flashLoan rewritten as ERC-3156

src/IPartyPool.sol

@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: UNLICENSED
 pragma solidity ^0.8.30;
 
+import "../lib/openzeppelin-contracts/contracts/interfaces/IERC3156FlashBorrower.sol";
 import "./LMSRStabilized.sol";
 import {IERC20Metadata} from "../lib/openzeppelin-contracts/contracts/token/ERC20/extensions/IERC20Metadata.sol";
 import {IERC20} from "../lib/openzeppelin-contracts/contracts/token/ERC20/IERC20.sol";
@@ -135,12 +136,14 @@ interface IPartyPool is IERC20Metadata {
     /// @param maxAmountIn maximum gross input allowed (inclusive of fee)
     /// @param limitPrice maximum acceptable marginal price (pass 0 to ignore)
     /// @return amountIn gross input amount to transfer (includes fee), amountOut output amount user would receive, fee fee amount taken
+/*
     function swapAmounts(
         uint256 inputTokenIndex,
         uint256 outputTokenIndex,
         uint256 maxAmountIn,
         int128 limitPrice
     ) external view returns (uint256 amountIn, uint256 amountOut, uint256 fee);
+*/
 
     /// @notice Swap input token inputTokenIndex -> token outputTokenIndex. Payer must approve token inputTokenIndex.
     /// @dev This function transfers the exact gross input (including fee) from payer and sends the computed output to receiver.
@@ -215,17 +218,17 @@ interface IPartyPool is IERC20Metadata {
         uint256 deadline
     ) external returns (uint256 amountOutUint);
 
-    /// @notice Receive token amounts and require them to be repaid plus a fee inside a callback.
-    /// @dev The caller must implement IPartyFlashCallback#partyFlashCallback which receives (amounts, repaymentAmounts, data).
-    ///      This function verifies that, after the callback returns, the pool's balances have increased by at least the fees
-    ///      for each borrowed token. Reverts if repayment (including fee) did not occur.
-    /// @param recipient The address which will receive the token amounts
-    /// @param amounts The amount of each token to send (array length must equal pool size)
-    /// @param data Any data to be passed through to the callback
-    function flash(
-        address recipient,
-        uint256[] memory amounts,
+    /**
+     * @dev Initiate a flash loan.
+     * @param receiver The receiver of the tokens in the loan, and the receiver of the callback.
+     * @param token The loan currency.
+     * @param amount The amount of tokens lent.
+     * @param data Arbitrary data structure, intended to contain user-defined parameters.
+     */
+    function flashLoan(
+        IERC3156FlashBorrower receiver,
+        address token,
+        uint256 amount,
         bytes calldata data
-    ) external;
-
+    ) external returns (bool);
 }