colourmeok/ColourMeOKGame/Assets/Scripts/GameManager.cs

using UnityEngine;
using UnityEngine.UIElements;

/// <summary>
///     singleton for a single source of truth game state and flow management
/// </summary>
public class GameManager : MonoBehaviour
{
    /// <summary>
    ///     enum for available menus in the game, for use with <c>ShowMenu()</c>
    /// </summary>
    public enum DisplayState
    {
        ScreenStart,
        OverlayAccountManagement,
        OverlaySettings,
        OverlayLeaderboard,
        Game,
        UnassociatedState
    }

    /// <summary>
    ///     singleton pattern: define instance field for accessing the singleton elsewhere
    /// </summary>
    public static GameManager Instance;

    /// <summary>
    ///     the visual element object for game ui (hud/prompts/tooltips)
    /// </summary>
    private VisualElement _ui;

    /// <summary>
    ///     backend object for handling communication with the firebase backend
    /// </summary>
    public Backend Backend;

    /// <summary>
    ///     enforces singleton behaviour; sets doesn't destroy on load and checks for multiple instances
    /// </summary>
    private void Awake()
    {
        // check if instance hasn't been set yet
        if (Instance == null)
        {
            Debug.Log("awake as singleton instance, setting self as the forever-alive instance");
            Instance = this;
            DontDestroyOnLoad(gameObject);
        }
        // check if instance is already set and it's not this instance
        else if (Instance != null && Instance != this)
        {
            Debug.Log("awake as non-singleton instance, destroying self");
            Destroy(gameObject);
        }
    }

    /// <summary>
    ///     called when the game object is enabled
    /// </summary>
    private void OnEnable()
    {
        Backend = new Backend();
        Backend.Initialise();
    }

    /// <summary>
    ///     called when the game object is disabled
    /// </summary>
    private void OnDestroy()
    {
        Backend.Cleanup();
    }
}