eventParser.ts

import {ContractLog} from "./model";

export enum EventType {
    Sync = 'Sync',
    SwapTokens = 'SwapTokens',
    PairMint = 'PairMint',
    PairBurn = 'PairBurn',
    Mint = 'Mint',
    Transfer = 'Transfer',
    Burn = 'Burn',
}

export interface Event {
    eventType: EventType;
    reserve0?: bigint;
    reserve1?: bigint;
    deltaReserve0?: bigint;
    deltaReserve1?: bigint;
    balanceChange?: {
        [address: string]: bigint;
    }
}

export class EventParser {
    private readonly SYNC_EVENT_HASH = '6O232NLB36RGK54HEJPVDFJVCSIVFV29KPORC07CSSDARM7LV4L0====';
    private readonly SWAP_TOKENS_EVENT_HASH = 'K39AB2I57LEUOUQ04LTEOMSJPJC3G9VGFRKVNJ5QLRMVCMDOPIMG====';
    private readonly PAIR_BURN_EVENT_HASH = 'OIS2ALGSJ03MTP2BR5RBFL1GOUGESRVPGE58LGM0MVG9K3VAFKUG====';
    private readonly PAIR_MINT_EVENT_HASH = 'L2BEDU7I5T8OSEUPB61900P8FJR637OE4MC4A9875C390RMQHSN0====';
    private readonly MINT_EVENT_HASH = 'QS0FEGR42QJOOJ65BU8F5LHHDSUAI6MLUGP3NAI8MPD4HCIKVCHG====';
    private readonly BURN_EVENT_HASH = 'GEBBU7TVBOEK82KF7RRQIBMTB259DC4QATN6IIDDTKLFOQE1I830====';
    private readonly TRANSFER_EVENT_HASH = '48U3JOKTVTI6FVMTK2BLHM8NG72JEBG93VS6MENPSC8E71IM5FNG====';

    public parseEvent(log: ContractLog): Event | undefined {


        const parseEventData = (data: string): bigint[] => {
            return data.split('|').map((d) => BigInt(d));
        };

        switch (log.event_hash) {
            case this.SYNC_EVENT_HASH:
                // Sync
                // args: [balance0, balance1], data: empty
                return {
                    eventType: EventType.Sync,
                    reserve0: BigInt(log.args[0]),
                    reserve1: BigInt(log.args[1]),
                };
            case this.SWAP_TOKENS_EVENT_HASH:
                // SwapTokens
                // args: [_, _], data: [amount0In, amount1In, amount0Out, amount1Out]
                const swapTokensData = parseEventData(log.data);
                return {
                    eventType: EventType.SwapTokens,
                    deltaReserve0: swapTokensData[0] - swapTokensData[2],
                    deltaReserve1: swapTokensData[1] - swapTokensData[3],
                };
            case this.PAIR_MINT_EVENT_HASH:
                // PairMint
                // args: [_, amount0, amount1], data: empty
                return {
                    eventType: EventType.PairMint,
                    deltaReserve0: BigInt(log.args[1]),
                    deltaReserve1: BigInt(log.args[2]),
                };
            case this.PAIR_BURN_EVENT_HASH:
                // PairBurn
                // args: [_, _], data: [amount0, amount1]
                const pairBurnData = parseEventData(log.data);
                return {
                    eventType: EventType.PairBurn,
                    deltaReserve0: 0n - pairBurnData[0],
                    deltaReserve1: 0n - pairBurnData[1],
                };
            case this.MINT_EVENT_HASH:
                // Mint
                // args: [address, amount]

                return {
                    eventType: EventType.Mint,
                    balanceChange: {
                        [log.args[0]]: BigInt(log.args[1]),
                    }
                };
            case this.BURN_EVENT_HASH:
                // Burn
                // args: [address, amount]
                return {
                    eventType: EventType.Burn,
                    balanceChange: {
                        [log.args[0]]: 0n - BigInt(log.args[1]),
                    }
                };
            case this.TRANSFER_EVENT_HASH:
                // Transfer
                // args: [from, to, amount]
                return {
                    eventType: EventType.Transfer,
                    balanceChange: {
                        [log.args[0]]: 0n - BigInt(log.args[2]),
                        [log.args[1]]: BigInt(log.args[2]),
                    }
                };

            default:
                // console.log('No matching event hash found');
                // console.log(`Parsing event with hash: ${log.event_hash}`);
                // console.log(`Event name: ${log.event_name}`);
                // console.log(`Event data: ${log.data}`);
                // console.log(`Event args: ${log.args.join(', ')}`);
                return undefined;
        }
    }
}