feat: support batch repayments

contracts/operators/MoveDebtOperator.sol

@@ -18,8 +18,9 @@ contract MoveDebtOperator is ExactOutputFlashSwap {
     struct MoveDebtParams {
         uint256 maxExtraAmount;
         address originalSender;
-        address originalBorrower;
-        uint256 repayAmount;
+        address[] originalBorrowers;
+        uint256[] repayAmounts;
+        uint256 totalRepayAmount;
         IVBep20 vTokenToBorrow;
     }
 
@@ -37,16 +38,50 @@ contract MoveDebtOperator is ExactOutputFlashSwap {
         uint256 maxExtraAmount,
         bytes memory path
     ) external {
+        address[] memory originalBorrowers = new address[](1);
+        uint256[] memory repayAmounts = new uint256[](1);
+        originalBorrowers[0] = originalBorrower;
+        repayAmounts[0] = repayAmount;
+        _moveDebts(originalBorrowers, repayAmounts, repayAmount, vTokenToBorrow, maxExtraAmount, path);
+    }
+
+    function moveAllDebts(
+        address[] memory originalBorrowers,
+        IVBep20 vTokenToBorrow,
+        uint256 maxExtraAmount,
+        bytes memory path
+    ) external {
+        uint256 borrowersCount = originalBorrowers.length;
+        IVBep20 vTokenToRepay = DELEGATE.vTokenToRepay();
+
+        uint256[] memory repayAmounts = new uint256[](borrowersCount);
+        uint256 totalRepayAmount = 0;
+        for (uint256 i = 0; i < borrowersCount; ++i) {
+            uint256 amount = vTokenToRepay.borrowBalanceCurrent(originalBorrowers[i]);
+            repayAmounts[i] = amount;
+            totalRepayAmount += amount;
+        }
+        _moveDebts(originalBorrowers, repayAmounts, totalRepayAmount, vTokenToBorrow, maxExtraAmount, path);
+    }
+
+    function _moveDebts(
+        address[] memory originalBorrowers,
+        uint256[] memory repayAmounts,
+        uint256 totalRepayAmount,
+        IVBep20 vTokenToBorrow,
+        uint256 maxExtraAmount,
+        bytes memory path
+    ) internal {
         MoveDebtParams memory params = MoveDebtParams({
             maxExtraAmount: maxExtraAmount,
             originalSender: msg.sender,
-            originalBorrower: originalBorrower,
-            repayAmount: repayAmount,
+            originalBorrowers: originalBorrowers,
+            repayAmounts: repayAmounts,
+            totalRepayAmount: totalRepayAmount,
             vTokenToBorrow: vTokenToBorrow
         });
-
         bytes memory data = abi.encode(params);
-        _flashSwap(FlashSwapParams({ amountOut: repayAmount, path: path, data: data }));
+        _flashSwap(FlashSwapParams({ amountOut: totalRepayAmount, path: path, data: data }));
     }
 
     function _onMoneyReceived(bytes memory data) internal override returns (IERC20 tokenIn, uint256 maxAmountIn) {
@@ -56,8 +91,11 @@ contract MoveDebtOperator is ExactOutputFlashSwap {
 
         uint256 balanceBefore = borrowToken.balanceOf(address(this));
 
-        approveOrRevert(repayToken, address(DELEGATE), params.repayAmount);
-        DELEGATE.moveDebt(params.originalBorrower, params.repayAmount, params.vTokenToBorrow);
+        approveOrRevert(repayToken, address(DELEGATE), params.totalRepayAmount);
+        uint256 borrowersCount = params.originalBorrowers.length;
+        for (uint256 i = 0; i < borrowersCount; ++i) {
+            DELEGATE.moveDebt(params.originalBorrowers[i], params.repayAmounts[i], params.vTokenToBorrow);
+        }
         approveOrRevert(repayToken, address(DELEGATE), 0);
 
         if (params.maxExtraAmount > 0) {

tests/fork/MoveDebtOperator.ts

@@ -1,12 +1,14 @@
+import { anyValue } from "@nomicfoundation/hardhat-chai-matchers/withArgs";
 import { loadFixture } from "@nomicfoundation/hardhat-network-helpers";
 import { expect } from "chai";
-import { parseEther, parseUnits } from "ethers/lib/utils";
+import { formatUnits, parseEther, parseUnits } from "ethers/lib/utils";
 import { ethers } from "hardhat";
 import { SignerWithAddress } from "hardhat-deploy-ethers/signers";
 
 import {
   IERC20,
   IERC20__factory,
+  IVBep20,
   MoveDebtDelegate,
   MoveDebtOperator,
   MoveDebtOperator__factory,
@@ -68,13 +70,15 @@ forking({ bscmainnet: 34341800 } as const, addresses => {
     let admin: SignerWithAddress;
     let busd: IERC20;
     let usdt: IERC20;
+    let vBUSD: IVBep20;
     let moveDebtOperator: MoveDebtOperator;
     let moveDebtDelegate: MoveDebtDelegate;
 
     beforeEach(async () => {
       [admin] = await ethers.getSigners();
       ({ moveDebtOperator, busd, usdt } = await loadFixture(moveDebtOperatorFixture));
       moveDebtDelegate = await ethers.getContractAt("MoveDebtDelegate", addresses.MoveDebtDelegate);
+      vBUSD = await ethers.getContractAt("IVBep20", addresses.vBUSD);
     });
 
     it("should work with a single-hop path from BUSD to USDT", async () => {
@@ -98,6 +102,71 @@ forking({ bscmainnet: 34341800 } as const, addresses => {
       await expect(tx).to.emit(busd, "Transfer").withArgs(moveDebtDelegate.address, addresses.vBUSD, repayAmount);
     });
 
+    it("should repay all debts of a list of borrowers", async () => {
+      const path = ethers.utils.hexlify(ethers.utils.concat([addresses.BUSD, "0x000064", addresses.USDT]));
+      const borrowers = [
+        "0x6b69d62616633d71d36cf253021ae717db2e09c7",
+        "0xc870b1b5a7787ef5877190fe10851fdceb402d47",
+        "0xca925c8900f6f27e89b9bebc4987a655cb43911f",
+        "0xdc9af4213dee2321c0461a59e761f76e4677fdb9",
+        "0xdf99f63bc8f1ce2fd7aa0c0140a0340f91fb4680",
+        "0xac0c96c50bb4080bcb920a7c84dc23f0decddbd6",
+        "0xd3a5eb04d919d17b846d81b9875c652720b7be97",
+        "0xd53f6bae74603aaf74145e8150d11dbdb6fc805d",
+        "0xc4050213225baf4e2e9fb53f877caa727f05faf5",
+        "0x60f2563424db41fbfe308f46034f155f1c1e5d29",
+        "0x1e803cf10460bcd7235a87527105d1e2a3c6319b",
+        "0xf51c2e6a7e838923f30367b3d2f6d22db85a83b5",
+        "0x37e1e4b215c2a1d026444899b90f0bf29ef12576",
+        "0x3b052f0a3cfe703b63ac6fe688bbf16a67ecf738",
+        "0xcbc090c20d32b4415edacfc70665d4101cd940f6",
+        "0xccb5c516c5c3dddf1e46db9b3c399b0f5e542251",
+        "0xe9caddbc9f620098171c67385f5237b829a55db6",
+        "0x981e41c791f9cf5b5b0470df0637b95a5b4e00a2",
+        "0x8915cf710645794dad5eaee96b3e56675bf62651",
+        "0x0794e8235fbdfaf2061a6721ade61126d8493b35",
+        "0x7d6936e3dbeb9ff00e9d77ecc40eb59bf96c82b3",
+        "0xe7404e8c8c5607aea3ddfc6820c143bd21e750a1",
+        "0x82ec5d22cff969aa01afa7d082891b2cf5714769",
+        "0xabb3ed61b1928dc0a57839d6c8a38446762bdbfe",
+        "0x0e8c66bbfec32aa3fab86bba641f4f20fe457ca9",
+        "0xc7d785ffb0b5f92beb21382d44539048a5b5df62",
+        "0xd4e982b86590428588934fbd5510a61342ef7214",
+        "0x7261c1a6a47e596dfcf0e2f21140217acc5eded8",
+        "0xe33fca60a281431d82ac9ad55e37be9b587ead63",
+        "0xb75a7d3049654242617015dcedf2c49e1ca7ea65",
+        "0x88511937ddb0c65cf2b925200e185f590a43a267",
+        "0xdf38cd49bb821a3984277a252b4ecdda4ab7631c",
+        "0x614146018042d47dcde01a9400a8d14343047b67",
+        "0xd071f60ea1e2d4855cf34a6022372c33d046e34b",
+        "0x6dc3353dc6ba9d0cdc97af9d7eb5a4475ded4a3f",
+        "0x53d4bc5ccb0fa8ce8b853eb90086df93d1217026",
+        "0x58ceb7d9abbe3039e4aec356446f7c59aadae376",
+        "0x9edb330cac62e21f616d113754c7f7451179b5b2",
+        "0x22d1eca04a0ab99ebb57b9feeed45dee3df4e444",
+        "0x1956b3aae9c3e583584143d566612e7e721de141",
+        "0x0db95671310f0ba4cc0f29106593f8090037027a",
+        "0x00e1dfbb710d0d854f0d6736170b874b3690d0d7",
+        "0x4d390a71b61bdbee803960a00961de839d7c09d0",
+        "0xa139f8b283199b61efbe9c934c3a74656ed82618",
+        "0x8764c54e16304a26cd9356635431ce9a709d634c",
+        "0x6bc65848bfa839005c65d4d49989fcca9925f4ce",
+        "0x19132c5d648e0706bda8afa9e8ef3c57e86f50a9",
+        "0xe2a6d1c95672211a7d86fe394cc7eb1969e6258d",
+        "0x604c235ec0ab0b303090449a70550bab044e6be3",
+        "0xce1f6f19faec15e0806c8ad6378a3e9a7f74994e",
+      ].map(ethers.utils.getAddress);
+      await usdt.connect(admin).approve(moveDebtOperator.address, parseUnits("100", 18));
+      const maxUsdtToSpend = parseUnits("30", 18);
+      const tx = await moveDebtOperator.connect(admin).moveAllDebts(borrowers, addresses.vUSDT, maxUsdtToSpend, path);
+      for (const borrower of borrowers) {
+        await expect(tx)
+          .to.emit(moveDebtDelegate, "DebtMoved")
+          .withArgs(borrower, addresses.vBUSD, anyValue, BNB_EXPLOITER, addresses.vUSDT, anyValue);
+        expect(await vBUSD.callStatic.borrowBalanceCurrent(borrower)).to.equal(0);
+      }
+    });
+
     it("should work with a multi-hop path from BUSD to USDT", async () => {
       const path = ethers.utils.hexlify(
         ethers.utils.concat([addresses.BUSD, "0x0001f4", addresses.WBNB, "0x0001f4", addresses.USDT]),