simple_coin_selection.py

from random import shuffle


def is_accepted_output(output):
    """Determine, if the output qualifies as input for an Omni transaction.

    Any input with a type other than "pay-to-pubkey-hash" and "pay-to-script-hash"
    invalidates an Omni transaction."""
    return output['type'] == 'pubkeyhash' or output['type'] == 'scripthash'


def select_outputs(unspent_outputs, target_amount, sender):
    """Select outputs to be used as input for an Omni transaction."""
    selected_amount = 0
    selected_outputs = []

    unspent_outputs = shuffle(unspent_outputs)

    for output in unspent_outputs:
        if not is_accepted_output(output):
            continue

        if sender not in output['addresses']:
            continue

        selected_amount += output['amount']
        selected_outputs.append(output)

        if selected_amount >= target_amount:
            break

    # It should then be checked by the caller (...), if the available, selected
    # amount is actually sufficient
    return selected_amount, unspent_outputs