acceptOffer

Function Type: external
Function Signature: acceptOffer(address,string,uint256,address,uint256,uint256,uint256,bytes,bytes) Function Selector: 0xae36fe72

Allows the current owner (user) of a username (username) to accept a specific, active offer (offerID) made by another user. Accepting the offer triggers the transfer of the agreed principal tokens from the offeror to the owner, and transfers the ownership of the username to the original offeror.

Parameters

Parameter Name	Type	Description
user	address	The address of the current owner of the username who is accepting the offer.
username	string	The username associated with the offer being accepted.
offerID	uint256	The unique identifier of the specific offer being accepted.
token	address	The address of the token to be used for payment.
amount	uint256	The total amount to be transferred for the offer.
priorityFee	uint256	The priority fee amount.
nonce	uint256	The nonce value for the signature.
signature_EVVM	bytes	The EVVM payment signature.
signature	bytes	The NameService accept offer signature.

Signature Links & EVVM Payment

• The EVVM payment signature (signature_EVVM) covers the total amount and uses the Single Payment Signature Structure.
• The NameService accept offer signature (signature) must be generated by the current owner (user) and follows the Accept Offer Signature Structure.
• The EVVM parameters facilitate the transfer of the offer funds and any optional priority fee from the offeror (user).

Execution Methods

This function can be executed by any address.

Workflow

Failure at validation steps typically reverts the transaction.

1. Username Owner Verification: Checks if the provided _user address is the registered owner of the _username (e.g., using an internal ownership check like onlyAdminOfIdentity). Reverts if _user is not the owner.
2. NameService Nonce Verification: Checks if the provided _nonce is unused for the _user using the verifyIfNonceIsAvailable modifier. Reverts if the nonce is already used.
3. Offer validation: Retrieves the offer data associated with _username and _offerID. Checks that the offer exists (e.g., offerer != address(0)) and that its expireDate has not passed based on the current block timestamp. Reverts if the offer is invalid or expired.
4. Signature Verification: Validates the _signature provided by _user (the owner) against the reconstructed message hash using verifyMessageSignedForAcceptOffer. Reverts if the signature is invalid according to the Accept Offer Signature Structure.
5. EVVM Payment Execution (Optional Priority Fee): If _priorityFeeForFisher is greater than zero:
   • Calls an internal helper function (e.g., makePay) designed to interact with the EVVM's payMateStaker function.
   • Uses the provided _nonce_Evvm, _priority_Evvm, and _signature_Evvm parameters to authorize the EVVM payment.
   • This action attempts to transfer the _priorityFeeForFisher amount of principal tokens from the _user address to the msg.sender address via the EVVM contract mechanism.
   • Reverts if this EVVM payment process fails.
6. Transaction Execution (Pay Seller): Calls an internal helper function (e.g., makeCaPay) to transfer the accepted offer funds (retrieved from usernameOffers[_username][_offerID].amount).
7. Ownership Transfer: Transfers the ownership of the _username within the NameService system from the current owner (_user) to the address of the original offeror (retrieved from usernameOffers[_username][_offerID].offerer).
8. Offer Cleanup: Updates the usernameOffers[_username][_offerID] entry by setting the offerer field to address(0), marking the offer as fulfilled and the slot as empty/invalid.
9. Reward Distribution (to Executor): Calls an internal helper function (e.g., makeCaPay) to distribute rewards in principal tokens to msg.sender (the executor). The rewards consist of:
   • A base MATE reward, typically fetched from the EVVM contract (e.g., 1 * seeMateReward()).
   • The _priorityFeeForFisher, if it was greater than zero and successfully paid in Step 5.
   • An additional amount calculated based on the withdrawn offer's value: 0.125% of the amount stored in usernameOffers[_username][_offerID]. (This is derived from the 0.5% fee structure associated with the offer).
10. Nonce Management: Marks the NameService _nonce (provided as input parameter) as used for the _user address within the mateNameServiceNonce mapping to prevent replay of this specific accept action.