What about caculating avoid_reuse locally (e.g. const bool avoid = !(m_wallet->IsWalletFlagSet(WALLET_FLAG_AVOID_REUSE)); at the beginning of the function), instead of passing it? I thought @achow101's comment was referring to include that too but maybe I'm wrong.

have it always compute the used balance for us rather than having the caller do this extra computation.

My understanding of this part of @achow101 comment was to move the calculation for the used balance to GetBalance(...)

I have updated the PR and added GetFullBalance() which adds used balance to GetBalance(...)

This needs to be in the above if so that the min_depth check is still being done.

My understanding from the above line is min_depth should be zero when calculating full_balance hence I didn't include the statement below in the above if since it uses min_depth provided by the caller

I didn't include the check in this if since tx_depth is always >= 0

I don't think it makes sense to return m_mine_used without respecting min_depth. The original code passes 0 for min_depth because that is the default value but it needs to pass the avoid_reuse flag. It is not because used balance should always calculated with a min depth of 0. Ignoring it is a layer violation here.

When the avoid_reuse flag is passed, tx_credit_mine and tx_credit_mine_used will be the same so the returned used_balance will be 0. That seems incorrect.