@atomiqlabs/chain-evm/src/evm/swaps/modules/EVMSwapInit.ts

EVM specific base implementation

import {SignatureVerificationError, SwapCommitStateType, SwapDataVerificationError} from "@atomiqlabs/base";
import { EVMSwapModule } from "../EVMSwapModule";
import {EVMSwapData} from "../EVMSwapData";
import {keccak256, TransactionRequest, ZeroHash} from "ethers";
import {EVMFees} from "../../chain/modules/EVMFees";
import {EVMSigner} from "../../wallet/EVMSigner";
import {EVMTx} from "../../chain/modules/EVMTransactions";
import {tryWithRetries} from "../../../utils/Utils";

export type EVMPreFetchVerification = {
    safeBlockTime?: number
};

const Initialize = [
    { name: "swapHash", type: "bytes32" },
    { name: "offerer", type: "address" },
    { name: "claimer", type: "address" },
    { name: "amount", type: "uint256" },
    { name: "token", type: "address" },
    { name: "payIn", type: "bool" },
    { name: "payOut", type: "bool" },
    { name: "trackingReputation", type: "bool" },
    { name: "claimHandler", type: "address" },
    { name: "claimData", type: "bytes32" },
    { name: "refundHandler", type: "address" },
    { name: "refundData", type: "bytes32" },
    { name: "securityDeposit", type: "uint256" },
    { name: "claimerBounty", type: "uint256" },
    { name: "depositToken", type: "address" },
    { name: "claimActionHash", type: "bytes32" },
    { name: "deadline", type: "uint256" },
    { name: "extraDataHash", type: "bytes32" }
];

export class EVMSwapInit extends EVMSwapModule {

    private static readonly GasCosts = {
        BASE: 45_000 + 21_000,
        ERC20_TRANSFER: 40_000,
        LP_VAULT_TRANSFER: 10_000
    };

    /**
     * bare Init action based on the data passed in swapData
     *
     * @param sender
     * @param swapData
     * @param timeout
     * @param signature
     * @param feeRate
     * @private
     */
    private async Init(sender: string, swapData: EVMSwapData, timeout: bigint, signature: string, feeRate: string): Promise<TransactionRequest> {
        let value = 0n;
        if(swapData.isPayIn()) {
            if(swapData.isOfferer(sender) && swapData.isToken(this.root.getNativeCurrencyAddress())) value += swapData.getAmount();
        }
        if(swapData.isDepositToken(this.root.getNativeCurrencyAddress())) value += swapData.getTotalDeposit();
        const tx = await this.swapContract.initialize.populateTransaction(swapData.toEscrowStruct(), signature, timeout, "0x"+(swapData.extraData ?? ""), {
            value
        });
        tx.from = sender;
        EVMFees.applyFeeRate(tx, this.getInitGas(swapData), feeRate);
        return tx;
    }

    /**
     * Returns auth prefix to be used with a specific swap, payIn=true & payIn=false use different prefixes (these
     *  actually have no meaning for the smart contract in the EVM case)
     *
     * @param swapData
     * @private
     */
    private getAuthPrefix(swapData: EVMSwapData): string {
        return swapData.isPayIn() ? "claim_initialize" : "initialize";
    }

    public async preFetchForInitSignatureVerification(): Promise<EVMPreFetchVerification> {
        return {
            safeBlockTime: await this.root.Blocks.getBlockTime(this.root.config.safeBlockTag)
        };
    }

    /**
     * Signs swap initialization authorization, using data from preFetchedBlockData if provided & still valid (subject
     *  to SIGNATURE_PREFETCH_DATA_VALIDITY)
     *
     * @param signer
     * @param swapData
     * @param authorizationTimeout
     * @public
     */
    public async signSwapInitialization(
        signer: EVMSigner,
        swapData: EVMSwapData,
        authorizationTimeout: number
    ): Promise<{prefix: string, timeout: string, signature: string}> {
        const authExpiry = Math.floor(Date.now()/1000)+authorizationTimeout;

        const signature = await this.root.Signatures.signTypedMessage(this.contract.contractAddress, signer, Initialize, "Initialize", {
            "swapHash": "0x"+swapData.getEscrowHash(),
            "offerer": swapData.offerer,
            "claimer": swapData.claimer,
            "amount": swapData.amount,
            "token": swapData.token,
            "payIn": swapData.isPayIn(),
            "payOut": swapData.isPayOut(),
            "trackingReputation": swapData.reputation,
            "claimHandler": swapData.claimHandler,
            "claimData": "0x"+swapData.getClaimHash(),
            "refundHandler": swapData.refundHandler,
            "refundData": swapData.refundData.startsWith("0x") ? swapData.refundData : "0x"+swapData.refundData,
            "securityDeposit": swapData.securityDeposit,
            "claimerBounty": swapData.claimerBounty,
            "depositToken": swapData.depositToken,
            "claimActionHash": ZeroHash,
            "deadline": authExpiry,
            "extraDataHash": keccak256("0x"+(swapData.extraData ?? ""))
        });

        return {
            prefix: this.getAuthPrefix(swapData),
            timeout: authExpiry.toString(10),
            signature
        };
    }

    /**
     * Checks whether the provided signature data is valid, using preFetchedData if provided and still valid
     *
     * @param sender
     * @param swapData
     * @param timeout
     * @param prefix
     * @param signature
     * @param preFetchData
     * @public
     */
    public async isSignatureValid(
        sender: string,
        swapData: EVMSwapData,
        timeout: string,
        prefix: string,
        signature: string,
        preFetchData?: EVMPreFetchVerification
    ): Promise<null> {
        if(!swapData.isOfferer(sender) && !swapData.isClaimer(sender))
            throw new SignatureVerificationError("TX sender not offerer nor claimer");

        const signer = swapData.isOfferer(sender) ? swapData.claimer : swapData.offerer;

        if(await this.contract.isExpired(sender, swapData)) {
            throw new SignatureVerificationError("Swap will expire too soon!");
        }

        if(prefix!==this.getAuthPrefix(swapData)) throw new SignatureVerificationError("Invalid prefix");

        const currentTimestamp = BigInt(Math.floor(Date.now() / 1000));
        const timeoutBN = BigInt(timeout);
        const isExpired = (timeoutBN - currentTimestamp) < BigInt(this.contract.authGracePeriod);
        if (isExpired) throw new SignatureVerificationError("Authorization expired!");
        if(await this.isSignatureExpired(timeout, preFetchData)) throw new SignatureVerificationError("Authorization expired!");

        const valid = await this.root.Signatures.isValidSignature(this.contract.contractAddress, signature, signer, Initialize, "Initialize", {
            "swapHash": "0x"+swapData.getEscrowHash(),
            "offerer": swapData.offerer,
            "claimer": swapData.claimer,
            "amount": swapData.amount,
            "token": swapData.token,
            "payIn": swapData.isPayIn(),
            "payOut": swapData.isPayOut(),
            "trackingReputation": swapData.reputation,
            "claimHandler": swapData.claimHandler,
            "claimData": "0x"+swapData.getClaimHash(),
            "refundHandler": swapData.refundHandler,
            "refundData": swapData.refundData.startsWith("0x") ? swapData.refundData : "0x"+swapData.refundData,
            "securityDeposit": swapData.securityDeposit,
            "claimerBounty": swapData.claimerBounty,
            "depositToken": swapData.depositToken,
            "claimActionHash": ZeroHash,
            "deadline": timeoutBN,
            "extraDataHash": keccak256("0x"+(swapData.extraData ?? ""))
        });

        if(!valid) throw new SignatureVerificationError("Invalid signature!");

        return null;
    }

    /**
     * Gets expiry of the provided signature data, this is a minimum of slot expiry & swap signature expiry
     *
     * @param timeout
     * @public
     */
    public async getSignatureExpiry(
        timeout: string
    ): Promise<number> {
        const now = Date.now();
        const timeoutExpiryTime = (parseInt(timeout)-this.contract.authGracePeriod)*1000;

        if(timeoutExpiryTime<now) return 0;

        return timeoutExpiryTime;
    }

    /**
     * Checks whether signature is expired for good, compares the timestamp to the current "pending" block timestamp
     *
     * @param timeout
     * @param preFetchData
     * @public
     */
    public async isSignatureExpired(
        timeout: string,
        preFetchData?: EVMPreFetchVerification
    ): Promise<boolean> {
        if(preFetchData==null || preFetchData.safeBlockTime==null) {
            preFetchData = await this.preFetchForInitSignatureVerification();
        }
        return preFetchData.safeBlockTime > parseInt(timeout);
    }

    /**
     * Creates init transaction with a valid signature from an LP
     *
     * @param sender
     * @param swapData swap to initialize
     * @param timeout init signature timeout
     * @param prefix init signature prefix
     * @param signature init signature
     * @param skipChecks whether to skip signature validity checks
     * @param feeRate fee rate to use for the transaction
     */
    public async txsInit(
        sender: string,
        swapData: EVMSwapData,
        timeout: string,
        prefix: string,
        signature: string,
        skipChecks?: boolean,
        feeRate?: string
    ): Promise<EVMTx[]> {
        if(
            swapData.isClaimer(sender) && swapData.isPayIn() &&
            swapData.isToken(this.root.getNativeCurrencyAddress())
        ) throw new Error("Cannot initialize as claimer for payIn=true and native currency!");

        if(!skipChecks) {
            const [_, payStatus] = await Promise.all([
                swapData.isOfferer(sender) && !swapData.reputation ? Promise.resolve() : tryWithRetries(
                    () => this.isSignatureValid(sender, swapData, timeout, prefix, signature),
                    this.retryPolicy, (e) => e instanceof SignatureVerificationError
                ),
                tryWithRetries(() => this.contract.getCommitStatus(sender, swapData), this.retryPolicy)
            ]);
            if(payStatus.type!==SwapCommitStateType.NOT_COMMITED) throw new SwapDataVerificationError("Invoice already being paid for or paid");
        }

        feeRate ??= await this.root.Fees.getFeeRate();

        const txs: EVMTx[] = [];
        const requiredApprovals: {[address: string]: bigint} = {};
        if(swapData.isPayIn() && swapData.isOfferer(sender)) {
            if(!swapData.isToken(this.root.getNativeCurrencyAddress())) {
                requiredApprovals[swapData.token.toLowerCase()] = swapData.amount;
            }
        }
        if(swapData.getTotalDeposit() !== 0n) {
            if(!swapData.isDepositToken(this.root.getNativeCurrencyAddress())) {
                requiredApprovals[swapData.depositToken.toLowerCase()] ??= 0n;
                requiredApprovals[swapData.depositToken.toLowerCase()] += swapData.getTotalDeposit();
            }
        }

        const requiredApprovalTxns = await Promise.all(
            Object.keys(requiredApprovals).map(token => this.root.Tokens.checkAndGetApproveTx(sender, token, requiredApprovals[token], this.contract.contractAddress, feeRate))
        );
        requiredApprovalTxns.forEach(tx => tx!=null && txs.push(tx));

        txs.push(await this.Init(sender, swapData, BigInt(timeout), signature ?? "0x", feeRate));

        this.logger.debug("txsInitPayIn(): create swap init TX, swap: "+swapData.getClaimHash()+
            " feerate: "+feeRate);

        return txs;
    }

    private getInitGas(swapData: EVMSwapData): number {
        let totalGas = EVMSwapInit.GasCosts.BASE;
        if(swapData.isPayIn()) {
            if(!swapData.isToken(this.root.getNativeCurrencyAddress())) {
                totalGas += EVMSwapInit.GasCosts.ERC20_TRANSFER;
            }
        } else {
            totalGas += EVMSwapInit.GasCosts.LP_VAULT_TRANSFER;
        }
        if(swapData.getTotalDeposit() > 0) {
            if(!swapData.isPayIn() || !swapData.isDepositToken(swapData.token)) {
                if(!swapData.isDepositToken(this.root.getNativeCurrencyAddress())) {
                    totalGas += EVMSwapInit.GasCosts.ERC20_TRANSFER;
                }
            }
        }
        return totalGas;
    }

    /**
     * Get the estimated fee of the init transaction
     */
    async getInitFee(swapData: EVMSwapData, feeRate?: string): Promise<bigint> {
        feeRate ??= await this.root.Fees.getFeeRate();
        let totalFee = EVMFees.getGasFee(this.getInitGas(swapData), feeRate);
        if(swapData.isPayIn()) {
            if(!swapData.isToken(this.root.getNativeCurrencyAddress())) {
                totalFee += await this.root.Tokens.getApproveFee(feeRate);
            }
        }
        if(swapData.getTotalDeposit() > 0) {
            if(!swapData.isPayIn() || !swapData.isDepositToken(swapData.token)) {
                if(!swapData.isDepositToken(this.root.getNativeCurrencyAddress())) {
                    totalFee += await this.root.Tokens.getApproveFee(feeRate);
                }
            }
        }

        return totalFee;
    }
}