Epochs feature

contracts/protocol/bases/mixins/FundsManager.sol

@@ -10,7 +10,7 @@
 import { FermionStorage } from "../../libs/Storage.sol";
 import { ContextLib } from "../../libs/ContextLib.sol";
 import { FermionFNFTLib } from "../../libs/FermionFNFTLib.sol";
 import { IFermionFNFT } from "../../interfaces/IFermionFNFT.sol";
 import { IFundsEvents } from "../../interfaces/events/IFundsEvents.sol";
 
 /**
@@ -74,23 +74,12 @@
      * @param _amount - amount to be transferred
      */
     function transferERC20ToProtocol(address _tokenAddress, address _from, uint256 _amount) internal {
-        // protocol balance before the transfer
-        uint256 protocolTokenBalanceBefore;
-        uint256 protocolTokenBalanceAfter;
+        // prevent ERC721 deposits
+        isERC721Contract(_tokenAddress, false);
 
-        // transfer ERC20 tokens from the caller
-        if (checkFNFTContract(_tokenAddress)) {
-            protocolTokenBalanceBefore = IFermionFNFT(_tokenAddress).balanceOfERC20(address(this));
-            _tokenAddress.transferFrom(_from, address(this), _amount);
-            protocolTokenBalanceAfter = IFermionFNFT(_tokenAddress).balanceOfERC20(address(this));
-        } else {
-            // prevent ERC721 deposits
-            isERC721Contract(_tokenAddress, false);
-
-            protocolTokenBalanceBefore = IERC20(_tokenAddress).balanceOf(address(this));
-            IERC20(_tokenAddress).safeTransferFrom(_from, address(this), _amount);
-            protocolTokenBalanceAfter = IERC20(_tokenAddress).balanceOf(address(this));
-        }
+        uint256 protocolTokenBalanceBefore = IERC20(_tokenAddress).balanceOf(address(this));
+        IERC20(_tokenAddress).safeTransferFrom(_from, address(this), _amount);
+        uint256 protocolTokenBalanceAfter = IERC20(_tokenAddress).balanceOf(address(this));
 
         // make sure that expected amount of tokens was transferred
         uint256 receivedAmount = protocolTokenBalanceAfter - protocolTokenBalanceBefore;
@@ -175,12 +164,7 @@
             (bool success, bytes memory errorMessage) = _to.call{ value: _amount }("");
             if (!success) revert FundsErrors.TokenTransferFailed(_to, _amount, errorMessage);
         } else {
-            // transfer ERC20 tokens
-            if (checkFNFTContract(_tokenAddress)) {
-                _tokenAddress.transfer(_to, _amount);
-            } else {
-                IERC20(_tokenAddress).safeTransfer(_to, _amount);
-            }
+            IERC20(_tokenAddress).safeTransfer(_to, _amount);
         }
     }
 

contracts/protocol/clients/Common.sol

@@ -4,6 +4,8 @@
 import { ERC721Upgradeable as ERC721 } from "@openzeppelin/contracts-upgradeable/token/ERC721/ERC721Upgradeable.sol";
 import { FermionTypes } from "../domain/Types.sol";
 import { FractionalisationErrors } from "../domain/Errors.sol";
+import { IERC20 } from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
+import { FermionFractionsERC20 } from "./FermionFractionsERC20.sol";
 
 error InvalidStateOrCaller(uint256 tokenId, address sender, FermionTypes.TokenState state);
 event TokenStateChange(uint256 indexed tokenId, FermionTypes.TokenState state);
@@ -20,7 +22,7 @@
     }
 
     // keccak256(abi.encode(uint256(keccak256("fermion.common.storage")) - 1)) & ~bytes32(uint256(0xff))
     bytes32 private constant CommonStorageLocation = 0x7d46dfbe85229102c9de7236c77f143aeebfb8807e422547099ad6d89710cd00;
 
     function _getFermionCommonStorage() internal pure returns (CommonStorage storage $) {
         assembly {
@@ -28,8 +30,18 @@
         }
     }
 
+    // keccak256(abi.encode(uint256(keccak256("fermion.fractions.storage")) - 1)) & ~bytes32(uint256(0xff))
+    bytes32 private constant FermionFractionsStorageLocation =
+        0x4a7c305e00776741ac7013c3447ca536097b753ba0aa5e566dd79e90f6126200;
+
+    function _getFermionFractionsStorage() internal pure returns (FermionTypes.FermionFractionsStorage storage $) {
+        assembly {
+            $.slot := FermionFractionsStorageLocation
+        }
+    }
+
     // keccak256(abi.encode(uint256(keccak256("openzeppelin.storage.ERC721")) - 1)) & ~bytes32(uint256(0xff))
     bytes32 private constant ERC721StorageLocation = 0x80bb2b638cc20bc4d0a60d66940f3ab4a00c1d7b313497ca82fb0b4ab0079300;
 
     function _getERC721Storage() internal pure returns (ERC721.ERC721Storage storage $) {
         assembly {
@@ -37,13 +49,40 @@
         }
     }
 
+    // NOTE: storing the initial buyout auction here when epoch = 0
     // keccak256(abi.encode(uint256(keccak256("fermion.buyout.auction.storage")) - 1)) & ~bytes32(uint256(0xff));
     bytes32 private constant BuyoutAuctionStorageLocation =
         0x224d6815573209d133aab26f2f52964556d2c06abbb82d0961460cd2e673cd00;
 
-    function _getBuyoutAuctionStorage() internal pure returns (FermionTypes.BuyoutAuctionStorage storage $) {
-        assembly {
-            $.slot := BuyoutAuctionStorageLocation
+    // NOTE: pointer to mapping(uint256 epoch => BuyoutAuctionStorageLocation)
+    // keccak256(abi.encode(uint256(keccak256("fermion.buyout.auction.storage.epochs")) - 1)) & ~bytes32(uint256(0xff));
+    bytes32 private constant BuyoutAuctionStorageEpochsLocation =
+        0x7ea90b6250b50fe4d5b733a96ceefb11247134d8b2fa5878319c586d1d546a00;
+
+    /**
+     * @notice Get the buyout auction storage for a specific epoch
+     * @dev epoch = 0 is special case and stored directly in the storage location.
+     *       epoch != 0 is stored in the mapping(uint256 epoch => BuyoutAuctionStorageLocation)
+     *       where BuyoutAuctionStorageEpochsLocation is the mapping pointer location
+     *
+     * @param _epoch The epoch
+     * @return $ The storage
+     */
+    function _getBuyoutAuctionStorage(
+        uint256 _epoch
+    ) internal pure returns (FermionTypes.BuyoutAuctionStorage storage $) {
+        if (_epoch == 0) {
+            assembly {
+                $.slot := BuyoutAuctionStorageLocation
+            }
+        } else {
+            // Calculate the storage slot directly in assembly instead of reading from storage.
+            // This is more efficient and avoids the need for external storage reads.
+            assembly {
+                mstore(0x00, _epoch)
+                mstore(0x20, BuyoutAuctionStorageEpochsLocation)
+                $.slot := keccak256(0x00, 0x40)
+            }
         }
     }
 
@@ -101,4 +140,42 @@
             return auctions[auctions.length - 1];
         }
     }
+
+    /**
+     * @notice Returns the liquid number of fractions for current epoch. Represents fractions of F-NFTs that are fractionalised
+     * @dev This function is used in multiple contracts to calculate the available supply
+     * @param _epoch The epoch to check
+     * @return The liquid supply of fractions
+     */
+    function liquidSupply(uint256 _epoch) internal view returns (uint256) {
+        FermionTypes.FermionFractionsStorage storage fractionStorage = _getFermionFractionsStorage();
+        if (_epoch >= fractionStorage.epochToClone.length) return 0;
+        address erc20Clone = fractionStorage.epochToClone[_epoch];
+
+        FermionTypes.BuyoutAuctionStorage storage $ = _getBuyoutAuctionStorage(_epoch);
+
+        return
+            IERC20(erc20Clone).totalSupply() -
+            $.unrestricedRedeemableSupply -
+            $.lockedRedeemableSupply -
+            $.pendingRedeemableSupply;
+    }
+
+    /**
+     * @notice Helper function to transfer fractions between addresses
+     * @param _from The address to transfer from
+     * @param _to The address to transfer to
+     * @param _amount The amount of fractions to transfer
+     * @param _epoch The epoch of the fractions
+     */
+    function _transferFractions(address _from, address _to, uint256 _amount, uint256 _epoch) internal {
+        FermionTypes.FermionFractionsStorage storage fractionStorage = _getFermionFractionsStorage();
+        address erc20Clone = fractionStorage.epochToClone[_epoch];
+
+        if (_from == address(this)) {
+            FermionFractionsERC20(erc20Clone).transfer(_to, _amount);
+        } else {
+            FermionFractionsERC20(erc20Clone).transferFractionsFrom(_from, _to, _amount);
+        }
+    }
 }