staker-pnl.js

const ethers = require('ethers');

const address = `${process.argv[2]}`;
const api = `${process.env.PROVIDER_URL}`;

const provider = new ethers.providers.JsonRpcProvider(api);

const ABI = require('./Synthetix.json');

const synthetixAddress = '0x8700daec35af8ff88c16bdf0418774cb3d7599b4';
const synthetixUsdAddress = '0x8c6f28f2F1A3C87F0f938b96d27520d9751ec8d9';

const BATCH_SIZE = 1000000;

async function findBlockByNumber(time, start = 0, end = 'latest') {

	if (end === 'latest') {
		end = await provider.getBlockNumber();
	}

	if (end - start <= 1) {
		return start;
	}

	const checkBlock = Math.floor((start + end) / 2);
	console.log('check block', checkBlock);

	const block = await provider.getBlock(checkBlock);

	console.log(block.timestamp, '<', time);
	if (block.timestamp < time) {
		return await findBlockByNumber(time, checkBlock, end);
	} else {
		return await findBlockByNumber(time, start, checkBlock);
	}
}

async function sumEvents(contract, filter, startBlock, endBlock) {
	let summed = ethers.BigNumber.from(0);

	for (let i = startBlock; i < endBlock; i += BATCH_SIZE) {
		try {
			console.log('querying', i, endBlock);
			const events = await provider.getLogs({
				fromBlock: i,
				toBlock: i + BATCH_SIZE,
				address: contract,
				topics: filter
			});
			if (events.length) console.log(`found ${events.length} events`);
			for (const e of events) {
				// get the txn associated with this event to make sure it meets a standard
				const txn = await provider.getTransaction(e.transactionHash);
				//console.log(txn);
				// must match function selector
				if (
					txn.data.startsWith('0xaf086c7e') || // issueMaxSynths
					txn.data.startsWith('0x320223db') || // issue max synths on behalf
					txn.data.startsWith('0x8a290014') || // issue synths
					txn.data.startsWith('0xe8e09b8b') || // issue synths on behalf
					txn.data.startsWith('0x295da87d') || // burn synths
					txn.data.startsWith('0xc2bf3880') || // burn synths on behalf
					txn.data.startsWith('0x9741fb22') || // burn synths to target
					txn.data.startsWith('0x2c955fa7') // burn synths to target on behalf
				) {				
					//console.log(e);
					summed = summed.add(ethers.utils.defaultAbiCoder.decode(['uint256'], e.data)[0]);
				} else {
					console.log('skip non-matching selector');
				}
			}
		} catch (err) {
			console.log('skip', err);
		}
	}

	return summed;
}

async function calculateStakerPnl(address, taxYear) {
	const contract = new ethers.Contract(synthetixAddress, ABI, provider);

	const startTime = Math.floor(Date.parse(taxYear) / 1000);
	const endTime = taxYear + 31536000;

	const startBlockTag = await findBlockByNumber(startTime);
	const endBlockTag = await findBlockByNumber(endTime);

	const startDebt = await contract.debtBalanceOf(address, ethers.utils.formatBytes32String('sUSD'), { blockTag: startBlockTag });
	const endDebt = await contract.debtBalanceOf(address, ethers.utils.formatBytes32String('sUSD'), { blockTag: endBlockTag });

	// figure out all the mints and burns in between
	const minted = await sumEvents(synthetixUsdAddress, [ethers.utils.id('Issued(address,uint256)'), ethers.utils.defaultAbiCoder.encode(['address'], [address])], startBlockTag, endBlockTag);
	const burned = await sumEvents(synthetixUsdAddress, [ethers.utils.id('Burned(address,uint256)'), ethers.utils.defaultAbiCoder.encode(['address'], [address])], startBlockTag, endBlockTag);


	console.log('start debt', ethers.utils.formatEther(startDebt));
	console.log('end debt', ethers.utils.formatEther(endDebt));

	console.log('total mint', ethers.utils.formatEther(minted));
	console.log('total burn', ethers.utils.formatEther(burned));

	// add it all together
	const total = minted.add(startDebt).sub(endDebt).sub(burned);
	
	console.log('debt pool profit/loss:', ethers.utils.formatEther(total));

	return total;
}

calculateStakerPnl(process.argv[2], process.argv[3]);