Merge pull request #1001 from thesandboxgame/feat/signedMultiGiveaway…

…_package

Feat/signed multi giveaway package

packages/giveaway/.eslintignore

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+node_modules
+.env
+coverage
+coverage.json
+typechain
+typechain-types
+
+# Hardhat files
+cache
+artifacts
+
+# generated docs
+generated-markups
+
+# editors
+.idea

packages/giveaway/.eslintrc.js

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+const path = require('path');
+const tsconfigPath = path.join(__dirname, 'tsconfig.json');
+module.exports = {
+  root: true,
+  extends: [
+    'eslint:recommended',
+    'plugin:mocha/recommended',
+    'plugin:prettier/recommended',
+  ],
+  parserOptions: {
+    ecmaVersion: 2020,
+  },
+  plugins: ['mocha'],
+  env: {
+    commonjs: true,
+    node: true,
+    mocha: true,
+  },
+  overrides: [
+    {
+      files: ['*.ts'],
+      parser: '@typescript-eslint/parser',
+      parserOptions: {
+        project: [tsconfigPath],
+        ecmaVersion: 2020,
+        sourceType: 'module',
+      },
+      plugins: ['mocha', '@typescript-eslint'],
+      extends: [
+        'eslint:recommended',
+        'plugin:@typescript-eslint/recommended',
+        'plugin:mocha/recommended',
+        'plugin:prettier/recommended',
+      ],
+      rules: {
+        '@typescript-eslint/no-misused-promises': 'error',
+        '@typescript-eslint/no-floating-promises': 'error',
+      },
+    },
+  ],
+};

packages/giveaway/.gitignore

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+node_modules
+.env
+coverage
+coverage.json
+typechain
+typechain-types
+
+# Hardhat files
+cache
+artifacts
+
+# generated docs
+generated-markups
+
+# editors
+.idea

packages/giveaway/.prettierignore

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+node_modules
+.env
+coverage
+coverage.json
+typechain
+typechain-types
+
+# Hardhat files
+cache
+artifacts
+
+# generated docs
+generated-markups
+
+# editors
+.idea

packages/giveaway/.prettierrc.js

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+module.exports = {
+  singleQuote: true,
+  bracketSpacing: false,
+  plugins: ['prettier-plugin-solidity'],
+  overrides: [
+    {
+      files: '*.sol',
+      options: {
+        printWidth: 120,
+        tabWidth: 4,
+        singleQuote: false,
+      },
+    },
+  ],
+};

packages/giveaway/.solcover.js

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+module.exports = {
+  mocha: {
+    grep: '@skip-on-coverage', // Find everything with this tag
+    invert: true, // Run the grep's inverse set.
+  },
+};

packages/giveaway/.solhint.json

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+{
+  "extends": "solhint:recommended",
+  "plugins": ["prettier"],
+  "rules": {
+    "prettier/prettier": [
+      "error",
+      {
+        "endOfLine": "auto"
+      }
+    ],
+    "code-complexity": ["error", 7],
+    "compiler-version": ["error", "^0.8.0"],
+    "const-name-snakecase": "off",
+    "func-name-mixedcase": "off",
+    "constructor-syntax": "error",
+    "func-visibility": ["error", {"ignoreConstructors": true}],
+    "not-rely-on-time": "off",
+    "no-inline-assembly": "off",
+    "reason-string": ["warn", {"maxLength": 64}]
+  }
+}

packages/giveaway/README.md

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+# Signed Giveaways
+
+This is a hardhat project, see [https://hardhat.org](https://hardhat.org)
+
+The main contract gives rewards in any ERC20, ERC721 or ERC1155 when the backend authorize it via message signing.
+
+The message is composed of:
+
+- A list of signatures. If the contract holt too much value more than one signature is needed. Ideally the systems that
+  sign must be independent.
+- A list of claim ids used by the backend to avoid double spending.
+- Expiration the expiration time of the message in unix timestamp. After the expiration the message cannot be used
+  anymore.
+- From: usually the rewards must be transferred to the contract and this value is address(this), if a strategy with
+  approve and transfer is used this is the address of the source.
+- To: the destination address that will get the rewards.
+- Claims: A list of union structs (ClaimEntry) that include: token type (ERC20, ERC721, ERC1155, etc), token address and
+  a data field that depending on the token type may have: amount, tokenId, etc.
+
+# Usage
+
+```shell
+yarn hardhat help
+yarn hardhat test
+yarn hardhat coverage
+REPORT_GAS=true yarn hardhat test
+yarn hardhat markup
+```
+
+# Deployment
+
+This package exports the contract source code, for deployments see: [@sandbox-smart-contract/deploy](../deploy) package.
+

packages/giveaway/contracts/ERC2771Handler.sol

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+// SPDX-License-Identifier: MIT
+// solhint-disable-next-line compiler-version
+pragma solidity 0.8.18;
+
+/// @dev minimal ERC2771 handler to keep bytecode-size down
+/// based on: https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v4.6.0/contracts/metatx/ERC2771Context.sol
+/// with an initializer for proxies and a mutable forwarder
+
+abstract contract ERC2771Handler {
+    address internal _trustedForwarder;
+
+    function __ERC2771Handler_initialize(address forwarder) internal {
+        _trustedForwarder = forwarder;
+    }
+
+    function isTrustedForwarder(address forwarder) public view returns (bool) {
+        return forwarder == _trustedForwarder;
+    }
+
+    function getTrustedForwarder() external view returns (address) {
+        return _trustedForwarder;
+    }
+
+    function trustedForwarder() external view returns (address) {
+        return _trustedForwarder;
+    }
+
+    function _msgSender() internal view virtual returns (address sender) {
+        if (isTrustedForwarder(msg.sender)) {
+            // The assembly code is more direct than the Solidity version using `abi.decode`.
+            // solhint-disable-next-line no-inline-assembly
+            assembly {
+                sender := shr(96, calldataload(sub(calldatasize(), 20)))
+            }
+        } else {
+            return msg.sender;
+        }
+    }
+}