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dfb775d | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 | // SPDX-License-Identifier: Apache-2.0
pragma solidity ^0.8.26;
/// @title X402Receiver
/// @notice Receives x402 HTTP 402 payment proofs and validates Algorand settlement
/// hashes against an off-chain facilitator (parsec-wallet or Coinbase).
/// @dev Cypherpunk2048 standard: immutable, no proxy, no admin. The facilitator
/// address is fixed at deploy time; rotating it requires deploying a new
/// contract.
contract X402Receiver {
address public immutable facilitator;
bytes32 public immutable assetIdHash; // hash of (chain, asset_id) tuple, e.g. ("algorand", 203977300)
mapping(bytes32 => bool) public seen;
event PaymentValidated(
bytes32 indexed invoiceId,
bytes32 indexed settlementProof,
address indexed payer,
uint256 amount
);
error AlreadySeen(bytes32 invoiceId);
error NotFacilitator(address sender);
constructor(address facilitator_, bytes32 assetIdHash_) {
facilitator = facilitator_;
assetIdHash = assetIdHash_;
}
/// @notice The facilitator submits a settlement proof; this contract records it.
/// @dev Off-chain x402 flow: caller pays the Algorand asset, parsec-wallet
/// builds an EIP-712 attestation, the facilitator submits it here.
function recordSettlement(
bytes32 invoiceId,
bytes32 settlementProof,
address payer,
uint256 amount
) external {
if (msg.sender != facilitator) revert NotFacilitator(msg.sender);
if (seen[invoiceId]) revert AlreadySeen(invoiceId);
seen[invoiceId] = true;
emit PaymentValidated(invoiceId, settlementProof, payer, amount);
}
}
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