feat: initial commit

.editorconfig

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+# EditorConfig  http://EditorConfig.org
+
+# top-most EditorConfig file
+root = true
+
+# All files
+[*]
+charset = utf-8
+end_of_line = lf
+indent_size = 2
+indent_style = space
+insert_final_newline = true
+trim_trailing_whitespace = true
+
+[*.sol]
+indent_size = 4
+
+[*.tree]
+indent_size = 1

.env.example

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+export API_KEY_ALCHEMY="YOUR_API_KEY_ALCHEMY"
+export API_KEY_ETHERSCAN="YOUR_API_KEY_ETHERSCAN"
+export FOUNDRY_PROFILE="default"

.github/workflows/ci.yml

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+name: "CI"
+
+env:
+  API_KEY_ALCHEMY: ${{ secrets.API_KEY_ALCHEMY }}
+  FOUNDRY_PROFILE: "ci"
+
+on:
+  workflow_dispatch:
+  pull_request:
+  push:
+    branches:
+      - "main"
+
+jobs:
+  lint:
+    runs-on: "ubuntu-latest"
+    steps:
+      - name: "Check out the repo"
+        uses: "actions/checkout@v4"
+
+      - name: "Install Foundry"
+        uses: "foundry-rs/foundry-toolchain@v1"
+
+      - name: Use Node.js 21
+        uses: actions/setup-node@v3
+        with:
+          node-version: 21
+          cache: 'npm'
+
+      - name: "Install the Node.js dependencies"
+        run: "npm install"
+
+      - name: "Lint the code"
+        run: "npm run lint"
+
+      - name: "Add lint summary"
+        run: |
+          echo "## Lint result" >> $GITHUB_STEP_SUMMARY
+          echo "✅ Passed" >> $GITHUB_STEP_SUMMARY
+
+  build:
+    runs-on: "ubuntu-latest"
+    steps:
+      - name: "Check out the repo"
+        uses: "actions/checkout@v4"
+
+      - name: "Install Foundry"
+        uses: "foundry-rs/foundry-toolchain@v1"
+
+      - name: Use Node.js 21
+        uses: actions/setup-node@v3
+        with:
+          node-version: 21
+          cache: 'npm'
+
+      - name: "Install the Node.js dependencies"
+        run: "npm install"
+
+      - name: "Build the contracts and print their size"
+        run: "forge build --sizes"
+
+      - name: "Add build summary"
+        run: |
+          echo "## Build result" >> $GITHUB_STEP_SUMMARY
+          echo "✅ Passed" >> $GITHUB_STEP_SUMMARY
+
+  test:
+    needs: ["lint", "build"]
+    runs-on: "ubuntu-latest"
+    steps:
+      - name: "Check out the repo"
+        uses: "actions/checkout@v4"
+
+      - name: "Install Foundry"
+        uses: "foundry-rs/foundry-toolchain@v1"
+
+      - name: Use Node.js 21
+        uses: actions/setup-node@v3
+        with:
+          node-version: 21
+          cache: 'npm'
+
+      - name: "Install the Node.js dependencies"
+        run: "npm install"
+
+      - name: "Show the Foundry config"
+        run: "forge config"
+
+      - name: "Generate a fuzz seed that changes weekly to avoid burning through RPC allowance"
+        run: >
+          echo "FOUNDRY_FUZZ_SEED=$(
+            echo $(($EPOCHSECONDS - $EPOCHSECONDS % 604800))
+          )" >> $GITHUB_ENV
+
+      - name: "Run the tests"
+        run: "forge test"
+
+      - name: "Add test summary"
+        run: |
+          echo "## Tests result" >> $GITHUB_STEP_SUMMARY
+          echo "✅ Passed" >> $GITHUB_STEP_SUMMARY

.github/workflows/use-template.yml

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+name: "Create"
+
+# The workflow will run when the "Use this template" button is used
+on:
+  push:
+
+jobs:
+  create:
+    # We only run this action when the repository isn't the template repository. References:
+    # - https://docs.github.com/en/actions/learn-github-actions/contexts
+    # - https://docs.github.com/en/actions/learn-github-actions/expressions
+    if: ${{ !github.event.repository.is_template }}
+    permissions: "write-all"
+    runs-on: "ubuntu-latest"
+    steps:
+      - name: "Check out the repo"
+        uses: "actions/checkout@v4"
+
+      - name: "Update package.json"
+        env:
+          GITHUB_REPOSITORY_DESCRIPTION: ${{ github.event.repository.description }}
+        run:
+          ./.github/scripts/rename.sh "$GITHUB_REPOSITORY" "$GITHUB_REPOSITORY_OWNER" "$GITHUB_REPOSITORY_DESCRIPTION"
+
+      - name: "Add rename summary"
+        run: |
+          echo "## Commit result" >> $GITHUB_STEP_SUMMARY
+          echo "✅ Passed" >> $GITHUB_STEP_SUMMARY
+
+      - name: "Remove files not needed in the user's copy of the template"
+        run: |
+          rm -f "./.github/FUNDING.yml"
+          rm -f "./.github/scripts/rename.sh"
+          rm -f "./.github/workflows/create.yml"
+
+      - name: "Add remove summary"
+        run: |
+          echo "## Remove result" >> $GITHUB_STEP_SUMMARY
+          echo "✅ Passed" >> $GITHUB_STEP_SUMMARY
+
+      - name: "Update commit"
+        uses: "stefanzweifel/git-auto-commit-action@v4"
+        with:
+          commit_message: "feat: initial commit"
+          commit_options: "--amend"
+          push_options: "--force"
+          skip_fetch: true
+
+      - name: "Add commit summary"
+        run: |
+          echo "## Commit result" >> $GITHUB_STEP_SUMMARY
+          echo "✅ Passed" >> $GITHUB_STEP_SUMMARY

.gitignore

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+# directories
+cache
+coverage
+node_modules
+out
+
+# files
+*.env
+*.log
+.DS_Store
+.pnp.*
+lcov.info
+package-lock.json
+pnpm-lock.yaml
+yarn.lock
+
+# broadcasts
+!broadcast
+broadcast/*
+broadcast/*/31337/

.prettierignore

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+# directories
+broadcast
+cache
+coverage
+node_modules
+out
+
+# files
+*.env
+*.log
+.DS_Store
+.pnp.*
+lcov.info
+package-lock.json
+pnpm-lock.yaml
+yarn.lock

.prettierrc.yml

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+bracketSpacing: true
+printWidth: 120
+proseWrap: "always"
+singleQuote: false
+tabWidth: 2
+trailingComma: "all"
+useTabs: false

.solhint.json

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+{
+  "extends": "solhint:recommended",
+  "rules": {
+    "code-complexity": ["error", 8],
+    "compiler-version": ["error", ">=0.8.25"],
+    "func-name-mixedcase": "off",
+    "func-visibility": ["error", { "ignoreConstructors": true }],
+    "max-line-length": ["error", 120],
+    "named-parameters-mapping": "warn",
+    "no-console": "off",
+    "not-rely-on-time": "off",
+    "one-contract-per-file": "off"
+  }
+}

.vscode/settings.json

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+{
+  "[solidity]": {
+    "editor.defaultFormatter": "JuanBlanco.solidity"
+  },
+  "[toml]": {
+    "editor.defaultFormatter": "tamasfe.even-better-toml"
+  },
+  "solidity.formatter": "forge",
+  "solidity.compileUsingRemoteVersion": "v0.8.25+commit.b61c2a91"
+}

LICENSE.md

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+MIT License
+
+Copyright (c) 2024 Paul Razvan Berg
+
+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.

README.md

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+# Token Vendor Machine Challenge
+
+This project is designed to test your skills in smart contract development using Solidity.
+
+## Project Overview
+
+You are tasked with implementing a token vendor machine that allows users to buy and sell tokens. The project consists of two main contracts:
+
+1. `BlockfulToken.sol`: An ERC20 token contract
+2. `TokenVendor.sol`: A vendor contract for buying and selling tokens
+
+## Getting Started
+
+To get started with this project, follow these steps:
+
+1. Clone this repository.
+2. Run `npm install` to install Node.js dependencies
+
+## Your Tasks
+
+1. Implement the `BlockfulToken` contract:
+   - It should be an ERC20 token with a name, symbol, and 18 decimals.
+   - Initial supply should be 1,000,000 tokens.
+
+2. Implement the `TokenVendor` contract with the following functionality:
+   - Allow users to buy tokens with ETH (1 ETH = 100 tokens)
+   - Allow users to sell tokens back to the contract
+   - Allow the owner to withdraw ETH from the contract
+   - Implement proper access control (only owner can withdraw)
+   - Emit events for token purchases, sales, and ETH withdrawals
+
+3. Complete the test file `test/TokenVendor.t.sol`:
+   - We've provided some basic "happy path" tests
+   - Implement additional tests for edge cases and potential failure scenarios
+   - Aim for at least 90% test coverage
+
+4. Update this README with:
+   - Any additional setup or testing instructions
+   - An explanation of your design decisions
+   - Any potential improvements or considerations for a real-world deployment
+
+## Bonus Tasks
+
+If you complete the main tasks and want to demonstrate more advanced skills:
+
+1. Implement a simple dynamic pricing mechanism (e.g., price increases as supply decreases)
+2. Add a feature to pause/unpause the contract (owner only)
+3. Implement a whitelist system for early access to token sales
+
+## Usage
+
+Here are some common commands you'll need:
+
+### Build
+
+```sh
+npm run build
+```
+
+### Test
+
+```sh
+npm run  test
+```
+
+### Coverage
+
+```sh
+npm run test:coverage
+```
+
+## Evaluation Criteria
+
+Your submission will be evaluated based on:
+
+- Correctness of the implementation
+- Code quality and organization
+- Test coverage and quality
+- Security considerations
+- Testnet deployment
+- Documentation and comments
+- (For bonus tasks) Creativity and effectiveness of additional features
+
+## Submission
+
+Please submit your completed project as a Git repository. Make sure to include:
+
+- All source code files
+- Complete test suite
+- Updated README with your notes and explanations
+
+## Note
+
+This project uses [Foundry](https://getfoundry.sh/). If you're new to Foundry, check out the [Foundry Book](https://book.getfoundry.sh/) for detailed instructions and tutorials.
+
+Good luck with the challenge! We're excited to see your implementation.