A comprehensive smart contract implementation for managing tontines (rotating savings and credit associations) on the Cosmos blockchain using CosmWasm.

A tontine is a financial arrangement where a group of people contribute to a common fund, and each member receives the entire fund in rotation. This smart contract provides a secure, automated, and transparent way to manage tontines with features like:

• Member Management: Registration, removal, and replacement of members
• Round Management: Automated rounds with configurable frequency and deadlines
• Contribution Handling: Support for both native tokens and CW20 tokens
• Penalty System: Late payment penalties and dispute resolution
• Fee Management: Protocol fees and administrative fee collection
• Security Features: Reentrancy protection, escrow mechanisms, and access controls

• Member Registration: Admin-controlled member management
• Tontine Lifecycle: Start, pause, resume, and close tontine operations
• Round Management: Automated round progression with beneficiary rotation
• Contribution Processing: Handle deposits from members with deadline enforcement
• Distribution: Automated fund distribution to beneficiaries
• Penalty Management: Late payment detection and penalty application

• Multi-Token Support: Native Cosmos tokens and CW20 tokens
• Dispute Resolution: Arbitration system for conflict resolution
• Escrow Management: Secure fund holding until distribution
• Early Closure: Quorum-based early termination options
• Migration Support: Contract upgrade capabilities
• Comprehensive Queries: Extensive state and historical data access

• Reentrancy Protection: Prevents recursive contract calls
• Access Control: Role-based permissions (admin, arbitrator, members)
• Input Validation: Comprehensive parameter validation
• State Consistency: Atomic operations and rollback protection
• Event Logging: Complete audit trail for all operations

src/
├── lib.rs          # Main entry points and module exports
├── contract.rs     # Core contract logic and orchestration
├── error.rs        # Custom error types and handling
├── msg.rs          # Message structures and types
├── state.rs        # State management and storage
├── execute.rs      # Execute message implementations
├── query.rs        # Query message implementations
└── receive.rs      # CW20 and native token handling

• Config: Immutable configuration parameters
• TontineState: Current contract status and round information
• Members: Member registry with status and balance tracking
• Rounds: Round-by-round state and deposit tracking
• Penalties: Outstanding penalty tracking
• Disputes: Active dispute management

• Indexed Storage: Efficient member and round queries
• Atomic Operations: Consistent state updates
• Optimized Access: Minimized storage reads/writes

let msg = InstantiateMsg {
    admin: "cosmos1...".to_string(),
    token_denom: "usaf".to_string(),
    contribution_amount: "1000000".to_string(), // 1 ATOM
    round_frequency: 86400, // 1 day in seconds
    beneficiaries: vec!["cosmos1...".to_string()],
    late_penalty: "50000".to_string(), // 0.05 ATOM
    protocol_fees: "10000".to_string(), // 0.01 ATOM
    arbitrator: "cosmos1...".to_string(),
    time_guards: 3600, // 1 hour in seconds
};

// Register a new member
ExecuteMsg::RegisterMember { address: "cosmos1...".to_string() }

// Replace a member
ExecuteMsg::ReplaceMember {
    old_address: "cosmos1...".to_string(),
    new_address: "cosmos1...".to_string()
}

// Start the tontine
ExecuteMsg::StartTontine {}

// Pause operations
ExecuteMsg::PauseTontine {}

// Resume operations
ExecuteMsg::ResumeTontine {}

// Deposit contribution
ExecuteMsg::DepositContribution {}

// Distribute to beneficiary
ExecuteMsg::DistributeToBeneficiary {}

// Get full configuration
QueryMsg::GetConfig {}

// Get admin address
QueryMsg::GetAdmin {}

// Get all members
QueryMsg::GetMembers {}

// Get specific member
QueryMsg::GetMember { address: "cosmos1...".to_string() }

// Get current round
QueryMsg::GetCurrentRound {}

// Get round details
QueryMsg::GetRoundInfo { round: 1 }

• Rust 1.70+
• CosmWasm SDK 1.4.0+
• wasm-pack (for building)

# Build the contract
cargo build --target wasm32-unknown-unknown --release

# Run tests
cargo test

# Generate schema
cargo schema

# Run all tests
cargo test

# Run specific test
cargo test test_instantiate

# Run with output
cargo test -- --nocapture

• Admin: Full control over contract configuration and member management
• Arbitrator: Dispute resolution and emergency operations
• Members: Limited to contribution and penalty payment operations

• Global reentrancy guard prevents recursive calls
• State updates are atomic and consistent

• Comprehensive parameter validation
• Address format verification
• Amount range checking
• State consistency validation

• Funds are held securely until distribution
• No direct withdrawal capabilities for members
• Admin-controlled fund release

• Cosmos Hub (ATOM)
• Osmosis (OSMO)
• Any Cosmos SDK chain with CosmWasm support

1. Compile Contract: Build the WASM binary
2. Upload Code: Upload to target network
3. Instantiate: Deploy with configuration parameters
4. Verify: Confirm contract functionality
5. Register Members: Add initial member set
6. Start Tontine: Begin operations

• Token Denomination: Native token or CW20 contract address
• Contribution Amount: Fixed amount per round per member
• Round Frequency: Time between rounds in seconds
• Beneficiaries: Ordered list of beneficiary addresses
• Penalties: Late payment penalty amounts
• Fees: Protocol and administrative fees
• Time Guards: Additional time buffers for operations

• Follow Rust best practices and CosmWasm patterns
• Comprehensive error handling and validation
• Extensive testing coverage
• Clear documentation and comments
• Consistent code formatting

• Unit tests for all functions
• Integration tests for workflows
• Edge case coverage
• Security scenario testing
• Performance benchmarking

This project is licensed under the MIT License - see the LICENSE file for details.

For questions, issues, or contributions:

• Open an issue on GitHub
• Submit a pull request
• Contact the development team

This software is provided "as is" without warranty. Users should conduct their own security audits and testing before using in production environments.