Compliance Without Surveillance

[BasaltContract]
public class TokenContract
{
    private readonly StorageMap<byte[], ulong> _balances = new("balances");
    private readonly StorageValue<ulong> _totalSupply = new("totalSupply");

    [BasaltConstructor]
    public void Initialize(string name, ulong initialSupply)
    {
        _totalSupply.Set(initialSupply);
        _balances.Set(Context.Caller, initialSupply);
        Context.Emit(new TransferEvent { From = null, To = Context.Caller, Amount = initialSupply });
    }

    [BasaltEntrypoint]
    public void Transfer(byte[] to, ulong amount)
    {
        var sender = Context.Caller;
        var balance = _balances.Get(sender);
        Context.Require(balance >= amount, "Insufficient balance");

        _balances.Set(sender, balance - amount);
        _balances.Set(to, _balances.Get(to) + amount);
        Context.Emit(new TransferEvent { From = sender, To = to, Amount = amount });
    }

    [BasaltView]
    public ulong BalanceOf(byte[] account) => _balances.Get(account);

    [BasaltEvent]
    public class TransferEvent
    {
        [Indexed] public byte[] From { get; set; }
        [Indexed] public byte[] To { get; set; }
        public ulong Amount { get; set; }
    }
}