Task Bounty System Smart Contract

Overview

The Task Bounty System is a decentralized smart contract that allows users to create and participate in task-based bounties. Employers can post tasks with rewards in ETH, freelancers can apply, and the task owner selects a winner who receives the reward.

Features

• ✅ Task Creation: Users can create tasks with ETH rewards and deadlines.
• ✅ Freelancer Applications: Freelancers can apply for open tasks.
• ✅ Winner Selection: Task owners select a freelancer to complete the task and receive the reward.
• ✅ Automatic Payments: ETH is automatically transferred to the winner upon selection.
• ✅ Task Cancellation: Task owners can cancel tasks and reclaim their funds (before selecting a winner).
• ✅ Reputation System: Freelancers earn reputation points for completing tasks.

Smart Contract Functions

🛠 Task Management

createTask(string memory _description, uint _duration) payable

• Creates a new task with a deadline.
• Requires ETH to be sent as a reward.

applyForTask(uint _taskId, string memory _proposal)

• Allows freelancers to submit a proposal for a task.
• Task must be active and not expired.

selectWinner(uint _taskId, address _freelancer)

• Task owner selects a winner from the list of applicants.
• The freelancer receives the ETH reward.

cancelTask(uint _taskId)

• Task owner can cancel the task and reclaim funds (before selecting a winner).

🔍 Utility Functions

getApplicants(uint _taskId) returns (address[])

• Returns the list of freelancers who applied for a task.

getFreelancerReputation(address _freelancer) returns (uint)

• Retrieves a freelancer's reputation score based on completed tasks.

How It Works

1. Employer Posts a Task: Calls createTask() and sends ETH as a reward.
2. Freelancers Apply: Call applyForTask() with a proposal.
3. Employer Selects a Winner: Calls selectWinner(), and the freelancer receives ETH.
4. Freelancer Reputation Increases: The freelancer gains a reputation point.

Security & Best Practices

• ✅ Uses the checks-effects-interactions pattern to prevent re-entrancy attacks.
• ✅ Ensures only the task owner can select a winner or cancel a task.
• ✅ Prevents expired tasks from being manipulated.

Deployment & Testing

Deploying on Remix

1. Open Remix IDE.
2. Create a new Solidity file (TaskBounty.sol).
3. Copy and paste the contract code.
4. Compile and deploy using an Ethereum testnet.

Testing with Hardhat

1. Install dependencies:

   npm install hardhat ethers chai

2. Write test cases in Hardhat and run:

   npx hardhat test

License

This project is licensed under the MIT License.

Author

Developed by [Mrinal Singh]. Feel free to contribute or modify as needed!