FarmerRegistry.sol

The first contract deployed. Stores verified farmer identities, MAAIF national IDs, GPS farm data references, and cooperative memberships. All other contracts depend on it.

Responsibilities

• Stores the canonical list of verified farmers
• Links MAAIF national farmer IDs to cooperative wallet addresses
• References GPS polygon IPFS CIDs (not raw coordinates on-chain)
• Controls which cooperative agents can register farmers (AGENT_ROLE)
• GFW deforestation check is recorded at registration

Key Data Structure

struct Farmer {
    string  maaifFarmerId;        // e.g. "UG-KAS-2024-001234"
    address cooperativeWallet;    // The cooperative this farmer belongs to
    bytes32 farmBoundaryIpfsCid;  // IPFS CID hash of GeoJSON polygon
    uint256 farmAreaHectares;     // Scaled by 100 (e.g. 240 = 2.40 ha)
    uint256 registrationTimestamp;
    bool    gfwDeforestationFree; // Confirmed at registration
    bool    active;
}

mapping(address => Farmer) public farmers;       // wallet → Farmer
mapping(string => address) public maaifToWallet; // maaifId → wallet

Interface

// Register a new farmer (AGENT_ROLE required)
function registerFarmer(
    address farmerWallet,
    string calldata maaifFarmerId,
    bytes32 farmBoundaryIpfsCid,
    uint256 farmAreaHectares,
    bool gfwDeforestationFree
) external onlyRole(AGENT_ROLE);

// Verify a farmer is registered and active
function isRegistered(address farmerWallet) external view returns (bool);

// Get farmer data (used by BatchToken.sol at mint time)
function getFarmer(address farmerWallet) external view returns (Farmer memory);

// Deactivate a farmer (COOP_ROLE — for deceased, relocated, or fraudulent records)
function deactivateFarmer(address farmerWallet) external onlyRole(COOP_ROLE);

Access Control Roles

Role	Granted to	Permission
DEFAULT_ADMIN_ROLE	AsiliChain deployer multisig	Grant/revoke all roles
COOP_ROLE	Cooperative wallet	Deactivate farmers, update cooperative metadata
AGENT_ROLE	Field agent wallets	Register new farmers

Registration Flow

Field agent opens agent app (or MAAIF NTS API called)
        ↓
MAAIF NTS: returns farmerID + GPS polygon GeoJSON
        ↓
API: GFW check on farm polygon centroid
        ↓
API: pinGeoJSON(polygon) → Pinata → IPFS CID returned
        ↓
API: FarmerRegistry.registerFarmer(wallet, maaifId, ipfsCid, area, gfwStatus)
        ↓
HCS: REGISTERED event written

Events

event FarmerRegistered(
    address indexed farmerWallet,
    string maaifFarmerId,
    address indexed cooperative,
    uint256 timestamp
);

event FarmerDeactivated(
    address indexed farmerWallet,
    address indexed deactivatedBy,
    uint256 timestamp
);