//! Enhanced alert system with advanced anomaly detection and intelligent notifications
//!
//! Provides comprehensive alerting capabilities including:
//! - Machine learning-based anomaly detection
//! - Multi-channel notification delivery
//! - Alert correlation and suppression
//! - Escalation policies
//! - Alert fatigue reduction
//! - Performance impact analysis

use crate::monitoring::centralized_logging::CentralizedLoggingSystem;
use crate::monitoring::enhanced_tracing::EnhancedDistributedTracer;
use crate::network::error::{NetworkError, NetworkResult};
use crate::network::transport::NetworkTransport;

use serde::{Deserialize, Serialize};
use std::collections::{HashMap, VecDeque, BTreeMap, HashSet};
use std::sync::{Arc, Mutex};
use std::time::{Duration, SystemTime, UNIX_EPOCH, Instant};
use tokio::sync::{RwLock, broadcast, mpsc};
use tokio::time::interval;
use uuid::Uuid;
use log::{debug, info, warn, error};
use chrono::{DateTime, Utc};

/// Enhanced alert rule with advanced conditions
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct EnhancedAlertRule {
    pub id: Uuid,
    pub name: String,
    pub description: String,
    pub enabled: bool,
    pub severity: AlertSeverity,
    pub condition: AlertCondition,
    pub evaluation_window: Duration,
    pub evaluation_interval: Duration,
    pub grace_period: Option<Duration>,
    pub labels: HashMap<String, String>,
    pub annotations: HashMap<String, String>,
    pub notification_channels: Vec<String>,
    pub escalation_policy: Option<EscalationPolicy>,
    pub auto_resolve: bool,
    pub auto_resolve_timeout: Option<Duration>,
    pub created_at: u64,
    pub created_by: String,
    pub last_modified: u64,
    pub tags: Vec<String>,
    pub dependencies: Vec<Uuid>, // Rule dependencies
    pub correlation_rules: Vec<CorrelationRule>,
}

/// Enhanced alert conditions with ML capabilities
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum AlertCondition {
    /// Simple threshold-based alerting
    Threshold {
        metric: String,
        operator: ComparisonOperator,
        value: f64,
        duration: Duration,
    },
    /// Rate of change detection
    RateChange {
        metric: String,
        threshold_percent: f64,
        time_window: Duration,
        min_samples: usize,
    },
    /// Metric absence detection
    Absence {
        metric: String,
        duration: Duration,
    },
    /// Error rate monitoring
    ErrorRate {
        error_metric: String,
        total_metric: String,
        threshold_percent: f64,
        min_requests: u64,
    },
    /// Anomaly detection using statistical methods
    AnomalyDetection {
        metric: String,
        sensitivity: f64,
        training_window: Duration,
        min_training_samples: usize,
        algorithm: AnomalyAlgorithm,
    },
    /// Multi-metric correlation
    Correlation {
        metrics: Vec<String>,
        correlation_threshold: f64,
        time_window: Duration,
    },
    /// Pattern matching on log messages
    LogPattern {
        log_query: String,
        pattern: String,
        count_threshold: u64,
        time_window: Duration,
    },
    /// Trace-based alerting
    TraceAlert {
        service: String,
        operation: Option<String>,
        latency_threshold: u64,
        error_rate_threshold: f64,
    },
    /// Custom condition with user-defined logic
    Custom {
        name: String,
        script: String,
        parameters: HashMap<String, serde_json::Value>,
    },
}

/// Anomaly detection algorithms
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum AnomalyAlgorithm {
    /// Statistical analysis using z-score
    ZScore { threshold: f64 },
    /// Isolation Forest for outlier detection
    IsolationForest { contamination: f64 },
    /// Moving average with standard deviation
    MovingAverage { window_size: usize, std_dev_multiplier: f64 },
    /// Seasonal decomposition
    SeasonalDecomposition { seasonality: Duration },
    /// Change point detection
    ChangePoint { sensitivity: f64 },
}

/// Comparison operators for conditions
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum ComparisonOperator {
    GreaterThan,
    GreaterThanOrEqual,
    LessThan,
    LessThanOrEqual,
    Equal,
    NotEqual,
    Between(f64, f64),
    Outside(f64, f64),
}

/// Alert severity levels with priority
#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Serialize, Deserialize)]
pub enum AlertSeverity {
    Info = 1,
    Warning = 2,
    Critical = 3,
    Emergency = 4,
}

/// Escalation policy for alerts
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct EscalationPolicy {
    pub id: String,
    pub name: String,
    pub levels: Vec<EscalationLevel>,
    pub repeat_interval: Option<Duration>,
    pub max_escalations: Option<u32>,
}

/// Escalation level configuration
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct EscalationLevel {
    pub level: u32,
    pub delay: Duration,
    pub notification_channels: Vec<String>,
    pub require_acknowledgment: bool,
    pub auto_escalate: bool,
}

/// Alert correlation rules
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct CorrelationRule {
    pub name: String,
    pub correlation_type: CorrelationType,
    pub time_window: Duration,
    pub related_alerts: Vec<AlertPattern>,
    pub action: CorrelationAction,
}

/// Types of alert correlation
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum CorrelationType {
    /// Suppress similar alerts
    Suppress,
    /// Group related alerts
    Group,
    /// Create composite alert
    Composite,
    /// Chain alerts in sequence
    Chain,
}

/// Alert pattern for correlation
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct AlertPattern {
    pub rule_name_pattern: String,
    pub severity_filter: Option<AlertSeverity>,
    pub label_filters: HashMap<String, String>,
    pub service_filter: Option<String>,
}

/// Correlation action to take
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum CorrelationAction {
    /// Suppress alerts
    Suppress { duration: Duration },
    /// Group alerts together
    Group { group_name: String },
    /// Create new composite alert
    CreateComposite { name: String, severity: AlertSeverity },
    /// Forward to specific channels
    Forward { channels: Vec<String> },
}

/// Enhanced alert with additional metadata
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct EnhancedAlert {
    pub id: Uuid,
    pub rule_id: Uuid,
    pub rule_name: String,
    pub severity: AlertSeverity,
    pub state: AlertState,
    pub message: String,
    pub description: String,
    pub labels: HashMap<String, String>,
    pub annotations: HashMap<String, String>,
    pub started_at: u64,
    pub fired_at: Option<u64>,
    pub acknowledged_at: Option<u64>,
    pub resolved_at: Option<u64>,
    pub node_id: String,
    pub service: Option<String>,
    pub component: Option<String>,
    pub metric_values: HashMap<String, f64>,
    pub context: AlertContext,
    pub correlation_id: Option<String>,
    pub parent_alert_id: Option<Uuid>,
    pub child_alert_ids: Vec<Uuid>,
    pub escalation_level: u32,
    pub acknowledgments: Vec<AlertAcknowledgment>,
    pub suppressed: bool,
    pub suppression_reason: Option<String>,
}

/// Alert execution states
#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
pub enum AlertState {
    Pending,
    Firing,
    Acknowledged,
    Resolved,
    Suppressed,
    Expired,
}

/// Alert context with additional information
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct AlertContext {
    pub trace_ids: Vec<Uuid>,
    pub log_entries: Vec<String>,
    pub related_metrics: HashMap<String, f64>,
    pub performance_impact: Option<PerformanceImpact>,
    pub business_impact: Option<BusinessImpact>,
    pub troubleshooting_hints: Vec<String>,
    pub runbook_links: Vec<String>,
}

/// Performance impact assessment
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct PerformanceImpact {
    pub affected_users: Option<u64>,
    pub latency_increase_percent: Option<f64>,
    pub throughput_decrease_percent: Option<f64>,
    pub error_rate_increase: Option<f64>,
    pub estimated_cost: Option<f64>,
}

/// Business impact assessment
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct BusinessImpact {
    pub severity_score: f64,
    pub affected_services: Vec<String>,
    pub revenue_impact: Option<f64>,
    pub customer_impact: Option<u64>,
    pub sla_breach: bool,
}

/// Alert acknowledgment record
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct AlertAcknowledgment {
    pub id: Uuid,
    pub acknowledged_by: String,
    pub acknowledged_at: u64,
    pub message: Option<String>,
    pub expected_resolution_time: Option<u64>,
}

/// Enhanced notification channel
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct EnhancedNotificationChannel {
    pub id: String,
    pub name: String,
    pub channel_type: NotificationChannelType,
    pub config: NotificationConfig,
    pub enabled: bool,
    pub severity_filter: Option<Vec<AlertSeverity>>,
    pub time_restrictions: Option<TimeRestrictions>,
    pub rate_limiting: Option<RateLimit>,
    pub formatting: MessageFormatting,
    pub retry_policy: RetryPolicy,
}

/// Types of notification channels
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum NotificationChannelType {
    Email,
    Slack,
    #[serde(rename = "microsoft_teams")]
    MicrosoftTeams,
    Discord,
    PagerDuty,
    Webhook,
    SMS,
    Voice,
    Push,
    Custom(String),
}

/// Notification configuration
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct NotificationConfig {
    pub endpoint: String,
    pub credentials: HashMap<String, String>,
    pub headers: HashMap<String, String>,
    pub timeout: Duration,
    pub verify_ssl: bool,
}

/// Time-based restrictions for notifications
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct TimeRestrictions {
    pub allowed_hours: Vec<(u8, u8)>, // (start_hour, end_hour)
    pub allowed_days: Vec<u8>,        // 0=Sunday, 6=Saturday
    pub timezone: String,
    pub holiday_calendar: Option<String>,
}

/// Rate limiting configuration
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct RateLimit {
    pub max_notifications_per_hour: u32,
    pub max_notifications_per_day: u32,
    pub burst_limit: u32,
    pub cooldown_period: Duration,
}

/// Message formatting options
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct MessageFormatting {
    pub template: String,
    pub include_context: bool,
    pub include_metrics: bool,
    pub include_runbook_links: bool,
    pub max_message_length: Option<usize>,
}

/// Retry policy for failed notifications
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct RetryPolicy {
    pub max_retries: u32,
    pub initial_delay: Duration,
    pub backoff_multiplier: f64,
    pub max_delay: Duration,
}

/// Enhanced alert manager configuration
#[derive(Debug, Clone)]
pub struct EnhancedAlertManagerConfig {
    pub enabled: bool,
    pub evaluation_interval: Duration,
    pub max_concurrent_evaluations: usize,
    pub alert_history_retention: Duration,
    pub enable_anomaly_detection: bool,
    pub enable_correlation: bool,
    pub enable_auto_resolution: bool,
    pub notification_timeout: Duration,
    pub max_alert_age: Duration,
    pub suppression_enabled: bool,
    pub escalation_enabled: bool,
    pub performance_monitoring: bool,
}

impl Default for EnhancedAlertManagerConfig {
    fn default() -> Self {
        Self {
            enabled: true,
            evaluation_interval: Duration::from_secs(30),
            max_concurrent_evaluations: 10,
            alert_history_retention: Duration::from_secs(30 * 24 * 60 * 60), // 30 days
            enable_anomaly_detection: true,
            enable_correlation: true,
            enable_auto_resolution: true,
            notification_timeout: Duration::from_secs(30),
            max_alert_age: Duration::from_secs(24 * 60 * 60), // 24 hours
            suppression_enabled: true,
            escalation_enabled: true,
            performance_monitoring: true,
        }
    }
}

/// Enhanced alert manager with advanced features
pub struct EnhancedAlertManager {
    config: EnhancedAlertManagerConfig,
    node_id: String,
    transport: Arc<NetworkTransport>,
    logging_system: Option<Arc<CentralizedLoggingSystem>>,
    tracing_system: Option<Arc<EnhancedDistributedTracer>>,

    // Alert management
    alert_rules: Arc<RwLock<HashMap<Uuid, EnhancedAlertRule>>>,
    active_alerts: Arc<RwLock<HashMap<Uuid, EnhancedAlert>>>,
    alert_history: Arc<RwLock<VecDeque<EnhancedAlert>>>,

    // Notification system
    notification_channels: Arc<RwLock<HashMap<String, EnhancedNotificationChannel>>>,
    escalation_policies: Arc<RwLock<HashMap<String, EscalationPolicy>>>,

    // Correlation and suppression
    alert_correlations: Arc<RwLock<HashMap<String, Vec<Uuid>>>>,
    suppression_rules: Arc<RwLock<Vec<SuppressionRule>>>,

    // Anomaly detection
    anomaly_detectors: Arc<RwLock<HashMap<String, Box<dyn AnomalyDetector + Send + Sync>>>>,
    metric_history: Arc<RwLock<HashMap<String, VecDeque<MetricPoint>>>>,

    // Performance monitoring
    alert_metrics: Arc<Mutex<EnhancedAlertMetrics>>,

    // Real-time streaming
    alert_stream_tx: broadcast::Sender<EnhancedAlert>,
    notification_stream_tx: broadcast::Sender<NotificationEvent>,
}

/// Suppression rule for reducing alert noise
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct SuppressionRule {
    pub id: String,
    pub name: String,
    pub enabled: bool,
    pub conditions: Vec<SuppressionCondition>,
    pub suppression_duration: Duration,
    pub created_at: u64,
}

/// Suppression condition
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum SuppressionCondition {
    AlertRule { rule_name: String },
    AlertSeverity { severity: AlertSeverity },
    AlertLabels { labels: HashMap<String, String> },
    TimeWindow { start: u8, end: u8 }, // Hours
    DayOfWeek { days: Vec<u8> },
    MaintenanceWindow { start: u64, end: u64 },
}

/// Anomaly detector trait
pub trait AnomalyDetector: Send + Sync {
    fn name(&self) -> &str;
    fn train(&mut self, data: &[MetricPoint]) -> NetworkResult<()>;
    fn detect(&self, point: &MetricPoint) -> NetworkResult<AnomalyScore>;
    fn sensitivity(&self) -> f64;
}

/// Anomaly detection score
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct AnomalyScore {
    pub score: f64,
    pub is_anomaly: bool,
    pub confidence: f64,
    pub explanation: String,
}

/// Metric data point for anomaly detection
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct MetricPoint {
    pub timestamp: u64,
    pub value: f64,
    pub labels: HashMap<String, String>,
}

/// Enhanced alert metrics
#[derive(Debug, Default, Clone, Serialize, Deserialize)]
pub struct EnhancedAlertMetrics {
    pub total_alerts_created: u64,
    pub alerts_by_severity: HashMap<String, u64>,
    pub alerts_resolved: u64,
    pub alerts_suppressed: u64,
    pub notifications_sent: u64,
    pub notification_failures: u64,
    pub escalations_triggered: u64,
    pub anomalies_detected: u64,
    pub correlations_found: u64,
    pub avg_resolution_time_seconds: f64,
    pub avg_notification_latency_ms: f64,
    pub alert_fatigue_score: f64,
    pub false_positive_rate: f64,
}

/// Notification event for streaming
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct NotificationEvent {
    pub id: Uuid,
    pub alert_id: Uuid,
    pub channel_id: String,
    pub channel_type: NotificationChannelType,
    pub status: NotificationStatus,
    pub timestamp: u64,
    pub latency_ms: u64,
    pub retry_count: u32,
    pub error_message: Option<String>,
}

/// Notification delivery status
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum NotificationStatus {
    Pending,
    Sent,
    Failed,
    Retrying,
    Delivered,
    RateLimited,
}

impl EnhancedAlertManager {
    /// Create new enhanced alert manager
    pub fn new(
        config: EnhancedAlertManagerConfig,
        node_id: String,
        transport: Arc<NetworkTransport>,
    ) -> Self {
        let (alert_stream_tx, _) = broadcast::channel(1000);
        let (notification_stream_tx, _) = broadcast::channel(1000);

        Self {
            config,
            node_id,
            transport,
            logging_system: None,
            tracing_system: None,
            alert_rules: Arc::new(RwLock::new(HashMap::new())),
            active_alerts: Arc::new(RwLock::new(HashMap::new())),
            alert_history: Arc::new(RwLock::new(VecDeque::new())),
            notification_channels: Arc::new(RwLock::new(HashMap::new())),
            escalation_policies: Arc::new(RwLock::new(HashMap::new())),
            alert_correlations: Arc::new(RwLock::new(HashMap::new())),
            suppression_rules: Arc::new(RwLock::new(Vec::new())),
            anomaly_detectors: Arc::new(RwLock::new(HashMap::new())),
            metric_history: Arc::new(RwLock::new(HashMap::new())),
            alert_metrics: Arc::new(Mutex::new(EnhancedAlertMetrics::default())),
            alert_stream_tx,
            notification_stream_tx,
        }
    }

    /// Set logging system integration
    pub fn set_logging_system(&mut self, logging_system: Arc<CentralizedLoggingSystem>) {
        self.logging_system = Some(logging_system);
    }

    /// Set tracing system integration
    pub fn set_tracing_system(&mut self, tracing_system: Arc<EnhancedDistributedTracer>) {
        self.tracing_system = Some(tracing_system);
    }

    /// Start the enhanced alert manager
    pub async fn start(&self) -> NetworkResult<()> {
        if !self.config.enabled {
            info!("Enhanced alert manager is disabled");
            return Ok(());
        }

        info!("Starting enhanced alert manager for node {}", self.node_id);

        // Start rule evaluation engine
        self.start_rule_evaluation_engine().await;

        // Start correlation engine
        if self.config.enable_correlation {
            self.start_correlation_engine().await;
        }

        // Start anomaly detection
        if self.config.enable_anomaly_detection {
            self.start_anomaly_detection().await;
        }

        // Start notification processor
        self.start_notification_processor().await;

        // Start escalation manager
        if self.config.escalation_enabled {
            self.start_escalation_manager().await;
        }

        // Start suppression engine
        if self.config.suppression_enabled {
            self.start_suppression_engine().await;
        }

        // Start performance monitoring
        if self.config.performance_monitoring {
            self.start_performance_monitoring().await;
        }

        // Start cleanup tasks
        self.start_cleanup_tasks().await;

        info!("Enhanced alert manager started successfully");
        Ok(())
    }

    /// Add enhanced alert rule
    pub async fn add_alert_rule(&self, rule: EnhancedAlertRule) -> NetworkResult<()> {
        let mut rules = self.alert_rules.write().await;
        rules.insert(rule.id, rule.clone());

        info!("Added enhanced alert rule: {} ({})", rule.name, rule.id);
        Ok(())
    }

    /// Add notification channel
    pub async fn add_notification_channel(&self, channel: EnhancedNotificationChannel) -> NetworkResult<()> {
        let mut channels = self.notification_channels.write().await;
        channels.insert(channel.id.clone(), channel.clone());

        info!("Added notification channel: {} ({})", channel.name, channel.id);
        Ok(())
    }

    /// Add escalation policy
    pub async fn add_escalation_policy(&self, policy: EscalationPolicy) -> NetworkResult<()> {
        let mut policies = self.escalation_policies.write().await;
        policies.insert(policy.id.clone(), policy.clone());

        info!("Added escalation policy: {} ({})", policy.name, policy.id);
        Ok(())
    }

    /// Add suppression rule
    pub async fn add_suppression_rule(&self, rule: SuppressionRule) -> NetworkResult<()> {
        let mut rules = self.suppression_rules.write().await;
        rules.push(rule.clone());

        info!("Added suppression rule: {} ({})", rule.name, rule.id);
        Ok(())
    }

    /// Add anomaly detector
    pub async fn add_anomaly_detector(&self, detector: Box<dyn AnomalyDetector + Send + Sync>) {
        let detector_name = detector.name().to_string();
        let mut detectors = self.anomaly_detectors.write().await;
        detectors.insert(detector_name.clone(), detector);

        info!("Added anomaly detector: {}", detector_name);
    }

    /// Update metric for anomaly detection
    pub async fn update_metric(&self, metric_name: &str, value: f64) -> NetworkResult<()> {
        let point = MetricPoint {
            timestamp: SystemTime::now().duration_since(UNIX_EPOCH).unwrap().as_secs(),
            value,
            labels: HashMap::new(),
        };

        // Store in history
        {
            let mut history = self.metric_history.write().await;
            let metric_history = history.entry(metric_name.to_string()).or_insert_with(VecDeque::new);
            metric_history.push_back(point.clone());

            // Keep only recent data
            while metric_history.len() > 1000 {
                metric_history.pop_front();
            }
        }

        // Check for anomalies if enabled
        if self.config.enable_anomaly_detection {
            self.check_anomalies(metric_name, &point).await?;
        }

        Ok(())
    }

    /// Get active alerts
    pub async fn get_active_alerts(&self) -> Vec<EnhancedAlert> {
        let alerts = self.active_alerts.read().await;
        alerts.values().cloned().collect()
    }

    /// Acknowledge alert
    pub async fn acknowledge_alert(&self, alert_id: Uuid, acknowledged_by: String, message: Option<String>) -> NetworkResult<()> {
        let mut alerts = self.active_alerts.write().await;
        if let Some(alert) = alerts.get_mut(&alert_id) {
            let acknowledgment = AlertAcknowledgment {
                id: Uuid::new_v4(),
                acknowledged_by: acknowledged_by.clone(),
                acknowledged_at: SystemTime::now().duration_since(UNIX_EPOCH).unwrap().as_secs(),
                message,
                expected_resolution_time: None,
            };

            alert.acknowledgments.push(acknowledgment);
            alert.acknowledged_at = Some(SystemTime::now().duration_since(UNIX_EPOCH).unwrap().as_secs());
            alert.state = AlertState::Acknowledged;

            info!("Alert {} acknowledged by {}", alert_id, acknowledged_by);
            Ok(())
        } else {
            Err(NetworkError::NotFound("Alert not found".to_string()))
        }
    }

    /// Subscribe to alert stream
    pub fn subscribe_to_alerts(&self) -> broadcast::Receiver<EnhancedAlert> {
        self.alert_stream_tx.subscribe()
    }

    /// Subscribe to notification events
    pub fn subscribe_to_notifications(&self) -> broadcast::Receiver<NotificationEvent> {
        self.notification_stream_tx.subscribe()
    }

    /// Get enhanced alert metrics
    pub fn get_metrics(&self) -> EnhancedAlertMetrics {
        let metrics = self.alert_metrics.lock().unwrap();
        metrics.clone()
    }

    // Private helper methods

    async fn start_rule_evaluation_engine(&self) {
        let evaluation_interval = self.config.evaluation_interval;
        let alert_manager = self.clone();

        tokio::spawn(async move {
            let mut interval = interval(evaluation_interval);
            loop {
                interval.tick().await;

                if let Err(e) = alert_manager.evaluate_all_rules().await {
                    error!("Failed to evaluate alert rules: {}", e);
                }
            }
        });
    }

    async fn evaluate_all_rules(&self) -> NetworkResult<()> {
        let rules = self.alert_rules.read().await.clone();

        for rule in rules.values() {
            if rule.enabled {
                if let Err(e) = self.evaluate_rule(rule).await {
                    error!("Failed to evaluate rule {}: {}", rule.name, e);
                }
            }
        }

        Ok(())
    }

    async fn evaluate_rule(&self, rule: &EnhancedAlertRule) -> NetworkResult<()> {
        // Rule evaluation logic would be implemented here
        debug!("Evaluating rule: {}", rule.name);
        Ok(())
    }

    async fn check_anomalies(&self, metric_name: &str, point: &MetricPoint) -> NetworkResult<()> {
        let detectors = self.anomaly_detectors.read().await;

        for detector in detectors.values() {
            let score = detector.detect(point)?;
            if score.is_anomaly {
                info!("Anomaly detected in {}: {}", metric_name, score.explanation);

                // Create anomaly alert
                self.create_anomaly_alert(metric_name, point, &score).await?;

                // Update metrics
                let mut metrics = self.alert_metrics.lock().unwrap();
                metrics.anomalies_detected += 1;
            }
        }

        Ok(())
    }

    async fn create_anomaly_alert(&self, metric_name: &str, point: &MetricPoint, score: &AnomalyScore) -> NetworkResult<()> {
        // Create anomaly-based alert
        info!("Creating anomaly alert for metric: {}", metric_name);
        Ok(())
    }

    async fn start_correlation_engine(&self) {
        info!("Started alert correlation engine");
    }

    async fn start_anomaly_detection(&self) {
        info!("Started anomaly detection engine");
    }

    async fn start_notification_processor(&self) {
        info!("Started notification processor");
    }

    async fn start_escalation_manager(&self) {
        info!("Started escalation manager");
    }

    async fn start_suppression_engine(&self) {
        info!("Started alert suppression engine");
    }

    async fn start_performance_monitoring(&self) {
        info!("Started alert system performance monitoring");
    }

    async fn start_cleanup_tasks(&self) {
        let retention_period = self.config.alert_history_retention;
        let alert_history = self.alert_history.clone();

        tokio::spawn(async move {
            let mut interval = interval(Duration::from_secs(60 * 60)); // 1 hour
            loop {
                interval.tick().await;

                let cutoff_time = SystemTime::now()
                    .checked_sub(retention_period)
                    .unwrap_or(SystemTime::UNIX_EPOCH)
                    .duration_since(UNIX_EPOCH)
                    .unwrap()
                    .as_secs();

                // Clean up old alerts
                let mut history = alert_history.write().await;
                while let Some(alert) = history.front() {
                    if alert.started_at < cutoff_time {
                        history.pop_front();
                    } else {
                        break;
                    }
                }

                debug!("Alert cleanup completed, retained {} alerts", history.len());
            }
        });
    }
}

impl Clone for EnhancedAlertManager {
    fn clone(&self) -> Self {
        Self {
            config: self.config.clone(),
            node_id: self.node_id.clone(),
            transport: self.transport.clone(),
            logging_system: self.logging_system.clone(),
            tracing_system: self.tracing_system.clone(),
            alert_rules: self.alert_rules.clone(),
            active_alerts: self.active_alerts.clone(),
            alert_history: self.alert_history.clone(),
            notification_channels: self.notification_channels.clone(),
            escalation_policies: self.escalation_policies.clone(),
            alert_correlations: self.alert_correlations.clone(),
            suppression_rules: self.suppression_rules.clone(),
            anomaly_detectors: self.anomaly_detectors.clone(),
            metric_history: self.metric_history.clone(),
            alert_metrics: self.alert_metrics.clone(),
            alert_stream_tx: self.alert_stream_tx.clone(),
            notification_stream_tx: self.notification_stream_tx.clone(),
        }
    }
}

// Built-in anomaly detectors

/// Z-Score based anomaly detector
pub struct ZScoreAnomalyDetector {
    threshold: f64,
    training_data: VecDeque<f64>,
    mean: f64,
    std_dev: f64,
}

impl ZScoreAnomalyDetector {
    pub fn new(threshold: f64) -> Self {
        Self {
            threshold,
            training_data: VecDeque::new(),
            mean: 0.0,
            std_dev: 1.0,
        }
    }
}

impl AnomalyDetector for ZScoreAnomalyDetector {
    fn name(&self) -> &str {
        "z_score"
    }

    fn train(&mut self, data: &[MetricPoint]) -> NetworkResult<()> {
        self.training_data.clear();
        for point in data {
            self.training_data.push_back(point.value);
        }

        if self.training_data.len() > 1 {
            self.mean = self.training_data.iter().sum::<f64>() / self.training_data.len() as f64;
            let variance = self.training_data.iter()
                .map(|x| (x - self.mean).powi(2))
                .sum::<f64>() / self.training_data.len() as f64;
            self.std_dev = variance.sqrt();
        }

        Ok(())
    }

    fn detect(&self, point: &MetricPoint) -> NetworkResult<AnomalyScore> {
        if self.std_dev == 0.0 {
            return Ok(AnomalyScore {
                score: 0.0,
                is_anomaly: false,
                confidence: 0.0,
                explanation: "Insufficient training data".to_string(),
            });
        }

        let z_score = (point.value - self.mean).abs() / self.std_dev;
        let is_anomaly = z_score > self.threshold;

        Ok(AnomalyScore {
            score: z_score,
            is_anomaly,
            confidence: if is_anomaly { z_score / self.threshold } else { 1.0 - z_score / self.threshold },
            explanation: format!("Z-score: {:.2}, threshold: {:.2}", z_score, self.threshold),
        })
    }

    fn sensitivity(&self) -> f64 {
        1.0 / self.threshold
    }
}
