Tamago NFT wrapper example

contracts/samples/tamago.sol

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+// SPDX-License-Identifier: MIT
+pragma solidity 0.6.12;
+pragma experimental ABIEncoderV2;
+
+/* TO-DO
+- use minimal proxy for tamago tokens
+- make generalized NFT fractionalization tool? (i.e., fully erc20.... so lose some gas savings)
+*/
+
+/// @notice Interface for BENTO deposit and withdraw.
+interface IBentoBridge {
+    function balanceOf(IERC20, address) external view returns (uint256);
+
+    function registerProtocol() external;
+
+    function deposit( 
+        IERC20 token_,
+        address from,
+        address to,
+        uint256 amount,
+        uint256 share
+    ) external payable returns (uint256 amountOut, uint256 shareOut);
+
+    function withdraw(
+        IERC20 token_,
+        address from,
+        address to,
+        uint256 amount,
+        uint256 share
+    ) external returns (uint256 amountOut, uint256 shareOut);
+}
+
+/// @notice Interface to wrap NFT / includes Zora Protocol `permit()` format.
+interface IERC721Wrap {
+    struct EIP712Signature {
+        uint256 deadline;
+        uint8 v;
+        bytes32 r;
+        bytes32 s;
+    }
+
+    function transferFrom(address from, address to, uint256 tokenId) external;
+    function safeTransferFrom(address from, address to, uint256 tokenId) external;
+
+    /// @notice EIP 2612 adapted for ERC 721.
+    function permit(
+        address spender,
+        uint256 tokenId,
+        EIP712Signature calldata sig
+    ) external;
+}
+
+interface IERC20 {} contract TamagoToken is IERC20 {
+    string constant public name = "TAMAGO";
+    string constant public symbol = "TAMA";
+    uint8 constant public decimals = 18;
+
+    uint256 immutable public totalSupply;
+
+    event Transfer(address indexed from, address indexed to, uint256 amount);
+
+    constructor(uint256 _totalSupply) public {
+        totalSupply = _totalSupply;
+    }
+
+    function transferFrom(address from, address to, uint256 amount) external returns (bool) {
+        emit Transfer(from, to, amount);
+        return true;
+    }
+}
+
+/// @notice Gas-optimized contract to wrap NFT into BENTO. 
+contract Tamago {
+    IBentoBridge constant bento = IBentoBridge(0xF5BCE5077908a1b7370B9ae04AdC565EBd643966); // BENTO vault contract
+
+    mapping(IERC20 => Tama) public tamas;
+
+    struct Tama {
+        IERC721Wrap nft;
+        uint64 tokenId;
+        uint64 ctrlSupply;
+        uint128 totalSupply;
+    }
+
+    constructor() public {
+        bento.registerProtocol();
+    }
+
+    function wrapNFT(IERC721Wrap nft, uint64 tokenId, uint64 ctrlSupply, uint128 totalSupply) external returns (IERC20 wrapper) {
+        nft.transferFrom(msg.sender, address(this), tokenId);
+        wrapper = new TamagoToken(totalSupply);
+        tamas[wrapper] = Tama(nft, tokenId, ctrlSupply, totalSupply);
+        bento.deposit(wrapper, address(this), msg.sender, totalSupply, 0);
+    }
+
+    function unwrapNFT(IERC20 wrapper) external {
+        Tama storage tama = tamas[wrapper];
+        require(bento.balanceOf(wrapper, msg.sender) >= tama.ctrlSupply, "!ctrlSupply");
+        bento.withdraw(wrapper, address(this), msg.sender, tama.totalSupply, 0);
+        tama.nft.transferFrom(address(this), msg.sender, tama.tokenId);
+    }
+}