feat: cross-chain messaging

contracts/messaging/.eslintignore

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+.yarn
+artifacts
+cache
+coverage
+node_modules
+typechain-types

contracts/messaging/.eslintrc.js

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+const path = require("path");
+
+/**
+ * @type {import("eslint").Linter.Config}
+ */
+module.exports = {
+  env: {
+    browser: false,
+    es2021: true,
+    mocha: true,
+    node: true,
+  },
+  extends: ["plugin:prettier/recommended"],
+  parser: "@typescript-eslint/parser",
+  parserOptions: {
+    ecmaVersion: 12,
+  },
+  plugins: [
+    "@typescript-eslint",
+    "prettier",
+    "simple-import-sort",
+    "sort-keys-fix",
+    "typescript-sort-keys",
+  ],
+  rules: {
+    "@typescript-eslint/sort-type-union-intersection-members": "error",
+    camelcase: "off",
+    "simple-import-sort/exports": "error",
+    "simple-import-sort/imports": "error",
+    "sort-keys-fix/sort-keys-fix": "error",
+    "typescript-sort-keys/interface": "error",
+    "typescript-sort-keys/string-enum": "error",
+  },
+  settings: {
+    "import/parsers": {
+      "@typescript-eslint/parser": [".js", ".jsx", ".ts", ".tsx", ".d.ts"],
+    },
+    "import/resolver": {
+      node: {
+        extensions: [".js", ".jsx", ".ts", ".tsx", ".d.ts"],
+      },
+      typescript: {
+        project: path.join(__dirname, "tsconfig.json"),
+      },
+    },
+  },
+};

contracts/messaging/.gitignore

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+node_modules
+.env
+coverage
+coverage.json
+typechain
+typechain-types
+dependencies
+
+# Hardhat files
+cache
+artifacts
+
+# Foundry files
+out
+cache_forge
+
+access_token
+
+localnet.json

contracts/messaging/LICENSE

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+MIT License
+
+Copyright (c) 2023 ZetaChain
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

contracts/messaging/README.md

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+# Cross-Chain Messaging

contracts/messaging/contracts/Example.sol

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+// SPDX-License-Identifier: MIT
+pragma solidity 0.8.26;
+
+import "./Messaging.sol";
+
+contract Example is Messaging {
+    event OnMessageReceiveEvent(bytes);
+    event OnMessageRevertEvent();
+
+    constructor(
+        address payable gateway,
+        address owner,
+        address router
+    ) Messaging(gateway, owner, router) {}
+
+    function onMessageReceive(
+        bytes memory data,
+        address sender,
+        uint256 amount
+    ) internal override {
+        emit OnMessageReceiveEvent(data);
+    }
+
+    function onMessageRevert(
+        bytes memory data,
+        address sender,
+        uint256 amount
+    ) internal override {
+        emit OnMessageRevertEvent();
+        // Revert from destination chain
+    }
+
+    function onRevert(
+        RevertContext calldata context
+    ) external payable override onlyGateway {
+        if (context.sender != router) revert("Unauthorized");
+        emit OnRevertEvent("Event from onRevert()", context);
+        // Revert from ZetaChain
+    }
+
+    function sendMessage(
+        address destination,
+        bytes memory data,
+        CallOptions memory callOptions,
+        RevertOptions memory revertOptions
+    ) external payable {
+        bytes memory message = abi.encode(
+            connected[destination],
+            destination,
+            data,
+            callOptions,
+            revertOptions
+        );
+        gateway.depositAndCall{value: msg.value}(
+            router,
+            message,
+            revertOptions
+        );
+    }
+
+    // Simplified function for demo purposes
+
+    function sendSimpleMessage(
+        address destination,
+        string memory data
+    ) external payable {
+        RevertOptions memory revertOptions = RevertOptions(
+            address(0),
+            false,
+            address(0),
+            "",
+            0
+        );
+        bytes memory message = abi.encode(
+            connected[destination],
+            destination,
+            data,
+            CallOptions(200000, false),
+            revertOptions
+        );
+        gateway.depositAndCall{value: msg.value}(
+            router,
+            message,
+            revertOptions
+        );
+    }
+
+    // Send a message with an ERC-20 token. Currently, not supported.
+    //
+    // function sendMessage(
+    //     address targetToken,
+    //     uint256 amount,
+    //     address asset,
+    //     bytes memory data,
+    //     CallOptions memory callOptions,
+    //     RevertOptions memory revertOptions
+    // ) external {
+    //     bytes memory message = abi.encode(
+    //         abi.encodePacked(counterparty),
+    //         targetToken,
+    //         data,
+    //         callOptions,
+    //         revertOptions
+    //     );
+    //     if (!IERC20(asset).transferFrom(msg.sender, address(this), amount)) {
+    //         revert TransferFailed();
+    //     }
+    //     if (!IERC20(asset).approve(address(gateway), amount)) {
+    //         revert ApprovalFailed();
+    //     }
+
+    //     gateway.depositAndCall(router, amount, asset, message, revertOptions);
+    // }
+}

contracts/messaging/contracts/Messaging.sol

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+// SPDX-License-Identifier: MIT
+pragma solidity 0.8.26;
+
+import "@openzeppelin/contracts/access/Ownable.sol";
+import "@zetachain/protocol-contracts/contracts/evm/GatewayEVM.sol";
+import {RevertContext} from "@zetachain/protocol-contracts/contracts/Revert.sol";
+import {CallOptions} from "@zetachain/protocol-contracts/contracts/zevm/interfaces/IGatewayZEVM.sol";
+
+contract Messaging is Ownable {
+    GatewayEVM public immutable gateway;
+    uint256 private _nextTokenId;
+    address public router;
+
+    event HelloEvent(string, string);
+    event OnCallEvent(string);
+    event OnRevertEvent(string, RevertContext);
+
+    error Unauthorized();
+    error TransferFailed();
+    error ApprovalFailed();
+
+    modifier onlyGateway() {
+        if (msg.sender != address(gateway)) revert Unauthorized();
+        _;
+    }
+
+    mapping(address => address) public connected;
+
+    function setConnected(
+        address zrc20,
+        address contractAddress
+    ) external onlyOwner {
+        connected[zrc20] = contractAddress;
+    }
+
+    constructor(
+        address payable gatewayAddress,
+        address ownerAddress,
+        address routerAddress
+    ) Ownable(ownerAddress) {
+        gateway = GatewayEVM(gatewayAddress);
+        router = routerAddress;
+    }
+
+    function onCall(
+        MessageContext calldata context,
+        bytes calldata message
+    ) external payable onlyGateway returns (bytes4) {
+        if (context.sender != router) revert Unauthorized();
+        (
+            bytes memory data,
+            address sender,
+            uint256 amount,
+            bool isCall,
+            address zrc20
+        ) = abi.decode(message, (bytes, address, uint256, bool, address));
+        if (sender != connected[zrc20]) revert Unauthorized();
+        if (isCall) {
+            onMessageReceive(data, sender, amount);
+        } else {
+            onMessageRevert(data, sender, amount);
+        }
+        return "";
+    }
+
+    // onRevert is executed when router's onCall reverts
+    function onRevert(
+        RevertContext calldata context
+    ) external payable virtual onlyGateway {
+        if (context.sender != router) revert("Unauthorized");
+        emit OnRevertEvent("Event from onRevert()", context);
+    }
+
+    function onMessageReceive(
+        bytes memory data,
+        address sender,
+        uint256 amount
+    ) internal virtual {
+        // To be overridden in the child contract
+    }
+
+    function onMessageRevert(
+        bytes memory data,
+        address sender,
+        uint256 amount
+    ) internal virtual {
+        // To be overridden in the child contract
+    }
+
+    receive() external payable {}
+}