// findOutputs returns a set of spendable outputs that add up to at least
// `amount` of coins, returning an error if it cannot. It also returns the
// `total`, which is the sum of all the outputs that were found, since it's
// unlikely that it will equal amount exaclty.
func (w *Wallet) findOutputs(amount types.Currency) (knownOutputs []*knownOutput, total types.Currency, err error) {
if amount.IsZero() {
err = errors.New("cannot fund amount <= 0")
return
}
// Iterate through all outputs until enough coins have been assembled.
for _, key := range w.keys {
if !key.spendable {
continue
}
for _, knownOutput := range key.outputs {
if !knownOutput.spendable {
continue
}
if knownOutput.age > w.age-AgeDelay {
continue
}
total = total.Add(knownOutput.output.Value)
knownOutputs = append(knownOutputs, knownOutput)
if total.Cmp(amount) >= 0 {
return
}
}
}
// This code will only be reached if total < amount, meaning insufficient
// funds.
err = modules.LowBalanceErr
return
}