@atomiqlabs/sdk-lib/src/swaps/spv_swaps/SpvFromBTCSwap.ts

Basic SDK functionality library for atomiq

import {isISwapInit, ISwap, ISwapInit, ppmToPercentage} from "../ISwap";
import {
    ChainType,
    SpvWithdrawalClaimedState,
    SpvWithdrawalClosedState,
    SpvWithdrawalFrontedState,
    SpvWithdrawalState,
    SpvWithdrawalStateType
} from "@atomiqlabs/base";
import {SwapType} from "../enums/SwapType";
import {SpvFromBTCWrapper} from "./SpvFromBTCWrapper";
import {getLogger, timeoutPromise, toCoinselectAddressType, toOutputScript} from "../../utils/Utils";
import {getInputType, Transaction} from "@scure/btc-signer";
import {BitcoinTokens, BtcToken, SCToken, TokenAmount, toTokenAmount} from "../../Tokens";
import {Buffer} from "buffer";
import {Fee, FeeType} from "../fee/Fee";
import {IBitcoinWallet, isIBitcoinWallet} from "../../btc/wallet/IBitcoinWallet";
import {IntermediaryAPI} from "../../intermediaries/IntermediaryAPI";
import {IBTCWalletSwap} from "../IBTCWalletSwap";
import {SingleAddressBitcoinWallet} from "../../btc/wallet/SingleAddressBitcoinWallet";

export enum SpvFromBTCSwapState {
    CLOSED = -5,
    FAILED = -4, //Btc tx double-spent, or btc tx inputs double-spent
    DECLINED = -3,
    QUOTE_EXPIRED = -2,
    QUOTE_SOFT_EXPIRED = -1,
    CREATED = 0, //Swap data received from the LP
    SIGNED = 1, //Swap bitcoin tx funded and signed by the client
    POSTED = 2, //Swap bitcoin tx posted to the LP
    BROADCASTED = 3, //LP broadcasted the posted tx
    FRONTED = 4, //Payout on SC was fronted
    BTC_TX_CONFIRMED = 5, //Bitcoin transaction confirmed
    CLAIMED = 6 //Funds claimed
}

export type SpvFromBTCSwapInit = ISwapInit & {
    quoteId: string;
    recipient: string;
    vaultOwner: string;
    vaultId: bigint;
    vaultRequiredConfirmations: number;
    vaultTokenMultipliers: bigint[];
    vaultBtcAddress: string;
    vaultUtxo: string;
    vaultUtxoValue: bigint;
    btcDestinationAddress: string;
    btcAmount: bigint;
    btcAmountSwap: bigint;
    btcAmountGas: bigint;
    minimumBtcFeeRate: number;
    outputTotalSwap: bigint;
    outputSwapToken: string;
    outputTotalGas: bigint;
    outputGasToken: string;
    gasSwapFeeBtc: bigint;
    gasSwapFee: bigint;
    callerFeeShare: bigint;
    frontingFeeShare: bigint;
    executionFeeShare: bigint;
};

export function isSpvFromBTCSwapInit(obj: any): obj is SpvFromBTCSwapInit {
    return typeof obj === "object" &&
        typeof(obj.quoteId)==="string" &&
        typeof(obj.recipient)==="string" &&
        typeof(obj.vaultOwner)==="string" &&
        typeof(obj.vaultId)==="bigint" &&
        typeof(obj.vaultRequiredConfirmations)==="number" &&
        Array.isArray(obj.vaultTokenMultipliers) && obj.vaultTokenMultipliers.reduce((prev: boolean, curr: any) => prev && typeof(curr)==="bigint", true) &&
        typeof(obj.vaultBtcAddress)==="string" &&
        typeof(obj.vaultUtxo)==="string" &&
        typeof(obj.vaultUtxoValue)==="bigint" &&
        typeof(obj.btcDestinationAddress)==="string" &&
        typeof(obj.btcAmount)==="bigint" &&
        typeof(obj.btcAmountSwap)==="bigint" &&
        typeof(obj.btcAmountGas)==="bigint" &&
        typeof(obj.minimumBtcFeeRate)==="number" &&
        typeof(obj.outputTotalSwap)==="bigint" &&
        typeof(obj.outputSwapToken)==="string" &&
        typeof(obj.outputTotalGas)==="bigint" &&
        typeof(obj.outputGasToken)==="string" &&
        typeof(obj.gasSwapFeeBtc)==="bigint" &&
        typeof(obj.gasSwapFee)==="bigint" &&
        typeof(obj.callerFeeShare)==="bigint" &&
        typeof(obj.frontingFeeShare)==="bigint" &&
        typeof(obj.executionFeeShare)==="bigint" &&
        isISwapInit(obj);
}

export class SpvFromBTCSwap<T extends ChainType> extends ISwap<T, SpvFromBTCSwapState> implements IBTCWalletSwap {
    readonly TYPE = SwapType.SPV_VAULT_FROM_BTC;

    readonly wrapper: SpvFromBTCWrapper<T>;

    readonly quoteId: string;
    readonly recipient: string;

    readonly vaultOwner: string;
    readonly vaultId: bigint;
    readonly vaultRequiredConfirmations: number;
    readonly vaultTokenMultipliers: bigint[];

    readonly vaultBtcAddress: string;
    readonly vaultUtxo: string;
    readonly vaultUtxoValue: bigint;

    readonly btcDestinationAddress: string;
    readonly btcAmount: bigint;
    readonly btcAmountSwap: bigint;
    readonly btcAmountGas: bigint;
    readonly minimumBtcFeeRate: number;

    readonly outputTotalSwap: bigint;
    readonly outputSwapToken: string;
    readonly outputTotalGas: bigint;
    readonly outputGasToken: string;

    readonly gasSwapFeeBtc: bigint;
    readonly gasSwapFee: bigint;

    readonly callerFeeShare: bigint;
    readonly frontingFeeShare: bigint;
    readonly executionFeeShare: bigint;

    claimTxId: string;
    frontTxId: string;
    data: T["SpvVaultWithdrawalData"];

    constructor(wrapper: SpvFromBTCWrapper<T>, init: SpvFromBTCSwapInit);
    constructor(wrapper: SpvFromBTCWrapper<T>, obj: any);
    constructor(wrapper: SpvFromBTCWrapper<T>, initOrObject: SpvFromBTCSwapInit | any) {
        if(isSpvFromBTCSwapInit(initOrObject)) initOrObject.url += "/frombtc_spv";
        super(wrapper, initOrObject);
        if(isSpvFromBTCSwapInit(initOrObject)) {
            this.state = SpvFromBTCSwapState.CREATED;
            const vaultAddressType = toCoinselectAddressType(toOutputScript(this.wrapper.options.bitcoinNetwork, this.vaultBtcAddress));
            if(vaultAddressType!=="p2tr" && vaultAddressType!=="p2wpkh" && vaultAddressType!=="p2wsh")
                throw new Error("Vault address type must be of witness type: p2tr, p2wpkh, p2wsh");
        } else {
            this.quoteId = initOrObject.quoteId;
            this.recipient = initOrObject.recipient;
            this.vaultOwner = initOrObject.vaultOwner;
            this.vaultId = BigInt(initOrObject.vaultId);
            this.vaultRequiredConfirmations = initOrObject.vaultRequiredConfirmations;
            this.vaultTokenMultipliers = initOrObject.vaultTokenMultipliers.map(val => BigInt(val));
            this.vaultBtcAddress = initOrObject.vaultBtcAddress;
            this.vaultUtxo = initOrObject.vaultUtxo;
            this.vaultUtxoValue = BigInt(initOrObject.vaultUtxoValue);
            this.btcDestinationAddress = initOrObject.btcDestinationAddress;
            this.btcAmount = BigInt(initOrObject.btcAmount);
            this.btcAmountSwap = BigInt(initOrObject.btcAmountSwap);
            this.btcAmountGas = BigInt(initOrObject.btcAmountGas);
            this.minimumBtcFeeRate = initOrObject.minimumBtcFeeRate;
            this.outputTotalSwap = BigInt(initOrObject.outputTotalSwap);
            this.outputSwapToken = initOrObject.outputSwapToken;
            this.outputTotalGas = BigInt(initOrObject.outputTotalGas);
            this.outputGasToken = initOrObject.outputGasToken;
            this.gasSwapFeeBtc = BigInt(initOrObject.gasSwapFeeBtc);
            this.gasSwapFee = BigInt(initOrObject.gasSwapFee);
            this.callerFeeShare = BigInt(initOrObject.callerFeeShare);
            this.frontingFeeShare = BigInt(initOrObject.frontingFeeShare);
            this.executionFeeShare = BigInt(initOrObject.executionFeeShare);
            this.claimTxId = initOrObject.claimTxId;
            this.frontTxId = initOrObject.frontTxId;
            this.data = initOrObject.data==null ? null : new this.wrapper.spvWithdrawalDataDeserializer(initOrObject.data);
        }
        this.tryCalculateSwapFee();
        this.logger = getLogger("SPVFromBTC("+this.getId()+"): ");
    }

    protected upgradeVersion() { /*NOOP*/ }

    /**
     * In case swapFee in BTC is not supplied it recalculates it based on swap price
     * @protected
     */
    protected tryCalculateSwapFee() {
        if(this.swapFeeBtc==null) {
            this.swapFeeBtc = this.swapFee * this.btcAmountSwap / this.getOutputWithoutFee().rawAmount;
        }

        if(this.pricingInfo.swapPriceUSatPerToken==null) {
            this.pricingInfo = this.wrapper.prices.recomputePriceInfoReceive(
                this.chainIdentifier,
                this.btcAmountSwap,
                this.pricingInfo.satsBaseFee,
                this.pricingInfo.feePPM,
                this.getOutputWithoutFee().rawAmount,
                this.outputSwapToken
            );
        }
    }


    //////////////////////////////
    //// Pricing

    async refreshPriceData(): Promise<void> {
        if(this.pricingInfo==null) return null;
        this.pricingInfo = await this.wrapper.prices.isValidAmountReceive(
            this.chainIdentifier,
            this.btcAmountSwap,
            this.pricingInfo.satsBaseFee,
            this.pricingInfo.feePPM,
            this.getOutputWithoutFee().rawAmount,
            this.outputSwapToken
        );
    }


    //////////////////////////////
    //// Getters & utils

    _getInitiator(): string {
        return this.recipient;
    }

    _getEscrowHash(): string {
        return this.data?.btcTx?.txid;
    }

    getId(): string {
        return this.quoteId+this.randomNonce;
    }

    getQuoteExpiry(): number {
        return this.expiry - 20*1000;
    }

    verifyQuoteValid(): Promise<boolean> {
        return Promise.resolve(this.expiry<Date.now() && this.state===SpvFromBTCSwapState.CREATED);
    }

    getOutputAddress(): string | null {
        return this.recipient;
    }

    getOutputTxId(): string | null {
        return this.frontTxId ?? this.claimTxId;
    }

    getInputTxId(): string | null {
        return this.data?.btcTx?.txid;
    }

    requiresAction(): boolean {
        return this.state===SpvFromBTCSwapState.BTC_TX_CONFIRMED;
    }

    isFinished(): boolean {
        return this.state===SpvFromBTCSwapState.CLAIMED || this.state===SpvFromBTCSwapState.QUOTE_EXPIRED || this.state===SpvFromBTCSwapState.FAILED;
    }

    isClaimable(): boolean {
        return this.state===SpvFromBTCSwapState.BTC_TX_CONFIRMED;
    }

    isSuccessful(): boolean {
        return this.state===SpvFromBTCSwapState.FRONTED || this.state===SpvFromBTCSwapState.CLAIMED;
    }

    isFailed(): boolean {
        return this.state===SpvFromBTCSwapState.FAILED || this.state===SpvFromBTCSwapState.DECLINED || this.state===SpvFromBTCSwapState.CLOSED;
    }

    isQuoteExpired(): boolean {
        return this.state===SpvFromBTCSwapState.QUOTE_EXPIRED;
    }

    isQuoteSoftExpired(): boolean {
        return this.state===SpvFromBTCSwapState.QUOTE_EXPIRED || this.state===SpvFromBTCSwapState.QUOTE_SOFT_EXPIRED;
    }


    //////////////////////////////
    //// Amounts & fees

    protected getInputSwapAmountWithoutFee(): bigint {
        return (this.btcAmountSwap - this.swapFeeBtc) * 100_000n / (100_000n + this.callerFeeShare + this.frontingFeeShare + this.executionFeeShare);
    }

    protected getInputGasAmountWithoutFee(): bigint {
        return (this.btcAmountGas - this.gasSwapFeeBtc) * 100_000n / (100_000n + this.callerFeeShare + this.frontingFeeShare);
    }

    protected getInputAmountWithoutFee(): bigint {
        return this.getInputSwapAmountWithoutFee() + this.getInputGasAmountWithoutFee();
    }

    protected getOutputWithoutFee(): TokenAmount<T["ChainId"], SCToken<T["ChainId"]>> {
        return toTokenAmount(
            (this.outputTotalSwap * (100_000n + this.callerFeeShare + this.frontingFeeShare + this.executionFeeShare) / 100_000n) + this.swapFee,
            this.wrapper.tokens[this.outputSwapToken], this.wrapper.prices
        );
    }

    protected getSwapFee(): Fee<T["ChainId"], BtcToken<false>, SCToken<T["ChainId"]>> {
        const outputToken = this.wrapper.tokens[this.outputSwapToken];
        const gasSwapFeeInOutputToken = this.gasSwapFeeBtc
            * (10n ** BigInt(outputToken.decimals))
            * 1_000_000n
            / this.pricingInfo.swapPriceUSatPerToken;

        const feeWithoutBaseFee = this.swapFeeBtc - this.pricingInfo.satsBaseFee;
        const swapFeePPM = feeWithoutBaseFee * 1000000n / (this.btcAmount - this.swapFeeBtc - this.gasSwapFeeBtc);

        return {
            amountInSrcToken: toTokenAmount(this.swapFeeBtc + this.gasSwapFeeBtc, BitcoinTokens.BTC, this.wrapper.prices),
            amountInDstToken: toTokenAmount(this.swapFee + gasSwapFeeInOutputToken, outputToken, this.wrapper.prices),
            usdValue: (abortSignal?: AbortSignal, preFetchedUsdPrice?: number) =>
                this.wrapper.prices.getBtcUsdValue(this.swapFeeBtc + this.gasSwapFeeBtc, abortSignal, preFetchedUsdPrice),
            composition: {
                base: toTokenAmount(this.pricingInfo.satsBaseFee, BitcoinTokens.BTC, this.wrapper.prices),
                percentage: ppmToPercentage(swapFeePPM)
            }
        };
    }

    protected getWatchtowerFee(): Fee<T["ChainId"], BtcToken<false>, SCToken<T["ChainId"]>> {
        const totalFeeShare = this.callerFeeShare + this.frontingFeeShare;
        const outputToken = this.wrapper.tokens[this.outputSwapToken];
        const watchtowerFeeInOutputToken = this.getInputGasAmountWithoutFee() * totalFeeShare
            * (10n ** BigInt(outputToken.decimals))
            * 1_000_000n
            / this.pricingInfo.swapPriceUSatPerToken
            / 100_000n;
        const feeBtc = this.getInputAmountWithoutFee() * (totalFeeShare + this.executionFeeShare) / 100_000n;
        return {
            amountInSrcToken: toTokenAmount(feeBtc, BitcoinTokens.BTC, this.wrapper.prices),
            amountInDstToken: toTokenAmount((this.outputTotalSwap * (totalFeeShare + this.executionFeeShare) / 100_000n) + watchtowerFeeInOutputToken, outputToken, this.wrapper.prices),
            usdValue: (abortSignal?: AbortSignal, preFetchedUsdPrice?: number) =>
                this.wrapper.prices.getBtcUsdValue(feeBtc, abortSignal, preFetchedUsdPrice)
        };
    }

    getFee(): Fee<T["ChainId"], BtcToken<false>, SCToken<T["ChainId"]>> {
        const swapFee = this.getSwapFee();
        const watchtowerFee = this.getWatchtowerFee();

        return {
            amountInSrcToken: toTokenAmount(swapFee.amountInSrcToken.rawAmount + watchtowerFee.amountInSrcToken.rawAmount, BitcoinTokens.BTC, this.wrapper.prices),
            amountInDstToken: toTokenAmount(swapFee.amountInDstToken.rawAmount + watchtowerFee.amountInDstToken.rawAmount, this.wrapper.tokens[this.outputSwapToken], this.wrapper.prices),
            usdValue: (abortSignal?: AbortSignal, preFetchedUsdPrice?: number) =>
                this.wrapper.prices.getBtcUsdValue(swapFee.amountInSrcToken.rawAmount + watchtowerFee.amountInSrcToken.rawAmount, abortSignal, preFetchedUsdPrice)
        };
    }

    getFeeBreakdown(): [
        {type: FeeType.SWAP, fee: Fee<T["ChainId"], BtcToken<false>, SCToken<T["ChainId"]>>},
        {type: FeeType.NETWORK_OUTPUT, fee: Fee<T["ChainId"], BtcToken<false>, SCToken<T["ChainId"]>>}
    ] {
        return [
            {
                type: FeeType.SWAP,
                fee: this.getSwapFee()
            },
            {
                type: FeeType.NETWORK_OUTPUT,
                fee: this.getWatchtowerFee()
            }
        ];
    }

    getOutput(): TokenAmount<T["ChainId"], SCToken<T["ChainId"]>> {
        return toTokenAmount(this.outputTotalSwap, this.wrapper.tokens[this.outputSwapToken], this.wrapper.prices);
    }

    getGasDropOutput(): TokenAmount<T["ChainId"], SCToken<T["ChainId"]>> {
        return toTokenAmount(this.outputTotalGas, this.wrapper.tokens[this.outputGasToken], this.wrapper.prices);
    }

    getInputWithoutFee(): TokenAmount<T["ChainId"], BtcToken<false>> {
        return toTokenAmount(this.getInputAmountWithoutFee(), BitcoinTokens.BTC, this.wrapper.prices);
    }

    getInput(): TokenAmount<T["ChainId"], BtcToken<false>> {
        return toTokenAmount(this.btcAmount, BitcoinTokens.BTC, this.wrapper.prices);
    }


    //////////////////////////////
    //// Bitcoin tx

    async getTransactionDetails(): Promise<{
        in0txid: string,
        in0vout: number,
        in0sequence: number,
        vaultAmount: bigint,
        vaultScript: Uint8Array,
        in1sequence: number,
        out1script: Uint8Array,
        out2amount: bigint,
        out2script: Uint8Array,
        locktime: number
    }> {
        const [txId, voutStr] = this.vaultUtxo.split(":");

        const vaultScript = toOutputScript(this.wrapper.options.bitcoinNetwork, this.vaultBtcAddress);

        const out2script = toOutputScript(this.wrapper.options.bitcoinNetwork, this.btcDestinationAddress);

        const opReturnData = this.wrapper.contract.toOpReturnData(
            this.recipient,
            [
                this.outputTotalSwap / this.vaultTokenMultipliers[0],
                this.outputTotalGas / this.vaultTokenMultipliers[1]
            ]
        );
        const out1script = Buffer.concat([
            opReturnData.length > 75 ? Buffer.from([0x6a, 0x4c, opReturnData.length]) : Buffer.from([0x6a, opReturnData.length]),
            opReturnData
        ]);

        if(this.callerFeeShare<0n || this.callerFeeShare>0xFFFFFn) throw new Error("Caller fee out of bounds!");
        if(this.frontingFeeShare<0n || this.frontingFeeShare>0xFFFFFn) throw new Error("Fronting fee out of bounds!");
        if(this.executionFeeShare<0n || this.executionFeeShare>0xFFFFFn) throw new Error("Execution fee out of bounds!");

        const nSequence0 = 0x80000000n | (this.callerFeeShare & 0xFFFFFn) | (this.frontingFeeShare & 0b1111_1111_1100_0000_0000n) << 10n;
        const nSequence1 = 0x80000000n | (this.executionFeeShare & 0xFFFFFn) | (this.frontingFeeShare & 0b0000_0000_0011_1111_1111n) << 20n;

        return {
            in0txid: txId,
            in0vout: parseInt(voutStr),
            in0sequence: Number(nSequence0),
            vaultAmount: this.vaultUtxoValue,
            vaultScript,
            in1sequence: Number(nSequence1),
            out1script,
            out2amount: this.btcAmount,
            out2script,
            locktime: 0
        };
    }

    async getPsbt(): Promise<{psbt: Transaction, in1sequence: number}> {
        const res = await this.getTransactionDetails();
        const psbt = new Transaction({
            allowUnknownOutputs: true,
            allowLegacyWitnessUtxo: true,
            lockTime: res.locktime
        });
        psbt.addInput({
            txid: res.in0txid,
            index: res.in0vout,
            witnessUtxo: {
                amount: res.vaultAmount,
                script: res.vaultScript
            },
            sequence: res.in0sequence
        });
        psbt.addOutput({
            amount: res.vaultAmount,
            script: res.vaultScript
        });
        psbt.addOutput({
            amount: 0n,
            script: res.out1script
        });
        psbt.addOutput({
            amount: res.out2amount,
            script: res.out2script
        });
        return {
            psbt,
            in1sequence: res.in1sequence
        };
    }

    async getFundedPsbt(_bitcoinWallet: IBitcoinWallet | { address: string, publicKey: string }, feeRate?: number): Promise<{psbt: Transaction, signInputs: number[]}> {
        let bitcoinWallet: IBitcoinWallet;
        if(isIBitcoinWallet(_bitcoinWallet)) {
            bitcoinWallet = _bitcoinWallet;
        } else {
            bitcoinWallet = new SingleAddressBitcoinWallet(this.wrapper.btcRpc, this.wrapper.options.bitcoinNetwork, _bitcoinWallet);
        }
        if(feeRate!=null) {
            if(feeRate<this.minimumBtcFeeRate) throw new Error("Bitcoin tx fee needs to be at least "+this.minimumBtcFeeRate+" sats/vB");
        } else {
            feeRate = Math.max(this.minimumBtcFeeRate, await bitcoinWallet.getFeeRate());
        }
        let {psbt, in1sequence} = await this.getPsbt();
        psbt = await bitcoinWallet.fundPsbt(psbt, feeRate);
        psbt.updateInput(1, {sequence: in1sequence});
        //Sign every input except the first one
        const signInputs: number[] = [];
        for(let i=1;i<psbt.inputsLength;i++) {
            signInputs.push(i);
        }
        return {psbt, signInputs};
    }

    async submitPsbt(psbt: Transaction): Promise<string> {
        //Ensure not expired
        if(this.expiry<Date.now()) {
            throw new Error("Quote expired!");
        }

        //Ensure valid state
        if(this.state!==SpvFromBTCSwapState.QUOTE_SOFT_EXPIRED && this.state!==SpvFromBTCSwapState.CREATED) {
            throw new Error("Invalid swap state!");
        }

        //Ensure all inputs except the 1st are finalized
        for(let i=1;i<psbt.inputsLength;i++) {
            psbt.finalizeIdx(i);
            if(getInputType(psbt.getInput(i)).txType==="legacy")
                throw new Error("Legacy (non-segwit) inputs are not allowed in the transaction!");
        }
        const btcTx = await this.wrapper.btcRpc.parseTransaction(Buffer.from(psbt.toBytes(true)).toString("hex"));
        const data = await this.wrapper.contract.getWithdrawalData(btcTx);

        this.logger.debug("submitPsbt(): parsed withdrawal data: ", data);

        //Verify correct withdrawal data
        if(
            !data.isRecipient(this.recipient) ||
            data.rawAmounts[0]*this.vaultTokenMultipliers[0] !== this.outputTotalSwap ||
            (data.rawAmounts[1] ?? 0n)*this.vaultTokenMultipliers[1] !== this.outputTotalGas ||
            data.callerFeeRate!==this.callerFeeShare ||
            data.frontingFeeRate!==this.frontingFeeShare ||
            data.executionFeeRate!==this.executionFeeShare ||
            data.getSpentVaultUtxo()!==this.vaultUtxo ||
            BigInt(data.getNewVaultBtcAmount())!==this.vaultUtxoValue ||
            !data.getNewVaultScript().equals(toOutputScript(this.wrapper.options.bitcoinNetwork, this.vaultBtcAddress)) ||
            data.getExecutionData()!=null
        ) {
            throw new Error("Invalid withdrawal tx data submitted!");
        }

        //Verify correct LP output
        const lpOutput = psbt.getOutput(2);
        if(
            lpOutput.amount!==this.btcAmount ||
            !toOutputScript(this.wrapper.options.bitcoinNetwork, this.btcDestinationAddress).equals(Buffer.from(lpOutput.script))
        ) {
            throw new Error("Invalid LP bitcoin output in transaction!");
        }

        //Verify vault utxo not spent yet
        if(await this.wrapper.btcRpc.isSpent(this.vaultUtxo)) {
            throw new Error("Vault UTXO already spent, please create new swap!");
        }

        //Verify tx is parsable by the contract
        try {
            await this.wrapper.contract.checkWithdrawalTx(data);
        } catch (e) {
            throw new Error("Transaction not parsable by the contract: "+(e.message ?? e.toString()));
        }

        //Ensure still not expired
        if(this.expiry<Date.now()) {
            throw new Error("Quote expired!");
        }

        this.data = data;
        this.initiated = true;
        await this._saveAndEmit(SpvFromBTCSwapState.SIGNED);

        try {
            await IntermediaryAPI.initSpvFromBTC(
                this.chainIdentifier,
                this.url,
                {
                    quoteId: this.quoteId,
                    psbtHex: Buffer.from(psbt.toPSBT(0)).toString("hex")
                }
            );
            await this._saveAndEmit(SpvFromBTCSwapState.POSTED);
        } catch (e) {
            await this._saveAndEmit(SpvFromBTCSwapState.DECLINED);
            throw e;
        }

        return this.data.getTxId();
    }

    async estimateBitcoinFee(wallet: IBitcoinWallet, feeRate?: number): Promise<TokenAmount<any, BtcToken<false>>> {
        const txFee = await wallet.getFundedPsbtFee((await this.getPsbt()).psbt, feeRate);
        return toTokenAmount(txFee==null ? null : BigInt(txFee), BitcoinTokens.BTC, this.wrapper.prices);
    }

    async sendBitcoinTransaction(wallet: IBitcoinWallet, feeRate?: number): Promise<string> {
        let {psbt, signInputs} = await this.getFundedPsbt(wallet, feeRate);
        psbt = await wallet.signPsbt(psbt, signInputs);
        return await this.submitPsbt(psbt);
    }


    //////////////////////////////
    //// Bitcoin tx listener

    /**
     * Checks whether a bitcoin payment was already made, returns the payment or null when no payment has been made.
     */
    protected async getBitcoinPayment(): Promise<{
        txId: string,
        confirmations: number,
        targetConfirmations: number
    } | null> {
        if(this.data?.btcTx?.txid==null) return null;

        const result = await this.wrapper.btcRpc.getTransaction(this.data?.btcTx?.txid);
        if(result==null) return null;

        return {
            txId: result.txid,
            confirmations: result.confirmations,
            targetConfirmations: this.vaultRequiredConfirmations
        }
    }

    /**
     * Waits till the bitcoin transaction confirms and swap becomes claimable
     *
     * @param abortSignal Abort signal
     * @param checkIntervalSeconds How often to check the bitcoin transaction
     * @param updateCallback Callback called when txId is found, and also called with subsequent confirmations
     * @throws {Error} if in invalid state (must be CLAIM_COMMITED)
     */
    async waitForBitcoinTransaction(
        abortSignal?: AbortSignal,
        checkIntervalSeconds?: number,
        updateCallback?: (txId: string, confirmations: number, targetConfirmations: number, txEtaMs: number) => void
    ): Promise<string> {
        if(
            this.state!==SpvFromBTCSwapState.POSTED &&
            this.state!==SpvFromBTCSwapState.BROADCASTED &&
            this.state!==SpvFromBTCSwapState.QUOTE_SOFT_EXPIRED
        ) throw new Error("Must be in POSTED or BROADCASTED state!");

        const result = await this.wrapper.btcRpc.waitForTransaction(
            this.data.btcTx.txid,
            this.vaultRequiredConfirmations,
            (confirmations: number, txId: string, txEtaMs: number) => {
                if(updateCallback!=null) updateCallback(txId, confirmations, this.vaultRequiredConfirmations, txEtaMs);
                if(
                    txId!=null &&
                    (this.state===SpvFromBTCSwapState.POSTED || this.state==SpvFromBTCSwapState.QUOTE_SOFT_EXPIRED)
                ) this._saveAndEmit(SpvFromBTCSwapState.BROADCASTED);
            },
            abortSignal,
            checkIntervalSeconds
        );

        if(abortSignal!=null) abortSignal.throwIfAborted();

        if(
            (this.state as SpvFromBTCSwapState)!==SpvFromBTCSwapState.FRONTED &&
            (this.state as SpvFromBTCSwapState)!==SpvFromBTCSwapState.CLAIMED
        ) {
            await this._saveAndEmit(SpvFromBTCSwapState.BTC_TX_CONFIRMED);
        }

        return result.txid;
    }


    //////////////////////////////
    //// Claim

    /**
     * Returns transactions required to claim the swap on-chain (and possibly also sync the bitcoin light client)
     *  after a bitcoin transaction was sent and confirmed
     *
     * @throws {Error} If the swap is in invalid state (must be BTC_TX_CONFIRMED)
     */
    async txsClaim(signer?: T["Signer"]): Promise<T["TX"][]> {
        if(!this.isClaimable()) throw new Error("Must be in BTC_TX_CONFIRMED state!");

        const vaultData = await this.wrapper.contract.getVaultData(this.vaultOwner, this.vaultId);

        const txs = [await this.wrapper.btcRpc.getTransaction(this.data.btcTx.txid)];

        //Trace back from current tx to the vaultData-specified UTXO
        const vaultUtxo = vaultData.getUtxo();
        while(txs[0].ins[0].txid+":"+txs[0].ins[0].vout!==vaultUtxo) {
            txs.unshift(await this.wrapper.btcRpc.getTransaction(txs[0].ins[0].txid));
        }

        //Parse transactions to withdrawal data
        const withdrawalData: T["SpvVaultWithdrawalData"][] = [];
        for(let tx of txs) {
            withdrawalData.push(await this.wrapper.contract.getWithdrawalData(tx));
        }

        return await this.wrapper.contract.txsClaim(
            signer==null ? this._getInitiator() : signer.getAddress(), vaultData,
            withdrawalData.map(tx => {return {tx}}),
            this.wrapper.synchronizer, true
        );
    }

    /**
     * Claims and finishes the swap
     *
     * @param signer Signer to sign the transactions with, can also be different to the initializer
     * @param abortSignal Abort signal to stop waiting for transaction confirmation
     */
    async claim(signer: T["Signer"], abortSignal?: AbortSignal): Promise<string> {
        let txIds: string[];
        try {
            txIds = await this.wrapper.chain.sendAndConfirm(
                signer, await this.txsClaim(signer), true, abortSignal
            );
        } catch (e) {
            this.logger.info("claim(): Failed to claim ourselves, checking swap claim state...");
            if(this.state===SpvFromBTCSwapState.CLAIMED) {
                this.logger.info("claim(): Transaction state is CLAIMED, swap was successfully claimed by the watchtower");
                return this.claimTxId;
            }
            const withdrawalState = await this.wrapper.contract.getWithdrawalState(this.data.btcTx.txid);
            if(withdrawalState.type===SpvWithdrawalStateType.CLAIMED) {
                this.logger.info("claim(): Transaction status is CLAIMED, swap was successfully claimed by the watchtower");
                this.claimTxId = withdrawalState.txId;
                await this._saveAndEmit(SpvFromBTCSwapState.CLAIMED);
                return null;
            }
            throw e;
        }

        this.claimTxId = txIds[0];
        if(
            this.state===SpvFromBTCSwapState.POSTED || this.state===SpvFromBTCSwapState.BROADCASTED ||
            this.state===SpvFromBTCSwapState.BTC_TX_CONFIRMED || this.state===SpvFromBTCSwapState.FAILED ||
            this.state===SpvFromBTCSwapState.FRONTED
        ) {
            await this._saveAndEmit(SpvFromBTCSwapState.CLAIMED);
        }
        return txIds[0];
    }

    /**
     * Periodically checks the chain to see whether the swap was finished (claimed or refunded)
     *
     * @param abortSignal
     * @param interval How often to check (in seconds), default to 5s
     * @protected
     */
    protected async watchdogWaitTillResult(abortSignal?: AbortSignal, interval: number = 5): Promise<
        SpvWithdrawalClaimedState | SpvWithdrawalFrontedState | SpvWithdrawalClosedState
    > {
        let status: SpvWithdrawalState = {type: SpvWithdrawalStateType.NOT_FOUND};
        while(status.type===SpvWithdrawalStateType.NOT_FOUND) {
            await timeoutPromise(interval*1000, abortSignal);
            try {
                status = await this.wrapper.contract.getWithdrawalState(this.data.btcTx.txid);
            } catch (e) {
                this.logger.error("watchdogWaitTillResult(): Error when fetching commit status: ", e);
            }
        }
        if(abortSignal!=null) abortSignal.throwIfAborted();
        return status;
    }

    /**
     * Waits till the swap is successfully executed
     *
     * @param abortSignal AbortSignal
     * @throws {Error} If swap is in invalid state (must be BTC_TX_CONFIRMED)
     * @throws {Error} If the LP refunded sooner than we were able to claim
     */
    async waitTillClaimedOrFronted(abortSignal?: AbortSignal): Promise<void> {
        if(this.state===SpvFromBTCSwapState.CLAIMED || SpvFromBTCSwapState.FRONTED) return Promise.resolve();

        const abortController = new AbortController();
        if(abortSignal!=null) abortSignal.addEventListener("abort", () => abortController.abort(abortSignal.reason));
        const res = await Promise.race([
            this.watchdogWaitTillResult(abortController.signal),
            this.waitTillState(SpvFromBTCSwapState.CLAIMED, "eq", abortController.signal).then(() => 0),
            this.waitTillState(SpvFromBTCSwapState.FRONTED, "eq", abortController.signal).then(() => 1),
            this.waitTillState(SpvFromBTCSwapState.FAILED, "eq", abortController.signal).then(() => 2),
        ]);
        abortController.abort();

        if(typeof(res)==="number") {
            if(res===0) {
                this.logger.debug("waitTillClaimedOrFronted(): Resolved from state change (CLAIMED)");
                return;
            }
            if(res===1) {
                this.logger.debug("waitTillClaimedOrFronted(): Resolved from state change (FRONTED)");
                return;
            }
            if(res===2) {
                this.logger.debug("waitTillClaimedOrFronted(): Resolved from state change (FAILED)");
                throw new Error("Swap failed while waiting for claim or front");
            }
            return;
        }
        this.logger.debug("waitTillClaimedOrFronted(): Resolved from watchdog");

        if(res.type===SpvWithdrawalStateType.FRONTED) {
            if(
                (this.state as SpvFromBTCSwapState)!==SpvFromBTCSwapState.FRONTED ||
                (this.state as SpvFromBTCSwapState)!==SpvFromBTCSwapState.CLAIMED
            ) await this._saveAndEmit(SpvFromBTCSwapState.FRONTED);
        }
        if(res.type===SpvWithdrawalStateType.CLAIMED) {
            if(
                (this.state as SpvFromBTCSwapState)!==SpvFromBTCSwapState.CLAIMED
            ) await this._saveAndEmit(SpvFromBTCSwapState.FRONTED);
        }
        if(res.type===SpvWithdrawalStateType.CLOSED) {
            if(
                (this.state as SpvFromBTCSwapState)!==SpvFromBTCSwapState.CLOSED
            ) await this._saveAndEmit(SpvFromBTCSwapState.CLOSED);
        }
    }

    /**
     * Waits till the bitcoin transaction confirms and swap is claimed
     *
     * @param abortSignal Abort signal
     * @param checkIntervalSeconds How often to check the bitcoin transaction
     * @param updateCallback Callback called when txId is found, and also called with subsequent confirmations
     * @throws {Error} if in invalid state (must be CLAIM_COMMITED)
     */
    async waitTillExecuted(
        abortSignal?: AbortSignal,
        checkIntervalSeconds?: number,
        updateCallback?: (txId: string, confirmations: number, targetConfirmations: number, txEtaMs: number) => void
    ): Promise<void> {
        await this.waitForBitcoinTransaction(abortSignal, checkIntervalSeconds, updateCallback);
        await this.waitTillClaimedOrFronted(abortSignal);
    }


    //////////////////////////////
    //// Storage

    serialize(): any {
        return {
            ...super.serialize(),
            quoteId: this.quoteId,
            recipient: this.recipient,
            vaultOwner: this.vaultOwner,
            vaultId: this.vaultId.toString(10),
            vaultRequiredConfirmations: this.vaultRequiredConfirmations,
            vaultTokenMultipliers: this.vaultTokenMultipliers.map(val => val.toString(10)),
            vaultBtcAddress: this.vaultBtcAddress,
            vaultUtxo: this.vaultUtxo,
            vaultUtxoValue: this.vaultUtxoValue.toString(10),
            btcDestinationAddress: this.btcDestinationAddress,
            btcAmount: this.btcAmount.toString(10),
            btcAmountSwap: this.btcAmountSwap.toString(10),
            btcAmountGas: this.btcAmountGas.toString(10),
            minimumBtcFeeRate: this.minimumBtcFeeRate,
            outputTotalSwap: this.outputTotalSwap.toString(10),
            outputSwapToken: this.outputSwapToken,
            outputTotalGas: this.outputTotalGas.toString(10),
            outputGasToken: this.outputGasToken,
            gasSwapFeeBtc: this.gasSwapFeeBtc.toString(10),
            gasSwapFee: this.gasSwapFee.toString(10),
            callerFeeShare: this.callerFeeShare.toString(10),
            frontingFeeShare: this.frontingFeeShare.toString(10),
            executionFeeShare: this.executionFeeShare.toString(10),

            claimTxId: this.claimTxId,
            frontTxId: this.frontTxId,
            data: this.data?.serialize()
        };
    }


    //////////////////////////////
    //// Swap ticks & sync

    private async syncStateFromBitcoin(save: boolean) {
        if(this.data?.btcTx==null) return false;

        //Check if bitcoin payment was confirmed
        const res = await this.getBitcoinPayment();
        if(res==null) {
            //Check inputs double-spent
            for(let input of this.data.btcTx.ins) {
                if(await this.wrapper.btcRpc.isSpent(input.txid+":"+input.vout, true)) {
                    if(
                        this.state===SpvFromBTCSwapState.SIGNED ||
                        this.state===SpvFromBTCSwapState.POSTED ||
                        this.state===SpvFromBTCSwapState.QUOTE_SOFT_EXPIRED ||
                        this.state===SpvFromBTCSwapState.DECLINED
                    ) {
                        //One of the inputs was double-spent
                        this.state = SpvFromBTCSwapState.QUOTE_EXPIRED;
                    } else {
                        //One of the inputs was double-spent
                        this.state = SpvFromBTCSwapState.FAILED;
                    }
                    if(save) await this._saveAndEmit();
                    return true;
                }
            }
        } else {
            if(res.confirmations>=this.vaultRequiredConfirmations) {
                if(
                    this.state!==SpvFromBTCSwapState.FRONTED &&
                    this.state!==SpvFromBTCSwapState.CLAIMED
                ) {
                    this.state = SpvFromBTCSwapState.BTC_TX_CONFIRMED;
                    if(save) await this._saveAndEmit();
                    return true;
                }
            } else if(
                this.state===SpvFromBTCSwapState.QUOTE_SOFT_EXPIRED ||
                this.state===SpvFromBTCSwapState.POSTED ||
                this.state===SpvFromBTCSwapState.SIGNED ||
                this.state===SpvFromBTCSwapState.DECLINED
            ) {
                this.state = SpvFromBTCSwapState.BROADCASTED;
                if(save) await this._saveAndEmit();
                return true;
            }
        }
        return false;
    }

    /**
     * Checks the swap's state on-chain and compares it to its internal state, updates/changes it according to on-chain
     *  data
     *
     * @private
     */
    private async syncStateFromChain(): Promise<boolean> {
        let changed: boolean = false;

        if(
            this.state===SpvFromBTCSwapState.SIGNED ||
            this.state===SpvFromBTCSwapState.POSTED ||
            this.state===SpvFromBTCSwapState.BROADCASTED ||
            this.state===SpvFromBTCSwapState.QUOTE_SOFT_EXPIRED ||
            this.state===SpvFromBTCSwapState.DECLINED
        ) {
            //Check BTC transaction
            if(await this.syncStateFromBitcoin(false)) changed ||= true;
        }

        if(this.state===SpvFromBTCSwapState.BROADCASTED || this.state===SpvFromBTCSwapState.BTC_TX_CONFIRMED) {
            const status = await this.wrapper.contract.getWithdrawalState(this.data.btcTx.txid);
            this.logger.debug("syncStateFromChain(): status of "+this.data.btcTx.txid, status);
            switch(status.type) {
                case SpvWithdrawalStateType.FRONTED:
                    this.frontTxId = status.txId;
                    this.state = SpvFromBTCSwapState.FRONTED;
                    changed ||= true;
                    break;
                case SpvWithdrawalStateType.CLAIMED:
                    this.claimTxId = status.txId;
                    this.state = SpvFromBTCSwapState.CLAIMED;
                    changed ||= true;
                    break;
                case SpvWithdrawalStateType.CLOSED:
                    this.state = SpvFromBTCSwapState.CLOSED;
                    changed ||= true;
                    break;
            }
        }

        if(
            this.state===SpvFromBTCSwapState.CREATED ||
            this.state===SpvFromBTCSwapState.SIGNED ||
            this.state===SpvFromBTCSwapState.POSTED
        ) {
            if(this.expiry<Date.now()) {
                if(this.state===SpvFromBTCSwapState.CREATED) {
                    this.state = SpvFromBTCSwapState.QUOTE_EXPIRED;
                } else {
                    this.state = SpvFromBTCSwapState.QUOTE_SOFT_EXPIRED;
                }
                changed ||= true;
            }
        }

        return changed;
    }

    async _sync(save?: boolean): Promise<boolean> {
        const changed = await this.syncStateFromChain();
        if(changed && save) await this._saveAndEmit();
        return changed;
    }

    async _tick(save?: boolean): Promise<boolean> {
        if(
            this.state===SpvFromBTCSwapState.CREATED ||
            this.state===SpvFromBTCSwapState.SIGNED
        ) {
            if(this.getQuoteExpiry()<Date.now()) {
                if(this.state===SpvFromBTCSwapState.CREATED) {
                    this.state = SpvFromBTCSwapState.QUOTE_EXPIRED;
                } else {
                    this.state = SpvFromBTCSwapState.QUOTE_SOFT_EXPIRED;
                }
                if(save) await this._saveAndEmit();
                return true;
            }
        }

        if(Math.floor(Date.now()/1000)%120===0) {
            if (
                this.state === SpvFromBTCSwapState.POSTED ||
                this.state === SpvFromBTCSwapState.BROADCASTED
            ) {
                try {
                    //Check if bitcoin payment was confirmed
                    return await this.syncStateFromBitcoin(save);
                } catch (e) {
                    this.logger.error("tickSwap("+this.getId()+"): ", e);
                }
            }
        }
    }

}