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47 lines
1.1 KiB
Go
47 lines
1.1 KiB
Go
package swap
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import (
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"errors"
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"github.com/btcsuite/btcd/chaincfg"
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"github.com/btcsuite/btcutil"
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"github.com/lightningnetwork/lnd/zpay32"
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)
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const (
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// FeeRateTotalParts defines the granularity of the fee rate.
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// Throughout the codebase, we'll use fix based arithmetic to compute
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// fees.
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FeeRateTotalParts = 1e6
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)
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// CalcFee returns the swap fee for a given swap amount.
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func CalcFee(amount, feeBase btcutil.Amount, feeRate int64) btcutil.Amount {
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return feeBase + amount*btcutil.Amount(feeRate)/
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btcutil.Amount(FeeRateTotalParts)
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}
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// FeeRateAsPercentage converts a feerate to a percentage.
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func FeeRateAsPercentage(feeRate int64) float64 {
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return float64(feeRate) / (FeeRateTotalParts / 100)
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}
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// GetInvoiceAmt gets the invoice amount. It requires an amount to be
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// specified.
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func GetInvoiceAmt(params *chaincfg.Params,
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payReq string) (btcutil.Amount, error) {
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swapPayReq, err := zpay32.Decode(
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payReq, params,
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)
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if err != nil {
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return 0, err
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}
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if swapPayReq.MilliSat == nil {
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return 0, errors.New("no amount in invoice")
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}
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return swapPayReq.MilliSat.ToSatoshis(), nil
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}
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