feat: add ScrubVault yield pools to scrub project (Kava USDt + Arbitrum USDC)

src/adaptors/scrub/index.js

@@ -0,0 +1,218 @@
+/**
+ * ScrubVault yield adapter for DefiLlama.
+ *
+ * ScrubVault is a delta-neutral managed vault where users deposit USDt (Kava)
+ * or USDC (Arbitrum) and receive share tokens representing their proportional
+ * ownership. The deposited capital is deployed off-chain across centralised and
+ * decentralised exchanges running a delta-neutral strategy that earns yield from
+ * funding rates and market-making activity.
+ *
+ * Why funds are not held in the vault contract:
+ *   The vault contract functions as an on-chain accounting and settlement layer.
+ *   Once a deposit batch is processed, the stablecoins are transferred to the
+ *   strategy wallet and actively deployed on exchanges. The on-chain variable
+ *   `totalVaultValue` is the authoritative AUM figure — it is updated by the
+ *   admin/strategy role via `distributeRewards()` each time PnL is settled.
+ *   TVL and APY reported here are therefore based on that on-chain accounting
+ *   value, not on a simple `balanceOf` check.
+ *
+ * APY methodology:
+ *   APR is derived from all `RewardDistributed` events within the past 3 days.
+ *   All events are included — negative (loss) days reduce the result so the
+ *   figure reflects the true rolling return, not just positive days.
+ *   Rewards are distributed once per day (6 pm - 1 am UTC), so a 3-day
+ *   lookback always captures at least one event.
+ *   APR formula: sum(rewardAmount over window) / prevTVL / windowDays * 365 * 100.
+ *
+ *   Logs are fetched via the DefiLlama SDK for both chains:
+ *   - Arbitrum: single sdk.api.util.getLogs call (no per-request block limit).
+ *   - Kava: RPC caps eth_getLogs at 10 000 blocks, so the 3-day window
+ *     (~43 200 blocks) is split into 5 parallel SDK calls.
+ *   - Kava's latest block is obtained via ethers.providers.JsonRpcProvider
+ *     because sdk.api.util.getLatestBlock does not support Kava.
+ */
+
+const sdk        = require('@defillama/sdk');
+const { ethers } = require('ethers');
+
+// ─── Constants ────────────────────────────────────────────────────────────────
+
+const PROJECT = 'scrub';
+
+const VAULTS = {
+  kava: {
+    chain:        'Kava',
+    address:      '0x7BFf6c730dA681dF03364c955B165576186370Bc',
+    stablecoin:   '0x919C1c267BC06a7039e03fcc2eF738525769109c', // USDt on Kava
+    symbol:       'USDt',
+    decimals:     6,
+    poolMeta:     'Delta Neutral USDt Vault',
+    logChunkSize: 10000, // Kava RPC limit per eth_getLogs request
+    blockTime:    6,     // seconds per block
+    rpcUrl:       'https://evm.kava.io',
+  },
+  arbitrum: {
+    chain:        'Arbitrum',
+    address:      '0x439a923517C4DFD3F3d0ABb0C36E356D39CF3f9D',
+    stablecoin:   '0xaf88d065e77c8cC2239327C5EDb3A432268e5831', // native USDC
+    symbol:       'USDC',
+    decimals:     6,
+    poolMeta:     'Delta Neutral USDC Vault',
+    logChunkSize: null,  // Arbitrum handles large ranges in one call
+    blockTime:    0.25,
+    rpcUrl:       null,  // use sdk.api.util.getLatestBlock
+  },
+};
+
+// ─── ABI / event setup ───────────────────────────────────────────────────────
+
+const TOTAL_VAULT_VALUE_ABI = {
+  inputs:          [],
+  name:            'totalVaultValue',
+  outputs:         [{ internalType: 'uint256', name: '', type: 'uint256' }],
+  stateMutability: 'view',
+  type:            'function',
+};
+
+const rewardIface  = new ethers.utils.Interface([
+  'event RewardDistributed(int256 rewardAmount, uint256 newTotalVaultValue, uint256 timestamp)',
+]);
+const REWARD_TOPIC = rewardIface.getEventTopic('RewardDistributed');
+
+// ─── Helpers ──────────────────────────────────────────────────────────────────
+
+async function getLatestBlockNumber(chainKey, rpcUrl) {
+  if (rpcUrl) {
+    // sdk.api.util.getLatestBlock does not support all chains (e.g. Kava).
+    // Fall back to a direct JSON-RPC call via ethers — already a dependency.
+    const provider = new ethers.providers.JsonRpcProvider(rpcUrl);
+    return provider.getBlockNumber();
+  }
+  return (await sdk.api.util.getLatestBlock(chainKey)).number;
+}
+
+async function fetchTvlUsd(chain, vaultAddress, decimals) {
+  const { output } = await sdk.api.abi.call({
+    abi:    TOTAL_VAULT_VALUE_ABI,
+    target: vaultAddress,
+    chain,
+  });
+  return Number(output) / 10 ** decimals;
+}
+
+async function fetchRewardLogs(chain, vaultAddress, latestBlock, blockTime, chunkSize) {
+  const blockWindow = Math.ceil(3 * 24 * 3600 / blockTime); // 3-day window
+  const fromBlock   = Math.max(0, latestBlock - blockWindow);
+
+  const logsCall = (from, to) =>
+    sdk.api.util.getLogs({
+      target:    vaultAddress,
+      topic:     '',
+      fromBlock: from,
+      toBlock:   to,
+      keys:      [],
+      topics:    [REWARD_TOPIC],
+      chain,
+    }).then((r) => r.output || []).catch(() => []);
+
+  if (!chunkSize) {
+    return logsCall(fromBlock, latestBlock);
+  }
+
+  // Kava: split 3-day window into parallel 10k-block chunks (~5 chunks)
+  const chunks = [];
+  for (let s = fromBlock; s <= latestBlock; s += chunkSize) {
+    chunks.push([s, Math.min(s + chunkSize - 1, latestBlock)]);
+  }
+  const results = await Promise.all(chunks.map(([f, t]) => logsCall(f, t)));
+  return results.flat();
+}
+
+function computeDailyApr(logs, decimals) {
+  // Parse all events in the window (logs are in chronological order, oldest first).
+  const events = [];
+  for (const log of logs) {
+    try {
+      const p = rewardIface.parseLog(log);
+      events.push({ reward: p.args.rewardAmount, newTvl: p.args.newTotalVaultValue });
+    } catch (_) {
+      // skip unparseable logs
+    }
+  }
+  if (!events.length) return 0;
+
+  // Sum all rewards across the window — negative (loss) days are included so
+  // the result reflects the true rolling return, not just positive days.
+  let totalReward = ethers.BigNumber.from(0);
+  for (const { reward } of events) {
+    totalReward = totalReward.add(reward);
+  }
+
+  // TVL before the earliest event in the window is used as the denominator.
+  const firstPrevTvl = events[0].newTvl.sub(events[0].reward);
+  if (firstPrevTvl.lte(0)) return 0;
+
+  // Use formatUnits instead of toNumber() to avoid Number.MAX_SAFE_INTEGER
+  // overflow on large balances (toNumber throws above 2^53-1, ~$9B at 6 decimals).
+  const totalRewardUsd = Number(ethers.utils.formatUnits(totalReward, decimals));
+  const prevTvlUsd     = Number(ethers.utils.formatUnits(firstPrevTvl, decimals));
+  if (prevTvlUsd <= 0) return 0;
+
+  // Annualise over the 3-day lookback window.
+  const WINDOW_DAYS = 3;
+  const apr = (totalRewardUsd / prevTvlUsd / WINDOW_DAYS) * 365 * 100;
+  return Number.isFinite(apr) ? apr : 0;
+}
+
+// ─── Main ─────────────────────────────────────────────────────────────────────
+
+const apy = async () => {
+  const pools = [];
+
+  for (const [chainKey, vault] of Object.entries(VAULTS)) {
+    // Wrap each vault independently so an RPC outage on one chain does not
+    // prevent the other chain's pool from being reported.
+    try {
+      const latestBlock = await getLatestBlockNumber(chainKey, vault.rpcUrl);
+
+      const [tvlUsd, logs] = await Promise.all([
+        fetchTvlUsd(chainKey, vault.address, vault.decimals),
+        fetchRewardLogs(
+          chainKey,
+          vault.address,
+          latestBlock,
+          vault.blockTime,
+          vault.logChunkSize,
+        ),
+      ]);
+
+      const apyBase  = computeDailyApr(logs, vault.decimals);
+      const vaultUrl =
+        `https://invest.scrub.money/vault/chain/${chainKey}/${vault.address.toLowerCase()}`;
+
+      pools.push({
+        pool:             `${vault.address}-${chainKey}`.toLowerCase(),
+        chain:            vault.chain,
+        project:          PROJECT,
+        symbol:           vault.symbol,
+        tvlUsd,
+        apyBase:          Math.round(apyBase * 100) / 100,
+        underlyingTokens: [vault.stablecoin],
+        poolMeta:         vault.poolMeta,
+        url:              vaultUrl,
+      });
+    } catch (err) {
+      console.error(
+        `[scrub] ${vault.chain} vault ${vault.address} failed: ${err.message}`,
+      );
+    }
+  }
+
+  return pools;
+};
+
+module.exports = {
+  timetravel: false,
+  apy,
+  url: 'https://invest.scrub.money/',
+};