Yield-Optimized Collateral Manager

const SPRINTER_API = "https://api.sprinter.tech";
const POLL_INTERVAL_MS = 60 * 60 * 1000; // 1 hour
const MIN_HEALTH_FACTOR = 1.5; // higher threshold during rebalancing
const MIN_YIELD_IMPROVEMENT = 0.5; // only rebalance if >= 0.5% APY improvement

interface ContractCall {
  to: string;
  data: string;
  value: string;
}

interface VaultPosition {
  strategy: string;
  amount: string;
  asset: string;
  apy: number;
}

async function getCreditInfo(account: string) {
  const res = await fetch(`${SPRINTER_API}/credit/accounts/${account}/info`);
  if (!res.ok) throw new Error(`Credit info failed: ${res.status}`);
  return res.json();
}

async function getProtocolConfig() {
  const res = await fetch(`${SPRINTER_API}/credit/protocol`);
  if (!res.ok) throw new Error(`Protocol config failed: ${res.status}`);
  return res.json();
}

async function buildUnlockCalls(
  account: string,
  amount: string,
  asset: string
): Promise<ContractCall[]> {
  const res = await fetch(
    `${SPRINTER_API}/credit/accounts/${account}/unlock?amount=${amount}&asset=${asset}`,
  );
  if (!res.ok) throw new Error(`Unlock calldata failed: ${res.status}`);
  const data = await res.json();
  return data.calls;
}

async function buildLockCalls(
  account: string,
  amount: string,
  asset: string,
  earn?: string
): Promise<ContractCall[]> {
  let url = `${SPRINTER_API}/credit/accounts/${account}/lock?amount=${amount}&asset=${asset}`;
  if (earn) url += `&earn=${earn}`;

  const res = await fetch(url);
  if (!res.ok) throw new Error(`Lock calldata failed: ${res.status}`);
  const data = await res.json();
  return data.calls;
}

async function executeCalls(calls: ContractCall[], signer: any): Promise<string> {
  let lastTxHash = "";
  for (const call of calls) {
    const tx = await signer.sendTransaction({
      to: call.to,
      data: call.data,
      value: call.value || "0",
    });
    const receipt = await tx.wait();
    if (!receipt || receipt.status !== 1) throw new Error(`Tx reverted: ${tx.hash}`);
    lastTxHash = tx.hash;
  }
  return lastTxHash;
}

async function optimizeYield(
  account: string,
  currentPosition: VaultPosition,
  signer: any
) {
  // 1. Check health factor
  const info = await getCreditInfo(account);
  const hf = parseFloat(info.data.USDC.healthFactor);

  if (hf < MIN_HEALTH_FACTOR) {
    console.log(`Health factor ${hf.toFixed(2)} too low to rebalance — skipping`);
    return;
  }

  // 2. Get available strategies from protocol config
  const config = await getProtocolConfig();
  const strategies = config.strategies ?? [];

  // 3. Find the best vault by yield
  const bestVault = strategies
    .filter((s: any) => s.id !== currentPosition.strategy)
    .sort((a: any, b: any) => b.apy - a.apy)[0];

  if (!bestVault) {
    console.log("No alternative vaults available");
    return;
  }

  const improvement = bestVault.apy - currentPosition.apy;
  if (improvement < MIN_YIELD_IMPROVEMENT) {
    console.log(
      `Best alternative: ${bestVault.apy}% APY (+${improvement.toFixed(2)}%) — below threshold`
    );
    return;
  }

  console.log(
    `Rebalancing: ${currentPosition.apy}% → ${bestVault.apy}% APY (+${improvement.toFixed(2)}%)`
  );

  // 4. Unlock from current vault
  const unlockCalls = await buildUnlockCalls(
    account,
    currentPosition.amount,
    currentPosition.asset
  );
  const unlockTx = await executeCalls(unlockCalls, signer);
  console.log(`Unlocked from ${currentPosition.strategy}: ${unlockTx}`);

  // 5. Lock into new vault with earn param
  const lockCalls = await buildLockCalls(
    account,
    currentPosition.amount,
    currentPosition.asset,
    bestVault.id
  );
  const lockTx = await executeCalls(lockCalls, signer);
  console.log(`Locked into ${bestVault.id}: ${lockTx}`);
}

// Run the optimizer loop
setInterval(() => {
  const currentPosition: VaultPosition = {
    strategy: "CURRENT_STRATEGY_ID",
    amount: "1000000000000000000",
    asset: "0xCOLLATERAL_TOKEN",
    apy: 4.2,
  };
  optimizeYield("0xUSER_ADDRESS", currentPosition, signer).catch(console.error);
}, POLL_INTERVAL_MS);

curl -X GET https://api.sprinter.tech/credit/protocol