Implementation of contracts

[walterthesmart]

Implement NextofKin Contract with Modular Architecture

Description:

This pull request introduces the implementation of the NextofKin smart contract using a modular architecture in Clarity. The NextofKin contract provides a way for users to designate recipients for their funds in case of inactivity.

Key Features:

1. Modular Design: The contract is split into multiple modules for better organization and maintainability.
2. Main Contract Interface: The main.clar file serves as the primary interface, delegating calls to specialized modules.
3. SIP-010 Compatibility: Implements the SIP-010 trait for fungible token standards.
4. Custom Trait Implementation: Implements a custom nok-trait.

Modules Overview:

• main.clar: The main contract that implements the nok-trait and coordinates with other modules.
• storage.clar: Handles data storage and retrieval.
• core.clar: Implements core functionality like deposits and recipient assignment.
• distribution.clar: Manages the distribution of funds to recipients.
• sip-010-trait.clar: Defines the SIP-010 trait for fungible tokens.
• nok-trait.clar: Defines the custom trait for the NextofKin contract.

Main Contract Functions:

1. deposit: Allows users to deposit funds.
2. assign-recipients: Enables users to designate fund recipients.
3. check-and-distribute: Initiates the fund distribution process.
4. get-balance: Retrieves a user's balance.
5. get-recipients: Fetches the list of designated recipients for a user.
6. get-last-activity: Retrieves the timestamp of a user's last activity.

Changes Made:

• Implemented the main contract structure in main.clar.
• Created separate modules for storage, core functionality, and distribution.
• Defined and implemented custom traits.
• Established inter-contract communication using contract-call?.

Testing:

• Unit tests have been added for each module to ensure correct functionality.
• Integration tests have been included to verify the interaction between modules.

Next Steps:

• Review and refine error handling across all modules.
• Optimize gas consumption for complex operations.
• Enhance documentation with detailed comments for each function.
• Consider adding events for important state changes.

This modular approach enhances the contract's readability, maintainability, and upgradability. It allows for easier testing and future expansions of functionality.

Reviewers, please pay special attention to:

1. The correctness of inter-contract calls.
2. Proper implementation of the nok-trait.
3. Security considerations in the deposit and distribution functions.
4. Efficiency of data storage and retrieval methods.

Your feedback and suggestions for improvements are highly appreciated.