@atomiqlabs/sdk/src/swaps/escrow_swaps/frombtc/IFromBTCWrapper.ts

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

import {ISwapWrapperOptions} from "../../ISwapWrapper";
import {Intermediary} from "../../../intermediaries/Intermediary";
import {IntermediaryError} from "../../../errors/IntermediaryError";
import {mapArrayToObject, randomBytes} from "../../../utils/Utils";
import {BigIntBufferUtils, ChainType} from "@atomiqlabs/base";
import {IEscrowSwapDefinition, IEscrowSwapWrapper} from "../IEscrowSwapWrapper";
import {IEscrowSwap} from "../IEscrowSwap";
import {AmountData} from "../../../types/AmountData";

export type IFromBTCDefinition<T extends ChainType, W extends IFromBTCWrapper<T, any>, S extends IEscrowSwap<T>> = IEscrowSwapDefinition<T, W, S>;

/**
 * Base class for wrappers of escrow-based Bitcoin (on-chain & lightning) -> Smart chain swaps
 *
 * @category Swaps/Abstract
 */
export abstract class IFromBTCWrapper<
    T extends ChainType,
    D extends IFromBTCDefinition<T, IFromBTCWrapper<T, D>, IEscrowSwap<T, D>>,
    O extends ISwapWrapperOptions = ISwapWrapperOptions
> extends IEscrowSwapWrapper<T, D, O> {

    /**
     * Returns a random sequence to be used for swaps
     *
     * @returns Random 64-bit sequence number
     *
     * @internal
     */
    protected getRandomSequence(): bigint {
        return BigIntBufferUtils.fromBuffer(randomBytes(8));
    }

    /**
     * Pre-fetches smart chain fee rate for initiating a swap escrow on the smart chain side
     *
     * @param signer Address initiating the swap
     * @param amountData
     * @param claimHash optional claim hash of the swap or null
     * @param abortController
     *
     * @param contractVersions
     * @returns Fee rate
     *
     * @internal
     */
    protected preFetchFeeRate(
        signer: string,
        amountData: AmountData,
        claimHash: {[contractVersion: string]: string} | undefined,
        abortController: AbortController,
        contractVersions: string[]
    ): {[contractVersion: string]: Promise<string | undefined>} {
        return mapArrayToObject(contractVersions, (contractVersion) => {
            return this._contract(contractVersion).getInitFeeRate(this._chain.randomAddress(), signer, amountData.token, claimHash?.[contractVersion])
                .catch(e => {
                    this.logger.warn("preFetchFeeRate(): Error: ", e);
                    abortController.abort(e);
                    return undefined;
                });
        });
    }

    /**
     * Pre-fetches intermediary (LP) available smart chain liquidity
     *
     * @param amountData
     * @param lp Intermediary
     * @param abortController
     *
     * @param contractVersion
     * @returns Intermediary's liquidity balance
     *
     * @internal
     */
    protected preFetchIntermediaryLiquidity(
        amountData: AmountData,
        lp: Intermediary,
        abortController: AbortController,
        contractVersion: string
    ): Promise<bigint | undefined> {
        return lp.getLiquidity(this.chainIdentifier, this._contract(contractVersion), amountData.token.toString(), abortController.signal).catch(e => {
            this.logger.warn("preFetchIntermediaryLiquidity(): Error: ", e);
            abortController.abort(e);
            return undefined;
        })
    }

    /**
     * Verifies whether the intermediary (LP) has enough available liquidity such that we can initiate the swap
     *
     * @param amount Swap amount that the recipient should receive
     * @param liquidityPromise pre-fetched liquidity promise as obtained from {@link preFetchIntermediaryLiquidity}
     *
     * @throws {IntermediaryError} if intermediary's liquidity is lower than what's required for the swap
     *
     * @internal
     */
    protected async verifyIntermediaryLiquidity(
        amount: bigint,
        liquidityPromise: Promise<bigint>
    ): Promise<void> {
        const liquidity = await liquidityPromise;
        if(liquidity < amount) throw new IntermediaryError("Intermediary doesn't have enough liquidity");
    }

}