using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using MyTypes;
using TMPro;
using UnityEngine.SceneManagement;

public class GameManager : MonoBehaviour
{
    static GameManager _instance;
    public static GameManager Instance
    {
        get
        {
            if (_instance == null)
            {
                _instance = GameObject.FindObjectOfType<GameManager>();

                if (_instance == null)
                {
                    GameObject container = new GameObject("GameManager");
                    _instance = container.AddComponent<GameManager>();
                }
            }

            return _instance;
        }
    }
    


    //game references
    private MyTypes.MyGrid grid;
    public MyTypes.MyGrid Grid
    {
        get
        {
            return grid;
        }
    }

    [System.NonSerialized]
    public GameObject player;
    public List<GameObject> enemies;
    public List<GameObject> spikes;

    public GameObject scoreCanvas;
    private ScoreSystem scoreSys;
    public ScoreSystem ScoreSys { get { return scoreSys; } }
    public Animator fade;
    public LevelGeneration levelGeneration;

    public bool autoStart = false;
    //Testing
    public bool hardStart = false;
    private int round = 0;

    private bool gameActive = false;


    private void Start()
    {        
        CreateGrid();
        InitializeScore();
        if (SceneManager.GetActiveScene().buildIndex == 1)
        {
            Debug.Log(SceneManager.GetActiveScene().buildIndex);
            StartGame();
        }else if (hardStart){
            StartGame();
        }

        AudioManager.instance.Play("MainMusic");
    }

    public void Lose(){
        AudioManager.instance.Play("GameOver");
        PlayerPrefs.SetInt("Score", scoreSys.Score);
        StartCoroutine(Lose(2f));
    }
    IEnumerator Lose(float delay){
        yield return new WaitForSeconds(delay);
        fade.SetTrigger("FadeIn");
        yield return new WaitForSeconds(1f);
        Loader.Load(4);
    }

    private float timeSinceStart = 0;
    private void Update()
    {
        if (gameActive) {
            timeSinceStart += (Time.deltaTime*(round+1));
            if (timeSinceStart>=1)
            {
                timeSinceStart = 0;
                scoreSys.AddScore(1);
            }
        }
    }

    private void InitializeScore()
    {
        scoreSys = scoreCanvas.GetComponentInChildren<ScoreSystem>();
    }
    private void CreateGrid()
    {

        //grid initialization
        grid = new MyTypes.MyGrid(MyVars.gridWidth, MyVars.gridHeight);

        //grid population
        for (int i = 0; i < MyVars.gridWidth; ++i)
        {
            for (int j = 0; j < MyVars.gridHeight; ++j)
            {
                grid.grid[i, j] = new MyCell(i, j);
                grid.AddAvailableCell(grid.grid[i, j]);
            }
        }
    }

    public void StopGame()
    {
        GameManager.Instance.gameActive = false;
    }
    public void StartGame(){

        GameManager.Instance.player = Spawner.Instance.SpawnPlayer();
        GameManager.Instance.spikes = new List<GameObject>(Spawner.Instance.SpawnSpike((int)MyVars.spikeAmount));
        GameManager.Instance.enemies = new List<GameObject>(Spawner.Instance.SpawnEnemy((int)MyVars.minEnemyAmount)); //add the enemies last since it is relevant for grid cell purposes

        GameManager.Instance.scoreCanvas.SetActive(true);

        GameManager.Instance.gameActive = true;

        if(levelGeneration!=null)
            levelGeneration.StartGeneration();
    }
    public void movePawn(MyPawn pawn, MyCell targetCell)
    {
        grid.movePawn(pawn, targetCell);
    }
    public void movePawn(MyPawn pawn, MyDirection dir)
    {
        Vector2Int pawnPos = pawn.CurrentCell.position;

        //prevent movement if you are on the edge of the screen
        if (pawnPos.x == MyVars.gridWidth - 1 && dir == MyDirection._RIGHT)
            return;
        else if (pawnPos.x == 0 && dir == MyDirection._LEFT)
            return;
        else if (pawnPos.y == MyVars.gridHeight - 1 && dir == MyDirection._UP)
            return;
        else if (pawnPos.y == 0 && dir == MyDirection._DOWN)
            return;


        //look up destination cell
        MyCell targetCell;
        switch (dir)
        {
            default:
            case MyDirection._UP:
                targetCell = grid.grid[pawn.CurrentCell.position.x, pawn.CurrentCell.position.y+1];
                break;
            case MyDirection._DOWN:
                targetCell = grid.grid[pawn.CurrentCell.position.x, pawn.CurrentCell.position.y - 1];
                break;
            case MyDirection._RIGHT:
                targetCell = grid.grid[pawn.CurrentCell.position.x+1, pawn.CurrentCell.position.y];
                break;
            case MyDirection._LEFT:
                targetCell = grid.grid[pawn.CurrentCell.position.x-1, pawn.CurrentCell.position.y];
                break;
        }


        //if cell is empty, proceed
        if (targetCell.Pawn == null)
        {
            grid.movePawn(pawn, targetCell);
        }
    }

    public void SlowTime(bool slowmo)
    {
        if (slowmo)
            Time.timeScale = MyVars.slowTime;
        else
            Time.timeScale = MyVars.defaultTime;
    }

    public void nextRound()
    {
        round++;
        enemies.AddRange(Spawner.Instance.SpawnEnemy((int)Mathf.Min(MyVars.minEnemyAmount+round*MyVars.enemyAmountGrowth, MyVars.maxEnemyAmount), Mathf.Min(MyVars.enemyMaxSpeed, round* MyVars.enemySpeedGrowth)));
    }

    private void ClearGame()
    {
        foreach (GameObject go in enemies)
            Destroy(go);
        enemies.Clear();

        foreach (GameObject go in spikes)
            Destroy(go);
        spikes.Clear();

        scoreSys.Score = 0;

        Destroy(player);

        CreateGrid();
    }

    public void PlayAgain()
    {
        ClearGame();
        StartGame();
        round = 0;
    }
    public void Exit()
    {
#if UNITY_STANDALONE
        //Quit the application
        Application.Quit();
#endif

        //If we are running in the editor
#if UNITY_EDITOR
        //Stop playing the scene
        UnityEditor.EditorApplication.isPlaying = false;
#endif
    }
}