// SPDX-License-Identifier: MIT
pragma solidity ^0.8.23;

// interfaces
import {IAuthorizedClaimers} from "./IAuthorizedClaimers.sol";

// libraries
import {AuthorizedClaimerStorage} from "./AuthorizedClaimerStorage.sol";
import {ECDSA} from "solady/utils/ECDSA.sol";

// contracts
import {EIP712Facet} from "@towns-protocol/diamond/src/utils/cryptography/EIP712Facet.sol";

contract AuthorizedClaimers is IAuthorizedClaimers, EIP712Facet {
    // keccak256("Authorize(address owner,address claimer,uint256 nonce,uint256 expiry)")
    bytes32 private constant _AUTHORIZE_TYPEHASH =
        0x496b440527e20b246a460857dca887b9c1f290387cfc6ac9aa91bb6554be05ac;

    function authorizeClaimerBySig(
        address owner,
        address claimer,
        uint256 nonce,
        uint256 expiry,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external {
        if (expiry != 0 && block.timestamp >= expiry) {
            revert AuthorizedClaimers_ExpiredSignature();
        }

        address signer = ECDSA.recover(
            _hashTypedDataV4(
                keccak256(abi.encode(_AUTHORIZE_TYPEHASH, owner, claimer, nonce, expiry))
            ),
            v,
            r,
            s
        );

        if (signer != owner) {
            revert AuthorizedClaimers_InvalidSignature();
        }

        _useCheckedNonce(owner, nonce);
        _authorizeClaimer(owner, claimer);
    }

    /// @inheritdoc IAuthorizedClaimers
    function authorizeClaimer(address claimer) external {
        _authorizeClaimer(msg.sender, claimer);
    }

    /// @inheritdoc IAuthorizedClaimers
    function removeAuthorizedClaimer() external {
        _authorizeClaimer(msg.sender, address(0));
    }

    /// @inheritdoc IAuthorizedClaimers
    function getAuthorizedClaimer(address authorizer) external view returns (address) {
        return AuthorizedClaimerStorage.layout().authorizedClaimers[authorizer];
    }

    // =============================================================
    //                          Internal
    // =============================================================
    function _authorizeClaimer(address signer, address claimer) internal {
        AuthorizedClaimerStorage.Layout storage ds = AuthorizedClaimerStorage.layout();

        if (claimer == address(0)) {
            delete ds.authorizedClaimers[signer];
            emit AuthorizedClaimerRemoved(signer);
        } else {
            address currentClaimer = ds.authorizedClaimers[signer];
            if (currentClaimer == claimer) {
                revert AuthorizedClaimers_ClaimerAlreadyAuthorized();
            }

            ds.authorizedClaimers[signer] = claimer;

            emit AuthorizedClaimerChanged(signer, claimer);
        }
    }
}