/**
 * Performance Analyzer - Real-time performance monitoring and bottleneck detection
 *
 * Monitors system performance, detects bottlenecks, analyzes trends, and provides
 * intelligent recommendations for optimization across the AI integration ecosystem.
 */

import * as os from 'os';

import { EventEmitter } from 'eventemitter3';

import {
  PerformanceConfig,
  PerformanceMetrics,
  Bottleneck,
  Task,
  OperationResult,
} from '../types';

export class PerformanceAnalyzer extends EventEmitter {
  private config: PerformanceConfig;
  private metricsCollector: MetricsCollector;
  private bottleneckDetector: BottleneckDetector;
  private trendAnalyzer: TrendAnalyzer;
  private alertManager: AlertManager;
  private performanceHistory: PerformanceSnapshot[] = [];
  private monitoringTimer: NodeJS.Timeout | null = null;
  private isMonitoring: boolean = false;

  constructor(config: PerformanceConfig) {
    super();
    this.config = config;
    this.metricsCollector = new MetricsCollector();
    this.bottleneckDetector = new BottleneckDetector(config);
    this.trendAnalyzer = new TrendAnalyzer();
    this.alertManager = new AlertManager(config);
  }

  async initialize(): Promise<OperationResult> {
    try {
      // Initialize subsystems
      await this.metricsCollector.initialize();
      await this.bottleneckDetector.initialize();
      await this.trendAnalyzer.initialize();
      await this.alertManager.initialize();

      // Start monitoring if enabled
      if (this.config.metricsCollection) {
        await this.startMonitoring();
      }

      return {
        success: true,
        message: 'Performance Analyzer initialized successfully',
      };
    } catch (error) {
      return {
        success: false,
        message: `Performance Analyzer initialization failed: ${error.message}`,
        error: error,
      };
    }
  }

  private async startMonitoring(): Promise<void> {
    if (this.isMonitoring) return;

    this.isMonitoring = true;

    // Start periodic monitoring
    this.monitoringTimer = setInterval(async () => {
      await this.collectAndAnalyzeMetrics();
    }, 5000); // Collect metrics every 5 seconds

    this.emit('monitoring-started');
  }

  private async collectAndAnalyzeMetrics(): Promise<void> {
    try {
      // Collect current metrics
      const metrics = await this.metricsCollector.collectMetrics();

      // Create performance snapshot
      const snapshot: PerformanceSnapshot = {
        timestamp: new Date(),
        metrics: metrics,
        systemLoad: await this.calculateSystemLoad(metrics),
        healthScore: this.calculateHealthScore(metrics),
      };

      // Store snapshot
      this.performanceHistory.push(snapshot);

      // Maintain history size
      if (this.performanceHistory.length > 1000) {
        this.performanceHistory.shift();
      }

      // Analyze for bottlenecks
      if (this.config.bottleneckDetection) {
        const bottlenecks =
          await this.bottleneckDetector.detectBottlenecks(snapshot);
        if (bottlenecks.length > 0) {
          await this.handleBottlenecks(bottlenecks);
        }
      }

      // Analyze trends
      const trends = await this.trendAnalyzer.analyzeTrends(
        this.performanceHistory
      );

      // Check alert conditions
      await this.alertManager.checkAlerts(snapshot, trends);

      this.emit('metrics-collected', snapshot);
    } catch (error) {
      console.error('Failed to collect metrics:', error);
      this.emit('metrics-error', error);
    }
  }

  private async calculateSystemLoad(
    metrics: PerformanceMetrics
  ): Promise<number> {
    let load = 0;

    // CPU load (30%)
    load += (metrics.cpuUsage / 100) * 0.3;

    // Memory load (25%)
    load += (metrics.memoryUsage / 100) * 0.25;

    // Response time load (20%)
    const responseTimeScore = Math.min(metrics.responseTime / 5000, 1); // 5s max
    load += responseTimeScore * 0.2;

    // Error rate load (15%)
    load += metrics.errorRate * 0.15;

    // Queue length load (10%)
    const queueScore = Math.min(metrics.queueLength / 100, 1); // 100 max
    load += queueScore * 0.1;

    return Math.min(load, 1);
  }

  private calculateHealthScore(metrics: PerformanceMetrics): number {
    let health = 1.0;

    // Penalize high response times
    if (metrics.responseTime > this.config.alertThresholds.responseTime) {
      health -= 0.3;
    }

    // Penalize high error rates
    if (metrics.errorRate > this.config.alertThresholds.errorRate) {
      health -= 0.4;
    }

    // Penalize high memory usage
    if (metrics.memoryUsage > this.config.alertThresholds.memoryUsage) {
      health -= 0.2;
    }

    // Penalize low throughput
    if (metrics.throughput < 10) {
      health -= 0.1;
    }

    return Math.max(health, 0);
  }

  private async handleBottlenecks(bottlenecks: Bottleneck[]): Promise<void> {
    for (const bottleneck of bottlenecks) {
      this.emit('bottleneck-detected', bottleneck);

      // Apply auto-optimization if enabled
      if (this.config.autoOptimization) {
        await this.applyOptimization(bottleneck);
      }
    }
  }

  private async applyOptimization(bottleneck: Bottleneck): Promise<void> {
    try {
      const optimization = this.generateOptimizationStrategy(bottleneck);

      // Execute optimization actions
      for (const action of optimization.actions) {
        await this.executeOptimizationAction(action);
      }

      this.emit('optimization-applied', { bottleneck, optimization });
    } catch (error) {
      console.error(
        `Failed to apply optimization for ${bottleneck.type}:`,
        error
      );
      this.emit('optimization-failed', { bottleneck, error });
    }
  }

  private generateOptimizationStrategy(
    bottleneck: Bottleneck
  ): OptimizationStrategy {
    const strategy: OptimizationStrategy = {
      target: bottleneck.type,
      severity: bottleneck.severity,
      actions: [],
      expectedImpact: 'medium',
    };

    switch (bottleneck.type) {
      case 'memory':
        strategy.actions = [
          'trigger-memory-cleanup',
          'enable-compression',
          'optimize-cache-size',
        ];
        strategy.expectedImpact = 'high';
        break;

      case 'cpu':
        strategy.actions = [
          'distribute-workload',
          'optimize-algorithms',
          'enable-parallel-processing',
        ];
        strategy.expectedImpact = 'medium';
        break;

      case 'network':
        strategy.actions = [
          'enable-compression',
          'optimize-batch-sizes',
          'implement-caching',
        ];
        strategy.expectedImpact = 'medium';
        break;

      case 'agent':
        strategy.actions = [
          'spawn-additional-agents',
          'redistribute-tasks',
          'optimize-agent-selection',
        ];
        strategy.expectedImpact = 'high';
        break;

      case 'task-queue':
        strategy.actions = [
          'increase-parallelism',
          'optimize-priority-scheduling',
          'implement-load-balancing',
        ];
        strategy.expectedImpact = 'high';
        break;
    }

    return strategy;
  }

  private async executeOptimizationAction(action: string): Promise<void> {
    // Simulate optimization action execution
    console.info(`Executing optimization action: ${action}`);

    switch (action) {
      case 'trigger-memory-cleanup':
        // Trigger garbage collection or memory cleanup
        if (global.gc) {
          global.gc();
        }
        break;

      case 'enable-compression':
        // Enable data compression
        break;

      case 'distribute-workload':
        // Redistribute workload across agents
        break;

      default:
        console.info(`Action ${action} not implemented yet`);
    }

    // Simulate execution time
    await new Promise(resolve => setTimeout(resolve, 100));
  }

  /**
   * Analyze task performance
   */
  async analyzeTask(task: Task): Promise<TaskAnalysis> {
    const analysis: TaskAnalysis = {
      taskId: task.id,
      complexity: this.calculateTaskComplexity(task),
      estimatedResources: this.estimateResourceRequirements(task),
      riskFactors: this.identifyRiskFactors(task),
      recommendations: [],
      confidence: 0.8,
    };

    // Generate recommendations based on analysis
    analysis.recommendations = this.generateTaskRecommendations(analysis);

    return analysis;
  }

  private calculateTaskComplexity(task: Task): number {
    let complexity = 1;

    // Base complexity from description
    complexity += Math.min(task.description.length / 100, 3);

    // Capability requirements
    complexity += task.requiredCapabilities.length * 0.5;

    // Priority weight
    const priorityWeights = { low: 1, medium: 1.5, high: 2, critical: 3 };
    complexity *= priorityWeights[task.priority] || 1;

    // Type complexity
    const typeComplexity = {
      coding: 2.5,
      review: 1.5,
      testing: 2.0,
      analysis: 3.0,
      documentation: 1.2,
      deployment: 3.5,
      optimization: 4.0,
    };

    complexity *= typeComplexity[task.type] || 1;

    return Math.round(complexity * 10) / 10;
  }

  private estimateResourceRequirements(task: Task): ResourceRequirements {
    const complexity = this.calculateTaskComplexity(task);

    return {
      cpuEstimate: Math.min(complexity * 10, 90), // Max 90% CPU
      memoryEstimate: Math.min(complexity * 50, 500), // Max 500MB
      timeEstimate: Math.ceil(complexity * 1000), // In milliseconds
      agentsRequired: Math.min(Math.ceil(complexity / 2), 6), // Max 6 agents
    };
  }

  private identifyRiskFactors(task: Task): RiskFactor[] {
    const risks: RiskFactor[] = [];

    // High complexity risk
    const complexity = this.calculateTaskComplexity(task);
    if (complexity > 8) {
      risks.push({
        type: 'high-complexity',
        severity: 'high',
        description:
          'Task complexity may lead to longer execution times and higher resource usage',
        mitigation: 'Consider breaking down into smaller subtasks',
      });
    }

    // Resource contention risk
    if (task.requiredCapabilities.length > 5) {
      risks.push({
        type: 'resource-contention',
        severity: 'medium',
        description:
          'Multiple capability requirements may cause agent contention',
        mitigation: 'Ensure adequate agent pool availability',
      });
    }

    // Priority conflict risk
    if (task.priority === 'critical') {
      risks.push({
        type: 'priority-conflict',
        severity: 'medium',
        description: 'Critical tasks may disrupt other ongoing work',
        mitigation: 'Plan resource allocation carefully',
      });
    }

    return risks;
  }

  private generateTaskRecommendations(analysis: TaskAnalysis): string[] {
    const recommendations: string[] = [];

    // Complexity-based recommendations
    if (analysis.complexity > 6) {
      recommendations.push('Consider decomposing into smaller subtasks');
      recommendations.push('Allocate additional monitoring resources');
    }

    // Resource-based recommendations
    if (analysis.estimatedResources.memoryEstimate > 300) {
      recommendations.push('Enable memory optimization');
      recommendations.push('Consider distributed execution');
    }

    // Risk-based recommendations
    for (const risk of analysis.riskFactors) {
      recommendations.push(risk.mitigation);
    }

    // Performance-based recommendations
    const recentPerformance = this.getRecentPerformanceAverage();
    if (recentPerformance.responseTime > 3000) {
      recommendations.push(
        'System is under load - consider delaying non-critical tasks'
      );
    }

    return [...new Set(recommendations)]; // Remove duplicates
  }

  private getRecentPerformanceAverage(): PerformanceMetrics {
    const recent = this.performanceHistory.slice(-10); // Last 10 snapshots

    if (recent.length === 0) {
      return {
        responseTime: 0,
        throughput: 0,
        errorRate: 0,
        memoryUsage: 0,
        cpuUsage: 0,
        activeConnections: 0,
        queueLength: 0,
      };
    }

    const avg = recent.reduce(
      (sum, snapshot) => ({
        responseTime: sum.responseTime + snapshot.metrics.responseTime,
        throughput: sum.throughput + snapshot.metrics.throughput,
        errorRate: sum.errorRate + snapshot.metrics.errorRate,
        memoryUsage: sum.memoryUsage + snapshot.metrics.memoryUsage,
        cpuUsage: sum.cpuUsage + snapshot.metrics.cpuUsage,
        activeConnections:
          sum.activeConnections + snapshot.metrics.activeConnections,
        queueLength: sum.queueLength + snapshot.metrics.queueLength,
      }),
      {
        responseTime: 0,
        throughput: 0,
        errorRate: 0,
        memoryUsage: 0,
        cpuUsage: 0,
        activeConnections: 0,
        queueLength: 0,
      }
    );

    const count = recent.length;
    return {
      responseTime: avg.responseTime / count,
      throughput: avg.throughput / count,
      errorRate: avg.errorRate / count,
      memoryUsage: avg.memoryUsage / count,
      cpuUsage: avg.cpuUsage / count,
      activeConnections: avg.activeConnections / count,
      queueLength: avg.queueLength / count,
    };
  }

  /**
   * Get comprehensive performance report
   */
  async generatePerformanceReport(): Promise<PerformanceReport> {
    const currentMetrics = await this.metricsCollector.collectMetrics();
    const recentTrends = await this.trendAnalyzer.analyzeTrends(
      this.performanceHistory
    );
    const activeBottlenecks =
      await this.bottleneckDetector.getCurrentBottlenecks();

    return {
      timestamp: new Date(),
      currentMetrics,
      trends: recentTrends,
      bottlenecks: activeBottlenecks,
      healthScore: this.calculateHealthScore(currentMetrics),
      recommendations: this.generateSystemRecommendations(
        currentMetrics,
        recentTrends
      ),
      historicalData: {
        totalSnapshots: this.performanceHistory.length,
        timespan: this.calculateHistoryTimespan(),
        averagePerformance: this.getRecentPerformanceAverage(),
      },
    };
  }

  private generateSystemRecommendations(
    metrics: PerformanceMetrics,
    trends: any
  ): string[] {
    const recommendations: string[] = [];

    // Memory recommendations
    if (metrics.memoryUsage > 80) {
      recommendations.push(
        'High memory usage detected - consider enabling compression'
      );
      recommendations.push('Review memory retention policies');
    }

    // Performance recommendations
    if (metrics.responseTime > this.config.alertThresholds.responseTime) {
      recommendations.push(
        'Response times are elevated - investigate bottlenecks'
      );
      recommendations.push('Consider scaling up agent pool');
    }

    // Throughput recommendations
    if (metrics.throughput < 5) {
      recommendations.push(
        'Low throughput detected - check for blocking operations'
      );
    }

    // Trend-based recommendations
    if (trends.memoryTrend === 'increasing') {
      recommendations.push(
        'Memory usage trend is increasing - monitor for leaks'
      );
    }

    if (trends.errorTrend === 'increasing') {
      recommendations.push(
        'Error rate is trending upward - investigate root causes'
      );
    }

    return recommendations;
  }

  private calculateHistoryTimespan(): number {
    if (this.performanceHistory.length < 2) return 0;

    const oldest = this.performanceHistory[0].timestamp.getTime();
    const newest =
      this.performanceHistory[
        this.performanceHistory.length - 1
      ].timestamp.getTime();

    return newest - oldest;
  }

  async getMetrics(): Promise<any> {
    const currentMetrics = await this.metricsCollector.collectMetrics();

    return {
      isMonitoring: this.isMonitoring,
      currentMetrics,
      historySize: this.performanceHistory.length,
      metricsCollectionEnabled: this.config.metricsCollection,
      bottleneckDetectionEnabled: this.config.bottleneckDetection,
      autoOptimizationEnabled: this.config.autoOptimization,
      alertThresholds: this.config.alertThresholds,
    };
  }

  async shutdown(): Promise<OperationResult> {
    try {
      // Stop monitoring
      if (this.monitoringTimer) {
        clearInterval(this.monitoringTimer);
        this.monitoringTimer = null;
      }

      this.isMonitoring = false;

      // Shutdown subsystems
      await this.metricsCollector.shutdown();
      await this.bottleneckDetector.shutdown();
      await this.trendAnalyzer.shutdown();
      await this.alertManager.shutdown();

      // Clear history
      this.performanceHistory.length = 0;

      return {
        success: true,
        message: 'Performance Analyzer shutdown completed',
      };
    } catch (error) {
      return {
        success: false,
        message: `Shutdown failed: ${error.message}`,
        error: error,
      };
    }
  }
}

// Supporting Classes and Interfaces

interface PerformanceSnapshot {
  timestamp: Date;
  metrics: PerformanceMetrics;
  systemLoad: number;
  healthScore: number;
}

interface TaskAnalysis {
  taskId: string;
  complexity: number;
  estimatedResources: ResourceRequirements;
  riskFactors: RiskFactor[];
  recommendations: string[];
  confidence: number;
}

interface ResourceRequirements {
  cpuEstimate: number;
  memoryEstimate: number;
  timeEstimate: number;
  agentsRequired: number;
}

interface RiskFactor {
  type: string;
  severity: 'low' | 'medium' | 'high' | 'critical';
  description: string;
  mitigation: string;
}

interface OptimizationStrategy {
  target: string;
  severity: string;
  actions: string[];
  expectedImpact: 'low' | 'medium' | 'high';
}

interface PerformanceReport {
  timestamp: Date;
  currentMetrics: PerformanceMetrics;
  trends: any;
  bottlenecks: Bottleneck[];
  healthScore: number;
  recommendations: string[];
  historicalData: {
    totalSnapshots: number;
    timespan: number;
    averagePerformance: PerformanceMetrics;
  };
}

class MetricsCollector {
  // Rolling window of latency samples (ms) for percentile calculations
  private latencySamples: number[] = [];
  private readonly maxSamples = 1000;

  // Request/error counters and the timestamp of the last throughput window
  private requestCount = 0;
  private errorCount = 0;
  private activeConnections = 0;
  private queueLength = 0;
  private lastThroughputWindowStart: bigint = process.hrtime.bigint();
  private requestsInWindow = 0;

  // CPU measurement state: snapshot of (idle, total) times per core
  private prevCpuTimes: Array<{ idle: number; total: number }> = [];

  async initialize(): Promise<void> {
    this.prevCpuTimes = this.snapshotCpuTimes();
  }

  /**
   * Record the completion of a single request so that throughput, latency,
   * and error-rate counters stay accurate between collectMetrics() calls.
   *
   * @param latencyMs   Wall-clock duration of the request in milliseconds.
   * @param isError     Whether the request ended with an error.
   */
  recordRequest(latencyMs: number, isError = false): void {
    this.requestCount++;
    this.requestsInWindow++;
    if (isError) this.errorCount++;

    this.latencySamples.push(latencyMs);
    if (this.latencySamples.length > this.maxSamples) {
      this.latencySamples.shift();
    }
  }

  /** Adjust the active-connection gauge (positive to add, negative to remove). */
  adjustConnections(delta: number): void {
    this.activeConnections = Math.max(0, this.activeConnections + delta);
  }

  /** Set the current task-queue depth. */
  setQueueLength(length: number): void {
    this.queueLength = Math.max(0, length);
  }

  async collectMetrics(): Promise<PerformanceMetrics> {
    const memUsage = process.memoryUsage();
    const cpuUsage = this.getCPUUsage();

    // --- throughput (requests per second over the elapsed window) ---
    const nowNs = process.hrtime.bigint();
    const elapsedSec =
      Number(nowNs - this.lastThroughputWindowStart) / 1_000_000_000;
    const throughput = elapsedSec > 0 ? this.requestsInWindow / elapsedSec : 0;

    // Reset the throughput window
    this.requestsInWindow = 0;
    this.lastThroughputWindowStart = nowNs;

    // --- error rate ---
    const errorRate =
      this.requestCount > 0 ? this.errorCount / this.requestCount : 0;

    // --- p50 response time (median) as the primary responseTime metric ---
    const responseTime = this.percentile(this.latencySamples, 50);

    return {
      responseTime,
      throughput,
      errorRate,
      memoryUsage: (memUsage.heapUsed / memUsage.heapTotal) * 100,
      cpuUsage,
      activeConnections: this.activeConnections,
      queueLength: this.queueLength,
    };
  }

  // -----------------------------------------------------------------------
  // Private helpers
  // -----------------------------------------------------------------------

  private snapshotCpuTimes(): Array<{ idle: number; total: number }> {
    return os.cpus().map(cpu => {
      const times = cpu.times;
      const total =
        times.user + times.nice + times.sys + times.idle + times.irq;
      return { idle: times.idle, total };
    });
  }

  private getCPUUsage(): number {
    const current = this.snapshotCpuTimes();

    if (this.prevCpuTimes.length !== current.length) {
      // First call or CPU count changed – baseline only, return 0.
      this.prevCpuTimes = current;
      return 0;
    }

    let idleDelta = 0;
    let totalDelta = 0;
    for (let i = 0; i < current.length; i++) {
      idleDelta += current[i].idle - this.prevCpuTimes[i].idle;
      totalDelta += current[i].total - this.prevCpuTimes[i].total;
    }

    this.prevCpuTimes = current;

    if (totalDelta === 0) return 0;
    return ((totalDelta - idleDelta) / totalDelta) * 100;
  }

  /**
   * Compute the p-th percentile of an array of numbers.
   * Returns 0 when the array is empty.
   */
  private percentile(samples: number[], p: number): number {
    if (samples.length === 0) return 0;
    const sorted = [...samples].sort((a, b) => a - b);
    const index = Math.ceil((p / 100) * sorted.length) - 1;
    return sorted[Math.max(0, index)];
  }

  async shutdown(): Promise<void> {
    this.latencySamples = [];
    this.requestCount = 0;
    this.errorCount = 0;
    this.activeConnections = 0;
    this.queueLength = 0;
    this.requestsInWindow = 0;
    this.prevCpuTimes = [];
  }
}

class BottleneckDetector {
  private config: PerformanceConfig;
  private currentBottlenecks: Bottleneck[] = [];

  constructor(config: PerformanceConfig) {
    this.config = config;
  }

  async initialize(): Promise<void> {
    // Initialize bottleneck detection algorithms
  }

  async detectBottlenecks(
    snapshot: PerformanceSnapshot
  ): Promise<Bottleneck[]> {
    const bottlenecks: Bottleneck[] = [];
    const metrics = snapshot.metrics;

    // Memory bottleneck
    if (metrics.memoryUsage > this.config.alertThresholds.memoryUsage) {
      bottlenecks.push({
        type: 'memory',
        severity: this.calculateSeverity(
          'memory',
          metrics.memoryUsage,
          this.config.alertThresholds.memoryUsage
        ),
        description: `High memory usage: ${metrics.memoryUsage.toFixed(1)}%`,
        affectedComponents: ['agents', 'memory-manager', 'neural-pipeline'],
        suggestedActions: [
          'Enable compression',
          'Clear unused memories',
          'Optimize cache',
        ],
        detectedAt: snapshot.timestamp,
      });
    }

    // Response time bottleneck
    if (metrics.responseTime > this.config.alertThresholds.responseTime) {
      bottlenecks.push({
        type: 'network',
        severity: this.calculateSeverity(
          'response-time',
          metrics.responseTime,
          this.config.alertThresholds.responseTime
        ),
        description: `High response time: ${metrics.responseTime}ms`,
        affectedComponents: ['agents', 'coordination', 'communication'],
        suggestedActions: [
          'Scale agents',
          'Optimize coordination',
          'Enable batching',
        ],
        detectedAt: snapshot.timestamp,
      });
    }

    // Error rate bottleneck
    if (metrics.errorRate > this.config.alertThresholds.errorRate) {
      bottlenecks.push({
        type: 'agent',
        severity: this.calculateSeverity(
          'error-rate',
          metrics.errorRate,
          this.config.alertThresholds.errorRate
        ),
        description: `High error rate: ${(metrics.errorRate * 100).toFixed(2)}%`,
        affectedComponents: ['agents', 'task-execution', 'coordination'],
        suggestedActions: [
          'Check agent health',
          'Investigate failures',
          'Implement retry logic',
        ],
        detectedAt: snapshot.timestamp,
      });
    }

    // Queue length bottleneck
    if (metrics.queueLength > 25) {
      bottlenecks.push({
        type: 'task-queue',
        severity: this.calculateSeverity(
          'queue-length',
          metrics.queueLength,
          25
        ),
        description: `High queue length: ${metrics.queueLength}`,
        affectedComponents: ['task-orchestrator', 'agents', 'load-balancer'],
        suggestedActions: [
          'Increase parallelism',
          'Scale agents',
          'Optimize scheduling',
        ],
        detectedAt: snapshot.timestamp,
      });
    }

    // Update current bottlenecks
    this.currentBottlenecks = bottlenecks;

    return bottlenecks;
  }

  private calculateSeverity(
    type: string,
    current: number,
    threshold: number
  ): 'low' | 'medium' | 'high' | 'critical' {
    const ratio = current / threshold;

    if (ratio >= 2.0) return 'critical';
    if (ratio >= 1.5) return 'high';
    if (ratio >= 1.2) return 'medium';
    return 'low';
  }

  async getCurrentBottlenecks(): Promise<Bottleneck[]> {
    return [...this.currentBottlenecks];
  }

  async shutdown(): Promise<void> {
    this.currentBottlenecks = [];
  }
}

class TrendAnalyzer {
  async initialize(): Promise<void> {
    // Initialize trend analysis
  }

  async analyzeTrends(history: PerformanceSnapshot[]): Promise<any> {
    if (history.length < 5) {
      return { insufficient_data: true };
    }

    const recent = history.slice(-20); // Analyze last 20 snapshots

    return {
      memoryTrend: this.calculateTrend(recent.map(s => s.metrics.memoryUsage)),
      responseTrend: this.calculateTrend(
        recent.map(s => s.metrics.responseTime)
      ),
      errorTrend: this.calculateTrend(recent.map(s => s.metrics.errorRate)),
      throughputTrend: this.calculateTrend(
        recent.map(s => s.metrics.throughput)
      ),
      healthTrend: this.calculateTrend(recent.map(s => s.healthScore)),
      timespan:
        recent[recent.length - 1].timestamp.getTime() -
        recent[0].timestamp.getTime(),
    };
  }

  private calculateTrend(
    values: number[]
  ): 'increasing' | 'decreasing' | 'stable' {
    if (values.length < 3) return 'stable';

    const first = values.slice(0, Math.floor(values.length / 2));
    const last = values.slice(Math.floor(values.length / 2));

    const firstAvg = first.reduce((sum, val) => sum + val, 0) / first.length;
    const lastAvg = last.reduce((sum, val) => sum + val, 0) / last.length;

    const change = (lastAvg - firstAvg) / firstAvg;

    if (change > 0.1) return 'increasing';
    if (change < -0.1) return 'decreasing';
    return 'stable';
  }

  async shutdown(): Promise<void> {
    // Cleanup trend analysis
  }
}

class AlertManager {
  private config: PerformanceConfig;

  constructor(config: PerformanceConfig) {
    this.config = config;
  }

  async initialize(): Promise<void> {
    // Initialize alert management
  }

  async checkAlerts(snapshot: PerformanceSnapshot, trends: any): Promise<void> {
    const alerts: any[] = [];

    // Check threshold alerts
    if (
      snapshot.metrics.responseTime > this.config.alertThresholds.responseTime
    ) {
      alerts.push({
        type: 'threshold',
        metric: 'responseTime',
        current: snapshot.metrics.responseTime,
        threshold: this.config.alertThresholds.responseTime,
        severity: 'high',
      });
    }

    // Check trend alerts
    if (trends.errorTrend === 'increasing') {
      alerts.push({
        type: 'trend',
        metric: 'errorRate',
        trend: 'increasing',
        severity: 'medium',
      });
    }

    // Emit alerts
    for (const alert of alerts) {
      this.emitAlert(alert);
    }
  }

  private emitAlert(alert: any): void {
    console.warn(
      `ALERT [${alert.severity.toUpperCase()}]: ${alert.type} - ${alert.metric}`,
      alert
    );
  }

  async shutdown(): Promise<void> {
    // Cleanup alert management
  }
}