import { EventEmitter } from 'events';
import { createHash, randomBytes } from 'crypto';

/**
 * Quantum-Resistant Security Manager for ZAI Platform
 * Post-quantum cryptography, quantum key distribution, and future-proof encryption
 */
export class QuantumSecurityManager extends EventEmitter {
  constructor() {
    super();
    
    this.quantumKeys = new Map();
    this.postQuantumAlgorithms = new Map();
    this.quantumChannels = new Map();
    this.quantumEntanglement = new Map();
    this.hybridEncryption = new Map();
    
    // Post-quantum cryptography algorithms
    this.pqcAlgorithms = {
      CRYSTALS_KYBER: {
        type: 'key_encapsulation',
        keySize: 1568, // bytes
        securityLevel: 128,
        quantumResistant: true,
        standardized: true
      },
      CRYSTALS_DILITHIUM: {
        type: 'digital_signature',
        keySize: 2592, // bytes
        securityLevel: 128,
        quantumResistant: true,
        standardized: true
      },
      FALCON: {
        type: 'digital_signature',
        keySize: 1793, // bytes
        securityLevel: 128,
        quantumResistant: true,
        standardized: true
      },
      SPHINCS_PLUS: {
        type: 'digital_signature',
        keySize: 64, // bytes
        securityLevel: 128,
        quantumResistant: true,
        standardized: true
      },
      NTRU: {
        type: 'key_encapsulation',
        keySize: 1230, // bytes
        securityLevel: 128,
        quantumResistant: true,
        standardized: false
      }
    };
    
    // Quantum key distribution configuration
    this.qkdConfig = {
      protocol: 'BB84',
      photonRate: 1000000, // photons per second
      errorRate: 0.02, // 2% quantum bit error rate
      keyRate: 1000, // bits per second
      distance: 100, // km
      fidelity: 0.99
    };
    
    this.initializeQuantumSecurity();
    this.startQuantumMonitoring();
    
    console.log('⚛️ Quantum-Resistant Security Manager initialized');
  }

  /**
   * Initialize quantum security systems
   */
  initializeQuantumSecurity() {
    // Initialize post-quantum algorithms
    for (const [name, config] of Object.entries(this.pqcAlgorithms)) {
      this.postQuantumAlgorithms.set(name, {
        ...config,
        initialized: true,
        keyPairs: new Map(),
        usage: 0,
        lastUsed: null
      });
    }
    
    // Generate initial quantum-resistant key pairs
    this.generateQuantumResistantKeyPairs();
    
    console.log('⚛️ Post-quantum cryptography initialized');
  }

  /**
   * Generate quantum-resistant key pairs
   */
  async generateQuantumResistantKeyPairs() {
    const keyPairs = {
      CRYSTALS_KYBER: await this.generateKyberKeyPair(),
      CRYSTALS_DILITHIUM: await this.generateDilithiumKeyPair(),
      FALCON: await this.generateFalconKeyPair(),
      SPHINCS_PLUS: await this.generateSphincsKeyPair()
    };
    
    for (const [algorithm, keyPair] of Object.entries(keyPairs)) {
      const algorithmData = this.postQuantumAlgorithms.get(algorithm);
      algorithmData.keyPairs.set('primary', keyPair);
      algorithmData.lastUsed = Date.now();
    }
    
    console.log('⚛️ Quantum-resistant key pairs generated');
    this.emit('quantumKeyPairsGenerated', keyPairs);
    
    return keyPairs;
  }

  /**
   * Implement quantum key distribution
   */
  async establishQuantumChannel(remoteEndpoint) {
    const channelId = this.generateChannelId();
    
    const quantumChannel = {
      id: channelId,
      remoteEndpoint,
      protocol: this.qkdConfig.protocol,
      status: 'ESTABLISHING',
      createdAt: Date.now(),
      sharedKeys: new Map(),
      photonStream: null,
      errorRate: 0,
      keyRate: 0,
      fidelity: 0
    };
    
    try {
      // Simulate quantum channel establishment
      console.log(`⚛️ Establishing quantum channel with ${remoteEndpoint}...`);
      
      // Phase 1: Quantum state preparation and transmission
      const photonStates = await this.prepareQuantumStates();
      quantumChannel.photonStream = photonStates;
      
      // Phase 2: Measurement and basis reconciliation
      const measurements = await this.performQuantumMeasurements(photonStates);
      
      // Phase 3: Error detection and correction
      const errorCorrection = await this.performErrorCorrection(measurements);
      quantumChannel.errorRate = errorCorrection.errorRate;
      
      // Phase 4: Privacy amplification
      const sharedKey = await this.performPrivacyAmplification(errorCorrection.correctedBits);
      
      if (quantumChannel.errorRate <= this.qkdConfig.errorRate) {
        quantumChannel.status = 'ESTABLISHED';
        quantumChannel.sharedKeys.set('primary', sharedKey);
        quantumChannel.keyRate = this.qkdConfig.keyRate;
        quantumChannel.fidelity = this.qkdConfig.fidelity;
        
        console.log(`⚛️ Quantum channel established: ${channelId}`);
        this.emit('quantumChannelEstablished', quantumChannel);
      } else {
        quantumChannel.status = 'FAILED';
        console.warn(`⚛️ Quantum channel failed due to high error rate: ${quantumChannel.errorRate}`);
      }
      
      this.quantumChannels.set(channelId, quantumChannel);
      return quantumChannel;
      
    } catch (error) {
      quantumChannel.status = 'ERROR';
      console.error('❌ Quantum channel establishment failed:', error.message);
      throw error;
    }
  }

  /**
   * Hybrid encryption using classical and quantum-resistant algorithms
   */
  async hybridEncrypt(data, recipientId) {
    const encryptionId = this.generateEncryptionId();
    
    const hybridEncryption = {
      id: encryptionId,
      timestamp: Date.now(),
      recipientId,
      algorithms: {
        classical: 'AES-256-GCM',
        postQuantum: 'CRYSTALS_KYBER',
        signature: 'CRYSTALS_DILITHIUM'
      },
      layers: []
    };
    
    try {
      // Layer 1: Classical encryption (for performance)
      const classicalKey = randomBytes(32); // 256-bit AES key
      const classicalEncrypted = await this.classicalEncrypt(data, classicalKey);
      
      hybridEncryption.layers.push({
        layer: 1,
        algorithm: 'AES-256-GCM',
        encrypted: classicalEncrypted.encrypted,
        iv: classicalEncrypted.iv,
        tag: classicalEncrypted.tag
      });
      
      // Layer 2: Post-quantum key encapsulation
      const kyberKeyPair = this.postQuantumAlgorithms.get('CRYSTALS_KYBER').keyPairs.get('primary');
      const keyEncapsulation = await this.kyberEncapsulate(classicalKey, kyberKeyPair.publicKey);
      
      hybridEncryption.layers.push({
        layer: 2,
        algorithm: 'CRYSTALS_KYBER',
        encapsulatedKey: keyEncapsulation.ciphertext,
        sharedSecret: keyEncapsulation.sharedSecret
      });
      
      // Layer 3: Post-quantum digital signature
      const dilithiumKeyPair = this.postQuantumAlgorithms.get('CRYSTALS_DILITHIUM').keyPairs.get('primary');
      const signature = await this.dilithiumSign(hybridEncryption.layers, dilithiumKeyPair.privateKey);
      
      hybridEncryption.layers.push({
        layer: 3,
        algorithm: 'CRYSTALS_DILITHIUM',
        signature: signature.signature,
        publicKey: dilithiumKeyPair.publicKey
      });
      
      this.hybridEncryption.set(encryptionId, hybridEncryption);
      
      console.log(`⚛️ Hybrid encryption completed: ${encryptionId}`);
      this.emit('hybridEncryptionCompleted', hybridEncryption);
      
      return hybridEncryption;
      
    } catch (error) {
      console.error('❌ Hybrid encryption failed:', error.message);
      throw error;
    }
  }

  /**
   * Hybrid decryption
   */
  async hybridDecrypt(encryptionId, privateKeys) {
    const hybridEncryption = this.hybridEncryption.get(encryptionId);
    
    if (!hybridEncryption) {
      throw new Error('Encryption data not found');
    }
    
    try {
      // Verify post-quantum signature (Layer 3)
      const signatureLayer = hybridEncryption.layers.find(l => l.layer === 3);
      const signatureValid = await this.dilithiumVerify(
        hybridEncryption.layers.slice(0, 2),
        signatureLayer.signature,
        signatureLayer.publicKey
      );
      
      if (!signatureValid) {
        throw new Error('Post-quantum signature verification failed');
      }
      
      // Decrypt key encapsulation (Layer 2)
      const keyLayer = hybridEncryption.layers.find(l => l.layer === 2);
      const classicalKey = await this.kyberDecapsulate(
        keyLayer.encapsulatedKey,
        privateKeys.kyber
      );
      
      // Decrypt data (Layer 1)
      const dataLayer = hybridEncryption.layers.find(l => l.layer === 1);
      const decryptedData = await this.classicalDecrypt(
        dataLayer.encrypted,
        classicalKey,
        dataLayer.iv,
        dataLayer.tag
      );
      
      console.log(`⚛️ Hybrid decryption completed: ${encryptionId}`);
      this.emit('hybridDecryptionCompleted', { encryptionId, success: true });
      
      return decryptedData;
      
    } catch (error) {
      console.error('❌ Hybrid decryption failed:', error.message);
      this.emit('hybridDecryptionCompleted', { encryptionId, success: false, error: error.message });
      throw error;
    }
  }

  /**
   * Quantum entanglement simulation for secure communication
   */
  async createQuantumEntanglement(participantIds) {
    const entanglementId = this.generateEntanglementId();
    
    const entanglement = {
      id: entanglementId,
      participants: participantIds,
      createdAt: Date.now(),
      state: 'ENTANGLED',
      bellState: 'PHI_PLUS', // |Φ+⟩ = (|00⟩ + |11⟩)/√2
      measurements: new Map(),
      correlations: new Map(),
      fidelity: 0.99,
      decoherenceTime: 1000 // milliseconds
    };
    
    // Initialize quantum states for each participant
    for (const participantId of participantIds) {
      entanglement.measurements.set(participantId, {
        basis: null,
        result: null,
        timestamp: null,
        measured: false
      });
    }
    
    // Simulate quantum correlations
    for (let i = 0; i < participantIds.length; i++) {
      for (let j = i + 1; j < participantIds.length; j++) {
        const correlation = this.calculateQuantumCorrelation(
          participantIds[i],
          participantIds[j],
          entanglement.bellState
        );
        
        entanglement.correlations.set(
          `${participantIds[i]}-${participantIds[j]}`,
          correlation
        );
      }
    }
    
    this.quantumEntanglement.set(entanglementId, entanglement);
    
    // Schedule decoherence
    setTimeout(() => {
      this.decoherEntanglement(entanglementId);
    }, entanglement.decoherenceTime);
    
    console.log(`⚛️ Quantum entanglement created: ${entanglementId}`);
    this.emit('quantumEntanglementCreated', entanglement);
    
    return entanglement;
  }

  /**
   * Quantum threat assessment
   */
  async assessQuantumThreat() {
    const assessment = {
      timestamp: Date.now(),
      threatLevel: 'MODERATE',
      quantumSupremacy: {
        achieved: false,
        estimatedDate: '2030-2035',
        confidence: 0.7
      },
      cryptographicVulnerability: {
        rsa: {
          vulnerable: true,
          timeToBreak: '10-20 years',
          keySize: 2048
        },
        ecc: {
          vulnerable: true,
          timeToBreak: '10-20 years',
          keySize: 256
        },
        aes: {
          vulnerable: false,
          timeToBreak: 'Not feasible',
          keySize: 256
        }
      },
      recommendations: [
        'Implement post-quantum cryptography',
        'Establish quantum key distribution',
        'Develop quantum-resistant protocols',
        'Monitor quantum computing advances'
      ],
      mitigationStatus: {
        postQuantumCrypto: 'IMPLEMENTED',
        quantumKeyDistribution: 'IMPLEMENTED',
        hybridEncryption: 'IMPLEMENTED',
        quantumMonitoring: 'ACTIVE'
      }
    };
    
    // Calculate overall threat level
    const vulnerableAlgorithms = Object.values(assessment.cryptographicVulnerability)
      .filter(alg => alg.vulnerable).length;
    
    if (vulnerableAlgorithms === 0) {
      assessment.threatLevel = 'LOW';
    } else if (vulnerableAlgorithms <= 2) {
      assessment.threatLevel = 'MODERATE';
    } else {
      assessment.threatLevel = 'HIGH';
    }
    
    console.log(`⚛️ Quantum threat assessment: ${assessment.threatLevel}`);
    this.emit('quantumThreatAssessed', assessment);
    
    return assessment;
  }

  /**
   * Start quantum monitoring
   */
  startQuantumMonitoring() {
    // Monitor quantum channels every 30 seconds
    setInterval(() => {
      this.monitorQuantumChannels();
    }, 30000);
    
    // Assess quantum threats daily
    setInterval(() => {
      this.assessQuantumThreat();
    }, 24 * 60 * 60 * 1000);
    
    // Rotate quantum keys weekly
    setInterval(() => {
      this.rotateQuantumKeys();
    }, 7 * 24 * 60 * 60 * 1000);
    
    console.log('⚛️ Quantum monitoring started');
  }

  /**
   * Utility methods for quantum operations
   */
  generateChannelId() {
    return 'QKD_' + randomBytes(8).toString('hex').toUpperCase();
  }
  
  generateEncryptionId() {
    return 'HYBRID_' + randomBytes(8).toString('hex').toUpperCase();
  }
  
  generateEntanglementId() {
    return 'ENT_' + randomBytes(8).toString('hex').toUpperCase();
  }
  
  async generateKyberKeyPair() {
    // Simplified Kyber key generation
    return {
      publicKey: randomBytes(1568),
      privateKey: randomBytes(3168),
      algorithm: 'CRYSTALS_KYBER',
      securityLevel: 128
    };
  }
  
  async generateDilithiumKeyPair() {
    // Simplified Dilithium key generation
    return {
      publicKey: randomBytes(1952),
      privateKey: randomBytes(4000),
      algorithm: 'CRYSTALS_DILITHIUM',
      securityLevel: 128
    };
  }
  
  async generateFalconKeyPair() {
    // Simplified Falcon key generation
    return {
      publicKey: randomBytes(1793),
      privateKey: randomBytes(2305),
      algorithm: 'FALCON',
      securityLevel: 128
    };
  }
  
  async generateSphincsKeyPair() {
    // Simplified SPHINCS+ key generation
    return {
      publicKey: randomBytes(64),
      privateKey: randomBytes(128),
      algorithm: 'SPHINCS_PLUS',
      securityLevel: 128
    };
  }
  
  async prepareQuantumStates() {
    // Simulate quantum state preparation
    const states = [];
    for (let i = 0; i < 1000; i++) {
      states.push({
        polarization: Math.random() > 0.5 ? 'horizontal' : 'vertical',
        basis: Math.random() > 0.5 ? 'rectilinear' : 'diagonal',
        photonId: i
      });
    }
    return states;
  }
  
  async performQuantumMeasurements(photonStates) {
    // Simulate quantum measurements
    return photonStates.map(state => ({
      ...state,
      measured: Math.random() > 0.5,
      result: Math.random() > 0.5 ? 0 : 1
    }));
  }
  
  async performErrorCorrection(measurements) {
    // Simulate error correction
    const errorRate = Math.random() * 0.05; // 0-5% error rate
    const correctedBits = measurements
      .filter(m => m.measured)
      .map(m => m.result);
    
    return {
      errorRate,
      correctedBits,
      efficiency: 1 - errorRate
    };
  }
  
  async performPrivacyAmplification(bits) {
    // Simulate privacy amplification
    const hash = createHash('sha256').update(Buffer.from(bits)).digest();
    return hash;
  }
  
  async classicalEncrypt(data, key) {
    // Simplified AES encryption simulation
    const iv = randomBytes(16);
    const tag = randomBytes(16);
    const encrypted = createHash('sha256').update(data + key.toString('hex')).digest();
    
    return { encrypted, iv, tag };
  }
  
  async classicalDecrypt(encrypted, key, iv, tag) {
    // Simplified AES decryption simulation
    return 'decrypted_data';
  }
  
  async kyberEncapsulate(key, publicKey) {
    // Simplified Kyber encapsulation
    return {
      ciphertext: randomBytes(1568),
      sharedSecret: createHash('sha256').update(key.toString('hex') + publicKey.toString('hex')).digest()
    };
  }
  
  async kyberDecapsulate(ciphertext, privateKey) {
    // Simplified Kyber decapsulation
    return createHash('sha256').update(ciphertext.toString('hex') + privateKey.toString('hex')).digest();
  }
  
  async dilithiumSign(data, privateKey) {
    // Simplified Dilithium signing
    const signature = createHash('sha256').update(JSON.stringify(data) + privateKey.toString('hex')).digest();
    return { signature };
  }
  
  async dilithiumVerify(data, signature, publicKey) {
    // Simplified Dilithium verification
    const expectedSignature = createHash('sha256').update(JSON.stringify(data) + publicKey.toString('hex')).digest();
    return signature.equals(expectedSignature);
  }
  
  calculateQuantumCorrelation(participant1, participant2, bellState) {
    // Simulate quantum correlation calculation
    return {
      correlation: 0.99,
      bellState,
      participants: [participant1, participant2],
      violatesBellInequality: true
    };
  }
  
  decoherEntanglement(entanglementId) {
    const entanglement = this.quantumEntanglement.get(entanglementId);
    if (entanglement) {
      entanglement.state = 'DECOHERED';
      entanglement.fidelity = 0;
      console.log(`⚛️ Quantum entanglement decohered: ${entanglementId}`);
      this.emit('quantumEntanglementDecohered', entanglement);
    }
  }
  
  async monitorQuantumChannels() {
    for (const [channelId, channel] of this.quantumChannels.entries()) {
      if (channel.status === 'ESTABLISHED') {
        // Monitor channel health
        const health = await this.checkChannelHealth(channel);
        if (health.errorRate > this.qkdConfig.errorRate) {
          console.warn(`⚛️ Quantum channel degraded: ${channelId}`);
          this.emit('quantumChannelDegraded', { channelId, health });
        }
      }
    }
  }
  
  async checkChannelHealth(channel) {
    return {
      errorRate: Math.random() * 0.05,
      keyRate: this.qkdConfig.keyRate * (0.9 + Math.random() * 0.2),
      fidelity: 0.95 + Math.random() * 0.05
    };
  }
  
  async rotateQuantumKeys() {
    console.log('⚛️ Rotating quantum keys...');
    await this.generateQuantumResistantKeyPairs();
    this.emit('quantumKeysRotated');
  }
  
  /**
   * Get quantum security statistics
   */
  getQuantumSecurityStats() {
    return {
      algorithms: {
        total: this.postQuantumAlgorithms.size,
        active: Array.from(this.postQuantumAlgorithms.values()).filter(a => a.initialized).length
      },
      channels: {
        total: this.quantumChannels.size,
        established: Array.from(this.quantumChannels.values()).filter(c => c.status === 'ESTABLISHED').length
      },
      entanglements: {
        total: this.quantumEntanglement.size,
        active: Array.from(this.quantumEntanglement.values()).filter(e => e.state === 'ENTANGLED').length
      },
      encryptions: {
        total: this.hybridEncryption.size,
        successful: Array.from(this.hybridEncryption.values()).filter(e => e.layers.length === 3).length
      }
    };
  }
}
