// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

import { BaseChecker } from "../../checker/BaseChecker.sol";
import { IEAS } from "./IEAS.sol";

/// @title EASChecker
/// @notice EAS validator.
/// @dev Extends BaseChecker to implement EAS validation logic.
contract EASChecker is BaseChecker {
    // the reference to the EAS contract
    IEAS public eas;

    // the schema to check against
    bytes32 public schema;

    // the trusted attester
    address public attester;

    /// @notice custom errors
    error AttestationRevoked();
    error AttesterNotTrusted();
    error NotYourAttestation();
    error InvalidSchema();
    error AttestationExpired(uint256 expirationTime);

    /// @notice Initializes the contract.
    function _initialize() internal override {
        super._initialize();

        bytes memory data = _getAppendedBytes();
        (address _eas, address _attester, bytes32 _schema) = abi.decode(data, (address, address, bytes32));

        eas = IEAS(_eas);
        attester = _attester;
        schema = _schema;
    }

    /// @notice Throws errors if evidence and subject are not valid.
    /// @param subject Address to validate.
    /// @param evidence Encoded data used for validation.
    /// @return Boolean indicating whether the subject passes the check.
    function _check(address subject, bytes calldata evidence) internal view override returns (bool) {
        super._check(subject, evidence);

        // decode the argument
        bytes32 attestationId = abi.decode(evidence, (bytes32));

        // get the attestation from the EAS contract
        IEAS.Attestation memory attestation = eas.getAttestation(attestationId);

        // the schema must match
        if (attestation.schema != schema) {
            revert InvalidSchema();
        }

        // we check that the attestation attester is the trusted one
        if (attestation.attester != attester) {
            revert AttesterNotTrusted();
        }

        // we check that it was not revoked
        if (attestation.revocationTime != 0) {
            revert AttestationRevoked();
        }

        // one cannot enforce an attestation for another user
        if (attestation.recipient != subject) {
            revert NotYourAttestation();
        }

        // the attestation must not be expired
        if (attestation.expirationTime > 0 && attestation.expirationTime <= block.timestamp) {
            revert AttestationExpired(attestation.expirationTime);
        }

        return true;
    }
}