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import { Provider } from '@ethersproject/abstract-provider'
import { Logger } from '@eth-optimism/common-ts'
/**
* Finds
*
* @param
* @param
* @param
* @returns
*/
export const getLastFinalizedBlock = async (
l1RpcProvider: Provider,
faultProofWindow: number,
logger: Logger
): Promise<number> => {
let guessWindowStartBlock
try {
const l1Block = await l1RpcProvider.getBlock('latest')
// The time corresponding to the start of the FPW, based on the current block.
const windowStartTime = l1Block.timestamp - faultProofWindow
// Use the FPW to find the block number that is the start of the FPW.
guessWindowStartBlock = l1Block.number - faultProofWindow / 12
let block = await l1RpcProvider.getBlock(guessWindowStartBlock)
while (block.timestamp > windowStartTime) {
guessWindowStartBlock--
block = await l1RpcProvider.getBlock(guessWindowStartBlock)
}
return block.number
} catch (err) {
logger.fatal('error when calling querying for block', {
errors: err,
})
throw new Error(
`unable to find block number ${guessWindowStartBlock || 'latest'}`
)
}
}