Implement Lending Pool Smart Contract with Core Functionalities and Tests

[emmanuelist]

Overview

This pull request implements a comprehensive lending pool smart contract for the Stacks blockchain. The contract allows users to deposit and withdraw STX, borrow against their deposits, and repay loans. It includes administrative functions for managing the contract parameters and a suite of tests to ensure proper functionality.

Key Features

• Deposit and withdraw STX
• Borrow STX against collateral
• Repay loans with interest
• Dynamic collateral ratio and interest rate
• Contract pause/unpause functionality
• Comprehensive test suite

Changes Made

1. Implemented core contract functions:
   • Deposit and withdraw
   • Borrow and repay
   • Admin functions (set collateral ratio, interest rate, pause/unpause)
2. Added data maps for user deposits and borrows
3. Implemented read-only functions for querying contract state
4. Created private functions for interest calculation
5. Developed a comprehensive test suite covering all main functionalities

Test Results

All tests are passing successfully:

• Deposit functionality
• Withdrawal functionality
• Borrowing mechanism
• Loan repayment
• Collateral ratio enforcement
• Admin functions (setting parameters, pausing contract)
• Access control for admin functions

Code Quality

• Followed Clarity best practices and coding standards
• Implemented proper error handling and input validation
• Used descriptive variable and function names
• Added comments for complex logic

Security Considerations

• Implemented access control for admin functions
• Ensured proper validation of user inputs
• Added checks to prevent excessive borrowing
• Implemented contract pause functionality for emergency situations

Next Steps

• Conduct a thorough code review
• Perform additional security audits
• Consider implementing additional features (e.g., multiple asset support, liquidation mechanism)

Reviewers

@Tech-lead
@security-expert
@smart-contract-specialist

Please review this pull request and provide any feedback or suggestions for improvement. Thank you!