Psuedo IAccount

explain.cs

[Pure]
internal class AccountStateDeltaImpl : IValidatorSupportStateDelta, IAccountStateDelta
{
    [Pure]
    IAccount? IAccountStateView.GetAccount(Address address)
    {
        return UpdatedAccount.TryGetValue(address, out IAccount? account)
            ? account
            : AccountGetter(address);
    }

    [Pure]
    IAccountStateDelta IAccountStateDelta.SetAccount(IAccount account) =>
        UpdateAccount(UpdatedAccount.SetItem(account.address, account));
}

public class Account : IAccount
{
    public long Nonce => _blockChainStates.GetNextTxNonce(Address);
    public Address Address { get; }
    public HashDigest<SHA256> AccountStateRootHash => _accountStorage.Hash;

    private readonly ITrie _accountStorage;
    private readonly IBlockChainStates _blockChainStates;

    public Account(
        Address address,
        IBlockChainStates blockChainStates,
        Trie accountStorage)
    {
        Address = address;
        _accountStorage = accountStorage;
        _blockChainStates = blockChainStates;
    }

    public IValue? GetState(Address address)
    {
        return _accountStorage.Get(address);
    }

    public IAccount SetState(Address address, IValue value)
    {
        return new Account(
            Address,
            _blockChainStates,
            _accountStorage.Set(address, value));
    }
}

public static void ValidateWorldId(this IAccountStateView states, Address avatarAddress, int worldId)
{
    if (worldId > 1)
    {
        if (worldId == GameConfig.MimisbrunnrWorldId)
        {
            throw new InvalidWorldException();
        }

        // Make world first.
        IAccount? worldAccount = states.GetAccount(unlockedWorldIdsAddress);
        if(worldAccount is null)
        {
            throw new InvalidWorldException();
        }

        // Unlock first.
        if(!(worldIdsAccount.GetState(avatarAddress) { } IValue rawIds))
        {
            throw new InvalidWorldException();
        }

        List<int> unlockedWorldIds = rawIds.ToList(StateExtensions.ToInteger);
        if (!unlockedWorldIds.Contains(worldId))
        {
            throw new InvalidWorldException();
        }
    }
}

public static IAccountStateDelta SetWorldId(this IAccountStateDelta states, Address avatarAddress, int unlockedWorldId)
{
    IAccount? workdIdsAccount = state.GetState(unlockedWorldIdsAddress);
    if(worldAccount is null)
    {
        throw new InvalidWorldException();
    }

    worldAccount.SetState(avatarAddress, unlockedWorldId);
    return states.SetAccount(worldAccount);
}