@atomiqlabs/sdk-lib/src/swaps/ISwapWrapper.ts

Basic SDK functionality library for atomiq

import {
    ChainEvent,
    ChainType,
    ClaimEvent,
    InitializeEvent,
    RefundEvent, SignatureData,
    SignatureVerificationError, SwapCommitState,
    SwapEvent
} from "@atomiqlabs/base";
import {EventEmitter} from "events";
import {ISwap} from "./ISwap";
import {ISwapPrice, PriceInfoType} from "../prices/abstract/ISwapPrice";
import {IntermediaryError} from "../errors/IntermediaryError";
import {getLogger, tryWithRetries} from "../utils/Utils";
import {SCToken} from "../Tokens";
import {ChainIds, MultiChain} from "./swapper/Swapper";
import {UnifiedSwapEventListener} from "../events/UnifiedSwapEventListener";
import {SwapType} from "./enums/SwapType";
import {UnifiedSwapStorage} from "../storage/UnifiedSwapStorage";
import {Intermediary} from "../intermediaries/Intermediary";

export type AmountData = {
    amount: bigint,
    token: string,
    exactIn?: boolean
}

export type ISwapWrapperOptions = {
    getRequestTimeout?: number,
    postRequestTimeout?: number
};

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

export abstract class ISwapWrapper<
    T extends ChainType,
    S extends ISwap<T>,
    O extends ISwapWrapperOptions = ISwapWrapperOptions
> {
    abstract readonly TYPE: SwapType;
    protected readonly logger = getLogger(this.constructor.name+": ");

    public readonly abstract swapDeserializer: new (wrapper: ISwapWrapper<T, S, O>, data: any) => S;

    readonly unifiedStorage: UnifiedSwapStorage<T>;
    readonly unifiedChainEvents: UnifiedSwapEventListener<T>;

    readonly chainIdentifier: T["ChainId"];
    readonly chain: T["ChainInterface"];
    readonly prices: ISwapPrice;
    readonly events: EventEmitter<{swapState: [ISwap]}>;
    readonly options: O;
    readonly tokens: {
        [tokenAddress: string]: SCToken<T["ChainId"]>
    };
    readonly pendingSwaps: Map<string, WeakRef<S>> = new Map();

    isInitialized: boolean = false;
    tickInterval: NodeJS.Timeout = null;

    /**
     * @param chainIdentifier
     * @param unifiedStorage
     * @param unifiedChainEvents
     * @param chain
     * @param prices Swap pricing handler
     * @param tokens Chain specific token data
     * @param options
     * @param events Instance to use for emitting events
     */
    constructor(
        chainIdentifier: T["ChainId"],
        unifiedStorage: UnifiedSwapStorage<T>,
        unifiedChainEvents: UnifiedSwapEventListener<T>,
        chain: T["ChainInterface"],
        prices: ISwapPrice,
        tokens: WrapperCtorTokens,
        options: O,
        events?: EventEmitter<{swapState: [ISwap]}>
    ) {
        this.unifiedStorage = unifiedStorage;
        this.unifiedChainEvents = unifiedChainEvents;

        this.chainIdentifier = chainIdentifier;
        this.chain = chain;
        this.prices = prices;
        this.events = events || new EventEmitter();
        this.options = options;
        this.tokens = {};
        for(let tokenData of tokens) {
            const chainData = tokenData.chains[chainIdentifier];
            if(chainData==null) continue;
            this.tokens[chainData.address] = {
                chain: "SC",
                chainId: this.chainIdentifier,
                address: chainData.address,
                decimals: chainData.decimals,
                ticker: tokenData.ticker,
                name: tokenData.name,
                displayDecimals: chainData.displayDecimals
            };
        }
    }

    /**
     * Pre-fetches swap price for a given swap
     *
     * @param amountData
     * @param abortSignal
     * @protected
     * @returns Price of the token in uSats (micro sats)
     */
    protected preFetchPrice(amountData: { token: string }, abortSignal?: AbortSignal): Promise<bigint | null> {
        return this.prices.preFetchPrice(this.chainIdentifier, amountData.token, abortSignal).catch(e => {
            this.logger.error("preFetchPrice(): Error: ", e);
            return null;
        });
    }

    /**
     * Verifies returned  price for swaps
     *
     * @param lpServiceData Service data for the service in question (TO_BTCLN, TO_BTC, etc.) of the given intermediary
     * @param send Whether this is a send (SOL -> SC) or receive (BTC -> SC) swap
     * @param amountSats Amount in BTC
     * @param amountToken Amount in token
     * @param token Token used in the swap
     * @param feeData Fee data as returned by the intermediary
     * @param pricePrefetchPromise Price pre-fetch promise
     * @param abortSignal
     * @protected
     * @returns Price info object
     * @throws {IntermediaryError} if the calculated fee is too high
     */
    protected async verifyReturnedPrice(
        lpServiceData: {swapBaseFee: number, swapFeePPM: number},
        send: boolean,
        amountSats: bigint,
        amountToken: bigint,
        token: string,
        feeData: {
            networkFee?: bigint
        },
        pricePrefetchPromise: Promise<bigint> = Promise.resolve(null),
        abortSignal?: AbortSignal
    ): Promise<PriceInfoType> {
        const swapBaseFee = BigInt(lpServiceData.swapBaseFee);
        const swapFeePPM = BigInt(lpServiceData.swapFeePPM);
        if(send) amountToken = amountToken - feeData.networkFee;

        const isValidAmount = await (
            send ?
                this.prices.isValidAmountSend(this.chainIdentifier, amountSats, swapBaseFee, swapFeePPM, amountToken, token, abortSignal, await pricePrefetchPromise) :
                this.prices.isValidAmountReceive(this.chainIdentifier, amountSats, swapBaseFee, swapFeePPM, amountToken, token, abortSignal, await pricePrefetchPromise)
        );
        if(!isValidAmount.isValid) throw new IntermediaryError("Fee too high");

        return isValidAmount;
    }

    public abstract readonly pendingSwapStates: Array<S["state"]>;
    public abstract readonly tickSwapState: Array<S["state"]>;

    /**
     * Processes a single SC on-chain event
     * @private
     * @param event
     * @param swap
     */
    protected abstract processEvent?(event: ChainEvent<T["Data"]>, swap: S): Promise<boolean>;

    /**
     * Initializes the swap wrapper, needs to be called before any other action can be taken
     */
    public async init(noTimers: boolean = false, noCheckPastSwaps: boolean = false): Promise<void> {
        if(this.isInitialized) return;

        const hasEventListener = this.processEvent!=null;

        //Save events received in the meantime into the event queue and process them only after we've checked and
        // processed all the past swaps
        let eventQueue: {
            event: ChainEvent<T["Data"]>,
            swap: S
        }[] = [];
        const initListener = (event: SwapEvent<T["Data"]>, swap: S) => {
            eventQueue.push({event, swap});
            return Promise.resolve();
        }
        if(hasEventListener) this.unifiedChainEvents.registerListener(this.TYPE, initListener, this.swapDeserializer.bind(null, this));

        if(!noCheckPastSwaps) await this.checkPastSwaps();

        if(hasEventListener) {
            //Process accumulated event queue
            for(let event of eventQueue) {
                await this.processEvent(event.event, event.swap);
            }

            //Register the correct event handler
            this.unifiedChainEvents.unregisterListener(this.TYPE);
            this.unifiedChainEvents.registerListener(this.TYPE, this.processEvent.bind(this), this.swapDeserializer.bind(null, this));
        }

        if(!noTimers) this.startTickInterval();

        // this.logger.info("init(): Swap wrapper initialized");

        this.isInitialized = true;
    }

    protected startTickInterval(): void {
        if(this.tickSwapState==null || this.tickSwapState.length===0) return;
        this.tickInterval = setInterval(() => {
            this.tick();
        }, 1000);
    }

    protected async _checkPastSwaps(pastSwaps: S[]): Promise<{changedSwaps: S[], removeSwaps: S[]}> {
        const changedSwaps: S[] = [];
        const removeSwaps: S[] = [];

        await Promise.all(pastSwaps.map((swap: S) =>
            swap._sync(false).then(changed => {
                if(swap.isQuoteExpired()) {
                    removeSwaps.push(swap);
                    this.logger.debug("_checkPastSwaps(): Removing expired swap: "+swap.getId());
                } else {
                    if(changed) changedSwaps.push(swap);
                }
            }).catch(e => this.logger.error("_checkPastSwaps(): Error when checking swap "+swap.getId()+": ", e))
        ));

        return {changedSwaps, removeSwaps};
    }

    async checkPastSwaps(pastSwaps?: S[], noSave?: boolean): Promise<{ removeSwaps: S[], changedSwaps: S[] }> {
        if (pastSwaps == null) pastSwaps = await this.unifiedStorage.query<S>(
            [[{key: "type", value: this.TYPE}, {key: "state", value: this.pendingSwapStates}]],
            (val: any) => new this.swapDeserializer(this, val)
        );

        const {removeSwaps, changedSwaps} = await this._checkPastSwaps(pastSwaps);

        if (!noSave) {
            await this.unifiedStorage.removeAll(removeSwaps);
            await this.unifiedStorage.saveAll(changedSwaps);
        }

        return {
            removeSwaps,
            changedSwaps
        }
    }

    async tick(swaps?: S[]): Promise<void> {
        if(swaps==null) swaps = await this.unifiedStorage.query<S>(
            [[{key: "type", value: this.TYPE}, {key: "state", value: this.tickSwapState}]],
            (val: any) => new this.swapDeserializer(this, val)
        );

        for(let pendingSwap of this.pendingSwaps.values()) {
            const value = pendingSwap.deref();
            if(value != null) value._tick(true);
        }

        swaps.forEach(value => {
            value._tick(true)
        });
    }

    saveSwapData(swap: S): Promise<void> {
        if(!swap.isInitiated()) {
            this.logger.debug("saveSwapData(): Swap "+swap.getId()+" not initiated, saving to pending swaps");
            this.pendingSwaps.set(swap.getId(), new WeakRef<S>(swap));
            return Promise.resolve();
        } else {
            this.pendingSwaps.delete(swap.getId());
        }
        return this.unifiedStorage.save(swap);
    }

    removeSwapData(swap: S): Promise<void> {
        this.pendingSwaps.delete(swap.getId());
        if(!swap.isInitiated()) return Promise.resolve();
        return this.unifiedStorage.remove(swap);
    }

    recoverFromSwapDataAndState(
        init: {data: T["Data"], getInitTxId: () => Promise<string>, getTxBlock: () => Promise<{blockTime: number, blockHeight: number}>},
        state: SwapCommitState,
        lp: Intermediary
    ): Promise<S> {
        return Promise.resolve(null);
    }

    /**
     * Un-subscribes from event listeners on Solana
     */
    public async stop() {
        this.isInitialized = false;
        this.unifiedChainEvents.unregisterListener(this.TYPE);
        this.logger.info("stop(): Swap wrapper stopped");
        if(this.tickInterval!=null) clearInterval(this.tickInterval);
    }

    /**
     * Returns the smart chain's native token used to pay for fees
     */
    public getNativeToken(): SCToken<T["ChainId"]> {
        return this.tokens[this.chain.getNativeCurrencyAddress()];
    }

}