Voting Manager Tool is a comprehensive, blockchain-based voting management application. It leverages the power of Solidity smart contracts, a NestJS back-end service, a React front-end application, and GraphQL for efficient data handling. This combination of technologies provides a secure, efficient, and user-friendly platform for managing and participating in voting events.

The main technology stack used in this project includes:

• Solidity: For creating the smart contract that handles the voting mechanism.
• NestJS: For building the back-end service that listens to events emitted by the smart contract and syncs with our database.
• React: For developing the front-end application that displays the events from the smart contract to the users.
• GraphQL: Used in conjunction with TheGraph for efficient querying and indexing of blockchain data.

The smart contract, developed in Solidity and deployed on the Optimism Sepolia network, implements a voting mechanism. This contract allows for the creation of votes, casting of votes, and conclusion of voting. Additionally, it emits events for each of these actions.

The back-end service, integrated using a NestJS project, is responsible for listening to the events emitted by the smart contract. It has a cron job running periodically to listen for relevant blockchain events. When these events are heard, it syncs with our database, which feeds data to our front-end. It also provides RESTful APIs that serve the event data to the front-end.

The application integrates a subgraph using TheGraph for indexing blockchain data. This allows for efficient querying of blockchain events and data, enhancing the performance and user experience of the application.

The front-end application is responsible for displaying the events from the smart contract. This application has been modified to fetch event data from the back-end API instead of directly from the blockchain. The user interface is user-friendly and displays real-time updates.

Unit tests have been written for the smart contract and for the API endpoints. Comprehensive documentation is provided, including setup instructions for the smart contract, back-end service, and front-end application.

1. Clone the GitHub repository.

2. Navigate to the neitec api folder and create a .env file with the following environment variables:

   GRAPHQL_API_URL="your subgraph api url"
   MONGODB_URI="your mongodb uri"
   

3. Run npm install to install all dependencies.

4. Run npm run start to start the back-end service. Once this is done, our backend will be running, listening to events on the blockchain and syncing our MongoDB database as necessary.

5. Open another console, navigate to the voting-app folder.

6. Run npm install to install all dependencies.

7. Run npm run start to start the front-end application.

8. Follow the setup and running instructions for the smart contract, back-end service, and front-end application provided in the documentation.

9. Ensure you have available balance on the Optimism Sepolia network. You can get test balance from this faucet: https://faucet.quicknode.com/optimism/sepolia

10. Connect to the Optimism Sepolia network through MetaMask. You can do it directly from this link: https://chainlist.org/chain/11155420

To contribute to this project, please fork the repository and propose your changes via a pull request.

This project is licensed under the terms of the MIT license.