# network / infra
def network_policy.get_allowed_connections(src: str, dst: str) -> list[str]: ...

# data-access
def export_database() -> DatabaseDump: ...
def recent_logs() -> list[LogEntry]: ...
def scan_repo_files() -> list[str]: ...
def read_file(path: str) -> str: ...

# TLS inspection - TLSInfo has: .protocol (str e.g. 'TLSv1.2'), .cipher_strength (int), .cipher (str)
def inspect_tls(endpoint: str) -> TLSInfo: ...

# crypto / format
def is_encrypted_aes_256(value: str) -> bool: ...
def is_truncated_last_4(value: str) -> bool: ...
def is_hashed_with_salt(value: str) -> bool: ...
def is_tokenized(value: str) -> bool: ...
def redact(value: str) -> str: ...

# constants
CDE_API_ENDPOINTS: list[str] = [...]   # All API endpoints inside the CDE
DEPRECATED_CIPHERS: list[str] = [...]  # e.g. ['RC4', 'DES', '3DES', 'NULL']

# pci_scope.py
# untested CDE/non-CDE network policy drifts into a segmentation breach
CDE_SYSTEMS = {
    'payment-service',
    'tokenization-service',
    'card-vault-db',
    'pci-zone-fw',
}
NON_CDE_SYSTEMS = {
    'web-frontend',     # tokens only; no raw PAN
    'analytics',         # never sees PAN
    'support-tickets',   # never sees PAN
}

def test_cde_systems_isolated_from_non_cde():
    for cde_system in CDE_SYSTEMS:
        for non_cde in NON_CDE_SYSTEMS:
            # Network policy MUST block direct connections from non-CDE to CDE
            allowed = network_policy.get_allowed_connections(cde_system, non_cde)
            # Only via tokenization gateway (via PCI zone FW)
            assert allowed == [] or allowed == ['via-pci-zone-fw']

import re

# PAN slips into a log line if you trust developers never to log it
TRACK1_PATTERN = re.compile(r'%[A-Z]\d{12,19}\^[^\?]*\?\d*\?')   # Track 1
CVV_PATTERN    = re.compile(r'(?<!\d)\d{3,4}(?!\d)')               # naive; pair with DLP

def test_no_full_track_data_in_storage():
    """Req 3.2.1: track data must not be retained post-authorization."""
    db_dump = export_database()
    for table in db_dump.tables:
        for row in table:
            for value in row.values():
                assert not TRACK1_PATTERN.search(str(value)), \
                    f"Full track data in {table.name}"

def test_no_cvv_in_logs():
    """Req 3.2.2: CVV2/CVC2/CID must not be retained."""
    log_entries = recent_logs()
    for entry in log_entries:
        # Look for proximity of CVV-like 3-4 digit numbers near "cvv" / "card" tokens
        if 'cvv' in entry.text.lower() or 'card' in entry.text.lower():
            matches = CVV_PATTERN.findall(entry.text)
            for m in matches:
                assert m == '***' or m == '----', \
                    f"Possible CVV in log: {entry.id}"

# hardcoded encryption keys in the repo are a Req 3.6 violation and expose PAN

def test_pan_stored_encrypted():
    """Req 3.4: PAN unreadable wherever stored (encryption / truncation / hashing / tokenization).
    Prefer tokenization for new paths; treat the others as escape hatches for pre-existing systems.
    """
    card_record = CardVault.objects.first()
    raw_pan = card_record._raw_pan_field    # accessor for storage-format field

    # Format MUST be one of:
    #  - encrypted (AES-256 or stronger)         <- preferred for new paths
    #  - truncated (e.g., last 4 only)
    #  - hashed (with salt; one-way)
    #  - tokenized (replaced with non-sensitive token)  <- default for new systems
    valid_format = (
        is_encrypted_aes_256(raw_pan)
        or is_truncated_last_4(raw_pan)
        or is_hashed_with_salt(raw_pan)
        or is_tokenized(raw_pan)
    )
    assert valid_format, f"PAN stored unprotected: {redact(raw_pan)}"

def test_decryption_keys_not_in_app_repo():
    """Req 3.6: cryptographic keys protected against unauthorized access."""
    repo_files = scan_repo_files()
    for f in repo_files:
        content = read_file(f)
        # No hardcoded AES keys (high entropy + length 256+ bits)
        assert not re.search(r'AES_KEY\s*=\s*["\'][A-Za-z0-9+/=]{40,}', content), \
            f"Possible hardcoded AES key in {f}"
        # No KMS key file references
        assert 'kms-private-key.pem' not in f, \
            f"KMS private key file referenced in repo: {f}"

# TLS 1.0 / 1.1 still enabled is a Req 4 violation
def test_pan_only_transmitted_via_strong_crypto():
    """Req 4.2.1: strong crypto for transmission of cardholder data over open networks."""
    for endpoint in CDE_API_ENDPOINTS:
        tls_info = inspect_tls(endpoint)
        assert tls_info.protocol >= 'TLSv1.2', \
            f"Weak TLS protocol on {endpoint}: {tls_info.protocol}"
        assert tls_info.cipher_strength >= 256, \
            f"Cipher strength too low on {endpoint}: {tls_info.cipher_strength}"
        assert tls_info.cipher not in DEPRECATED_CIPHERS, \
            f"Deprecated cipher on {endpoint}: {tls_info.cipher}"

# generic shared accounts (e.g. 'admin' / 'svc-account') violate Req 8.2.1
def test_cde_access_requires_unique_id():
    """Req 8.2.1: assign all users a unique ID before access to system components."""
    # No shared / generic accounts
    response = client.post('/cde-api/login', json={'username': 'shared-svc', 'password': 'secret'})
    assert response.status_code == 403

def test_cde_access_requires_mfa():
    """Req 8.4: implement MFA for all access into the CDE."""
    response = client.post('/cde-api/login', json={
        'username': 'alice@example.com',
        'password': correct_password,
        # No MFA token
    })
    assert response.status_code == 401
    assert response.json()['error'] == 'mfa_required'

def test_pan_access_creates_audit_record():
    """Req 10.2: audit trails to reconstruct events."""
    user.access_card(card_id=123)
    audit = AuditLog.objects.filter(
        actor=user.id,
        action='pan_access',
        subject=f'card:{card_id}',
    ).first()
    assert audit is not None
    assert audit.timestamp is not None
    # Audit log itself MUST not contain the PAN:
    assert not re.search(r'\d{13,19}', audit.full_event_text), \
        "PAN found in audit log text - log masking is broken"