Referrals

A.parent = B

if B is whitelisted:
    A.initialInviter = B
else:
    A.initialInviter = B.initialInviter

W1 is whitelisted
Alice binds to W1

W1 (whitelisted root)
 └── Alice

W1 is whitelisted
Alice binds to W1
Bob binds to Alice

W1 (whitelisted root)
 └── Alice (parent = W1, initialInviter = W1)
      └── Bob (parent = Alice, initialInviter = W1)

W1 is whitelisted
Alice binds to W1
Bob binds to Alice
Charlie binds to Bob
Diana binds to Charlie

W1 (whitelisted root)
 └── Alice (parent = W1, initialInviter = W1)
      └── Bob (parent = Alice, initialInviter = W1)
           └── Charlie (parent = Bob, initialInviter = W1)
                └── Diana (parent = Charlie, initialInviter = W1)

W1 (whitelisted root)             W2 (whitelisted root)
 └── Alice                         └── Bob
      └── Charlie                       └── Diana

function isWhitelist(address user) view returns (bool);
function initialInviter(address user) view returns (address);
function parent(address user) view returns (address);
function inviteCount(address user) view returns (uint256);
function isBound(address user) view returns (bool);
function bind(address inviter);
function getInfo(address user)
    view
    returns (
        address _initialInviter,
        address _parent,
        uint256 _inviteCount,
        bool _isBound
    );

isBound(user)       -> whether the user already joined a referral tree
parent(user)        -> direct inviter
initialInviter(user)-> whitelisted root used for trade rewards
isWhitelist(user)   -> whether the address is an approved root
getInfo(user)       -> all common referral fields in one call

1. User opens a referral link or pastes a referral code.
2. The frontend extracts the referral code.
3. The API resolves the code to an inviter wallet.
4. The frontend checks that the inviter is eligible.
5. The user confirms the binding.
6. The frontend calls referral.bind(inviterAddress).
7. The backend mirror records the binding transaction for dashboard/indexing purposes.