using System;
using UnityEngine;
using Level;
using Objects;

public enum GameState
{
    Editing,
    Gameplay
}

public class GameManager : MonoBehaviour
{
    // Static
    private static GameManager instance;
    
    // Events
    public event GameStateChangedHandler GameStateChanged;
    public delegate void GameStateChangedHandler(GameState newState);

    // Public
    public GameState currentState { get; private set; } = GameState.Editing;

    // Private
    [SerializeField] private GameplayUI gameplayUI;
    private LevelData currentLevelData;

    // Properties
    public static GameManager Instance => instance;


    // Methods
    private void Awake()
    {
        if (instance != null && instance != this)
        {
            Destroy(gameObject);
            return;
        }

        instance = this;
    }


    private void Start()
    {
        Player.Instance.PlayerMoved += CheckWin;
    }


    // Used by button OnClick
    public void SetPlayState()
    {
        currentLevelData = LevelBuilder.Instance.CreateLevelData();
        SetState(GameState.Gameplay);
    }


    // Use by button OnClick
    public void SetEditState()
    {
        LevelBuilder.Instance.LoadLevelData(currentLevelData);
        SetState(GameState.Editing);
    }


    private void SetState(GameState newState)
    {
        currentState = newState;

        GameStateChanged?.Invoke(currentState);
    }


    private void CheckWin()
    {
        if (!LevelBuilder.Instance.UnoccupiedTargetExists())
        {
            gameplayUI.ShowWinScreen();
        }
    }
}