feat: add and test addLeverage (#14)

README.md

@@ -18,12 +18,15 @@ The following outlines principles for core protocol funcitonality.
 
 Logic:
 
--   None at the moment🙂
+-   None for now.
 
 Tests:
 
--   None at the moment🙂
+-   [ ] Create integration test for multiple calls `add()`
+-   [ ] Create integration test for multiple calls `addLeverage()`
+-   [ ] Create integration test for multiple calls `addWithPermit()`
+-   [ ] Remove all test_ActiveFork
 
 Considerations:
 
--   None at the moment🙂
+-   None for now.

src/Position.sol

@@ -8,22 +8,29 @@ import { SafeTransferLib, ERC20 } from "solmate/utils/SafeTransferLib.sol";
 import { FeeLib } from "src/libraries/FeeLib.sol";
 import { IERC20 } from "src/interfaces/token/IERC20.sol";
 import { IERC20Permit } from "src/interfaces/token/IERC20Permit.sol";
+import { IERC20Metadata } from "src/interfaces/token/IERC20Metadata.sol";
 
 /// @title Position
 /// @author Chain Rule, LLC
 /// @notice Manages the owner's individual position
 contract Position is DebtService, SwapService {
     // Immutables: no SLOAD to save gas
+    uint8 public immutable B_DECIMALS;
     address public immutable B_TOKEN;
 
+    // Errors
+    error TokenConflict();
+
     // Events
     event Add(uint256 cAmt, uint256 dAmt, uint256 bAmt);
+    event AddLeverage(uint256 cAmt, uint256 dAmt, uint256 bAmt);
     event Close(uint256 gains);
 
     constructor(address _owner, address _cToken, address _dToken, address _bToken)
         DebtService(_owner, _cToken, _dToken)
     {
         B_TOKEN = _bToken;
+        B_DECIMALS = IERC20Metadata(_bToken).decimals();
     }
 
     /**
@@ -86,12 +93,41 @@ contract Position is DebtService, SwapService {
         add(_cAmt, _ltv, _swapAmtOutMin, _poolFee, _client);
     }
 
+    /**
+     * @notice Adds leverage to this contract's short position. This function can only be used for positions where the
+     *         collateral token is the same as the base token.
+     * @param _ltv The desired loan-to-value ratio for this transaction-specific loan (ex: 75 is 75%).
+     * @param _swapAmtOutMin The minimum amount of output tokens from swap for the tx to go through.
+     * @param _poolFee The fee of the Uniswap pool.
+     * @param _client The address of the client operator. Use address(0) if not using a client.
+     */
+    function addLeverage(uint256 _ltv, uint256 _swapAmtOutMin, uint24 _poolFee, address _client)
+        public
+        payable
+        onlyOwner
+    {
+        // 1. Ensure that collateral token is the same as the base token
+        if (C_TOKEN != B_TOKEN) revert TokenConflict();
+
+        // 2. Take protocol fee
+        uint256 bAmtNet = FeeLib.takeProtocolFee(B_TOKEN, IERC20(B_TOKEN).balanceOf(address(this)), _client);
+
+        // 3. Borrow debt token
+        uint256 dAmt = _borrow(bAmtNet, _ltv);
+
+        // 4. Swap debt token for base token
+        (, uint256 bAmt) = _swapExactInput(D_TOKEN, B_TOKEN, dAmt, _swapAmtOutMin, _poolFee);
+
+        // 5. Emit event
+        emit AddLeverage(bAmtNet, dAmt, bAmt);
+    }
+
     /**
      * @notice Fully closes the short position.
      * @param _poolFee The fee of the Uniswap pool.
      * @param _exactOutput Whether to swap exact output or exact input (true for exact output, false for exact input).
      * @param _swapAmtOutMin The minimum amount of output tokens from swap for the tx to go through (only used if _exactOutput is false, supply 0 if true).
-     * @param _withdrawBuffer The amount of collateral left as safety buffer for tx to go through (default = 100_000, units: 8 decimals).
+     * @param _withdrawBuffer The amount of collateral left as safety buffer for tx to go through (at least 100_000 recommended, units: 8 decimals).
      */
     function close(uint24 _poolFee, bool _exactOutput, uint256 _swapAmtOutMin, uint256 _withdrawBuffer)
         public

src/interfaces/IPosition.sol

@@ -25,6 +25,21 @@ interface IPosition {
      */
     function B_TOKEN() external returns (address);
 
+    /**
+     * @notice Returns the number of decimals for this position's collateral token.
+     */
+    function C_DECIMALS() external returns (uint8);
+
+    /**
+     * @notice Returns the number of decimals for this position's debt token.
+     */
+    function D_DECIMALS() external returns (uint8);
+
+    /**
+     * @notice Returns the number of decimals for this position's base token.
+     */
+    function B_DECIMALS() external returns (uint8);
+
     /* ****************************************************************************
     **
     **  CORE FUNCTIONS
@@ -67,12 +82,22 @@ interface IPosition {
         bytes32 _s
     ) external payable;
 
+    /**
+     * @notice Adds leverage to this contract's short position. This function can only be used for positions where the
+     *         collateral token is the same as the base token.
+     * @param _ltv The desired loan-to-value ratio for this transaction-specific loan (ex: 75 is 75%).
+     * @param _swapAmtOutMin The minimum amount of output tokens from swap for the tx to go through.
+     * @param _poolFee The fee of the Uniswap pool.
+     * @param _client The address of the client operator. Use address(0) if not using a client.
+     */
+    function addLeverage(uint256 _ltv, uint256 _swapAmtOutMin, uint24 _poolFee, address _client) external payable;
+
     /**
      * @notice Fully closes the short position.
      * @param _poolFee The fee of the Uniswap pool.
      * @param _exactOutput Whether to swap exact output or exact input (true for exact output, false for exact input).
      * @param _swapAmtOutMin The minimum amount of output tokens from swap for the tx to go through (only used if _exactOutput is false, supply 0 if true).
-     * @param _withdrawBuffer The amount of collateral left as safety buffer for tx to go through (default = 100_000, units: 8 decimals).
+     * @param _withdrawBuffer The amount of collateral left as safety buffer for tx to go through (at least 100_000 recommended, units: 8 decimals).
      */
     function close(uint24 _poolFee, bool _exactOutput, uint256 _swapAmtOutMin, uint256 _withdrawBuffer)
         external
@@ -101,7 +126,7 @@ interface IPosition {
      * @notice Repays any outstanding debt to Aave and transfers remaining collateral from Aave to owner.
      * @param _dAmt The amount of debt token to repay to Aave (units: D_DECIMALS).
      *              To pay off entire debt, _dAmt = debtOwed + smallBuffer (to account for interest).
-     * @param _withdrawBuffer The amount of collateral left as safety buffer for tx to go through (default = 100_000, units: 8 decimals).
+     * @param _withdrawBuffer The amount of collateral left as safety buffer for tx to go through (at least 100_000 recommended, units: 8 decimals).
      */
     function repayAfterClose(uint256 _dAmt, uint256 _withdrawBuffer) external payable;
 
@@ -110,7 +135,7 @@ interface IPosition {
      *         with permit, obviating the need for a separate approve tx. This function can only be used for ERC-2612-compliant tokens.
      * @param _dAmt The amount of debt token to repay to Aave (units: D_DECIMALS).
      *              To pay off entire debt, _dAmt = debtOwed + smallBuffer (to account for interest).
-     * @param _withdrawBuffer The amount of collateral left as safety buffer for tx to go through (default = 100_000, units: 8 decimals).
+     * @param _withdrawBuffer The amount of collateral left as safety buffer for tx to go through (at least 100_000 recommended, units: 8 decimals).
      * @param _deadline The expiration timestamp of the permit.
      * @param _v The V parameter of ERC712 signature for the permit.
      * @param _r The R parameter of ERC712 signature for the permit.

src/services/DebtService.sol

@@ -19,10 +19,10 @@ contract DebtService is AdminService {
     address private constant AAVE_ORACLE = 0xb56c2F0B653B2e0b10C9b928C8580Ac5Df02C7C7;
 
     // Immutables: no SLOAD to save gas
-    uint8 public immutable C_DECIMALS;
-    uint8 public immutable D_DECIMALS;
     uint64 internal immutable _C_DEC_CONVERSION;
     uint64 internal immutable _D_DEC_CONVERSION;
+    uint8 public immutable C_DECIMALS;
+    uint8 public immutable D_DECIMALS;
     address public immutable C_TOKEN;
     address public immutable D_TOKEN;
 
@@ -75,7 +75,7 @@ contract DebtService is AdminService {
     /**
      * @notice Withdraws collateral token from Aave to specified recipient.
      * @param _recipient The recipient of the funds.
-     * @param _buffer The amount of collateral left as safety buffer for tx to go through (default = 100_000, units: 8 decimals).
+     * @param _buffer The amount of collateral left as safety buffer for tx to go through (at least 100_000 recommended, units: 8 decimals).
      */
     function _withdraw(address _recipient, uint256 _buffer) internal {
         IPool(AAVE_POOL).withdraw(C_TOKEN, _getMaxWithdrawAmt(_buffer), _recipient);
@@ -151,7 +151,7 @@ contract DebtService is AdminService {
      * @notice Repays any outstanding debt to Aave and transfers remaining collateral from Aave to owner.
      * @param _dAmt The amount of debt token to repay to Aave (units: D_DECIMALS).
      *              To pay off entire debt, _dAmt = debtOwed + smallBuffer (to account for interest).
-     * @param _withdrawBuffer The amount of collateral left as safety buffer for tx to go through (default = 100_000, units: 8 decimals).
+     * @param _withdrawBuffer The amount of collateral left as safety buffer for tx to go through (at least 100_000 recommended, units: 8 decimals).
      */
     function repayAfterClose(uint256 _dAmt, uint256 _withdrawBuffer) public payable onlyOwner {
         SafeTransferLib.safeTransferFrom(ERC20(D_TOKEN), msg.sender, address(this), _dAmt);
@@ -166,7 +166,7 @@ contract DebtService is AdminService {
      *         with permit, obviating the need for a separate approve tx. This function can only be used for ERC-2612-compliant tokens.
      * @param _dAmt The amount of debt token to repay to Aave (units: D_DECIMALS).
      *              To pay off entire debt, _dAmt = debtOwed + smallBuffer (to account for interest).
-     * @param _withdrawBuffer The amount of collateral left as safety buffer for tx to go through (default = 100_000, units: 8 decimals).
+     * @param _withdrawBuffer The amount of collateral left as safety buffer for tx to go through (at least 100_000 recommended, units: 8 decimals).
      * @param _deadline The expiration timestamp of the permit.
      * @param _v The V parameter of ERC712 signature for the permit.
      * @param _r The R parameter of ERC712 signature for the permit.

test/Position.t.sol

@@ -8,12 +8,14 @@ import { VmSafe } from "forge-std/Vm.sol";
 // Local Imports
 import { PositionFactory } from "src/PositionFactory.sol";
 import { AdminService } from "src/services/AdminService.sol";
+import { Position } from "src/Position.sol";
 import {
     Assets,
     CONTRACT_DEPLOYER,
     DAI,
     FEE_COLLECTOR,
     TEST_CLIENT,
+    TEST_POOL_FEE,
     USDC,
     WITHDRAW_BUFFER
 } from "test/common/Constants.t.sol";
@@ -36,6 +38,7 @@ contract PositionTest is Test, TokenUtils, DebtUtils {
     PositionFactory public positionFactory;
     Assets public assets;
     TestPosition[] public positions;
+    TestPosition[] public diffCTokenBTokenPositions;
 
     // Test Storage
     VmSafe.Wallet public wallet;
@@ -85,6 +88,14 @@ contract PositionTest is Test, TokenUtils, DebtUtils {
                 }
             }
         }
+
+        // Filter for positions where cToken != bToken and populate diffCTokenBTokenPositions
+        for (uint256 i = 0; i < positions.length; i++) {
+            TestPosition memory currentPosition = positions[i];
+            if (currentPosition.cToken != currentPosition.bToken) {
+                diffCTokenBTokenPositions.push(currentPosition);
+            }
+        }
     }
 
     /// @dev
@@ -95,7 +106,7 @@ contract PositionTest is Test, TokenUtils, DebtUtils {
 
     /// @dev
     // - It should revert with Unauthorized() error when called by an unauthorized sender.
-    function testFuzz_CannotShort(address _sender) public {
+    function testFuzz_CannotAdd(address _sender) public {
         // Setup
         uint256 ltv = 60;
 
@@ -120,7 +131,66 @@ contract PositionTest is Test, TokenUtils, DebtUtils {
             // Act
             vm.prank(_sender);
             vm.expectRevert(AdminService.Unauthorized.selector);
-            IPosition(addr).add(cAmt, ltv, 0, 3000, TEST_CLIENT);
+            IPosition(addr).add(cAmt, ltv, 0, TEST_POOL_FEE, TEST_CLIENT);
+
+            // Revert to snapshot
+            vm.revertTo(id);
+        }
+    }
+
+    /// @dev
+    // - It should revert with TokenConflict() error when cToken != bToken.
+    function test_CannotAddLeverageTokenConflict() public {
+        // Setup
+        uint256 ltv = 60;
+
+        // Take snapshot
+        uint256 id = vm.snapshot();
+
+        for (uint256 i; i < diffCTokenBTokenPositions.length; i++) {
+            // Test variables
+            address addr = diffCTokenBTokenPositions[i].addr;
+            address bToken = diffCTokenBTokenPositions[i].bToken;
+            uint256 bAmt = assets.maxCAmts(bToken);
+
+            // Fund contract with bToken
+            _fund(addr, bToken, bAmt);
+
+            // Act
+            vm.prank(owner);
+            vm.expectRevert(Position.TokenConflict.selector);
+            IPosition(addr).addLeverage(ltv, 0, TEST_POOL_FEE, TEST_CLIENT);
+
+            // Revert to snapshot
+            vm.revertTo(id);
+        }
+    }
+
+    /// @dev
+    // - It should revert with Unauthorized() error when called by an unauthorized sender.
+    function testFuzz_CannotAddLeverageUnauthorized(address _sender) public {
+        // Setup
+        uint256 ltv = 60;
+
+        // Take snapshot
+        uint256 id = vm.snapshot();
+
+        for (uint256 i; i < diffCTokenBTokenPositions.length; i++) {
+            // Test variables
+            address addr = diffCTokenBTokenPositions[i].addr;
+            address bToken = diffCTokenBTokenPositions[i].bToken;
+            uint256 bAmt = assets.maxCAmts(bToken);
+
+            // Assumptions
+            vm.assume(_sender != owner);
+
+            // Fund contract with bToken
+            _fund(addr, bToken, bAmt);
+
+            // Act
+            vm.prank(_sender);
+            vm.expectRevert(AdminService.Unauthorized.selector);
+            IPosition(addr).addLeverage(ltv, 0, TEST_POOL_FEE, TEST_CLIENT);
 
             // Revert to snapshot
             vm.revertTo(id);
@@ -129,15 +199,17 @@ contract PositionTest is Test, TokenUtils, DebtUtils {
 
     /// @dev
     // - It should revert with Unauthorized() error when called by an unauthorized sender.
-    function testFuzz_CannotShortWithPermit(address _sender) public {
+    function testFuzz_CannotAddWithPermit(address _sender) public {
+        // Setup
+        uint256 ltv = 60;
+
         // Take snapshot
         uint256 id = vm.snapshot();
 
         for (uint256 i; i < positions.length; i++) {
             // Test variables
             address cToken = positions[i].cToken;
             uint256 cAmt = assets.maxCAmts(cToken);
-            uint256 ltv = 60;
 
             // Assumptions
             vm.assume(_sender != owner);
@@ -152,7 +224,9 @@ contract PositionTest is Test, TokenUtils, DebtUtils {
             // Act
             vm.prank(_sender);
             vm.expectRevert(AdminService.Unauthorized.selector);
-            IPosition(positions[i].addr).addWithPermit(cAmt, ltv, 0, 3000, TEST_CLIENT, permitTimestamp, v, r, s);
+            IPosition(positions[i].addr).addWithPermit(
+                cAmt, ltv, 0, TEST_POOL_FEE, TEST_CLIENT, permitTimestamp, v, r, s
+            );
 
             // Revert to snapshot
             vm.revertTo(id);
@@ -180,7 +254,7 @@ contract PositionTest is Test, TokenUtils, DebtUtils {
             _fund(owner, positions[i].cToken, cAmt);
             vm.startPrank(owner);
             IERC20(positions[i].cToken).approve(addr, cAmt);
-            IPosition(addr).add(cAmt, ltv, 0, 3000, TEST_CLIENT);
+            IPosition(addr).add(cAmt, ltv, 0, TEST_POOL_FEE, TEST_CLIENT);
             vm.stopPrank();
 
             // Act

test/PositionFactory.t.sol

@@ -87,13 +87,15 @@ contract PositionFactoryTest is Test, TokenUtils {
                             cToken = IPosition(position).C_TOKEN();
                             dToken = IPosition(position).D_TOKEN();
                             bToken = IPosition(position).B_TOKEN();
+                            uint8 bDecimals = assets.decimals(IPosition(position).B_TOKEN());
 
                             // Assertions
                             assertNotEq(position, address(0));
                             assertEq(owner, positionOwner);
                             assertEq(cToken, supportedAssets[i]);
                             assertEq(dToken, supportedAssets[j]);
                             assertEq(bToken, supportedAssets[k]);
+                            assertEq(IPosition(position).B_DECIMALS(), bDecimals);
                         }
                     }
                 }

test/common/Constants.t.sol

@@ -19,6 +19,7 @@ address constant WBTC = 0x2f2a2543B76A4166549F7aaB2e75Bef0aefC5B0f;
 address constant USDC_HOLDER = 0x47c031236e19d024b42f8AE6780E44A573170703;
 
 // Uint constants
+uint24 constant TEST_POOL_FEE = 3000;
 uint256 constant PROFIT_PERCENT = 25;
 uint256 constant REPAY_PERCENT = 75;
 uint256 constant WITHDRAW_BUFFER = 100_000;