YachtDice/Assets/Scripts/Shop/ShopModel.cs

using System;
using System.Collections.Generic;

public sealed class ShopModel
{
    private readonly CurrencyBank currencyBank;
    private readonly InventoryModel inventoryModel;
    private readonly HashSet<string> purchasedPermanentIds = new();

    public event Action<ModifierData> OnItemPurchased;

    public ShopModel(CurrencyBank currencyBank, InventoryModel inventoryModel)
    {
        this.currencyBank = currencyBank;
        this.inventoryModel = inventoryModel;
    }

    public bool CanPurchase(ModifierData modifier)
    {
        if (modifier == null) return false;
        if (!currencyBank.CanAfford(modifier.ShopPrice)) return false;

        if (modifier.Durability == ModifierDurability.Permanent &&
            purchasedPermanentIds.Contains(modifier.Id))
            return false;

        return true;
    }

    public bool TryPurchase(ModifierData modifier)
    {
        if (!CanPurchase(modifier)) return false;

        if (!currencyBank.Spend(modifier.ShopPrice)) return false;

        if (modifier.Durability == ModifierDurability.Permanent)
            purchasedPermanentIds.Add(modifier.Id);

        inventoryModel.AddModifier(modifier);
        OnItemPurchased?.Invoke(modifier);
        return true;
    }

    public bool IsPermanentOwned(string modifierId) => purchasedPermanentIds.Contains(modifierId);

    public ShopItemState GetItemState(ModifierData modifier)
    {
        if (modifier == null) return ShopItemState.TooExpensive;

        if (modifier.Durability == ModifierDurability.Permanent &&
            purchasedPermanentIds.Contains(modifier.Id))
            return ShopItemState.Owned;

        if (!currencyBank.CanAfford(modifier.ShopPrice))
            return ShopItemState.TooExpensive;

        return modifier.Durability == ModifierDurability.LimitedUses
            ? ShopItemState.RepurchaseAvailable
            : ShopItemState.Available;
    }

    public void LoadPurchasedPermanentIds(IEnumerable<string> ids)
    {
        purchasedPermanentIds.Clear();
        if (ids != null)
            foreach (var id in ids) purchasedPermanentIds.Add(id);
    }

    public HashSet<string> GetPurchasedPermanentIds() => new(purchasedPermanentIds);
}

public enum ShopItemState
{
    Available,
    TooExpensive,
    Owned,
    RepurchaseAvailable
}