237-combo/examples/ts/compound3-supply-borrow.ts

/**
 * Compound III: Supply collateral and borrow base asset
 * 
 * This example demonstrates how to:
 * 1. Supply collateral to Compound III
 * 2. Borrow the base asset (e.g., USDC)
 * 
 * Note: In Compound III, you "borrow" by withdrawing the base asset
 * after supplying collateral. There's one base asset per market.
 */

import { createWalletRpcClient } from '../../src/utils/chain-config.js';
import { getCompound3Comet } from '../../src/utils/addresses.js';
import { getTokenMetadata, parseTokenAmount } from '../../src/utils/tokens.js';
import { waitForTransaction } from '../../src/utils/rpc.js';

const CHAIN_ID = 1; // Mainnet
const PRIVATE_KEY = process.env.PRIVATE_KEY as `0x${string}`;

// Compound III Comet ABI
const COMET_ABI = [
  {
    name: 'supply',
    type: 'function',
    stateMutability: 'nonpayable',
    inputs: [
      { name: 'asset', type: 'address' },
      { name: 'amount', type: 'uint256' },
    ],
    outputs: [],
  },
  {
    name: 'withdraw',
    type: 'function',
    stateMutability: 'nonpayable',
    inputs: [
      { name: 'asset', type: 'address' },
      { name: 'amount', type: 'uint256' },
    ],
    outputs: [],
  },
  {
    name: 'baseToken',
    type: 'function',
    stateMutability: 'view',
    inputs: [],
    outputs: [{ name: '', type: 'address' }],
  },
  {
    name: 'getBorrowBalance',
    type: 'function',
    stateMutability: 'view',
    inputs: [{ name: 'account', type: 'address' }],
    outputs: [{ name: '', type: 'uint256' }],
  },
  {
    name: 'getCollateralBalance',
    type: 'function',
    stateMutability: 'view',
    inputs: [
      { name: 'account', type: 'address' },
      { name: 'asset', type: 'address' },
    ],
    outputs: [{ name: '', type: 'uint256' }],
  },
] as const;

// ERC20 ABI for approvals
const ERC20_ABI = [
  {
    name: 'approve',
    type: 'function',
    stateMutability: 'nonpayable',
    inputs: [
      { name: 'spender', type: 'address' },
      { name: 'amount', type: 'uint256' },
    ],
    outputs: [{ name: '', type: 'bool' }],
  },
] as const;

async function supplyAndBorrow() {
  const walletClient = createWalletRpcClient(CHAIN_ID, PRIVATE_KEY);
  const publicClient = walletClient as any;
  const account = walletClient.account?.address;
  
  if (!account) {
    throw new Error('No account available');
  }

  const cometAddress = getCompound3Comet(CHAIN_ID);
  
  // Get base token (USDC for USDC market)
  console.log('Querying Comet contract...');
  const baseToken = await publicClient.readContract({
    address: cometAddress,
    abi: COMET_ABI,
    functionName: 'baseToken',
  }) as `0x${string}`;

  console.log(`Comet: ${cometAddress}`);
  console.log(`Base token: ${baseToken}`);

  // Use WETH as collateral (adjust based on market)
  const collateralToken = getTokenMetadata(CHAIN_ID, 'WETH');
  const baseTokenMetadata = getTokenMetadata(CHAIN_ID, 'USDC'); // Assuming USDC market
  
  const collateralAmount = parseTokenAmount('1', collateralToken.decimals); // 1 WETH
  const borrowAmount = parseTokenAmount('2000', baseTokenMetadata.decimals); // 2000 USDC

  console.log(`\nSupplying ${collateralAmount} ${collateralToken.symbol} as collateral`);
  console.log(`Borrowing ${borrowAmount} ${baseTokenMetadata.symbol} (base asset)`);

  // Step 1: Approve collateral token
  console.log('\n1. Approving collateral token...');
  const approveTx = await walletClient.writeContract({
    address: collateralToken.address,
    abi: ERC20_ABI,
    functionName: 'approve',
    args: [cometAddress, collateralAmount],
  });
  await waitForTransaction(publicClient, approveTx);
  console.log(`Approved: ${approveTx}`);

  // Step 2: Supply collateral
  console.log('\n2. Supplying collateral...');
  const supplyTx = await walletClient.writeContract({
    address: cometAddress,
    abi: COMET_ABI,
    functionName: 'supply',
    args: [collateralToken.address, collateralAmount],
  });
  await waitForTransaction(publicClient, supplyTx);
  console.log(`Supplied: ${supplyTx}`);

  // Step 3: "Borrow" by withdrawing base asset
  // In Compound III, borrowing is done by withdrawing the base asset
  console.log('\n3. Borrowing base asset (withdrawing)...');
  const borrowTx = await walletClient.writeContract({
    address: cometAddress,
    abi: COMET_ABI,
    functionName: 'withdraw',
    args: [baseToken, borrowAmount],
  });
  await waitForTransaction(publicClient, borrowTx);
  console.log(`Borrowed: ${borrowTx}`);

  // Step 4: Check balances
  console.log('\n4. Checking positions...');
  const borrowBalance = await publicClient.readContract({
    address: cometAddress,
    abi: COMET_ABI,
    functionName: 'getBorrowBalance',
    args: [account],
  }) as bigint;

  const collateralBalance = await publicClient.readContract({
    address: cometAddress,
    abi: COMET_ABI,
    functionName: 'getCollateralBalance',
    args: [account, collateralToken.address],
  }) as bigint;

  console.log(`Borrow balance: ${borrowBalance} ${baseTokenMetadata.symbol}`);
  console.log(`Collateral balance: ${collateralBalance} ${collateralToken.symbol}`);

  console.log('\n✅ Supply and borrow completed successfully!');
}

// Run if executed directly
if (import.meta.url === `file://${process.argv[1]}`) {
  supplyAndBorrow().catch(console.error);
}

export { supplyAndBorrow };