using System.Collections.Generic;

public class ResourceRegistry
{
    public static ResourceRegistry Instance { get; private set; }

    private readonly List<Resource> _items = new List<Resource>();

    public Resource[] Items => _items.ToArray();

    public readonly Metal Metal = new Metal();
    public readonly Electronics Electronics = new Electronics();
    public readonly Energy Energy = new Energy();
    public readonly Money Money = new Money();

    static ResourceRegistry()
    {
        Instance = new ResourceRegistry();
    }

    private ResourceRegistry()
    {
        RegisterResource(Metal, true);
        RegisterResource(Electronics, true); // TODO lock back
        RegisterResource(Energy, true); // TODO lock back
        RegisterResource(Money, true); // TODO lock back
    }

    private void RegisterResource(Resource resource, bool unlocked = false)
    {
        _items.Add(resource);
    }
}