Swapr subgraph: parse transactions

transaction.ts

import { Address, ethereum, log } from '@graphprotocol/graph-ts'
import { Mint, Transfer } from '../types/templates/Pair/Pair'
/**
 * The method ID for:
 * `Transfer(address indexed from, address indexed to, uint256 value)`
 */
export let TRANSFER_METHOD_ID = '0xddf252ad'

/**
 * The method ID for:
 * `Mint(address indexed sender, uint256 amount0, uint256 amount1)`
 */
export let MINT_METHOD_ID = '0x4c209b5f'

/**
 * @todo add other networks
 */
export function getSwaprFeeReceiver(): Address {
  return Address.fromString('0x65f29020d07A6CFa3B0bF63d749934d5A6E6ea18')
}

/**
 * Parses the events emitted from the transtaction and returns the
 * @param originalEvent The original event emitted from the transaction
 */
export function parseTransactionEvents(originalEvent: ethereum.Event): ethereum.Event[] {
  let transactionReceipt = originalEvent.receipt as ethereum.TransactionReceipt

  // Check
  if (!transactionReceipt) {
    return []
  }

  /**
   * Return value
   */
  let transactionEvents: ethereum.Event[] = []
  // Find the TokenTransfer event from the receipt
  let otherEventsFromPairContract: ethereum.Log[] = []
  let finalLogOutput = ''

  for (let i = 0; i < transactionReceipt.logs.length; i++) {
    let receiptLog = transactionReceipt.logs[i]

    // Mint event
    if (receiptLog.topics[0].toString().startsWith(MINT_METHOD_ID)) {
      // Parse the event

      let sender = new ethereum.EventParam(
        'sender',
        new ethereum.Value(ethereum.ValueKind.ADDRESS, receiptLog.topics[1].toU64())
      )
      // let amount0 = receiptLog.topics[2].toString()
      // let amount1 = receiptLog.topics[3].toString()

      transactionEvents.push(
        new Mint(
          receiptLog.address,
          receiptLog.logIndex,
          receiptLog.transactionIndex,
          'Mint',
          originalEvent.block,
          originalEvent.transaction,
          [sender], // parameters
          originalEvent.receipt
        )
      )
    }

    // ERC20 Transfers
    if (receiptLog.topics[0].toString().startsWith(TRANSFER_METHOD_ID)) {
      let from = new ethereum.EventParam(
        'from',
        new ethereum.Value(ethereum.ValueKind.ADDRESS, receiptLog.topics[1].toU64())
      )
      let to = new ethereum.EventParam(
        'to',
        new ethereum.Value(ethereum.ValueKind.ADDRESS, receiptLog.topics[2].toU64())
      )
      let value = new ethereum.EventParam('value', new ethereum.Value(ethereum.ValueKind.UINT, receiptLog.data.toU64()))

      transactionEvents.push(
        new Transfer(
          receiptLog.address,
          receiptLog.logIndex,
          receiptLog.transactionIndex,
          'Transfer',
          originalEvent.block,
          originalEvent.transaction,
          [from, to, value], // parameters
          originalEvent.receipt
        )
      )

      otherEventsFromPairContract.push(receiptLog)
      finalLogOutput.concat(
        '\r\n' +
          'receiptLog.topics: ' +
          receiptLog.data.toHexString() +
          ', receiptLog.data: ' +
          receiptLog.data.toHexString()
      )
    }
  }

  log.info(finalLogOutput, [])

  return transactionEvents
}