/**
 * Threat Correlation Engine
 * 
 * Advanced correlation system that combines threat intelligence from multiple feeds
 * - Cross-feed validation and confidence scoring
 * - Temporal analysis and pattern detection
 * - False positive reduction through consensus
 * - Threat enrichment and contextualization
 */

import { ThreatIndicator } from '../types';

// Correlation interfaces
// interface CorrelationResult {
//   indicator: EnrichedThreatIndicator;
//   sources: string[];
//   correlationScore: number;
//   consensusLevel: 'weak' | 'moderate' | 'strong' | 'consensus';
//   riskScore: number;
//   correlatedData: CorrelatedThreatData;
// }

// interface EnrichedThreatIndicator extends ThreatIndicator {
//   correlationScore: number;
//   consensusLevel: 'weak' | 'moderate' | 'strong' | 'consensus';
//   riskScore: number;
//   sourceFeedbacks: SourceFeedback[];
//   temporalAnalysis: TemporalAnalysis;
//   geoAnalysis?: GeoAnalysis;
//   patterns: ThreatPattern[];
// }

// interface SourceFeedback {
//   source: string;
//   confidence: number;
//   severity: 'low' | 'medium' | 'high' | 'critical';
//   lastSeen: Date;
//   reportCount?: number;
//   categories: string[];
//   agreement: number; // 0-1 score of agreement with other sources
// }

// interface TemporalAnalysis {
//   firstSeen: Date;
//   lastSeen: Date;
//   activityPeriod: number; // days
//   recentActivity: boolean;
//   activityTrend: 'increasing' | 'decreasing' | 'stable' | 'sporadic';
//   peakActivity?: Date;
// }

// interface GeoAnalysis {
//   countries: string[];
//   primaryCountry: string;
//   suspiciousGeoPatterns: boolean;
//   geoRiskScore: number;
// }

// interface ThreatPattern {
//   type: 'behavioral' | 'temporal' | 'network' | 'categorical';
//   pattern: string;
//   confidence: number;
//   evidenceSources: string[];
// }

interface CorrelatedThreatData {
  relatedIndicators: ThreatIndicator[];
  crossReferences: CrossReference[];
  enrichmentData: EnrichmentData;
  riskFactors: RiskFactor[];
  patterns?: string[];
  // Add properties needed by the code
  correlationScore?: number;
  consensusLevel?: 'weak' | 'moderate' | 'strong' | 'consensus';
  riskScore?: number;
  sources?: string[];
  indicators?: ThreatIndicator[]; // For backward compatibility
}

interface CrossReference {
  source: string;
  referenceType: 'similar_behavior' | 'same_campaign' | 'related_infrastructure';
  relatedValue: string;
  confidence: number;
}

interface EnrichmentData {
  asn?: {
    number: number;
    name: string;
    country: string;
  };
  geolocation?: {
    country: string;
    city: string;
    latitude?: number;
    longitude?: number;
  };
  dns?: {
    domain: string;
    reverseDns: string[];
  };
  reputation?: {
    overall: number;
    categories: string[];
  };
}

interface RiskFactor {
  factor: string;
  impact: 'low' | 'medium' | 'high' | 'critical';
  description: string;
  evidence: string[];
}

interface CorrelationConfig {
  minimumSources: number;
  consensusThreshold: number;
  temporalWindowDays: number;
  confidenceWeighting: Record<string, number>;
  enableGeolocationAnalysis: boolean;
  enablePatternDetection: boolean;
  riskScoreWeights: {
    consensus: number;
    recency: number;
    severity: number;
    sourceReliability: number;
  };
}

export class ThreatCorrelationEngine {
  private config: CorrelationConfig;
  // private sourceReliability: Map<string, number>;
  // private knownPatterns: Map<string, ThreatPattern[]>;
  // private correlationCache: Map<string, CorrelatedThreatData>;

  constructor(config: Partial<CorrelationConfig> = {}) {
    // Validate configuration
    if (config.minimumSources !== undefined && config.minimumSources < 1) {
      throw new Error('Invalid configuration: minimumSources must be at least 1');
    }
    
    if (config.consensusThreshold !== undefined && (config.consensusThreshold < 0 || config.consensusThreshold > 1)) {
      throw new Error('Invalid configuration: consensusThreshold must be between 0 and 1');
    }

    this.config = {
      minimumSources: 2,
      consensusThreshold: 0.5,
      temporalWindowDays: 7,
      confidenceWeighting: {},
      enableGeolocationAnalysis: false,
      enablePatternDetection: true,
      riskScoreWeights: {
        consensus: 0.4,
        recency: 0.3,
        severity: 0.3,
        sourceReliability: 0.2
      },
      ...config
    };
    
    // this.correlationCache = new Map();
    // this.sourceReliability = new Map();
    // this.knownPatterns = new Map();
  }

  /**
   * Main correlation method - simplified for Option A conservative approach
   */
  public async correlate(indicators: ThreatIndicator[]): Promise<CorrelatedThreatData> {
    if (indicators.length === 0) {
      return {
        relatedIndicators: [],
        crossReferences: [],
        enrichmentData: { reputation: { overall: 0, categories: [] } },
        riskFactors: [],
        patterns: [],
        correlationScore: 0,
        consensusLevel: 'weak',
        riskScore: 0,
        sources: [],
        indicators: []
      };
    }

    // Basic implementation for compatibility
    const sources = [...new Set(indicators.map(i => i.source))];
    const correlationScore = Math.min(indicators.length / this.config.minimumSources, 1);
    const consensusLevel = correlationScore > 0.7 ? 'strong' : correlationScore > 0.4 ? 'moderate' : 'weak';
    const riskScore = indicators.reduce((sum, i) => sum + i.confidence, 0) / indicators.length;

    return {
      relatedIndicators: indicators,
      crossReferences: [],
      enrichmentData: { reputation: { overall: riskScore * 100, categories: [] } },
      riskFactors: [],
      patterns: [],
      correlationScore,
      consensusLevel,
      riskScore,
      sources,
      indicators // For backward compatibility
    };
  }

  /**
   * Export results in various formats
   */
  public exportResult(result: CorrelatedThreatData, format: 'json' | 'stix' | 'csv' = 'json'): string {
    switch (format) {
    case 'json':
      return JSON.stringify({ ...result, timestamp: new Date().toISOString() }, null, 2);
      
    case 'stix': {
      const stixObject = {
        type: 'bundle',
        id: `bundle--${Date.now()}`,
        spec_version: '2.1',
        objects: [{
          type: 'indicator',
          id: `indicator--${Date.now()}`,
          created: new Date().toISOString(),
          modified: new Date().toISOString(),
          pattern: result.relatedIndicators?.[0]?.value || 'unknown',
          labels: ['malicious-activity'],
          confidence: Math.round((result.correlationScore || 0) * 100)
        }]
      };
      return JSON.stringify(stixObject, null, 2);
    }
      
    case 'csv': {
      const headers = 'type,value,confidence,sources,risk_score\n';
      const rows = (result.relatedIndicators || []).map((indicator: any) => 
        `${indicator.type},${indicator.value},${indicator.confidence},"${(result.sources || []).join(';')}",${result.riskScore || 0}`
      ).join('\n');
      return headers + rows;
    }
      
    default:
      throw new Error(`Unsupported export format: ${format}`);
    }
  }

  /**
   * Add integration - stub implementation
   */
  public addIntegration(_name: string, _integration: any): void {
    // Stub implementation for compatibility
  }

  /**
   * Share result - stub implementation  
   */
  public async shareResult(_result: CorrelatedThreatData, _platform: string): Promise<void> {
    // Stub implementation for compatibility
  }
}