refactor: accounting for PR comments

Author: kupermind

contracts/BondCalculator.sol

@@ -1,8 +1,9 @@
 // SPDX-License-Identifier: MIT
 pragma solidity ^0.8.25;
 
-import {GenericBondCalculator} from "./GenericBondCalculator.sol";
+import {mulDiv} from "@prb/math/src/Common.sol";
 import {IVotingEscrow} from "./interfaces/IVotingEscrow.sol";
+import "./interfaces/IUniswapV2Pair.sol";
 
 interface ITokenomics {
     /// @dev Gets number of new units that were donated in the last epoch.
@@ -63,12 +64,16 @@ struct Product {
 /// @author Aleksandr Kuperman - <[email protected]>
 /// @author Andrey Lebedev - <[email protected]>
 /// @author Mariapia Moscatiello - <[email protected]>
-contract BondCalculator is GenericBondCalculator {
+contract BondCalculator {
     event OwnerUpdated(address indexed owner);
     event DiscountParamsUpdated(DiscountParams newDiscountParams);
 
     // Maximum sum of discount factor weights
     uint256 public constant MAX_SUM_WEIGHTS = 10_000;
+    // OLAS contract address
+    address public immutable olas;
+    // Tokenomics contract address
+    address public immutable tokenomics;
     // veOLAS contract address
     address public immutable ve;
 
@@ -83,14 +88,14 @@ contract BondCalculator is GenericBondCalculator {
     /// @param _tokenomics Tokenomics contract address.
     /// @param _ve veOLAS contract address.
     /// @param _discountParams Discount factor parameters.
-    constructor(address _olas, address _tokenomics, address _ve, DiscountParams memory _discountParams)
-        GenericBondCalculator(_olas, _tokenomics)
-    {
-        // Check for zero address
-        if (_ve == address(0)) {
+    constructor(address _olas, address _tokenomics, address _ve, DiscountParams memory _discountParams) {
+        // Check for at least one zero contract address
+        if (_olas == address(0) || _tokenomics == address(0) || _ve == address(0)) {
             revert ZeroAddress();
         }
 
+        olas = _olas;
+        tokenomics = _tokenomics;
         ve = _ve;
         owner = msg.sender;
 
@@ -153,17 +158,14 @@ contract BondCalculator is GenericBondCalculator {
     }
 
     /// @dev Calculated inverse discount factor based on bonding and account parameters.
-    /// @param data Custom data that is used to calculate the IDF:
-    ///        - account Account address.
-    ///        - bondVestingTime Bond vesting time.
-    ///        - productMaxVestingTime Product max vesting time.
-    ///        - productSupply Current product supply.
-    ///        - productPayout Current product payout.
+    /// @param account Account address.
+    /// @param bondVestingTime Bond vesting time.
+    /// @param productMaxVestingTime Product max vesting time.
+    /// @param productSupply Current product supply.
+    /// @param productPayout Current product payout.
     /// @return idf Inverse discount factor in 18 decimals format.
-    function calculateIDF(bytes memory data) public view override returns (uint256 idf) {
-        // Decode the required data
-        (address account, uint256 bondVestingTime, uint256 productMaxVestingTime, uint256 productSupply,
-            uint256 productPayout) = abi.decode(data, (address, uint256, uint256, uint256, uint256));
+    function calculateIDF(address account, uint256 bondVestingTime, uint256 productMaxVestingTime, uint256 productSupply,
+        uint256 productPayout) public view returns (uint256 idf) {
 
         // Get the copy of the discount params
         DiscountParams memory localParams = discountParams;
@@ -226,6 +228,73 @@ contract BondCalculator is GenericBondCalculator {
         idf = 1e18 + discountBooster;
     }
 
+    /// @dev Calculates the amount of OLAS tokens based on the bonding calculator mechanism accounting for dynamic IDF.
+    /// @param account Account address.
+    /// @param tokenAmount LP token amount.
+    /// @param priceLP LP token price.
+    /// @param bondVestingTime Bond vesting time.
+    /// @param productMaxVestingTime Product max vesting time.
+    /// @param productSupply Current product supply.
+    /// @param productPayout Current product payout.
+    /// @return amountOLAS Resulting amount of OLAS tokens.
+    function calculatePayoutOLAS(
+        address account,
+        uint256 tokenAmount,
+        uint256 priceLP,
+        uint256 bondVestingTime,
+        uint256 productMaxVestingTime,
+        uint256 productSupply,
+        uint256 productPayout
+    ) external view returns (uint256 amountOLAS) {
+        // The result is divided by additional 1e18, since it was multiplied by in the current LP price calculation
+        // The resulting amountDF can not overflow by the following calculations: idf = 64 bits;
+        // priceLP = 2 * r0/L * 10^18 = 2*r0*10^18/sqrt(r0*r1) ~= 61 + 96 - sqrt(96 * 112) ~= 53 bits (if LP is balanced)
+        // or 2* r0/sqrt(r0) * 10^18 => 87 bits + 60 bits = 147 bits (if LP is unbalanced);
+        // tokenAmount is of the order of sqrt(r0*r1) ~ 104 bits (if balanced) or sqrt(96) ~ 10 bits (if max unbalanced);
+        // overall: 64 + 53 + 104 = 221 < 256 - regular case if LP is balanced, and 64 + 147 + 10 = 221 < 256 if unbalanced
+        // mulDiv will correctly fit the total amount up to the value of max uint256, i.e., max of priceLP and max of tokenAmount,
+        // however their multiplication can not be bigger than the max of uint192
+        uint256 totalTokenValue = mulDiv(priceLP, tokenAmount, 1);
+        // Check for the cumulative LP tokens value limit
+        if (totalTokenValue > type(uint192).max) {
+            revert Overflow(totalTokenValue, type(uint192).max);
+        }
+
+        // Calculate the dynamic inverse discount factor
+        uint256 idf = calculateIDF(account, bondVestingTime, productMaxVestingTime, productSupply, productPayout);
+
+        // Amount with the discount factor is IDF * priceLP * tokenAmount / 1e36
+        // At this point of time IDF is bound by the max of uint64, and totalTokenValue is no bigger than the max of uint192
+        amountOLAS = (idf * totalTokenValue) / 1e36;
+    }
+
+    /// @dev Gets current reserves of OLAS / totalSupply of Uniswap V2-like LP tokens.
+    /// @notice The price LP calculation is based on the UniswapV2Pair contract.
+    /// @param token Token address.
+    /// @return priceLP Resulting reserveX / totalSupply ratio with 18 decimals.
+    function getCurrentPriceLP(address token) external view returns (uint256 priceLP) {
+        IUniswapV2Pair pair = IUniswapV2Pair(token);
+        uint256 totalSupply = pair.totalSupply();
+        if (totalSupply > 0) {
+            address token0 = pair.token0();
+            address token1 = pair.token1();
+            uint256 reserve0;
+            uint256 reserve1;
+            // requires low gas
+            (reserve0, reserve1, ) = pair.getReserves();
+            // token0 != olas && token1 != olas, this should never happen
+            if (token0 == olas || token1 == olas) {
+                // If OLAS is in token0, assign its reserve to reserve1, otherwise the reserve1 is already correct
+                if (token0 == olas) {
+                    reserve1 = reserve0;
+                }
+                // Calculate the LP price based on reserves and totalSupply ratio multiplied by 1e18
+                // Inspired by: https://github.com/curvefi/curve-contract/blob/master/contracts/pool-templates/base/SwapTemplateBase.vy#L262
+                priceLP = (reserve1 * 1e18) / totalSupply;
+            }
+        }
+    }
+
     function getDiscountParams() external view returns (DiscountParams memory) {
         return discountParams;
     }

contracts/Depository.sol

@@ -9,14 +9,22 @@ import {ITreasury} from "./interfaces/ITreasury.sol";
 
 interface IBondCalculator {
     /// @dev Calculates the amount of OLAS tokens based on the bonding calculator mechanism accounting for dynamic IDF.
+    /// @param account Account address.
     /// @param tokenAmount LP token amount.
     /// @param priceLP LP token price.
-    /// @param data Custom data that is used to calculate the IDF.
+    /// @param bondVestingTime Bond vesting time.
+    /// @param productMaxVestingTime Product max vesting time.
+    /// @param productSupply Current product supply.
+    /// @param productPayout Current product payout.
     /// @return amountOLAS Resulting amount of OLAS tokens.
     function calculatePayoutOLAS(
+        address account,
         uint256 tokenAmount,
         uint256 priceLP,
-        bytes memory data
+        uint256 bondVestingTime,
+        uint256 productMaxVestingTime,
+        uint256 productSupply,
+        uint256 productPayout
     ) external view returns (uint256 amountOLAS);
 
     /// @dev Gets current reserves of OLAS / totalSupply of Uniswap V2-like LP tokens.
@@ -114,7 +122,7 @@ contract Depository is ERC721, IErrorsTokenomics {
 
     // OLAS token address
     address public immutable olas;
-    // Tkenomics contract address
+    // Tokenomics contract address
     address public tokenomics;
     // Treasury contract address
     address public treasury;
@@ -370,9 +378,8 @@ contract Depository is ERC721, IErrorsTokenomics {
 
         // Calculate the payout in OLAS tokens based on the LP pair with the inverse discount factor (IDF) calculation
         // Note that payout cannot be zero since the price LP is non-zero, otherwise the product would not be created
-        payout = IBondCalculator(bondCalculator).calculatePayoutOLAS(tokenAmount, product.priceLP,
-            // Encode parameters required for the IDF calculation
-            abi.encode(msg.sender, bondVestingTime, productMaxVestingTime, supply, product.payout));
+        payout = IBondCalculator(bondCalculator).calculatePayoutOLAS(msg.sender, tokenAmount, product.priceLP,
+            bondVestingTime, productMaxVestingTime, supply, product.payout);
 
         // Check for the sufficient supply
         if (payout > supply) {