from django_postgres_anon.utils import validate_function_syntax

# Safe functions (allowed)
validate_function_syntax("anon.fake_email()")          # True
validate_function_syntax("anon.hash(column_name)")     # True
validate_function_syntax("anon.partial(email, 2, '*', 2)")  # True

# Dangerous functions (blocked)
validate_function_syntax("DROP TABLE users;")         # False
validate_function_syntax("anon.fake_email(); DROP")   # False
validate_function_syntax("custom_function()")         # False (unless enabled)

from django_postgres_anon.models import MaskingLog

# All operations are logged
logs = MaskingLog.objects.filter(
    operation='apply_rule',
    success=True
).order_by('-timestamp')

try:
    apply_anonymization_rule(rule)
except Exception as e:
    # Log detailed error internally
    logger.error(f"Rule application failed: {e}")

    # Return sanitized error to user
    return {"success": False, "error": "Rule application failed"}

# settings.py - Production configuration
POSTGRES_ANON = {
    'ENABLED': True,
    'VALIDATE_FUNCTIONS': True,       # Always validate functions
    'ALLOW_CUSTOM_FUNCTIONS': False,  # Restrict to anon namespace
    'ENABLE_LOGGING': True,           # Full audit trail
}

# Don't commit database credentials
DATABASES = {
    'default': {
        'PASSWORD': os.environ.get('DB_PASSWORD'),  # From environment
        'USER': os.environ.get('DB_USER'),
    }
}

# Use SSL connections
DATABASES = {
    'default': {
        'OPTIONS': {
            'sslmode': 'require',
            'sslcert': '/path/to/client-cert.pem',
            'sslkey': '/path/to/client-key.pem',
            'sslrootcert': '/path/to/ca-cert.pem',
        }
    }
}

# Ensure proper authentication before anonymization
@login_required
def sensitive_view(request):
    if request.user.groups.filter(name='analysts').exists():
        # Only authenticated users in specific groups
        pass

# Regularly audit group membership
from django.contrib.auth.models import Group, User

def audit_group_membership():
    analysts = Group.objects.get(name='analysts')
    members = analysts.user_set.all()

    # Log and review membership
    for user in members:
        logger.info(f"User {user.username} has analyst access")

# settings.py - Secure session configuration
SESSION_COOKIE_SECURE = True      # HTTPS only
SESSION_COOKIE_HTTPONLY = True    # No JavaScript access
SESSION_COOKIE_SAMESITE = 'Strict'  # CSRF protection
SESSION_EXPIRE_AT_BROWSER_CLOSE = True

# Monitor for suspicious activity
import logging

logger = logging.getLogger('django_postgres_anon.security')

def monitor_role_switches():
    # Alert on excessive role switching
    # Monitor failed authentication attempts
    # Track unusual data access patterns
    pass

# DANGEROUS - Don't do this
function_expr = request.POST.get('function')  # User input
MaskingRule.objects.create(function_expr=function_expr)

# SAFE - Validate first
function_expr = request.POST.get('function')
if validate_function_syntax(function_expr):
    MaskingRule.objects.create(function_expr=function_expr)
else:
    raise ValidationError("Invalid function syntax")

# DANGEROUS
try:
    user = User.objects.get(email=email)
except User.DoesNotExist:
    return f"User with email {email} not found"  # Exposes email

# SAFE
try:
    user = User.objects.get(email=email)
except User.DoesNotExist:
    return "User not found"  # No sensitive data

# Critical events to monitor
events_to_monitor = [
    'rule_creation',           # New anonymization rules
    'rule_modification',       # Changes to existing rules
    'role_switch_failure',     # Failed role switches
    'permission_escalation',   # Unauthorized access attempts
    'bulk_operations',         # Large-scale data operations
    'configuration_changes',   # Settings modifications
]

# Example alerting logic
def check_security_alerts():
    # Alert on multiple failed role switches
    failed_switches = MaskingLog.objects.filter(
        operation='role_switch',
        success=False,
        timestamp__gte=timezone.now() - timedelta(minutes=5)
    ).count()

    if failed_switches > 5:
        send_security_alert("Multiple role switch failures detected")

# Monitor query performance
def monitor_query_performance():
    slow_queries = MaskingLog.objects.filter(
        duration__gt=timedelta(seconds=30)
    )

    if slow_queries.exists():
        # Investigate potential DoS or data extraction attempts
        pass

# Add to test suite
class SecurityTestCase(TestCase):
    def test_sql_injection_prevention(self):
        """Test that malicious functions are rejected."""
        malicious_functions = [
            "DROP TABLE users;",
            "'; DELETE FROM auth_user; --",
            "UNION SELECT * FROM sensitive_table",
        ]

        for func in malicious_functions:
            with self.assertRaises(ValidationError):
                MaskingRule.objects.create(
                    table_name='test_table',
                    column_name='test_column',
                    function_expr=func
                )