feat: add initial implementation of SBT contract

Author: Yash Agrawal

contracts/Admin.sol

@@ -0,0 +1,160 @@
+// SPDX-License-Identifier: MPL-2.0
+pragma solidity =0.8.9;
+
+import {IERC721EnumerableUpgradeable} from "@openzeppelin/contracts-upgradeable/token/ERC721/extensions/ERC721EnumerableUpgradeable.sol";
+import {IERC165Upgradeable} from "@openzeppelin/contracts-upgradeable/utils/introspection/IERC165Upgradeable.sol";
+import {ERC721Upgradeable} from "@openzeppelin/contracts-upgradeable/token/ERC721/ERC721Upgradeable.sol";
+import {ProxyAdmin} from "@openzeppelin/contracts/proxy/transparent/ProxyAdmin.sol";
+import {EnumerableSet} from "@openzeppelin/contracts/utils/structs/EnumerableSet.sol";
+import {Counters} from "@openzeppelin/contracts/utils/Counters.sol";
+
+import {ISBTToken} from "./interfaces/ISBTToken.sol";
+
+contract SBTToken is
+	ISBTToken,
+	IERC721EnumerableUpgradeable,
+	ERC721Upgradeable
+{
+	Counters.Counter private tokenIdCounter;
+
+	mapping(address => EnumerableSet.UintSet) private tokenIdsMapOfOwner;
+	mapping(uint256 => string) private tokenUriImage;
+	address private proxyAdmin;
+	/// @dev EOA with minting rights.
+	address private minter;
+
+	using Counters for Counters.Counter;
+	using EnumerableSet for EnumerableSet.UintSet;
+
+	modifier onlyMinter() {
+		require(minter == _msgSender(), "illegal access");
+		_;
+	}
+
+	function initialize(address _minter) external initializer {
+		__ERC721_init("Dev Protocol sTokens V1", "DEV-STOKENS-V1");
+		minter = _minter;
+	}
+
+	/**
+	 * @dev See {IERC165-supportsInterface}.
+	 */
+	function supportsInterface(
+		bytes4 interfaceId
+	)
+		public
+		view
+		virtual
+		override(IERC165Upgradeable, ERC721Upgradeable)
+		returns (bool)
+	{
+		return
+			interfaceId == type(IERC721EnumerableUpgradeable).interfaceId ||
+			super.supportsInterface(interfaceId);
+	}
+
+	/**
+	 * @dev See {IERC721Enumerable-totalSupply}.
+	 */
+	function totalSupply() public view virtual override(ISBTToken, IERC721EnumerableUpgradeable) returns (uint256) {
+		return tokenIdCounter.current();
+	}
+
+	/**
+	 * @dev See {IERC721Enumerable-tokenOfOwnerByIndex}.
+	 */
+	function tokenOfOwnerByIndex(
+		address _owner,
+		uint256 index
+	) public view virtual override(ISBTToken, IERC721EnumerableUpgradeable) returns (uint256) {
+		// solhint-disable-next-line reason-string
+		require(
+			index < tokenIdsMapOfOwner[_owner].length(),
+			"ERC721Enumerable: owner index out of bounds"
+		);
+		return tokenIdsMapOfOwner[_owner].at(index);
+	}
+
+	/**
+	 * @dev See {IERC721Enumerable-tokenByIndex}.
+	 */
+	function tokenByIndex(
+		uint256 index
+	) public view virtual override(ISBTToken, IERC721EnumerableUpgradeable) returns (uint256) {
+		// solhint-disable-next-line reason-string
+		require(
+			index < tokenIdCounter.current(),
+			"ERC721Enumerable: global index out of bounds"
+		);
+		return index + 1;
+	}
+
+	function owner() external view returns (address) {
+		return ProxyAdmin(proxyAdmin).owner();
+	}
+
+	function setProxyAdmin(address _proxyAdmin) external {
+		require(proxyAdmin == address(0), "already set");
+		proxyAdmin = _proxyAdmin;
+	}
+
+	function tokenURI(
+		uint256 _tokenId
+	) public view override returns (string memory) {
+		uint256 curretnTokenId = tokenIdCounter.current();
+		require(_tokenId <= curretnTokenId, "not found");
+		return _tokenURI(_tokenId);
+	}
+
+	function currentIndex() external view override returns (uint256) {
+		return tokenIdCounter.current();
+	}
+
+	function mint(
+		address _owner
+	) external override onlyMinter returns (uint256 tokenId_) {
+		tokenIdCounter.increment();
+		uint256 currentId = tokenIdCounter.current();
+		_mint(_owner, currentId);
+		emit Minted(currentId, _owner);
+		return currentId;
+	}
+
+	function setTokenURIImage(
+		uint256 _tokenId,
+		string memory _data
+	) external override onlyMinter {
+		tokenUriImage[_tokenId] = _data;
+	}
+
+	function tokensOfOwner(
+		address _owner
+	) external view override returns (uint256[] memory) {
+		return tokenIdsMapOfOwner[_owner].values();
+	}
+
+	function _tokenURI(uint256 _tokenId) private view returns (string memory) {
+		return tokenUriImage[_tokenId];
+	}
+
+	function _beforeTokenTransfer(
+		address from,
+		address to,
+		uint256 tokenId,
+		uint256 batchSize
+	) internal virtual override {
+		super._beforeTokenTransfer(from, to, tokenId, batchSize);
+
+		if (from == address(0)) {
+			// mint
+			tokenIdsMapOfOwner[to].add(tokenId);
+		} else if (to == address(0)) {
+			// burn
+			revert("SBT is not burned");
+		} else if (to != from) {
+			revert("SBT is non transferrable");
+		} else {
+			revert("Illegal operation");
+		}
+	}
+}

contracts/Example.sol

@@ -0,0 +1,68 @@
+// SPDX-License-Identifier: MPL-2.0
+pragma solidity ^0.8.9;
+
+interface ISBTToken {
+	/*
+	 * @dev The event fired when a token is minted.
+	 * @param tokenId The ID of the created new staking position
+	 * @param owner The address of the owner of the new staking position
+	 */
+	event Minted(uint256 tokenId, address owner);
+
+	/*
+	 * @dev Creates the new staking position for the caller.
+	 * Mint must be called by the minter address.
+	 * @param _owner The address of the owner of the new staking position
+	 */
+	function mint(address _owner) external returns (uint256);
+
+	/*
+	 * @dev Sets the token URI image for a token.
+	 * @notice must be called by the minter address.
+	 * @param _tokenId The token for which we are setting the image uri.
+	 * @param _data The data that is used as uri.
+	 */
+	function setTokenURIImage(
+		uint256 _tokenId,
+		string memory _data
+	) external;
+
+	/*
+	 * @dev get token ids by owner
+	 * @param _owner owner address
+	 * @return uint256[] token id list
+	 */
+	function tokensOfOwner(
+		address _owner
+	) external view returns (uint256[] memory);
+
+	/*
+	 * @dev get current token id
+	 * @return uint256 current token id
+	 */
+	function currentIndex() external view returns (uint256);
+
+	/// @notice Count NFTs tracked by this contract
+	/// @return A count of valid NFTs tracked by this contract, where each one of
+	///  them has an assigned and queryable owner not equal to the zero address
+	function totalSupply() external view returns (uint256);
+
+	/// @notice Enumerate valid NFTs
+	/// @dev Throws if `_index` >= `totalSupply()`.
+	/// @param _index A counter less than `totalSupply()`
+	/// @return The token identifier for the `_index`th NFT,
+	///  (sort order not specified)
+	function tokenByIndex(uint256 _index) external view returns (uint256);
+
+	/// @notice Enumerate NFTs assigned to an owner
+	/// @dev Throws if `_index` >= `balanceOf(_owner)` or if
+	///  `_owner` is the zero address, representing invalid NFTs.
+	/// @param _owner An address where we are interested in NFTs owned by them
+	/// @param _index A counter less than `balanceOf(_owner)`
+	/// @return The token identifier for the `_index`th NFT assigned to `_owner`,
+	///   (sort order not specified)
+	function tokenOfOwnerByIndex(
+		address _owner,
+		uint256 _index
+	) external view returns (uint256);
+}

contracts/SBTToken.sol

@@ -2,7 +2,7 @@ import '@typechain/hardhat'
 import '@nomiclabs/hardhat-ethers'
 import '@nomiclabs/hardhat-waffle'
 import '@nomiclabs/hardhat-etherscan'
-import { HardhatUserConfig } from 'hardhat/config'
+import { type HardhatUserConfig } from 'hardhat/config'
 import * as dotenv from 'dotenv'
 
 dotenv.config()