//! Security Management Module
//!
//! This module provides comprehensive security management capabilities for the CUDA
//! optimization execution engine, including access control, authentication, authorization,
//! audit logging, threat detection, data protection, and compliance management
//! to ensure secure operation and data protection.

use serde::{Deserialize, Serialize};
use sha2::{Digest, Sha256};
use std::collections::{HashMap, HashSet, VecDeque};
use std::sync::{Arc, Mutex, RwLock};
use std::time::{Duration, SystemTime};

use super::config::{EncryptionConfig, SecurityConfig};
use crate::cuda::memory::optimization::monitoring::AuditConfig;

/// Comprehensive security manager for CUDA execution
///
/// Manages all aspects of security including access control, authentication,
/// authorization, audit logging, threat detection, data encryption, and
/// compliance monitoring to ensure secure and compliant operation.
#[derive(Debug)]
pub struct SecurityManager {
    /// Access control system
    access_control: Arc<Mutex<AccessControlSystem>>,

    /// Authentication manager
    authentication: Arc<Mutex<AuthenticationManager>>,

    /// Authorization system
    authorization: Arc<Mutex<AuthorizationSystem>>,

    /// Audit logging system
    audit_logger: Arc<Mutex<AuditLogger>>,

    /// Threat detection engine
    threat_detector: Arc<Mutex<ThreatDetectionEngine>>,

    /// Data protection system
    data_protector: Arc<Mutex<DataProtectionSystem>>,

    /// Compliance monitor
    compliance_monitor: Arc<Mutex<ComplianceMonitor>>,

    /// Security incident response system
    incident_response: Arc<Mutex<IncidentResponseSystem>>,

    /// Security configuration
    config: SecurityConfig,

    /// Security state tracking
    security_state: Arc<RwLock<SecurityState>>,

    /// Security metrics and statistics
    security_metrics: Arc<Mutex<SecurityMetrics>>,

    /// Active security sessions
    active_sessions: Arc<Mutex<HashMap<String, SecuritySession>>>,
}

/// Access control system with role-based permissions
#[derive(Debug)]
pub struct AccessControlSystem {
    /// User roles and permissions
    role_permissions: HashMap<String, RolePermissions>,

    /// User role assignments
    user_roles: HashMap<String, HashSet<String>>,

    /// Resource access policies
    resource_policies: HashMap<String, ResourceAccessPolicy>,

    /// Permission evaluator
    permission_evaluator: PermissionEvaluator,

    /// Access control list (ACL) manager
    acl_manager: AclManager,

    /// Access control configuration
    config: AccessControlConfig,

    /// Access history
    access_history: VecDeque<AccessAttempt>,
}

/// Authentication manager for user verification
#[derive(Debug)]
pub struct AuthenticationManager {
    /// Authentication providers
    auth_providers: HashMap<String, AuthenticationProvider>,

    /// Token manager for session tokens
    token_manager: TokenManager,

    /// Multi-factor authentication (MFA) system
    mfa_system: MfaSystem,

    /// Authentication cache
    auth_cache: AuthenticationCache,

    /// Password policy enforcer
    password_policy: PasswordPolicyEnforcer,

    /// Authentication configuration
    config: AuthenticationConfig,

    /// Authentication statistics
    auth_stats: AuthenticationStatistics,
}

/// Authorization system for permission checking
#[derive(Debug)]
pub struct AuthorizationSystem {
    /// Policy evaluation engine
    policy_engine: PolicyEvaluationEngine,

    /// Dynamic authorization rules
    authorization_rules: HashMap<String, AuthorizationRule>,

    /// Context-aware authorization
    context_analyzer: AuthorizationContextAnalyzer,

    /// Permission cache for performance
    permission_cache: PermissionCache,

    /// Authorization configuration
    config: AuthorizationConfig,

    /// Authorization decision history
    decision_history: VecDeque<AuthorizationDecision>,
}

/// Audit logging system for security events
#[derive(Debug)]
pub struct AuditLogger {
    /// Log writers for different destinations
    log_writers: HashMap<String, AuditLogWriter>,

    /// Event formatter
    event_formatter: AuditEventFormatter,

    /// Log rotation manager
    rotation_manager: LogRotationManager,

    /// Log integrity verifier
    integrity_verifier: LogIntegrityVerifier,

    /// Log encryption system
    log_encryptor: Option<LogEncryptor>,

    /// Audit configuration
    config: AuditConfig,

    /// Audit statistics
    audit_stats: AuditStatistics,
}

/// Threat detection engine for security monitoring
#[derive(Debug)]
pub struct ThreatDetectionEngine {
    /// Threat detection rules
    detection_rules: HashMap<String, ThreatDetectionRule>,

    /// Behavioral analysis engine
    behavioral_analyzer: BehavioralAnalyzer,

    /// Anomaly detection system
    anomaly_detector: SecurityAnomalyDetector,

    /// Machine learning threat models
    ml_threat_models: Option<MlThreatModels>,

    /// Threat intelligence feeds
    threat_intelligence: ThreatIntelligenceFeed,

    /// Incident correlation engine
    correlation_engine: IncidentCorrelationEngine,

    /// Configuration
    config: ThreatDetectionConfig,

    /// Threat history
    threat_history: VecDeque<ThreatEvent>,
}

/// Data protection system for encryption and key management
#[derive(Debug)]
pub struct DataProtectionSystem {
    /// Encryption key manager
    key_manager: EncryptionKeyManager,

    /// Data classifier for protection levels
    data_classifier: DataClassifier,

    /// Encryption engines
    encryption_engines: HashMap<String, EncryptionEngine>,

    /// Data masking system
    data_masker: DataMaskingSystem,

    /// Secure deletion system
    secure_deletion: SecureDeletionSystem,

    /// Key rotation scheduler
    key_rotation: KeyRotationScheduler,

    /// Configuration
    config: EncryptionConfig,

    /// Protection statistics
    protection_stats: DataProtectionStatistics,
}

/// Compliance monitoring system
#[derive(Debug)]
pub struct ComplianceMonitor {
    /// Compliance frameworks
    compliance_frameworks: HashMap<String, ComplianceFramework>,

    /// Policy compliance checker
    policy_checker: PolicyComplianceChecker,

    /// Compliance report generator
    report_generator: ComplianceReportGenerator,

    /// Violation detector
    violation_detector: ComplianceViolationDetector,

    /// Remediation recommendation system
    remediation_system: RemediationRecommendationSystem,

    /// Configuration
    config: ComplianceConfig,

    /// Compliance status
    compliance_status: ComplianceStatus,
}

/// Security incident response system
#[derive(Debug)]
pub struct IncidentResponseSystem {
    /// Incident classification system
    incident_classifier: IncidentClassifier,

    /// Response playbooks
    response_playbooks: HashMap<String, ResponsePlaybook>,

    /// Incident workflow engine
    workflow_engine: IncidentWorkflowEngine,

    /// Escalation manager
    escalation_manager: IncidentEscalationManager,

    /// Communication system
    communication_system: IncidentCommunicationSystem,

    /// Configuration
    config: IncidentResponseConfig,

    /// Active incidents
    active_incidents: HashMap<String, SecurityIncident>,
}

// === Core Types and Structures ===

/// Security session for user activity tracking
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct SecuritySession {
    /// Session identifier
    pub session_id: String,

    /// User identifier
    pub user_id: String,

    /// Session token
    pub token: SessionToken,

    /// Session start time
    pub start_time: SystemTime,

    /// Last activity time
    pub last_activity: SystemTime,

    /// Session permissions
    pub permissions: HashSet<String>,

    /// Session metadata
    pub metadata: HashMap<String, String>,

    /// Session status
    pub status: SessionStatus,
}

/// Role-based permissions configuration
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct RolePermissions {
    /// Role name
    pub role_name: String,

    /// Granted permissions
    pub permissions: HashSet<Permission>,

    /// Resource access patterns
    pub resource_access: HashMap<String, AccessLevel>,

    /// Time-based restrictions
    pub time_restrictions: Option<TimeRestrictions>,

    /// Network access restrictions
    pub network_restrictions: Option<NetworkRestrictions>,
}

/// Access attempt record for audit trail
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct AccessAttempt {
    /// Attempt identifier
    pub attempt_id: String,

    /// User making the attempt
    pub user_id: String,

    /// Resource being accessed
    pub resource: String,

    /// Requested action
    pub action: String,

    /// Attempt timestamp
    pub timestamp: SystemTime,

    /// Attempt result
    pub result: AccessResult,

    /// Access context
    pub context: AccessContext,

    /// Client information
    pub client_info: ClientInformation,
}

/// Authentication provider for different auth methods
#[derive(Debug)]
pub struct AuthenticationProvider {
    /// Provider identifier
    pub provider_id: String,

    /// Provider type
    pub provider_type: AuthProviderType,

    /// Authentication function
    pub authenticator: Box<dyn Fn(&Credentials) -> AuthenticationResult + Send + Sync>,

    /// Provider configuration
    pub config: AuthProviderConfig,

    /// Provider status
    pub status: ProviderStatus,
}

/// Session token for authenticated users
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct SessionToken {
    /// Token value
    pub token: String,

    /// Token type
    pub token_type: TokenType,

    /// Expiration time
    pub expires_at: SystemTime,

    /// Token permissions
    pub permissions: HashSet<String>,

    /// Token metadata
    pub metadata: HashMap<String, String>,
}

/// Audit event for security logging
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct AuditEvent {
    /// Event identifier
    pub event_id: String,

    /// Event type
    pub event_type: AuditEventType,

    /// Event timestamp
    pub timestamp: SystemTime,

    /// User involved in the event
    pub user_id: Option<String>,

    /// Session identifier
    pub session_id: Option<String>,

    /// Resource involved
    pub resource: Option<String>,

    /// Event description
    pub description: String,

    /// Event details
    pub details: HashMap<String, String>,

    /// Event severity
    pub severity: EventSeverity,

    /// Event outcome
    pub outcome: EventOutcome,
}

/// Security threat event
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ThreatEvent {
    /// Threat identifier
    pub threat_id: String,

    /// Threat type
    pub threat_type: ThreatType,

    /// Detection timestamp
    pub detected_at: SystemTime,

    /// Threat severity
    pub severity: ThreatSeverity,

    /// Threat source
    pub source: ThreatSource,

    /// Affected resources
    pub affected_resources: Vec<String>,

    /// Threat indicators
    pub indicators: Vec<ThreatIndicator>,

    /// Threat description
    pub description: String,

    /// Recommended actions
    pub recommended_actions: Vec<String>,
}

/// Security incident record
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct SecurityIncident {
    /// Incident identifier
    pub incident_id: String,

    /// Incident type
    pub incident_type: IncidentType,

    /// Creation timestamp
    pub created_at: SystemTime,

    /// Incident status
    pub status: IncidentStatus,

    /// Incident severity
    pub severity: IncidentSeverity,

    /// Incident description
    pub description: String,

    /// Related events
    pub related_events: Vec<String>,

    /// Assigned responder
    pub assigned_to: Option<String>,

    /// Response actions taken
    pub response_actions: Vec<ResponseAction>,

    /// Resolution details
    pub resolution: Option<IncidentResolution>,
}

// === Enumerations and Configuration Types ===

/// Permission types for access control
#[derive(Debug, Clone, PartialEq, Eq, Hash, Serialize, Deserialize)]
pub enum Permission {
    /// Read access to resources
    Read,
    /// Write access to resources
    Write,
    /// Execute permissions
    Execute,
    /// Administrative permissions
    Admin,
    /// Create new resources
    Create,
    /// Delete resources
    Delete,
    /// Modify resource metadata
    Modify,
    /// Custom permission
    Custom(String),
}

/// Access levels for resource control
#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
pub enum AccessLevel {
    /// Full access to resource
    Full,
    /// Read-only access
    ReadOnly,
    /// Limited access based on context
    Limited,
    /// No access
    None,
}

/// Session status enumeration
#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
pub enum SessionStatus {
    Active,
    Inactive,
    Expired,
    Suspended,
    Terminated,
}

/// Access attempt results
#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
pub enum AccessResult {
    Granted,
    Denied,
    Partial,
    Error(String),
}

/// Authentication provider types
#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
pub enum AuthProviderType {
    Local,
    LDAP,
    OAuth2,
    SAML,
    Certificate,
    Custom,
}

/// Token types
#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
pub enum TokenType {
    JWT,
    Bearer,
    APIKey,
    SessionCookie,
}

/// Audit event types
#[derive(Debug, Clone, PartialEq, Eq, Hash, Serialize, Deserialize)]
pub enum AuditEventType {
    Authentication,
    Authorization,
    DataAccess,
    DataModification,
    SystemAccess,
    Configuration,
    SecurityIncident,
    PolicyViolation,
}

/// Event severity levels
#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Serialize, Deserialize)]
pub enum EventSeverity {
    Critical = 0,
    High = 1,
    Medium = 2,
    Low = 3,
    Info = 4,
}

/// Event outcomes
#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
pub enum EventOutcome {
    Success,
    Failure,
    Warning,
    Error,
}

/// Threat types
#[derive(Debug, Clone, PartialEq, Eq, Hash, Serialize, Deserialize)]
pub enum ThreatType {
    UnauthorizedAccess,
    DataBreach,
    MalwareDetection,
    SuspiciousBehavior,
    PolicyViolation,
    SystemIntrusion,
    DenialOfService,
    PrivilegeEscalation,
}

/// Threat severity levels
#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Serialize, Deserialize)]
pub enum ThreatSeverity {
    Critical = 0,
    High = 1,
    Medium = 2,
    Low = 3,
}

/// Incident types
#[derive(Debug, Clone, PartialEq, Eq, Hash, Serialize, Deserialize)]
pub enum IncidentType {
    SecurityBreach,
    DataLeak,
    SystemCompromise,
    PolicyViolation,
    AuthenticationFailure,
    AccessViolation,
    MalwareInfection,
    ConfigurationError,
}

/// Incident severity levels
#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Serialize, Deserialize)]
pub enum IncidentSeverity {
    Critical = 0,
    High = 1,
    Medium = 2,
    Low = 3,
}

/// Incident status
#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
pub enum IncidentStatus {
    Open,
    InProgress,
    Resolved,
    Closed,
    Escalated,
}

// === Configuration Structures ===

/// Access control configuration
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct AccessControlConfig {
    /// Enable role-based access control
    pub enable_rbac: bool,

    /// Default access level for new resources
    pub default_access_level: AccessLevel,

    /// Access attempt logging
    pub log_access_attempts: bool,

    /// Failed attempt threshold
    pub failed_attempt_threshold: usize,

    /// Account lockout duration
    pub lockout_duration: Duration,

    /// Session timeout
    pub session_timeout: Duration,
}

/// Authentication configuration
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct AuthenticationConfig {
    /// Enable multi-factor authentication
    pub enable_mfa: bool,

    /// Password complexity requirements
    pub password_requirements: PasswordRequirements,

    /// Token expiration time
    pub token_expiration: Duration,

    /// Maximum concurrent sessions per user
    pub max_concurrent_sessions: usize,

    /// Authentication timeout
    pub auth_timeout: Duration,
}

/// Authorization configuration
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct AuthorizationConfig {
    /// Enable dynamic authorization
    pub enable_dynamic_auth: bool,

    /// Permission cache timeout
    pub cache_timeout: Duration,

    /// Context evaluation timeout
    pub context_evaluation_timeout: Duration,

    /// Default deny policy
    pub default_deny: bool,
}

/// Threat detection configuration
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ThreatDetectionConfig {
    /// Enable real-time detection
    pub enable_realtime_detection: bool,

    /// Detection sensitivity level
    pub detection_sensitivity: DetectionSensitivity,

    /// Minimum threat severity for alerts
    pub min_alert_severity: ThreatSeverity,

    /// Behavioral analysis window
    pub analysis_window: Duration,

    /// Enable machine learning models
    pub enable_ml_models: bool,
}

/// Incident response configuration
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct IncidentResponseConfig {
    /// Automatic incident creation
    pub auto_create_incidents: bool,

    /// Incident escalation timeout
    pub escalation_timeout: Duration,

    /// Enable automated response actions
    pub enable_automated_response: bool,

    /// Notification settings
    pub notification_settings: NotificationSettings,
}

/// Compliance configuration
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ComplianceConfig {
    /// Enabled compliance frameworks
    pub enabled_frameworks: Vec<String>,

    /// Compliance check frequency
    pub check_frequency: Duration,

    /// Violation reporting threshold
    pub violation_threshold: usize,

    /// Enable automated remediation
    pub enable_auto_remediation: bool,
}

// === Implementation ===

impl SecurityManager {
    /// Create a new security manager
    pub fn new(config: SecurityConfig) -> Self {
        Self {
            access_control: Arc::new(Mutex::new(AccessControlSystem::new(&config))),
            authentication: Arc::new(Mutex::new(AuthenticationManager::new(&config))),
            authorization: Arc::new(Mutex::new(AuthorizationSystem::new(&config))),
            audit_logger: Arc::new(Mutex::new(AuditLogger::new(&config.audit))),
            threat_detector: Arc::new(Mutex::new(ThreatDetectionEngine::new(&config))),
            data_protector: Arc::new(Mutex::new(DataProtectionSystem::new(&config.encryption))),
            compliance_monitor: Arc::new(Mutex::new(ComplianceMonitor::new(&config))),
            incident_response: Arc::new(Mutex::new(IncidentResponseSystem::new(&config))),
            config,
            security_state: Arc::new(RwLock::new(SecurityState::new())),
            security_metrics: Arc::new(Mutex::new(SecurityMetrics::new())),
            active_sessions: Arc::new(Mutex::new(HashMap::new())),
        }
    }

    /// Authenticate a user
    pub fn authenticate(
        &self,
        credentials: Credentials,
    ) -> Result<AuthenticationResult, SecurityError> {
        let mut auth_manager = self.authentication.lock().expect("lock should not be poisoned");
        let result = auth_manager.authenticate(&credentials)?;

        // Log authentication attempt
        {
            let mut audit_logger = self.audit_logger.lock().expect("lock should not be poisoned");
            audit_logger.log_event(AuditEvent {
                event_id: uuid::Uuid::new_v4().to_string(),
                event_type: AuditEventType::Authentication,
                timestamp: SystemTime::now(),
                user_id: Some(credentials.username.clone()),
                session_id: None,
                resource: None,
                description: "User authentication attempt".to_string(),
                details: HashMap::new(),
                severity: EventSeverity::Info,
                outcome: if result.is_success() {
                    EventOutcome::Success
                } else {
                    EventOutcome::Failure
                },
            })?;
        }

        // Update metrics
        {
            let mut metrics = self.security_metrics.lock().expect("lock should not be poisoned");
            if result.is_success() {
                metrics.successful_authentications += 1;
            } else {
                metrics.failed_authentications += 1;
            }
        }

        Ok(result)
    }

    /// Check authorization for a specific action
    pub fn check_authorization(
        &self,
        user_id: &str,
        resource: &str,
        action: &str,
    ) -> Result<bool, SecurityError> {
        let mut authz_system = self.authorization.lock().expect("lock should not be poisoned");
        let authorized = authz_system.check_permission(user_id, resource, action)?;

        // Log authorization check
        {
            let mut audit_logger = self.audit_logger.lock().expect("lock should not be poisoned");
            audit_logger.log_event(AuditEvent {
                event_id: uuid::Uuid::new_v4().to_string(),
                event_type: AuditEventType::Authorization,
                timestamp: SystemTime::now(),
                user_id: Some(user_id.to_string()),
                session_id: None,
                resource: Some(resource.to_string()),
                description: format!("Authorization check for action: {}", action),
                details: HashMap::new(),
                severity: EventSeverity::Info,
                outcome: if authorized {
                    EventOutcome::Success
                } else {
                    EventOutcome::Failure
                },
            })?;
        }

        Ok(authorized)
    }

    /// Create a new security session
    pub fn create_session(
        &self,
        user_id: &str,
        permissions: HashSet<String>,
    ) -> Result<String, SecurityError> {
        let session_id = uuid::Uuid::new_v4().to_string();
        let token = SessionToken {
            token: self.generate_token()?,
            token_type: TokenType::JWT,
            expires_at: SystemTime::now() + Duration::from_secs(24 * 60 * 60),
            permissions: permissions.clone(),
            metadata: HashMap::new(),
        };

        let session = SecuritySession {
            session_id: session_id.clone(),
            user_id: user_id.to_string(),
            token,
            start_time: SystemTime::now(),
            last_activity: SystemTime::now(),
            permissions,
            metadata: HashMap::new(),
            status: SessionStatus::Active,
        };

        {
            let mut sessions = self.active_sessions.lock().expect("lock should not be poisoned");
            sessions.insert(session_id.clone(), session);
        }

        // Update metrics
        {
            let mut metrics = self.security_metrics.lock().expect("lock should not be poisoned");
            metrics.active_sessions += 1;
        }

        Ok(session_id)
    }

    /// Detect security threats
    pub fn detect_threats(&self) -> Result<Vec<ThreatEvent>, SecurityError> {
        let mut detector = self.threat_detector.lock().expect("lock should not be poisoned");
        let threats = detector.scan_for_threats()?;

        // Update metrics
        {
            let mut metrics = self.security_metrics.lock().expect("lock should not be poisoned");
            metrics.threats_detected += threats.len() as u64;
        }

        Ok(threats)
    }

    /// Encrypt sensitive data
    pub fn encrypt_data(
        &self,
        data: &[u8],
        classification: DataClassification,
    ) -> Result<Vec<u8>, SecurityError> {
        let mut protector = self.data_protector.lock().expect("lock should not be poisoned");
        let encrypted_data = protector.encrypt_data(data, classification)?;

        // Update metrics
        {
            let mut metrics = self.security_metrics.lock().expect("lock should not be poisoned");
            metrics.data_encrypted += data.len() as u64;
        }

        Ok(encrypted_data)
    }

    /// Check compliance status
    pub fn check_compliance(&self) -> Result<ComplianceStatus, SecurityError> {
        let monitor = self.compliance_monitor.lock().expect("lock should not be poisoned");
        Ok(monitor.get_compliance_status())
    }

    /// Get security metrics
    pub fn get_security_metrics(&self) -> SecurityMetrics {
        let metrics = self.security_metrics.lock().expect("lock should not be poisoned");
        metrics.clone()
    }

    // === Private Helper Methods ===

    fn generate_token(&self) -> Result<String, SecurityError> {
        // Implementation would generate a secure token
        let random_bytes = [0u8; 32]; // Would use secure random generation
        let mut hasher = Sha256::new();
        hasher.update(random_bytes);
        let result = hasher.finalize();
        Ok(format!("{:x}", result))
    }
}

impl AccessControlSystem {
    fn new(config: &SecurityConfig) -> Self {
        Self {
            role_permissions: HashMap::new(),
            user_roles: HashMap::new(),
            resource_policies: HashMap::new(),
            permission_evaluator: PermissionEvaluator::new(),
            acl_manager: AclManager::new(),
            config: config.access_control.clone().unwrap_or_default(),
            access_history: VecDeque::new(),
        }
    }
}

impl AuthenticationManager {
    fn new(config: &SecurityConfig) -> Self {
        Self {
            auth_providers: HashMap::new(),
            token_manager: TokenManager::new(),
            mfa_system: MfaSystem::new(),
            auth_cache: AuthenticationCache::new(),
            password_policy: PasswordPolicyEnforcer::new(),
            config: config.authentication.clone().unwrap_or_default(),
            auth_stats: AuthenticationStatistics::new(),
        }
    }

    fn authenticate(
        &mut self,
        credentials: &Credentials,
    ) -> Result<AuthenticationResult, SecurityError> {
        // Simple authentication logic - would be more complex in reality
        if credentials.username.is_empty() || credentials.password.is_empty() {
            return Ok(AuthenticationResult::Failed(
                "Invalid credentials".to_string(),
            ));
        }

        // Update statistics
        self.auth_stats.total_attempts += 1;

        Ok(AuthenticationResult::Success {
            user_id: credentials.username.clone(),
            session_token: "dummy_token".to_string(),
            expires_at: SystemTime::now() + Duration::from_secs(24 * 60 * 60),
        })
    }
}

impl AuthorizationSystem {
    fn new(config: &SecurityConfig) -> Self {
        Self {
            policy_engine: PolicyEvaluationEngine::new(),
            authorization_rules: HashMap::new(),
            context_analyzer: AuthorizationContextAnalyzer::new(),
            permission_cache: PermissionCache::new(),
            config: config.authorization.clone().unwrap_or_default(),
            decision_history: VecDeque::new(),
        }
    }

    fn check_permission(
        &mut self,
        user_id: &str,
        resource: &str,
        action: &str,
    ) -> Result<bool, SecurityError> {
        // Simple authorization logic
        let decision = AuthorizationDecision {
            user_id: user_id.to_string(),
            resource: resource.to_string(),
            action: action.to_string(),
            decision: true, // Would implement actual logic
            timestamp: SystemTime::now(),
            context: HashMap::new(),
        };

        self.decision_history.push_back(decision);

        // Limit history size
        if self.decision_history.len() > 10000 {
            self.decision_history.pop_front();
        }

        Ok(true) // Placeholder - would implement real authorization
    }
}

impl AuditLogger {
    fn new(config: &AuditConfig) -> Self {
        Self {
            log_writers: HashMap::new(),
            event_formatter: AuditEventFormatter::new(),
            rotation_manager: LogRotationManager::new(),
            integrity_verifier: LogIntegrityVerifier::new(),
            log_encryptor: None,
            config: config.clone(),
            audit_stats: AuditStatistics::new(),
        }
    }

    fn log_event(&mut self, event: AuditEvent) -> Result<(), SecurityError> {
        // Format the event
        let formatted_event = self.event_formatter.format(&event);

        // Write to all configured log writers
        for (writer_name, writer) in &mut self.log_writers {
            writer.write_event(&formatted_event)?;
        }

        // Update statistics
        self.audit_stats.events_logged += 1;

        Ok(())
    }
}

impl ThreatDetectionEngine {
    fn new(config: &SecurityConfig) -> Self {
        Self {
            detection_rules: HashMap::new(),
            behavioral_analyzer: BehavioralAnalyzer::new(),
            anomaly_detector: SecurityAnomalyDetector::new(),
            ml_threat_models: None,
            threat_intelligence: ThreatIntelligenceFeed::new(),
            correlation_engine: IncidentCorrelationEngine::new(),
            config: config.threat_detection.clone().unwrap_or_default(),
            threat_history: VecDeque::new(),
        }
    }

    fn scan_for_threats(&mut self) -> Result<Vec<ThreatEvent>, SecurityError> {
        let mut threats = Vec::new();

        // Scan using detection rules
        for (rule_name, rule) in &self.detection_rules {
            if let Some(threat) = rule.evaluate()? {
                threats.push(threat);
            }
        }

        // Update history
        for threat in &threats {
            self.threat_history.push_back(threat.clone());
        }

        Ok(threats)
    }
}

impl DataProtectionSystem {
    fn new(config: &EncryptionConfig) -> Self {
        Self {
            key_manager: EncryptionKeyManager::new(),
            data_classifier: DataClassifier::new(),
            encryption_engines: HashMap::new(),
            data_masker: DataMaskingSystem::new(),
            secure_deletion: SecureDeletionSystem::new(),
            key_rotation: KeyRotationScheduler::new(),
            config: config.clone(),
            protection_stats: DataProtectionStatistics::new(),
        }
    }

    fn encrypt_data(
        &mut self,
        data: &[u8],
        classification: DataClassification,
    ) -> Result<Vec<u8>, SecurityError> {
        // Simple encryption - would use proper encryption in reality
        let mut encrypted = data.to_vec();
        for byte in &mut encrypted {
            *byte = byte.wrapping_add(1); // Simple caesar cipher for demo
        }

        // Update statistics
        self.protection_stats.bytes_encrypted += data.len() as u64;

        Ok(encrypted)
    }
}

impl ComplianceMonitor {
    fn new(config: &SecurityConfig) -> Self {
        Self {
            compliance_frameworks: HashMap::new(),
            policy_checker: PolicyComplianceChecker::new(),
            report_generator: ComplianceReportGenerator::new(),
            violation_detector: ComplianceViolationDetector::new(),
            remediation_system: RemediationRecommendationSystem::new(),
            config: config.compliance.clone().unwrap_or_default(),
            compliance_status: ComplianceStatus::new(),
        }
    }

    fn get_compliance_status(&self) -> ComplianceStatus {
        self.compliance_status.clone()
    }
}

impl IncidentResponseSystem {
    fn new(config: &SecurityConfig) -> Self {
        Self {
            incident_classifier: IncidentClassifier::new(),
            response_playbooks: HashMap::new(),
            workflow_engine: IncidentWorkflowEngine::new(),
            escalation_manager: IncidentEscalationManager::new(),
            communication_system: IncidentCommunicationSystem::new(),
            config: config.incident_response.clone().unwrap_or_default(),
            active_incidents: HashMap::new(),
        }
    }
}

// === Error Handling ===

/// Security management errors
#[derive(Debug, Clone)]
pub enum SecurityError {
    /// Authentication error
    AuthenticationError(String),
    /// Authorization error
    AuthorizationError(String),
    /// Access control error
    AccessControlError(String),
    /// Audit logging error
    AuditError(String),
    /// Threat detection error
    ThreatDetectionError(String),
    /// Data protection error
    DataProtectionError(String),
    /// Compliance error
    ComplianceError(String),
    /// Configuration error
    ConfigurationError(String),
    /// System error
    SystemError(String),
}

/// Authentication results
#[derive(Debug, Clone)]
pub enum AuthenticationResult {
    /// Authentication successful
    Success {
        user_id: String,
        session_token: String,
        expires_at: SystemTime,
    },
    /// Authentication failed
    Failed(String),
    /// MFA required
    MfaRequired {
        challenge: String,
        methods: Vec<String>,
    },
}

impl AuthenticationResult {
    fn is_success(&self) -> bool {
        matches!(self, AuthenticationResult::Success { .. })
    }
}

// === Placeholder Types and Default Implementations ===

macro_rules! default_placeholder_type {
    ($name:ident) => {
        #[derive(Debug, Clone, Default, PartialEq, Eq, Hash, Serialize, Deserialize)]
        pub struct $name {
            pub placeholder: bool,
        }
    };
}

// Configuration types
default_placeholder_type!(PasswordRequirements);
default_placeholder_type!(NotificationSettings);
default_placeholder_type!(DetectionSensitivity);

// Core security types
default_placeholder_type!(Credentials);
default_placeholder_type!(ResourceAccessPolicy);
default_placeholder_type!(PermissionEvaluator);
default_placeholder_type!(AclManager);
default_placeholder_type!(TokenManager);
default_placeholder_type!(MfaSystem);
default_placeholder_type!(AuthenticationCache);
default_placeholder_type!(PasswordPolicyEnforcer);
default_placeholder_type!(AuthenticationStatistics);
default_placeholder_type!(PolicyEvaluationEngine);
default_placeholder_type!(AuthorizationRule);
default_placeholder_type!(AuthorizationContextAnalyzer);
default_placeholder_type!(PermissionCache);
default_placeholder_type!(AuthorizationDecision);
default_placeholder_type!(AuditLogWriter);
default_placeholder_type!(AuditEventFormatter);
default_placeholder_type!(LogRotationManager);
default_placeholder_type!(LogIntegrityVerifier);
default_placeholder_type!(LogEncryptor);
default_placeholder_type!(AuditStatistics);
default_placeholder_type!(ThreatDetectionRule);
default_placeholder_type!(BehavioralAnalyzer);
default_placeholder_type!(SecurityAnomalyDetector);
default_placeholder_type!(MlThreatModels);
default_placeholder_type!(ThreatIntelligenceFeed);
default_placeholder_type!(IncidentCorrelationEngine);
default_placeholder_type!(EncryptionKeyManager);
default_placeholder_type!(DataClassifier);
default_placeholder_type!(EncryptionEngine);
default_placeholder_type!(DataMaskingSystem);
default_placeholder_type!(SecureDeletionSystem);
default_placeholder_type!(KeyRotationScheduler);
default_placeholder_type!(DataProtectionStatistics);
default_placeholder_type!(ComplianceFramework);
default_placeholder_type!(PolicyComplianceChecker);
default_placeholder_type!(ComplianceReportGenerator);
default_placeholder_type!(ComplianceViolationDetector);
default_placeholder_type!(RemediationRecommendationSystem);
default_placeholder_type!(ComplianceStatus);
default_placeholder_type!(IncidentClassifier);
default_placeholder_type!(ResponsePlaybook);
default_placeholder_type!(IncidentWorkflowEngine);
default_placeholder_type!(IncidentEscalationManager);
default_placeholder_type!(IncidentCommunicationSystem);
default_placeholder_type!(TimeRestrictions);
default_placeholder_type!(NetworkRestrictions);
default_placeholder_type!(AccessContext);
default_placeholder_type!(ClientInformation);
default_placeholder_type!(AuthProviderConfig);
default_placeholder_type!(ProviderStatus);
default_placeholder_type!(ThreatSource);
default_placeholder_type!(ThreatIndicator);
default_placeholder_type!(ResponseAction);
default_placeholder_type!(IncidentResolution);
default_placeholder_type!(SecurityState);

// Data classification enum
#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
pub enum DataClassification {
    Public,
    Internal,
    Confidential,
    Restricted,
    TopSecret,
}

// Security metrics with actual fields
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct SecurityMetrics {
    pub successful_authentications: u64,
    pub failed_authentications: u64,
    pub active_sessions: u64,
    pub threats_detected: u64,
    pub data_encrypted: u64,
    pub audit_events_logged: u64,
    pub compliance_checks_performed: u64,
    pub incidents_created: u64,
}

// Implement constructors for types
impl Credentials {
    fn new(username: String, password: String) -> Self {
        Self::default()
    }
}

impl PermissionEvaluator {
    fn new() -> Self {
        Self::default()
    }
}

impl AclManager {
    fn new() -> Self {
        Self::default()
    }
}

impl TokenManager {
    fn new() -> Self {
        Self::default()
    }
}

impl MfaSystem {
    fn new() -> Self {
        Self::default()
    }
}

impl AuthenticationCache {
    fn new() -> Self {
        Self::default()
    }
}

impl PasswordPolicyEnforcer {
    fn new() -> Self {
        Self::default()
    }
}

impl AuthenticationStatistics {
    fn new() -> Self {
        Self {
            total_attempts: 0,
            ..Default::default()
        }
    }
}

impl PolicyEvaluationEngine {
    fn new() -> Self {
        Self::default()
    }
}

impl AuthorizationContextAnalyzer {
    fn new() -> Self {
        Self::default()
    }
}

impl PermissionCache {
    fn new() -> Self {
        Self::default()
    }
}

impl AuditEventFormatter {
    fn new() -> Self {
        Self::default()
    }

    fn format(&self, event: &AuditEvent) -> String {
        format!("{:?}", event) // Simple formatting for demo
    }
}

impl LogRotationManager {
    fn new() -> Self {
        Self::default()
    }
}

impl LogIntegrityVerifier {
    fn new() -> Self {
        Self::default()
    }
}

impl AuditStatistics {
    fn new() -> Self {
        Self {
            events_logged: 0,
            ..Default::default()
        }
    }
}

impl BehavioralAnalyzer {
    fn new() -> Self {
        Self::default()
    }
}

impl SecurityAnomalyDetector {
    fn new() -> Self {
        Self::default()
    }
}

impl ThreatIntelligenceFeed {
    fn new() -> Self {
        Self::default()
    }
}

impl IncidentCorrelationEngine {
    fn new() -> Self {
        Self::default()
    }
}

impl EncryptionKeyManager {
    fn new() -> Self {
        Self::default()
    }
}

impl DataClassifier {
    fn new() -> Self {
        Self::default()
    }
}

impl DataMaskingSystem {
    fn new() -> Self {
        Self::default()
    }
}

impl SecureDeletionSystem {
    fn new() -> Self {
        Self::default()
    }
}

impl KeyRotationScheduler {
    fn new() -> Self {
        Self::default()
    }
}

impl DataProtectionStatistics {
    fn new() -> Self {
        Self {
            bytes_encrypted: 0,
            ..Default::default()
        }
    }
}

impl PolicyComplianceChecker {
    fn new() -> Self {
        Self::default()
    }
}

impl ComplianceReportGenerator {
    fn new() -> Self {
        Self::default()
    }
}

impl ComplianceViolationDetector {
    fn new() -> Self {
        Self::default()
    }
}

impl RemediationRecommendationSystem {
    fn new() -> Self {
        Self::default()
    }
}

impl ComplianceStatus {
    fn new() -> Self {
        Self::default()
    }
}

impl IncidentClassifier {
    fn new() -> Self {
        Self::default()
    }
}

impl IncidentWorkflowEngine {
    fn new() -> Self {
        Self::default()
    }
}

impl IncidentEscalationManager {
    fn new() -> Self {
        Self::default()
    }
}

impl IncidentCommunicationSystem {
    fn new() -> Self {
        Self::default()
    }
}

impl SecurityState {
    fn new() -> Self {
        Self::default()
    }
}

impl SecurityMetrics {
    fn new() -> Self {
        Self {
            successful_authentications: 0,
            failed_authentications: 0,
            active_sessions: 0,
            threats_detected: 0,
            data_encrypted: 0,
            audit_events_logged: 0,
            compliance_checks_performed: 0,
            incidents_created: 0,
        }
    }
}

impl ThreatDetectionRule {
    fn evaluate(&self) -> Result<Option<ThreatEvent>, SecurityError> {
        // Placeholder implementation
        Ok(None)
    }
}

impl AuditLogWriter {
    fn write_event(&mut self, event: &str) -> Result<(), SecurityError> {
        // Placeholder implementation
        Ok(())
    }
}

// Default configurations
impl Default for AccessControlConfig {
    fn default() -> Self {
        Self {
            enable_rbac: true,
            default_access_level: AccessLevel::None,
            log_access_attempts: true,
            failed_attempt_threshold: 3,
            lockout_duration: Duration::from_secs(15 * 60),
            session_timeout: Duration::from_secs(8 * 60 * 60),
        }
    }
}

impl Default for AuthenticationConfig {
    fn default() -> Self {
        Self {
            enable_mfa: false,
            password_requirements: PasswordRequirements::default(),
            token_expiration: Duration::from_secs(24 * 60 * 60),
            max_concurrent_sessions: 5,
            auth_timeout: Duration::from_secs(30),
        }
    }
}

impl Default for AuthorizationConfig {
    fn default() -> Self {
        Self {
            enable_dynamic_auth: true,
            cache_timeout: Duration::from_secs(10 * 60),
            context_evaluation_timeout: Duration::from_secs(5),
            default_deny: true,
        }
    }
}

impl Default for ThreatDetectionConfig {
    fn default() -> Self {
        Self {
            enable_realtime_detection: true,
            detection_sensitivity: DetectionSensitivity::default(),
            min_alert_severity: ThreatSeverity::Medium,
            analysis_window: Duration::from_secs(10 * 60),
            enable_ml_models: false,
        }
    }
}

impl Default for IncidentResponseConfig {
    fn default() -> Self {
        Self {
            auto_create_incidents: true,
            escalation_timeout: Duration::from_secs(4 * 60 * 60),
            enable_automated_response: false,
            notification_settings: NotificationSettings::default(),
        }
    }
}

impl Default for ComplianceConfig {
    fn default() -> Self {
        Self {
            enabled_frameworks: vec!["SOC2".to_string(), "ISO27001".to_string()],
            check_frequency: Duration::from_secs(24 * 60 * 60),
            violation_threshold: 5,
            enable_auto_remediation: false,
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_security_manager_creation() {
        let config = SecurityConfig::default();
        let manager = SecurityManager::new(config);
        let metrics = manager.get_security_metrics();
        assert_eq!(metrics.successful_authentications, 0);
    }

    #[test]
    fn test_authentication() {
        let config = SecurityConfig::default();
        let manager = SecurityManager::new(config);

        let credentials = Credentials::default();
        let result = manager.authenticate(credentials).unwrap();
        assert!(result.is_success());
    }

    #[test]
    fn test_authorization() {
        let config = SecurityConfig::default();
        let manager = SecurityManager::new(config);

        let authorized = manager
            .check_authorization("test_user", "test_resource", "read")
            .unwrap();
        assert!(authorized);
    }

    #[test]
    fn test_session_creation() {
        let config = SecurityConfig::default();
        let manager = SecurityManager::new(config);

        let session_id = manager.create_session("test_user", HashSet::new()).unwrap();
        assert!(!session_id.is_empty());
    }

    #[test]
    fn test_threat_detection() {
        let config = SecurityConfig::default();
        let manager = SecurityManager::new(config);

        let threats = manager.detect_threats().unwrap();
        assert!(threats.is_empty()); // No threats initially
    }

    #[test]
    fn test_data_encryption() {
        let config = SecurityConfig::default();
        let manager = SecurityManager::new(config);

        let data = b"sensitive data";
        let encrypted = manager
            .encrypt_data(data, DataClassification::Confidential)
            .unwrap();
        assert_ne!(data.to_vec(), encrypted);
    }

    #[test]
    fn test_compliance_check() {
        let config = SecurityConfig::default();
        let manager = SecurityManager::new(config);

        let status = manager.check_compliance().unwrap();
        // ComplianceStatus should have default implementation
    }
}
