fips-core 0.3.73

use super::*;

#[test]
fn test_replay_window_basic() {
    let mut window = ReplayWindow::new();

    // First packet is always acceptable
    assert_eq!(window.rejection_reason(0), None);
    assert!(window.check(0));
    window.accept(0);
    assert_eq!(window.highest(), 0);

    // Replay of 0 should fail
    assert_eq!(window.rejection_reason(0), Some(ReplayRejection::Duplicate));
    assert!(!window.check(0));

    // New higher counter is acceptable
    assert!(window.check(1));
    window.accept(1);
    assert_eq!(window.highest(), 1);

    // Out-of-order within window is acceptable
    // (after accepting 10, 2 is still in window)
    window.accept(10);
    assert!(window.check(5));
    window.accept(5);

    // Replay of 5 should now fail
    assert_eq!(window.rejection_reason(5), Some(ReplayRejection::Duplicate));
    assert!(!window.check(5));
}

#[test]
fn test_replay_window_large_jump() {
    let mut window = ReplayWindow::new();

    // Accept counter 0
    window.accept(0);

    // Jump to a large counter
    window.accept(REPLAY_WINDOW_SIZE as u64 + 100);

    // Old counter should be outside window
    assert_eq!(window.rejection_reason(0), Some(ReplayRejection::TooOld));
    assert!(!window.check(0));
    assert_eq!(window.rejection_reason(50), Some(ReplayRejection::TooOld));
    assert!(!window.check(50));

    // Counters within window should work
    assert_eq!(
        window.rejection_reason(REPLAY_WINDOW_SIZE as u64 + 99),
        None
    );
    assert!(window.check(REPLAY_WINDOW_SIZE as u64 + 99));
    assert!(window.check(REPLAY_WINDOW_SIZE as u64 + 50));
}

#[test]
fn test_replay_window_boundary() {
    let mut window = ReplayWindow::new();

    // Accept at boundary
    window.accept(REPLAY_WINDOW_SIZE as u64 - 1);

    // Counter 0 should be exactly at the edge of the window
    assert!(window.check(0));
    window.accept(0);

    // Move window forward by 1
    window.accept(REPLAY_WINDOW_SIZE as u64);

    // Counter 0 is now outside the window
    assert!(!window.check(0));

    // Counter 1 is still in the window
    assert!(window.check(1));
}

#[test]
fn test_replay_window_sequential() {
    let mut window = ReplayWindow::new();

    // Accept counters 0-999 in order
    for i in 0..1000 {
        assert!(window.check(i), "Counter {} should be acceptable", i);
        window.accept(i);
    }

    // All should be marked as seen
    for i in 0..1000 {
        assert!(
            !window.check(i),
            "Counter {} should be rejected as replay",
            i
        );
    }

    assert_eq!(window.highest(), 999);
}

#[test]
fn test_replay_window_reset() {
    let mut window = ReplayWindow::new();

    window.accept(100);
    assert_eq!(window.highest(), 100);
    assert!(!window.check(100));

    window.reset();

    assert_eq!(window.highest(), 0);
    assert!(window.check(100));
}

#[test]
fn test_session_replay_protection() {
    let keypair1 = generate_keypair();
    let keypair2 = generate_keypair();

    let mut init = HandshakeState::new_initiator(keypair1, keypair2.public_key());
    init.set_local_epoch(generate_epoch());
    let mut resp = HandshakeState::new_responder(keypair2);
    resp.set_local_epoch(generate_epoch());

    let msg1 = init.write_message_1().unwrap();
    resp.read_message_1(&msg1).unwrap();
    let msg2 = resp.write_message_2().unwrap();
    init.read_message_2(&msg2).unwrap();

    let mut sender = init.into_session().unwrap();
    let mut receiver = resp.into_session().unwrap();

    // Encrypt a message
    let counter = sender.current_send_counter();
    let ciphertext = sender.encrypt(b"test message").unwrap();

    // First decryption should succeed
    let plaintext = receiver
        .decrypt_with_replay_check(&ciphertext, counter)
        .unwrap();
    assert_eq!(plaintext, b"test message");

    // Replay should fail
    let result = receiver.decrypt_with_replay_check(&ciphertext, counter);
    assert!(matches!(result, Err(NoiseError::ReplayDetected(_))));

    // Check method alone also detects replay
    assert!(receiver.check_replay(counter).is_err());
}