@atomiqlabs/sdk/src/swapper/Swapper.ts

atomiq labs SDK for cross-chain swaps between smart chains and bitcoin

import {ISwapPrice} from "../prices/abstract/ISwapPrice";
import {
    BitcoinNetwork, BitcoinRpc, BitcoinRpcWithAddressIndex, BtcBlock,
    BtcRelay,
    ChainData,
    ChainSwapType,
    ChainType, LightningNetworkApi,
    Messenger,
    RelaySynchronizer, SpvWithdrawalClaimedState, SpvWithdrawalFrontedState, SwapCommitState, SwapContract, SwapData
} from "@atomiqlabs/base";
import {
    ToBTCLNOptions,
    ToBTCLNWrapper
} from "../swaps/escrow_swaps/tobtc/ln/ToBTCLNWrapper";
import {ToBTCOptions, ToBTCWrapper} from "../swaps/escrow_swaps/tobtc/onchain/ToBTCWrapper";
import {FromBTCLNOptions, FromBTCLNWrapper} from "../swaps/escrow_swaps/frombtc/ln/FromBTCLNWrapper";
import {FromBTCOptions, FromBTCWrapper} from "../swaps/escrow_swaps/frombtc/onchain/FromBTCWrapper";
import {IntermediaryDiscovery, MultichainSwapBounds, SwapBounds} from "../intermediaries/IntermediaryDiscovery";
import {decode as bolt11Decode} from "@atomiqlabs/bolt11";
import {ISwap} from "../swaps/ISwap";
import {IntermediaryError} from "../errors/IntermediaryError";
import {SwapType} from "../enums/SwapType";
import {FromBTCLNSwap} from "../swaps/escrow_swaps/frombtc/ln/FromBTCLNSwap";
import {FromBTCSwap} from "../swaps/escrow_swaps/frombtc/onchain/FromBTCSwap";
import {ToBTCLNSwap} from "../swaps/escrow_swaps/tobtc/ln/ToBTCLNSwap";
import {ToBTCSwap} from "../swaps/escrow_swaps/tobtc/onchain/ToBTCSwap";
import {LnForGasWrapper} from "../swaps/trusted/ln/LnForGasWrapper";
import {LnForGasSwap} from "../swaps/trusted/ln/LnForGasSwap";
import {EventEmitter} from "events";
import {Intermediary} from "../intermediaries/Intermediary";
import {ISwapWrapper, WrapperCtorTokens} from "../swaps/ISwapWrapper";
import {bigIntCompare, bigIntMax, bigIntMin, fromDecimal, objectMap, randomBytes} from "../utils/Utils";
import {OutOfBoundsError} from "../errors/RequestError";
import {SwapperWithChain} from "./SwapperWithChain";
import {OnchainForGasSwap} from "../swaps/trusted/onchain/OnchainForGasSwap";
import {OnchainForGasWrapper} from "../swaps/trusted/onchain/OnchainForGasWrapper";
import {BTC_NETWORK, NETWORK, TEST_NETWORK} from "@scure/btc-signer/utils";
import {IUnifiedStorage, QueryParams} from "../storage/IUnifiedStorage";
import {
    UnifiedSwapStorage,
    UnifiedSwapStorageCompositeIndexes,
    UnifiedSwapStorageIndexes
} from "../storage/UnifiedSwapStorage";
import {UnifiedSwapEventListener} from "../events/UnifiedSwapEventListener";
import {IToBTCSwap} from "../swaps/escrow_swaps/tobtc/IToBTCSwap";
import {SpvFromBTCOptions, SpvFromBTCWrapper} from "../swaps/spv_swaps/SpvFromBTCWrapper";
import {SpvFromBTCSwap} from "../swaps/spv_swaps/SpvFromBTCSwap";
import {SwapperUtils} from "./SwapperUtils";
import {FromBTCLNAutoOptions, FromBTCLNAutoWrapper} from "../swaps/escrow_swaps/frombtc/ln_auto/FromBTCLNAutoWrapper";
import {FromBTCLNAutoSwap} from "../swaps/escrow_swaps/frombtc/ln_auto/FromBTCLNAutoSwap";
import {UserError} from "../errors/UserError";
import {SwapAmountType} from "../enums/SwapAmountType";
import {IClaimableSwap} from "../swaps/IClaimableSwap";
import {correctClock} from "../utils/AutomaticClockDriftCorrection";
import {isSwapType, SwapProtocolInfo, SwapTypeMapping} from "../utils/SwapUtils";
import {IndexedDBUnifiedStorage} from "../storage-browser/IndexedDBUnifiedStorage";
import {TokenAmount, toTokenAmount} from "../types/TokenAmount";
import {BitcoinTokens, BtcToken, isBtcToken, isSCToken, SCToken, Token} from "../types/Token";
import {AmountData} from "../types/AmountData";
import {getLogger} from "../utils/Logger";
import {isLNURLWithdraw, LNURLWithdraw} from "../types/lnurl/LNURLWithdraw";
import {isLNURLPay, LNURLPay} from "../types/lnurl/LNURLPay";
import {tryWithRetries} from "../utils/RetryUtils";
import {NotNever} from "../utils/TypeUtils";
import {IEscrowSwap} from "../swaps/escrow_swaps/IEscrowSwap";
import {LightningInvoiceCreateService, isLightningInvoiceCreateService} from "../types/wallets/LightningInvoiceCreateService";
import {SwapSide} from "../enums/SwapSide";
import {IntermediaryAPI} from "../intermediaries/apis/IntermediaryAPI";
import {BitcoinWalletUtxo, BitcoinWalletUtxoBase, IBitcoinWallet} from "../bitcoin/wallet/IBitcoinWallet";
import {MinimalBitcoinWalletInterface} from "../types/wallets/MinimalBitcoinWalletInterface";
import {toBitcoinWallet} from "../utils/BitcoinWalletUtils";
import {getSignedKeyBasedAuthHandler} from "../intermediaries/auth/SignedKeyBasedAuth";

/**
 * Configuration options for the Swapper
 * @category Core
 */
export type SwapperOptions = {
    /**
     * Manual override for the intermediary (LP) URLs for the SDK to use, by default these are fetched automatically
     * from the registry
     */
    intermediaryUrl?: string | string[],
    /**
     * Registry URL for where to look for active intermediary (LP) endpoint URLs
     */
    registryUrl?: string,

    /**
     * Bitcoin network to use for the swaps,
     */
    bitcoinNetwork?: BitcoinNetwork,

    /**
     * Timeout (in milliseconds) for HTTP GET requests done by the SDK
     */
    getRequestTimeout?: number,
    /**
     * Timeout (in milliseconds) for HTTP POST requests done by the SDK
     */
    postRequestTimeout?: number,
    /**
     * Additional parameters to be sent to the intermediaries (LPs), when requesting quotes from them
     */
    defaultAdditionalParameters?: {[key: string]: any},
    /**
     * Optional name prefix to use when creating a swap storage, you can use this to create separate storage
     *  instances that don't overlap.
     */
    storagePrefix?: string,
    /**
     * Sets the default intermediary (LP) to use for the trusted gas swaps, if not set the SDK uses a default one
     */
    defaultTrustedIntermediaryUrl?: string,

    /**
     * A function callback to retrieve a specific named storage container for swap persistency. If not present, the
     *  default IndexedDB storage adapter is used. When you use the SDK in non-browser based environments you need to
     *  provide this callback such that the SDK is able to use a custom storage adapter.
     *
     * @param storageName Name of the container to retrieve
     */
    swapStorage?: (storageName: string) => IUnifiedStorage<UnifiedSwapStorageIndexes, UnifiedSwapStorageCompositeIndexes>,

    /**
     * By setting this flag, the swapper doesn't schedule automatic tick timers. To make sure the swap states are
     * properly updated (e.g. the expired swaps properly move to the expired state), you should call the
     *  {@link Swapper._syncSwaps} function periodically. This flag should be set when you run an environment that
     *  doesn't support long-running timers - e.g. serverless environments like Azure Function Apps or AWS Lambda
     */
    noTimers?: boolean,
    /**
     * By setting this flag, the swapper doesn't subscribe to on-chain events. To make sure the swap states are
     *  properly updated you should either call the {@link Swapper._syncSwaps} function periodically, or use the
     *  {@link Swapper._pollChainEvents} function to manually poll for on-chain events. This flag should be set
     *  when you run an environment that doesn't support long-running timers and websocket connections - e.g.
     *  serverless environments like Azure Function Apps or AWS Lambda
     */
    noEvents?: boolean,
    /**
     * By setting this flag, the swap objects will not be cached in the SDK and instead will always be loaded from
     *  the persistent storage. By default, the SDK uses a `WeakRef` mapping of swaps, to ensure that when the same
     *  swap is loaded concurrently, it returns the same object reference to both, making the changes on the object
     *  atomic. This flag should be set to `true` when running in an environment where multiple instances of the SDK
     *  access the same swap database - e.g. serverless environments like Azure Function Apps or AWS Lambda
     */
    noSwapCache?: boolean,
    /**
     * Skip checking past swaps when the swapper is initiated with {@link Swapper.init}, you can call the
     * {@link Swapper._syncSwaps} function later, to check the swaps. By default, the SDK checks the state
     * of all the known swaps during init.
     */
    dontCheckPastSwaps?: boolean,
    /**
     * Skip fetching the LPs when the swapper is initiated with {@link Swapper.init}, this means the list of available
     *  tokens and swap limits won't be available immediately. LPs will be fetched automatically later, when a swap
     *  is requested
     */
    dontFetchLPs?: boolean,
    /**
     * Defaults to `true`, this means every swap regardless of it being initiated (i.e. when `commit()`, `execute()` or
     *  `waitTillPayment` is called) is saved to the persistent storage. This is a reasonable default for when you
     *  want to only create a swap, and then later on retrieve it with the `swapper.getSwapById()` function.
     *
     * Setting this to `false` means the SDK only saves and persists swaps that are considered initiated, i.e. when
     *  `commit()`, `execute()` or `waitTillPayment()` is called (or their respective txs... prefixed variations). This
     *  might save calls to the persistent storage for swaps that are never initiated. This is useful in e.g.
     *  frontend implementations where the frontend holds the swap object reference until it is initiated anyway, not
     *  necessitating the saving of the swap data to the persistent storage until it is actually initiated.
     */
    saveUninitializedSwaps?: boolean,
    /**
     * Automatically checks system time on initialize, if the system time drifts too far from the actual time
     *  (as checked from multiple server sources) it adjusts the `Date.now()` function to return proper actual time.
     */
    automaticClockDriftCorrection?: boolean,
    /**
     * Used in centralized API deployments to allow higher rate limits from LPs
     */
    signedKeyBasedAuth?: {
        certificate: string,
        privateKey: string
    },

    /**
     * If you set the option to `true` the chains for which the RPC is unresponsive are skipped and not initialized
     *  letting the swapper continue with only the available chains with responsive RPCs
     */
    gracefullyHandleChainErrors?: boolean,
};

/**
 * Type representing multiple blockchain configurations
 * @category Core
 */
export type MultiChain = {
    [chainIdentifier in string]: ChainType;
};

type ChainSpecificData<T extends ChainType> = {
    wrappers: {
        [SwapType.TO_BTCLN]: ToBTCLNWrapper<T>,
        [SwapType.TO_BTC]: ToBTCWrapper<T>,
        [SwapType.FROM_BTCLN]: FromBTCLNWrapper<T>,
        [SwapType.FROM_BTC]: FromBTCWrapper<T>,
        [SwapType.TRUSTED_FROM_BTCLN]: LnForGasWrapper<T>,
        [SwapType.TRUSTED_FROM_BTC]: OnchainForGasWrapper<T>,
        [SwapType.SPV_VAULT_FROM_BTC]: SpvFromBTCWrapper<T>,
        [SwapType.FROM_BTCLN_AUTO]: FromBTCLNAutoWrapper<T>
    }
    chainEvents: T["Events"],
    chainInterface: T["ChainInterface"],
    unifiedChainEvents: UnifiedSwapEventListener<T>,
    unifiedSwapStorage: UnifiedSwapStorage<T>,
    reviver: (val: any) => ISwap<T>,
    defaultVersion: string,

    versionedContracts: {
        [contractVersion: string]: {
            swapContract: T["Contract"],
            spvVaultContract: T["SpvVaultContract"],
            btcRelay: BtcRelay<any, T["TX"], BtcBlock, T["Signer"]>,
            synchronizer: RelaySynchronizer<any, T["TX"], BtcBlock>,
        }
    }
};

type MultiChainData<T extends MultiChain> = {
    [chainIdentifier in keyof T]: ChainSpecificData<T[chainIdentifier]>
};

type CtorMultiChainData<T extends MultiChain> = {
    [chainIdentifier in keyof T]: ChainData<T[chainIdentifier]>
};

type SwapperCtorTokens<T extends MultiChain = MultiChain> = {
    ticker: string,
    name: string,
    chains: {[chainId in ChainIds<T>]?: {
        address: string,
        decimals: number,
        displayDecimals?: number
    }}
}[];

/**
 * Type extracting chain identifiers from a MultiChain type
 * @category Core
 */
export type ChainIds<T extends MultiChain> = keyof T & string;

/**
 * Type helper to check if a chain supports a specific swap type
 * @category Core
 */
export type SupportsSwapType<
    C extends ChainType,
    Type extends SwapType
> = Type extends SwapType.SPV_VAULT_FROM_BTC ?
        NotNever<C["SpvVaultContract"]> :
    Type extends (SwapType.TRUSTED_FROM_BTCLN | SwapType.TRUSTED_FROM_BTC) ?
        true :
    Type extends SwapType.FROM_BTCLN_AUTO ? (C["Contract"]["supportsInitWithoutClaimer"] extends true ? true : false) :
        NotNever<C["Contract"]>;

/**
 * Core orchestrator for all atomiq swap operations
 *
 * @category Core
 */
export class Swapper<T extends MultiChain> extends EventEmitter<{
    lpsRemoved: [Intermediary[]],
    lpsAdded: [Intermediary[]],
    swapState: [ISwap],
    swapLimitsChanged: []
}> {
    private readonly logger = getLogger(this.constructor.name+": ");
    private readonly swapStateListener: (swap: ISwap) => void;

    private defaultTrustedIntermediary?: Intermediary;
    private readonly bitcoinNetwork: BitcoinNetwork;
    private readonly options: SwapperOptions;
    /**
     * Data propagation layer used for broadcasting messages to watchtowers
     */
    private readonly messenger: Messenger;

    /**
     * A dictionary of smart chains used by the SDK
     * @internal
     */
    readonly _chains: MultiChainData<T>;
    /**
     * Bitcoin RPC for fetching bitcoin chain data
     * @internal
     */
    readonly _bitcoinRpc: BitcoinRpcWithAddressIndex<any>;
    /**
     * Bitcoin network specification
     * @internal
     */
    readonly _btcNetwork: BTC_NETWORK;
    /**
     * Token data indexed by chain identifier and token addresses
     * @internal
     */
    readonly _tokens: {
        [chainId: string]: {
            [tokenAddress: string]: SCToken
        }
    };
    /**
     * Token data indexed by chain identifier and token tickers
     * @internal
     */
    readonly _tokensByTicker: {
        [chainId: string]: {
            [tokenTicker: string]: SCToken
        }
    };

    /**
     * Pricing API used by the SDK
     */
    readonly prices: ISwapPrice<T>;
    /**
     * API for contacting LPs
     */
    readonly lpApi: IntermediaryAPI;
    /**
     * Intermediary discovery instance
     */
    readonly intermediaryDiscovery: IntermediaryDiscovery;
    /**
     * Miscellaneous utility functions
     */
    readonly Utils: SwapperUtils<T>;

    /**
     * @internal
     */
    constructor(
        bitcoinRpc: BitcoinRpcWithAddressIndex<any>,
        lightningApi: LightningNetworkApi,
        bitcoinSynchronizer: (btcRelay: BtcRelay<any, any, any>) => RelaySynchronizer<any, any, any>,
        chainsData: CtorMultiChainData<T>,
        pricing: ISwapPrice<T>,
        tokens: SCToken[],
        messenger: Messenger,
        options?: SwapperOptions
    ) {
        super();
        const storagePrefix = options?.storagePrefix ?? "atomiq-";

        options ??= {};
        options.saveUninitializedSwaps ??= true;
        options.bitcoinNetwork = options.bitcoinNetwork==null ? BitcoinNetwork.TESTNET : options.bitcoinNetwork;
        const swapStorage = options.swapStorage ??= (name: string) => new IndexedDBUnifiedStorage(name);

        this.options = options;

        this.bitcoinNetwork = options.bitcoinNetwork;
        this._btcNetwork = options.bitcoinNetwork===BitcoinNetwork.MAINNET ? NETWORK :
            (options.bitcoinNetwork===BitcoinNetwork.TESTNET || options.bitcoinNetwork===BitcoinNetwork.TESTNET4) ? TEST_NETWORK : {
                bech32: 'bcrt',
                pubKeyHash: 111,
                scriptHash: 196,
                wif: 239
            };
        this.Utils = new SwapperUtils(this);

        this.prices = pricing;
        this._bitcoinRpc = bitcoinRpc;
        this.messenger = messenger;

        this._tokens = {};
        this._tokensByTicker = {};
        for(let tokenData of tokens) {
            const chainId = tokenData.chainId;
            this._tokens[chainId] ??= {};
            this._tokensByTicker[chainId] ??= {};
            this._tokens[chainId][tokenData.address] = this._tokensByTicker[chainId][tokenData.ticker] = tokenData;
        }

        const lpApi = new IntermediaryAPI(
            this.options.signedKeyBasedAuth!=null
                ? getSignedKeyBasedAuthHandler(this.options.signedKeyBasedAuth.certificate, this.options.signedKeyBasedAuth.privateKey)
                : undefined
        );
        this.lpApi = lpApi;

        this.swapStateListener = (swap: ISwap) => {
            this.emit("swapState", swap);
        };

        this._chains = objectMap<CtorMultiChainData<T>, MultiChainData<T>>(chainsData, <InputKey extends keyof CtorMultiChainData<T>>(chainData: CtorMultiChainData<T>[InputKey], key: string) => {
            let {
                chainInterface, chainEvents, chainId,
                btcRelay,
                swapContract, swapDataConstructor,
                spvVaultContract, spvVaultWithdrawalDataConstructor, spvVaultDataConstructor,
                defaultVersion, versions
            } = chainData;

            defaultVersion ??= "v1";

            if(versions==null) {
                versions = {
                    [defaultVersion]: {
                        btcRelay,
                        swapContract,
                        swapDataConstructor,
                        spvVaultContract,
                        spvVaultDataConstructor,
                        spvVaultWithdrawalDataConstructor
                    }
                }
            }

            const versionedContracts = objectMap(versions, (value, key) => {
                return {
                    swapContract: value.swapContract,
                    spvVaultContract: value.spvVaultContract,
                    btcRelay: value.btcRelay,
                    synchronizer: bitcoinSynchronizer(value.btcRelay)
                };
            });

            const storageHandler = swapStorage(storagePrefix + chainId);
            const unifiedSwapStorage = new UnifiedSwapStorage<T[InputKey]>(storageHandler, this.options.noSwapCache);
            const unifiedChainEvents = new UnifiedSwapEventListener<T[InputKey]>(unifiedSwapStorage, chainEvents);

            const wrappers: any = {};

            wrappers[SwapType.TO_BTCLN] = new ToBTCLNWrapper<T[InputKey]>(
                key,
                unifiedSwapStorage,
                unifiedChainEvents,
                chainInterface,
                pricing,
                this._tokens[chainId],
                versions,
                lpApi,
                {
                    getRequestTimeout: this.options.getRequestTimeout,
                    postRequestTimeout: this.options.postRequestTimeout,
                    saveUninitializedSwaps: this.options.saveUninitializedSwaps,
                }
            );
            wrappers[SwapType.TO_BTC] = new ToBTCWrapper<T[InputKey]>(
                key,
                unifiedSwapStorage,
                unifiedChainEvents,
                chainInterface,
                pricing,
                this._tokens[chainId],
                versions,
                this._bitcoinRpc,
                lpApi,
                {
                    getRequestTimeout: this.options.getRequestTimeout,
                    postRequestTimeout: this.options.postRequestTimeout,
                    saveUninitializedSwaps: this.options.saveUninitializedSwaps,
                    bitcoinNetwork: this._btcNetwork
                }
            );
            wrappers[SwapType.FROM_BTCLN] = new FromBTCLNWrapper<T[InputKey]>(
                key,
                unifiedSwapStorage,
                unifiedChainEvents,
                chainInterface,
                pricing,
                this._tokens[chainId],
                versions,
                lightningApi,
                lpApi,
                {
                    getRequestTimeout: this.options.getRequestTimeout,
                    postRequestTimeout: this.options.postRequestTimeout,
                    saveUninitializedSwaps: this.options.saveUninitializedSwaps,
                    unsafeSkipLnNodeCheck: this.bitcoinNetwork===BitcoinNetwork.TESTNET4 || this.bitcoinNetwork===BitcoinNetwork.REGTEST
                }
            );
            wrappers[SwapType.FROM_BTC] = new FromBTCWrapper<T[InputKey]>(
                key,
                unifiedSwapStorage,
                unifiedChainEvents,
                chainInterface,
                pricing,
                this._tokens[chainId],
                versions,
                versionedContracts,
                this._bitcoinRpc,
                lpApi,
                {
                    getRequestTimeout: this.options.getRequestTimeout,
                    postRequestTimeout: this.options.postRequestTimeout,
                    saveUninitializedSwaps: this.options.saveUninitializedSwaps,
                    bitcoinNetwork: this._btcNetwork
                }
            );
            wrappers[SwapType.TRUSTED_FROM_BTCLN] = new LnForGasWrapper<T[InputKey]>(
                key,
                unifiedSwapStorage,
                unifiedChainEvents,
                chainInterface,
                pricing,
                this._tokens[chainId],
                lpApi,
                {
                    getRequestTimeout: this.options.getRequestTimeout,
                    postRequestTimeout: this.options.postRequestTimeout,
                    saveUninitializedSwaps: this.options.saveUninitializedSwaps,
                }
            );
            wrappers[SwapType.TRUSTED_FROM_BTC] = new OnchainForGasWrapper<T[InputKey]>(
                key,
                unifiedSwapStorage,
                unifiedChainEvents,
                chainInterface,
                pricing,
                this._tokens[chainId],
                bitcoinRpc,
                lpApi,
                {
                    getRequestTimeout: this.options.getRequestTimeout,
                    postRequestTimeout: this.options.postRequestTimeout,
                    saveUninitializedSwaps: this.options.saveUninitializedSwaps,
                    bitcoinNetwork: this._btcNetwork
                }
            );

            // This is gated on the default version of the contracts
            if(spvVaultContract!=null) {
                wrappers[SwapType.SPV_VAULT_FROM_BTC] = new SpvFromBTCWrapper<T[InputKey]>(
                    key,
                    unifiedSwapStorage,
                    unifiedChainEvents,
                    chainInterface,
                    pricing,
                    this._tokens[chainId],
                    versions,
                    versionedContracts,
                    bitcoinRpc,
                    lpApi,
                    {
                        getRequestTimeout: this.options.getRequestTimeout,
                        postRequestTimeout: this.options.postRequestTimeout,
                        saveUninitializedSwaps: this.options.saveUninitializedSwaps,
                        bitcoinNetwork: this._btcNetwork
                    }
                );
            }

            // This is gated on the default version of the contracts
            if(swapContract.supportsInitWithoutClaimer) {
                wrappers[SwapType.FROM_BTCLN_AUTO] = new FromBTCLNAutoWrapper<T[InputKey]>(
                    key,
                    unifiedSwapStorage,
                    unifiedChainEvents,
                    chainInterface,
                    pricing,
                    this._tokens[chainId],
                    versions,
                    lightningApi,
                    this.messenger,
                    lpApi,
                    {
                        getRequestTimeout: this.options.getRequestTimeout,
                        postRequestTimeout: this.options.postRequestTimeout,
                        saveUninitializedSwaps: this.options.saveUninitializedSwaps,
                        unsafeSkipLnNodeCheck: this.bitcoinNetwork===BitcoinNetwork.TESTNET4 || this.bitcoinNetwork===BitcoinNetwork.REGTEST
                    }
                );
            }

            Object.keys(wrappers).forEach(key => wrappers[key].events.on("swapState", this.swapStateListener));

            const reviver = (val: any) => {
                const wrapper: ISwapWrapper<any, any> = wrappers[val.type];
                if(wrapper==null) return null;
                return new wrapper._swapDeserializer(wrapper, val);
            };

            return {
                chainEvents,
                chainInterface,

                wrappers,

                unifiedChainEvents,
                unifiedSwapStorage,

                defaultVersion,

                reviver,

                versionedContracts
            }
        });

        const contracts = objectMap(chainsData, (data) => data.versions ?? {[data.defaultVersion ?? "v1"]: {swapContract: data.swapContract, spvVaultContract: data.spvVaultContract}});
        if(options.intermediaryUrl!=null) {
            this.intermediaryDiscovery = new IntermediaryDiscovery(contracts, lpApi, options.registryUrl, Array.isArray(options.intermediaryUrl) ? options.intermediaryUrl : [options.intermediaryUrl], options.getRequestTimeout);
        } else {
            this.intermediaryDiscovery = new IntermediaryDiscovery(contracts, lpApi, options.registryUrl, undefined, options.getRequestTimeout);
        }

        this.intermediaryDiscovery.on("removed", (intermediaries: Intermediary[]) => {
            this.emit("lpsRemoved", intermediaries);
        });

        this.intermediaryDiscovery.on("added", (intermediaries: Intermediary[]) => {
            this.emit("lpsAdded", intermediaries);
        });
    }

    private async _init(): Promise<void> {
        this.logger.debug("init(): Initializing swapper");

        const abortController = new AbortController();

        const promises: Promise<void>[] = [];
        let automaticClockDriftCorrectionPromise: Promise<void> | undefined = undefined;
        if(this.options.automaticClockDriftCorrection) {
            promises.push(automaticClockDriftCorrectionPromise = tryWithRetries(correctClock, undefined, undefined, abortController.signal).catch((err) => {
                abortController.abort(err);
            }));
        }

        this.logger.debug("init(): Initializing intermediary discovery");
        if(!this.options.dontFetchLPs) promises.push(this.intermediaryDiscovery.init(abortController.signal).catch(err => {
            if(abortController.signal.aborted) return;
            this.logger.error("init(): Failed to fetch intermediaries/LPs: ", err);
        }));

        if(this.options.defaultTrustedIntermediaryUrl!=null) {
            promises.push(
                this.intermediaryDiscovery.getIntermediary(this.options.defaultTrustedIntermediaryUrl, abortController.signal)
                    .then(val => {
                        if(val==null) throw new Error("Cannot get trusted LP");
                        this.defaultTrustedIntermediary = val;
                    })
                    .catch(err => {
                        if(abortController.signal.aborted) return;
                        this.logger.error("init(): Failed to contact trusted LP url: ", err);
                    })
            );
        }

        if(automaticClockDriftCorrectionPromise!=null) {
            //We should await the promises here before checking the swaps
            await automaticClockDriftCorrectionPromise;
        }

        const chainPromises = [];
        for(let chainIdentifier in this._chains) {
            chainPromises.push((async() => {
                const {
                    chainInterface,
                    versionedContracts,
                    unifiedChainEvents,
                    unifiedSwapStorage,
                    wrappers,
                    reviver
                } = this._chains[chainIdentifier];

                try {
                    const _chainInterface: any = chainInterface;
                    if(_chainInterface.verifyNetwork!=null) {
                        await _chainInterface.verifyNetwork(this.bitcoinNetwork);
                    }

                    for(let contractVersion in versionedContracts) {
                        await versionedContracts[contractVersion].swapContract.start();
                        this.logger.debug("init(): Intialized swap contract: "+chainIdentifier+` version: ${contractVersion}`);
                    }

                    await unifiedSwapStorage.init();
                    if(unifiedSwapStorage.storage instanceof IndexedDBUnifiedStorage) {
                        //Try to migrate the data here
                        const storagePrefix = chainIdentifier==="SOLANA" ?
                            "SOLv4-"+this.bitcoinNetwork+"-Swaps-" :
                            "atomiqsdk-"+this.bitcoinNetwork+chainIdentifier+"-Swaps-";
                        await unifiedSwapStorage.storage.tryMigrate(
                            [
                                [storagePrefix+"FromBTC", SwapType.FROM_BTC],
                                [storagePrefix+"FromBTCLN", SwapType.FROM_BTCLN],
                                [storagePrefix+"ToBTC", SwapType.TO_BTC],
                                [storagePrefix+"ToBTCLN", SwapType.TO_BTCLN]
                            ],
                            (obj: any) => {
                                const swap = reviver(obj);
                                if(swap._randomNonce==null) {
                                    const oldIdentifierHash = swap.getId();
                                    swap._randomNonce = randomBytes(16).toString("hex");
                                    const newIdentifierHash = swap.getId();
                                    this.logger.info("init(): Found older swap version without randomNonce, replacing, old hash: "+oldIdentifierHash+
                                        " new hash: "+newIdentifierHash);
                                }
                                return swap;
                            }
                        )
                    }

                    await unifiedChainEvents.start(this.options.noEvents);
                    this.logger.debug("init(): Initialized events: "+chainIdentifier);
                } catch (e) {
                    if(!this.options.gracefullyHandleChainErrors) throw e;
                    this.logger.error(`init(): Failed to initialize ${chainIdentifier} (skipped): `, e);
                    delete this._chains[chainIdentifier];
                    return;
                }

                for(let key in wrappers) {
                    // this.logger.debug("init(): Initializing "+SwapType[key]+": "+chainIdentifier);
                    await wrappers[key as unknown as SwapType].init(this.options.noTimers, this.options.dontCheckPastSwaps);
                }
            })());
        }
        await Promise.all(chainPromises);

        await Promise.all(promises);

        this.logger.debug("init(): Initializing messenger");
        await this.messenger.init();
    }

    private initPromise?: Promise<void>;
    private initialized: boolean = false;

    /**
     * Initializes the swap storage and loads existing swaps, needs to be called before any other action
     */
    async init(): Promise<void> {
        if(this.initialized) return;
        if(this.initPromise!=null) {
            await this.initPromise;
            return;
        }

        try {
            const promise = this._init();
            this.initPromise = promise;
            await promise;
            delete this.initPromise;
            this.initialized = true;
        } catch (e) {
            delete this.initPromise;
            throw e;
        }
    }

    /**
     * Whether the SDK is initialized (after {@link init} is called)
     */
    isInitialized(): boolean {
        return this.initialized;
    }

    /**
     * Stops listening for onchain events and closes this Swapper instance
     */
    async stop() {
        if(this.initPromise) await this.initPromise;
        for(let chainIdentifier in this._chains) {
            const {
                wrappers,
                unifiedChainEvents
            } = this._chains[chainIdentifier];
            for(let key in wrappers) {
                const wrapper = wrappers[key as unknown as SwapType];
                wrapper.events.removeListener("swapState", this.swapStateListener);
                await wrapper.stop();
            }
            await unifiedChainEvents.stop();
            await this.messenger.stop();
        }
        this.initialized = false;
    }

    /**
     * Creates swap & handles intermediary, quote selection
     *
     * @param chainIdentifier
     * @param create Callback to create the
     * @param amountData Amount data as passed to the function
     * @param swapType Swap type of the execution
     * @param maxWaitTimeMS Maximum waiting time after the first intermediary returns the quote
     * @private
     * @throws {Error} when no intermediary was found
     * @throws {Error} if the chain with the provided identifier cannot be found
     */
    private async createSwap<ChainIdentifier extends ChainIds<T>, S extends ISwap<T[ChainIdentifier]>>(
        chainIdentifier: ChainIdentifier,
        create: (candidates: Intermediary[], abortSignal: AbortSignal, chain: ChainSpecificData<T[ChainIdentifier]>) => Promise<{
            quote: Promise<S>,
            intermediary: Intermediary
        }[]>,
        amountData: { amount?: bigint, token: string, exactIn: boolean },
        swapType: SwapType,
        maxWaitTimeMS: number = 2000
    ): Promise<S> {
        if(!this.initialized) throw new Error("Swapper not initialized, init first with swapper.init()!");
        if(this._chains[chainIdentifier]==null) throw new Error("Invalid chain identifier! Unknown chain: "+chainIdentifier);
        let candidates: Intermediary[];

        const inBtc: boolean = swapType===SwapType.TO_BTCLN || swapType===SwapType.TO_BTC ? !amountData.exactIn : amountData.exactIn;

        if(!inBtc || amountData.amount==null) {
            //Get candidates not based on the amount
            candidates = this.intermediaryDiscovery.getSwapCandidates(chainIdentifier, swapType, amountData.token);
        } else {
            candidates = this.intermediaryDiscovery.getSwapCandidates(chainIdentifier, swapType, amountData.token, amountData.amount);
        }

        let swapLimitsChanged = false;

        if(candidates.length===0)  {
            this.logger.warn("createSwap(): No valid intermediary found to execute the swap with, reloading intermediary database...");
            await this.intermediaryDiscovery.reloadIntermediaries();
            swapLimitsChanged = true;

            if(!inBtc || amountData.amount==null) {
                //Get candidates not based on the amount
                candidates = this.intermediaryDiscovery.getSwapCandidates(chainIdentifier, swapType, amountData.token);
            } else {
                candidates = this.intermediaryDiscovery.getSwapCandidates(chainIdentifier, swapType, amountData.token, amountData.amount);

                if(candidates.length===0) {
                    const min = this.intermediaryDiscovery.getSwapMinimum(chainIdentifier, swapType, amountData.token);
                    const max = this.intermediaryDiscovery.getSwapMaximum(chainIdentifier, swapType, amountData.token);
                    if(min!=null && max!=null) {
                        if(amountData.amount < BigInt(min)) throw new OutOfBoundsError("Swap amount too low! Try swapping a higher amount.", 200, BigInt(min), BigInt(max));
                        if(amountData.amount > BigInt(max)) throw new OutOfBoundsError("Swap amount too high! Try swapping a lower amount.", 200, BigInt(min), BigInt(max));
                    }
                }
            }

            if(candidates.length===0) throw new Error("No intermediary found for the requested pair and amount! You can try swapping different pair or higher/lower amount.");
        }

        const abortController = new AbortController();
        this.logger.debug("createSwap() Swap candidates: ", candidates.map(lp => lp.url).join());
        const quotePromises: {quote: Promise<S>, intermediary: Intermediary}[] = await create(candidates, abortController.signal, this._chains[chainIdentifier]);

        const promiseAll = new Promise<{
            quote: S,
            intermediary: Intermediary
        }[]>((resolve, reject) => {
            let min: bigint;
            let max: bigint;
            let error: Error;
            let numResolved = 0;
            let quotes: {
                quote: S,
                intermediary: Intermediary
            }[] = [];
            let timeout: NodeJS.Timeout;

            quotePromises.forEach(data => {
                data.quote.then(quote => {
                    if(numResolved===0) {
                        timeout = setTimeout(() => {
                            abortController.abort(new Error("Timed out waiting for quote!"));
                            resolve(quotes);
                        }, maxWaitTimeMS);
                    }
                    numResolved++;
                    quotes.push({
                        quote,
                        intermediary: data.intermediary
                    });
                    if(numResolved===quotePromises.length) {
                        clearTimeout(timeout);
                        resolve(quotes);
                        return;
                    }
                }).catch(e => {
                    numResolved++;
                    if(e instanceof IntermediaryError) {
                        //Blacklist that node
                        this.intermediaryDiscovery.removeIntermediary(data.intermediary);
                        swapLimitsChanged = true;
                    } else if(e instanceof OutOfBoundsError) {
                        if(min==null || max==null) {
                            min = e.min;
                            max = e.max;
                        } else {
                            min = bigIntMin(min, e.min);
                            max = bigIntMax(max, e.max);
                        }
                        data.intermediary.swapBounds[swapType] ??= {};
                        data.intermediary.swapBounds[swapType]![chainIdentifier] ??= {};
                        const tokenBoundsData = (data.intermediary.swapBounds[swapType]![chainIdentifier]![amountData.token] ??= {input: {}, output: {}});
                        if(amountData.exactIn) {
                            tokenBoundsData.input = {min: e.min, max: e.max};
                        } else {
                            tokenBoundsData.output = {min: e.min, max: e.max};
                        }
                        swapLimitsChanged = true;
                    }
                    this.logger.warn("createSwap(): Intermediary "+data.intermediary.url+" error: ", e);
                    error = e;

                    if(numResolved===quotePromises.length) {
                        if(timeout!=null) clearTimeout(timeout);
                        if(quotes.length>0) {
                            resolve(quotes);
                            return;
                        }
                        if(min!=null && max!=null) {
                            let msg = "Swap amount too high or too low! Try swapping a different amount.";
                            if(amountData.amount!=null) {
                                if(min > amountData.amount) msg = "Swap amount too low! Try swapping a higher amount.";
                                if(max < amountData.amount) msg = "Swap amount too high! Try swapping a lower amount.";
                            }
                            reject(new OutOfBoundsError(msg, 400, min, max));
                            return;
                        }
                        reject(error);
                    }
                });
            });
        });

        try {
            const quotes = await promiseAll;

            //TODO: Intermediary's reputation is not taken into account!
            quotes.sort((a, b) => {
                if(amountData.exactIn) {
                    //Compare outputs
                    return bigIntCompare(b.quote.getOutput().rawAmount!, a.quote.getOutput().rawAmount!);
                } else {
                    //Compare inputs
                    return bigIntCompare(a.quote.getInput().rawAmount!, b.quote.getInput().rawAmount!);
                }
            });

            this.logger.debug("createSwap(): Sorted quotes, best price to worst: ", quotes);

            if(swapLimitsChanged) this.emit("swapLimitsChanged");

            const quote = quotes[0].quote;
            await quote._save();
            return quote;
        } catch (e) {
            if(swapLimitsChanged) this.emit("swapLimitsChanged");
            throw e;
        }
    }

    /**
     * Creates Smart chain -> Bitcoin ({@link SwapType.TO_BTC}) swap
     *
     * @param chainIdentifier Chain identifier string of the source smart chain
     * @param signer Signer's address on the source chain
     * @param tokenAddress Token address to pay with
     * @param address Recipient's bitcoin address
     * @param amount Amount to send in token based units (if `exactIn=true`) or receive in satoshis (if `exactIn=false`)
     * @param exactIn Whether to use exact in instead of exact out
     * @param additionalParams Additional parameters sent to the LP when creating the swap
     * @param options Additional options for the swap
     */
    createToBTCSwap<ChainIdentifier extends ChainIds<T>>(
        chainIdentifier: ChainIdentifier,
        signer: string,
        tokenAddress: string,
        address: string,
        amount: bigint,
        exactIn: boolean = false,
        additionalParams: Record<string, any> | undefined = this.options.defaultAdditionalParameters,
        options?: ToBTCOptions
    ): Promise<ToBTCSwap<T[ChainIdentifier]>> {
        if(this._chains[chainIdentifier]==null) throw new Error("Invalid chain identifier! Unknown chain: "+chainIdentifier);
        if(address.startsWith("bitcoin:")) {
            address = address.substring(8).split("?")[0];
        }
        if(!this.Utils.isValidBitcoinAddress(address)) throw new Error("Invalid bitcoin address");
        if(!this._chains[chainIdentifier].chainInterface.isValidAddress(signer, true)) throw new Error("Invalid "+chainIdentifier+" address");
        signer = this._chains[chainIdentifier].chainInterface.normalizeAddress(signer);
        const amountData = {
            amount,
            token: tokenAddress,
            exactIn
        };
        return this.createSwap(
            chainIdentifier as ChainIdentifier,
            (candidates: Intermediary[], abortSignal, chain) => Promise.resolve(chain.wrappers[SwapType.TO_BTC].create(
                signer,
                address,
                amountData,
                candidates,
                options,
                additionalParams,
                abortSignal
            )),
            amountData,
            SwapType.TO_BTC
        );
    }

    /**
     * Creates Smart chain -> Bitcoin Lightning ({@link SwapType.TO_BTCLN}) swap
     *
     * @param chainIdentifier Chain identifier string of the source smart chain
     * @param signer Signer's address on the source chain
     * @param tokenAddress Token address to pay with
     * @param paymentRequest BOLT11 lightning network invoice to be paid (needs to have a fixed amount), and the swap
     *  amount is taken from this fixed amount, hence only exact output swaps are supported
     * @param additionalParams Additional parameters sent to the LP when creating the swap
     * @param options Additional options for the swap
     */
    async createToBTCLNSwap<ChainIdentifier extends ChainIds<T>>(
        chainIdentifier: ChainIdentifier,
        signer: string,
        tokenAddress: string,
        paymentRequest: string,
        additionalParams: Record<string, any> | undefined = this.options.defaultAdditionalParameters,
        options?: ToBTCLNOptions
    ): Promise<ToBTCLNSwap<T[ChainIdentifier]>> {
        if(this._chains[chainIdentifier]==null) throw new Error("Invalid chain identifier! Unknown chain: "+chainIdentifier);
        if(paymentRequest.startsWith("lightning:")) paymentRequest = paymentRequest.substring(10);
        if(!this.Utils.isValidLightningInvoice(paymentRequest)) throw new Error("Invalid lightning network invoice");
        if(!this._chains[chainIdentifier].chainInterface.isValidAddress(signer, true)) throw new Error("Invalid "+chainIdentifier+" address");
        signer = this._chains[chainIdentifier].chainInterface.normalizeAddress(signer);
        const parsedPR = bolt11Decode(paymentRequest);
        if(parsedPR.millisatoshis==null) throw new Error("Invalid lightning network invoice, no msat value field!");
        const amountData = {
            amount: (BigInt(parsedPR.millisatoshis) + 999n) / 1000n,
            token: tokenAddress,
            exactIn: false as const
        };
        return this.createSwap(
            chainIdentifier as ChainIdentifier,
            (candidates: Intermediary[], abortSignal: AbortSignal, chain) => chain.wrappers[SwapType.TO_BTCLN].create(
                signer,
                paymentRequest,
                amountData,
                candidates,
                options,
                additionalParams,
                abortSignal
            ),
            amountData,
            SwapType.TO_BTCLN
        );
    }

    /**
     * Creates Smart chain -> Bitcoin Lightning ({@link SwapType.TO_BTCLN}) swap via LNURL-pay link
     *
     * @param chainIdentifier Chain identifier string of the source smart chain
     * @param signer Signer's address on the source chain
     * @param tokenAddress Token address to pay with
     * @param lnurlPay LNURL-pay link to use for the payment
     * @param amount Amount to send in token based units (if `exactIn=true`) or receive in satoshis (if `exactIn=false`)
     * @param exactIn Whether to do an exact in swap instead of exact out
     * @param additionalParams Additional parameters sent to the LP when creating the swap
     * @param options Additional options for the swap
     */
    async createToBTCLNSwapViaLNURL<ChainIdentifier extends ChainIds<T>>(
        chainIdentifier: ChainIdentifier,
        signer: string,
        tokenAddress: string,
        lnurlPay: string | LNURLPay,
        amount: bigint,
        exactIn: boolean = false,
        additionalParams: Record<string, any> | undefined = this.options.defaultAdditionalParameters,
        options?: ToBTCLNOptions & {comment?: string}
    ): Promise<ToBTCLNSwap<T[ChainIdentifier]>> {
        if(this._chains[chainIdentifier]==null) throw new Error("Invalid chain identifier! Unknown chain: "+chainIdentifier);
        if(typeof(lnurlPay)==="string" && !this.Utils.isValidLNURL(lnurlPay)) throw new Error("Invalid LNURL-pay link");
        if(!this._chains[chainIdentifier].chainInterface.isValidAddress(signer, true)) throw new Error("Invalid "+chainIdentifier+" address");
        signer = this._chains[chainIdentifier].chainInterface.normalizeAddress(signer);
        const amountData = {
            amount,
            token: tokenAddress,
            exactIn
        };
        return this.createSwap(
            chainIdentifier as ChainIdentifier,
            (candidates: Intermediary[], abortSignal: AbortSignal, chain) => chain.wrappers[SwapType.TO_BTCLN].createViaLNURL(
                signer,
                typeof(lnurlPay)==="string" ? (lnurlPay.startsWith("lightning:") ? lnurlPay.substring(10): lnurlPay) : lnurlPay.params,
                amountData,
                candidates,
                options,
                additionalParams,
                abortSignal
            ),
            amountData,
            SwapType.TO_BTCLN
        );
    }

    /**
     * Creates Smart chain -> Bitcoin Lightning ({@link SwapType.TO_BTCLN}) swap via {@link LightningInvoiceCreateService}
     *
     * @param chainIdentifier Chain identifier string of the source smart chain
     * @param signer Signer's address on the source chain
     * @param tokenAddress Token address to pay with
     * @param service Invoice create service object which facilitates the creation of fixed amount LN invoices
     * @param amount Amount to send in token based units (if `exactIn=true`) or receive in satoshis (if `exactIn=false`)
     * @param exactIn Whether to do an exact in swap instead