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

import {Test} from "forge-std/Test.sol";
import {AereCryptoRegistry} from "../../contracts/pqc/AereCryptoRegistry.sol";

/**
 * @title  Symbolic (halmos) proofs for the AereCryptoRegistry governance/routing layer.
 *
 * WHAT IS PROVEN (see PROVEN-PROPERTIES.md):
 *   R1  FAIL-CLOSED: a REVOKED or UNKNOWN algorithm id can NEVER pass verify(), for
 *       any pubkey/message/signature, regardless of what the routed verifier returns.
 *   R2  status transitions are OWNER-ONLY: a non-owner call to setStatus (and
 *       setSuccessor) cannot change registry state.
 *   R3  resolveActive TERMINATES: the successor walk always halts (returns an ACTIVE
 *       id or reverts) within the bounded number of registered rows; it never
 *       diverges, even on a successor cycle.
 *
 * ASSUMPTIONS:
 *   - R1 does not need the precompile oracle at all: verify() gates on status BEFORE
 *     touching the verifier, so fail-closed holds independently of any precompile.
 *   - R3's termination proof relies on the loop being structurally bounded by _count
 *     and on halmos unrolling the loop to at least _count+1 iterations (--loop >= 12,
 *     with _count == 7 rows seeded here). We deliberately seed a successor CYCLE so
 *     the cycle-detection path is exercised.
 *   - Ownership: the test contract is the deployer, hence the Ownable owner. The
 *     symbolic non-owner caller is constrained to differ from it.
 */
contract AereCryptoRegistrySymbolic is Test {
    AereCryptoRegistry internal reg;

    function setUp() public {
        reg = new AereCryptoRegistry();
        reg.seedLiveSchemes(); // rows 1..5 (Falcon-512/1024, ML-DSA-44, SLH-DSA-128s ACTIVE; SHAKE256 hash-only)

        // Make row 1 REVOKED so the REVOKED branch of R1 is reachable and terminal.
        reg.setStatus(1, AereCryptoRegistry.Status.REVOKED);

        // Two extra rows (6, 7) put into a DEPRECATED successor CYCLE to exercise R3's
        // cycle detection (neither is ACTIVE, so resolveActive must walk then revert).
        reg.addAlgorithm("legacy-a", 100, address(0xBEEF), 32, 100, 0, 1000, true); // id 6
        reg.addAlgorithm("legacy-b", 101, address(0xCAFE), 32, 100, 0, 1000, true); // id 7
        reg.setStatus(6, AereCryptoRegistry.Status.DEPRECATED);
        reg.setStatus(7, AereCryptoRegistry.Status.DEPRECATED);
        reg.setSuccessor(6, 7);
        reg.setSuccessor(7, 6); // 6 -> 7 -> 6 -> ...  (cycle)
    }

    // ---------------------------------------------------------------------
    // R1 : fail-closed. Any REVOKED or UNKNOWN id can never verify true.
    // ---------------------------------------------------------------------
    function check_revokedOrUnknownNeverVerifies(
        uint256 id,
        bytes calldata pubKey,
        bytes32 messageHash,
        bytes calldata signature
    ) external view {
        AereCryptoRegistry.Status st = reg.statusOf(id);
        vm.assume(st == AereCryptoRegistry.Status.UNKNOWN || st == AereCryptoRegistry.Status.REVOKED);

        // For these statuses verify() short-circuits to false before ever routing to a
        // verifier, so the result is false for every possible signature/key/message.
        bool ok = reg.verify(id, pubKey, messageHash, signature);
        assert(ok == false);
    }

    // ---------------------------------------------------------------------
    // R2 : setStatus is owner-only. A non-owner cannot change status.
    // ---------------------------------------------------------------------
    function check_setStatusIsOwnerOnly(address caller, uint256 id, uint8 newStatusRaw) external {
        vm.assume(caller != reg.owner());
        vm.assume(newStatusRaw >= 1 && newStatusRaw <= 3); // ACTIVE/DEPRECATED/REVOKED (valid enum, decode-safe)

        AereCryptoRegistry.Status pre = reg.statusOf(id);

        vm.prank(caller);
        (bool ok,) = address(reg).call(
            abi.encodeCall(reg.setStatus, (id, AereCryptoRegistry.Status(newStatusRaw)))
        );

        assert(!ok); // onlyOwner must revert the non-owner call
        assert(reg.statusOf(id) == pre); // and status is provably unchanged
    }

    // ---------------------------------------------------------------------
    // R2b : setSuccessor is owner-only.
    // ---------------------------------------------------------------------
    function check_setSuccessorIsOwnerOnly(address caller, uint256 id, uint256 successorId) external {
        vm.assume(caller != reg.owner());

        AereCryptoRegistry.Status preStatus = reg.statusOf(id);

        vm.prank(caller);
        (bool ok,) = address(reg).call(abi.encodeCall(reg.setSuccessor, (id, successorId)));

        assert(!ok);
        assert(reg.statusOf(id) == preStatus);
    }

    // ---------------------------------------------------------------------
    // R3 : resolveActive terminates. Over any symbolic start id, the call always
    //      halts within the unroll bound and, when it returns, returns an ACTIVE id.
    //      (Reaching the end of this function at all == termination was demonstrated
    //      by halmos fully exploring the bounded loop.)
    // ---------------------------------------------------------------------
    function check_resolveActiveTerminatesAndReturnsActive(uint256 startId) external view {
        (bool ok, bytes memory ret) = address(reg).staticcall(
            abi.encodeCall(reg.resolveActive, (startId))
        );
        if (ok) {
            uint256 resolved = abi.decode(ret, (uint256));
            assert(reg.isActive(resolved)); // resolveActive only ever returns an ACTIVE row
        }
        // If !ok it reverted (UnknownAlgorithm / NoActiveSuccessor / SuccessorCycle):
        // that is still termination. The cycle 6->7->6 forces the SuccessorCycle path.
    }
}