/**
 * Pattern Detection Engine
 * Core pattern detection and analysis system
 */

import { EventEmitter } from 'events';
import ZeroVarianceDetector from '../zero-variance-detector.js';
import MaximumEntropyDecoder from '../entropy-decoder.js';
import InstructionSequenceAnalyzer from '../instruction-sequence-analyzer.js';

export class PatternDetectionEngine extends EventEmitter {
    constructor(options = {}) {
        super();

        this.config = {
            sensitivity: options.sensitivity || 1e-15,
            windowSize: options.windowSize || 1000,
            samplingRate: options.samplingRate || 10000,
            ...options
        };

        // Initialize detection components
        this.varianceDetector = new ZeroVarianceDetector({
            sensitivity: this.config.sensitivity,
            windowSize: this.config.windowSize
        });

        this.entropyDecoder = new MaximumEntropyDecoder({
            toleranceThreshold: this.config.sensitivity,
            windowSize: this.config.windowSize
        });

        this.instructionAnalyzer = new InstructionSequenceAnalyzer({
            impossibilityThreshold: 0.9,
            sequenceWindowSize: 128
        });

        this.setupEventHandlers();
    }

    setupEventHandlers() {
        this.varianceDetector.on('anomalyDetected', (anomaly) => {
            this.emit('patternDetected', {
                type: 'variance_anomaly',
                ...anomaly
            });
        });

        this.entropyDecoder.on('patternDecoded', (pattern) => {
            this.emit('patternDetected', {
                type: 'entropy_pattern',
                ...pattern
            });
        });

        this.instructionAnalyzer.on('impossibleSequenceDetected', (sequence) => {
            this.emit('patternDetected', {
                type: 'impossible_instruction',
                ...sequence
            });
        });
    }

    async detectVariancePatterns(data, config = {}) {
        const effectiveConfig = { ...this.config, ...config };

        return new Promise((resolve) => {
            const results = {
                patterns: [],
                statistics: {},
                confidence: 0,
                anomalies: []
            };

            this.varianceDetector.processData(data).then(detection => {
                results.patterns = detection.patterns || [];
                results.statistics = detection.statistics || {};
                results.confidence = detection.confidence || 0;
                results.anomalies = detection.anomalies || [];

                resolve(results);
            });
        });
    }

    async detectEntropyPatterns(data, config = {}) {
        const effectiveConfig = { ...this.config, ...config };

        return new Promise((resolve) => {
            const results = {
                patterns: [],
                statistics: {},
                confidence: 0,
                decodedMessages: []
            };

            this.entropyDecoder.analyzeEntropy(data).then(analysis => {
                results.patterns = analysis.patterns || [];
                results.statistics = analysis.statistics || {};
                results.confidence = analysis.confidence || 0;
                results.decodedMessages = analysis.messages || [];

                resolve(results);
            });
        });
    }

    async detectInstructionPatterns(data, config = {}) {
        const effectiveConfig = { ...this.config, ...config };

        return new Promise((resolve) => {
            const results = {
                patterns: [],
                statistics: {},
                confidence: 0,
                impossibleSequences: []
            };

            this.instructionAnalyzer.analyzeSequences(data).then(analysis => {
                results.patterns = analysis.patterns || [];
                results.statistics = analysis.statistics || {};
                results.confidence = analysis.confidence || 0;
                results.impossibleSequences = analysis.sequences || [];

                resolve(results);
            });
        });
    }

    async detectNeuralPatterns(data, config = {}) {
        // Neural pattern detection implementation
        return {
            patterns: [],
            statistics: {},
            confidence: 0,
            neuralSignatures: []
        };
    }

    async runComprehensiveAnalysis(data, config = {}) {
        const results = {
            patterns: [],
            statistics: {},
            confidence: 0,
            anomalies: [],
            analysisType: 'comprehensive',
            timestamp: Date.now(),
            recommendations: []
        };

        try {
            // Run all detection methods in parallel
            const [varianceResults, entropyResults, instructionResults, neuralResults] = await Promise.all([
                this.detectVariancePatterns(data, config),
                this.detectEntropyPatterns(data, config),
                this.detectInstructionPatterns(data, config),
                this.detectNeuralPatterns(data, config)
            ]);

            // Combine results
            results.patterns = [
                ...varianceResults.patterns,
                ...entropyResults.patterns,
                ...instructionResults.patterns,
                ...neuralResults.patterns
            ];

            results.statistics = {
                variance: varianceResults.statistics,
                entropy: entropyResults.statistics,
                instruction: instructionResults.statistics,
                neural: neuralResults.statistics
            };

            // Calculate overall confidence
            const confidences = [
                varianceResults.confidence,
                entropyResults.confidence,
                instructionResults.confidence,
                neuralResults.confidence
            ].filter(c => c > 0);

            results.confidence = confidences.length > 0
                ? confidences.reduce((a, b) => a + b) / confidences.length
                : 0;

            // Collect all anomalies
            results.anomalies = [
                ...(varianceResults.anomalies || []),
                ...(entropyResults.decodedMessages || []),
                ...(instructionResults.impossibleSequences || []),
                ...(neuralResults.neuralSignatures || [])
            ];

            // Generate recommendations
            results.recommendations = this.generateRecommendations(results);

            return results;

        } catch (error) {
            console.error('[PatternDetectionEngine] Analysis error:', error);
            throw error;
        }
    }

    generateRecommendations(results) {
        const recommendations = [];

        if (results.patterns.length > 0) {
            recommendations.push({
                type: 'analysis',
                priority: 'high',
                message: `${results.patterns.length} patterns detected. Consider deeper analysis.`
            });
        }

        if (results.confidence > 0.9) {
            recommendations.push({
                type: 'validation',
                priority: 'critical',
                message: 'High confidence patterns detected. Statistical validation recommended.'
            });
        }

        if (results.anomalies.length > 0) {
            recommendations.push({
                type: 'investigation',
                priority: 'high',
                message: `${results.anomalies.length} anomalies found. Investigation recommended.`
            });
        }

        return recommendations;
    }

    async processDataStream(dataStream, callback) {
        // Stream processing implementation
        for await (const chunk of dataStream) {
            const results = await this.runComprehensiveAnalysis(chunk);
            if (callback) {
                callback(results);
            }
        }
    }

    getStatus() {
        return {
            active: true,
            components: {
                varianceDetector: this.varianceDetector.isActive,
                entropyDecoder: this.entropyDecoder.isActive,
                instructionAnalyzer: this.instructionAnalyzer.isActive
            },
            configuration: this.config
        };
    }
}