backend: add argument to force highest fee rate in tx proposal

Previously, the highest fee rate was automatically applied to all
transaction proposals with a SLIP-24 payment request. For selling
and spending integrations that do not use SLIP-24 payment requests,
there should also be an option to trigger this same behaviour.

This commit replaces the previous conditioning on payment requests
with a general boolean field that is set independently and can be
used for other integrations. This also allows setting a custom fee
rate for transaction proposals with payment requests, if needed.

Author: sutterseba

backend/accounts/account.go

@@ -58,6 +58,7 @@ type TxProposalArgs struct {
 	SelectedUTXOs  map[wire.OutPoint]struct{}
 	Note           string
 	PaymentRequest *PaymentRequest
+	UseHighestFee  bool
 }
 
 // Interface is the API of a Account.

backend/coins/btc/handlers/handlers.go

@@ -454,6 +454,7 @@ func (input *sendTxInput) UnmarshalJSON(jsonBytes []byte) error {
 		Note           string         `json:"note"`
 		Counter        int            `json:"counter"`
 		PaymentRequest *slip24Request `json:"paymentRequest"`
+		UseHighestFee  bool           `json:"useHighestFee"`
 	}{}
 	if err := json.Unmarshal(jsonBytes, &jsonBody); err != nil {
 		return errp.WithStack(err)
@@ -488,6 +489,7 @@ func (input *sendTxInput) UnmarshalJSON(jsonBytes []byte) error {
 		}
 		input.PaymentRequest = paymentRequest
 	}
+	input.UseHighestFee = jsonBody.UseHighestFee
 	return nil
 }
 

backend/coins/btc/transaction.go

@@ -39,8 +39,7 @@ const unitSatoshi = 1e8
 // fee target (priority) if one is given, or the provided args.FeePerKb if the fee taret is
 // `FeeTargetCodeCustom`.
 func (account *Account) getFeePerKb(args *accounts.TxProposalArgs) (btcutil.Amount, error) {
-	isPaymentRequest := args.PaymentRequest != nil
-	if args.FeeTargetCode == accounts.FeeTargetCodeCustom && !isPaymentRequest {
+	if args.FeeTargetCode == accounts.FeeTargetCodeCustom && !args.UseHighestFee {
 		float, err := strconv.ParseFloat(args.CustomFee, 64)
 		if err != nil {
 			return 0, err
@@ -60,7 +59,7 @@ func (account *Account) getFeePerKb(args *accounts.TxProposalArgs) (btcutil.Amou
 	}
 
 	var feeTarget *FeeTarget
-	if isPaymentRequest {
+	if args.UseHighestFee {
 		feeTarget = account.feeTargets().highest()
 	} else {
 		for _, target := range account.feeTargets() {

frontends/web/src/api/account.ts

@@ -325,6 +325,7 @@ export type TTxInput = {
   sendAll: 'yes' | 'no';
   selectedUTXOs: string[];
   paymentRequest: Slip24 | null;
+  useHighestFee: boolean;
 };
 
 export type TTxProposalResult = {

frontends/web/src/routes/account/send/send.tsx

@@ -165,6 +165,7 @@ class Send extends Component<Props, State> {
       sendAll: (this.state.sendAll ? 'yes' : 'no'),
       selectedUTXOs: Object.keys(this.selectedUTXOs),
       paymentRequest: null,
+      useHighestFee: false
     };
   };
 

frontends/web/src/routes/exchange/pocket.tsx

@@ -212,6 +212,7 @@ export const Pocket = ({ code, action }: TProps) => {
       sendAll: 'no',
       selectedUTXOs: [],
       paymentRequest: message.slip24,
+      useHighestFee: true
     };
 
     let result = await proposeTx(code, txInput);