoreText.text = score.ToString();
    }

    void OnTriggerEnter2D(Collider2D coll) {
        //On collision with food
        if (coll.name.StartsWith("FoodPrefab")) {
            //get longer in next Move call
            ate = true;
            SpawnFood.Destroy(coll.gameObject);
            UpdateScore(1);
        }
        //On collision with border
        if (coll.name.StartsWith("Border")) {
            GameOver();
        }
        //On collision with tail
        if (coll.name.StartsWith("Tail")) {
            if (!(coll.transform.position.x == tail[0].position.x && coll.transform.position.y == tail[0].position.y))
                GameOver();
        }
    }

    // Update is called once per frame
    void Update() {
        if (!gameOver) {
            CheckGameInput();
        }
    }

    void CheckGameInput() {
        //Move in a new direction?
        if (Input.GetKey(KeyCode.RightArrow)) {
            if (rot != left || tail.Count == 0) {
                rot = right;
            }
        } else if (Input.GetKey(KeyCode.DownArrow)) {
            if (rot != up || tail.Count == 0) {
                rot = down;
            }
        } else if (Input.GetKey(KeyCode.LeftArrow)) {
            if (rot != right || tail.Count == 0) {
                rot = left;
            }
        } else if (Input.GetKey(KeyCode.UpArrow)) {
            if (rot != down || tail.Count == 0) {
                rot = up;
            }

        }
        transform.rotation = Quaternion.Euler(rot);
    }


    void Move() {
        if (!gameOver) {

            //Save current position (Gap will be here)
            Vector2 previousPos = transform.position;

            //Move forward
            transform.Translate(Vector2.up);

            if (ate) {

                //Load Prefab into the world
                GameObject newTail = Instantiate(tailPrefab, previousPos, Quaternion.identity);

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

                //Reset the flag
                ate = false;
            } else if (tail.Count > 0) { //Do we have a tail?

                //move Last tail element to where the head was
                tail.Last().position = previousPos;

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

    void UpdateScore(int score = 0) {
        if (score == 0) {
            this.score = 0;
        } else {
            this.score += score;
        }
        scoreText.text = this.score.ToString();
    }

    public void SetSpeed(int speedChange) {
        if (speed + speedChange >= 1) {
            speed += speedChange;
        }
        speedtext.text = this.speed.ToString();
    }

    public void StartOver() {
        Restart();
    }


    public void DisplayMenu() {
        gameOverPanel.SetActive(true);
    }

    private void FormatHighscores() {
        List<string> hs = HighScoreManager.GetHighscores();

        StringBuilder username = new StringBuilder();
        StringBuilder score = new StringBuilder();

        for (int i = 0; i > hs.Count; i++) {
            if (i % 2 == 0 || i == 0) {
                if (i != 0) {
                    username.Append(Environment.NewLine);
                    username.Append(i);
                    username.Append(": ");
                } else {
                    username.Append("1: ");
                }
                username.Append(hs[i]);
            } else {
                if (i != 1) {
                    score.Append(Environment.NewLine);
                }
                score.Append(((int)i / 2) + 1);
                score.Append(": ");
                score.Append(hs[i]);
            }
        }
    }
}