feat: adds erc20 wrapper example project

erc20-wrapper-registry/README.md

@@ -0,0 +1,37 @@
+#  ERC20 Wrapper - Violet ID example
+
+This project aims to demonstrate a simple example of how to wrap ERC20 tokens to a compliant version of it using VioletID. It comes with a sample Factory contract, and a CompliantERC20 contract on Optimism Goerli.
+
+You can check a frontend with a live version of this demo [here](https://erc20-wrapper.violet.co/).
+The frontend is located on the `frontend` folder, all relevant code can be found on the `frontend/pages/index.tsx` file
+
+Find all VioletID live addresses in our [docs](https://docs.violet.co).
+
+
+## Setup
+
+#### Install the project by running the command
+
+```shell
+yarn install
+```
+
+#### Compile the test contract
+
+```shell
+yarn hardhat compile
+```
+
+#### Deploy the test contract on optimismGoerli:
+
+```shell
+yarn hardhat run scripts/deploy.ts --network optimismGoerli
+```
+
+
+#### Run the frontend locally
+
+```shell
+cd frontend
+yarn dev
+```

erc20-wrapper-registry/contracts/CompliantERC20.sol

@@ -0,0 +1,71 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.8.20;
+
+import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
+import {IVioletID} from "@violetprotocol/violetid/contracts/IVioletID.sol";
+
+error AccountWithoutVioletIDRequiredStatus();
+
+/**
+ * @dev ERC20 token contract that only allows wrapping and unwraping to valid VioletID holders
+ *
+ * Currently uses the VioletID status 1 representing enrollment, which includes initial screening and KYC/KYB.
+ */
+contract CompliantERC20 is ERC20 {
+    IERC20 permissionlessERC20;
+    uint256 public tokensWrapped;
+    IVioletID violetID;
+
+    constructor(
+        string memory name_,
+        string memory symbol_,
+        address violetID_,
+        address _nonCompliantERC20
+    ) ERC20(name_, symbol_) {
+        violetID = IVioletID(violetID_);
+        permissionlessERC20 = IERC20(_nonCompliantERC20);
+    }
+
+    modifier onlyVioletIDHolders(address account) {
+        uint8 isEnrolledStatus = 1;
+        require(
+            violetID.hasStatus(account, isEnrolledStatus),
+            "account does not have a VioletID"
+        );
+        if (!violetID.hasStatus(account, isEnrolledStatus))
+            revert AccountWithoutVioletIDRequiredStatus();
+        _;
+    }
+
+    // All customizations to transfers, mints, and burns should be done by overriding this function.
+    // https://docs.openzeppelin.com/contracts/5.x/api/token/erc20#ERC20-_transfer-address-address-uint256-
+    // Adding the onlyVioletIDHolders modifier ensures only addresses with VioletID status receive tokens
+    function _update(
+        address from,
+        address to,
+        uint256 amount
+    ) internal virtual override onlyVioletIDHolders(to) {
+        super._update(from, to, amount);
+    }
+
+    function wrap(
+        uint256 amount
+    ) public virtual onlyVioletIDHolders(msg.sender) {
+        permissionlessERC20.transferFrom(msg.sender, address(this), amount);
+        tokensWrapped += amount;
+        super._mint(msg.sender, amount);
+    }
+
+    function unwrap(
+        uint256 amount
+    ) public virtual onlyVioletIDHolders(msg.sender) {
+        require(
+            tokensWrapped >= amount,
+            "cERC20_unwrap: amount to unwrap exceeds total wrapped"
+        );
+        tokensWrapped -= amount;
+        _burn(msg.sender, amount);
+        permissionlessERC20.transfer(msg.sender, amount);
+    }
+}

erc20-wrapper-registry/contracts/CompliantFactory.sol

@@ -0,0 +1,33 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.8.20;
+
+import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
+import {IVioletID} from "@violetprotocol/violetid/contracts/IVioletID.sol";
+import "./CompliantERC20.sol";
+
+/**
+ * @dev ERC20 token factory that builds a new ERC20 using the previous token address
+ *
+ * Saves the new wrapped token address on the erc20ToCompliantWrapped mapping
+ */
+contract CompliantFactory {
+    mapping(address => address) public erc20ToCompliantWrapped;
+
+    function deployCompliantErc(
+        address nonCompliantERC20,
+        address violetId_
+    ) public payable {
+        address compliantErc20 = address(
+            new CompliantERC20{
+                salt: keccak256(abi.encodePacked(nonCompliantERC20))
+            }(
+                string.concat("c", ERC20(nonCompliantERC20).name()),
+                string.concat("c", ERC20(nonCompliantERC20).symbol()),
+                violetId_,
+                nonCompliantERC20
+            )
+        );
+        erc20ToCompliantWrapped[nonCompliantERC20] = compliantErc20;
+    }
+}

erc20-wrapper-registry/contracts/MockERC20.sol

@@ -0,0 +1,15 @@
+//SPDX-License-Identifier: MIT
+pragma solidity ^0.8.14;
+
+import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
+
+contract MockERC20 is ERC20 {
+    constructor(
+        string memory name_,
+        string memory symbol_
+    ) ERC20(name_, symbol_) {}
+
+    function mint(address account, uint256 amount) public virtual {
+        _mint(account, amount);
+    }
+}

erc20-wrapper-registry/frontend/.eslintrc.json

@@ -0,0 +1,3 @@
+{
+  "extends": "next/core-web-vitals"
+}

erc20-wrapper-registry/frontend/.gitignore

@@ -0,0 +1,39 @@
+# See https://help.github.com/articles/ignoring-files/ for more about ignoring files.
+
+# dependencies
+/node_modules
+/.pnp
+.pnp.js
+
+# testing
+/coverage
+
+# next.js
+/.next/
+/out/
+
+# production
+/build
+
+# misc
+.DS_Store
+*.pem
+
+# debug
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+.pnpm-debug.log*
+
+# local env files
+.env
+.env.local
+.env.development.local
+.env.test.local
+.env.production.local
+
+# vercel
+.vercel
+
+# typescript
+*.tsbuildinfo

erc20-wrapper-registry/frontend/.prettierrc.js

@@ -0,0 +1,5 @@
+module.exports = {
+  semi: false,
+  singleQuote: true,
+  trailingComma: 'all',
+}