/**
 * Authentication System for the Prime Resonance Network
 * Handles multi-factor authentication with quantum signature support
 */

import { IIdentity } from "./interfaces";
import { IdentityId, Timestamp } from "./types";
import { BaseSerializable } from "../core/interfaces";
import { globalAuditTrail, AuditEventType, AuditSeverity } from "./audit-trail";

/**
 * Authentication methods
 */
export enum AuthMethod {
  PASSWORD = 0,
  BIOMETRIC = 1,
  HARDWARE_KEY = 2,
  QUANTUM_SIGNATURE = 3,
  MULTI_FACTOR = 4
}

/**
 * Session status
 */
export enum SessionStatus {
  ACTIVE = 0,
  EXPIRED = 1,
  REVOKED = 2,
  SUSPENDED = 3
}

/**
 * Authentication challenge
 */
export class AuthChallenge {
  id: string;
  method: AuthMethod;
  challenge: string;
  createdAt: Timestamp;
  expiresAt: Timestamp;
  attempts: i32;
  maxAttempts: i32;

  constructor(method: AuthMethod, challenge: string, validityMs: i64 = 300000) {
    this.id = "challenge-" + Date.now().toString() + "-" + Math.random().toString();
    this.method = method;
    this.challenge = challenge;
    this.createdAt = Date.now();
    this.expiresAt = this.createdAt + validityMs;
    this.attempts = 0;
    this.maxAttempts = 3;
  }

  /**
   * Check if challenge is expired
   */
  isExpired(): boolean {
    return Date.now() > this.expiresAt;
  }

  /**
   * Check if challenge is valid
   */
  isValid(): boolean {
    return !this.isExpired() && this.attempts < this.maxAttempts;
  }

  /**
   * Record an attempt
   */
  recordAttempt(): void {
    this.attempts++;
  }

  /**
   * Verify challenge response
   */
  verify(response: string): boolean {
    if (!this.isValid()) {
      return false;
    }

    this.recordAttempt();
    
    // Simple verification - in real implementation this would be more sophisticated
    return response == this.challenge;
  }
}

/**
 * Authentication session
 */
export class AuthSession {
  id: string;
  identityId: IdentityId;
  method: AuthMethod;
  status: SessionStatus;
  createdAt: Timestamp;
  lastAccessAt: Timestamp;
  expiresAt: Timestamp;
  ipAddress: string;
  userAgent: string;
  metadata: Map<string, string>;

  constructor(
    identityId: IdentityId,
    method: AuthMethod,
    validityMs: i64 = 3600000, // 1 hour
    ipAddress: string = "",
    userAgent: string = ""
  ) {
    this.id = "session-" + Date.now().toString() + "-" + Math.random().toString();
    this.identityId = identityId;
    this.method = method;
    this.status = SessionStatus.ACTIVE;
    this.createdAt = Date.now();
    this.lastAccessAt = this.createdAt;
    this.expiresAt = this.createdAt + validityMs;
    this.ipAddress = ipAddress;
    this.userAgent = userAgent;
    this.metadata = new Map<string, string>();
  }

  /**
   * Check if session is expired
   */
  isExpired(): boolean {
    return Date.now() > this.expiresAt;
  }

  /**
   * Check if session is valid
   */
  isValid(): boolean {
    return this.status == SessionStatus.ACTIVE && !this.isExpired();
  }

  /**
   * Refresh session
   */
  refresh(additionalMs: i64 = 3600000): void {
    if (this.isValid()) {
      this.lastAccessAt = Date.now();
      this.expiresAt = this.lastAccessAt + additionalMs;
    }
  }

  /**
   * Revoke session
   */
  revoke(): void {
    this.status = SessionStatus.REVOKED;
  }

  /**
   * Suspend session
   */
  suspend(): void {
    this.status = SessionStatus.SUSPENDED;
  }

  /**
   * Set metadata
   */
  setMetadata(key: string, value: string): void {
    this.metadata.set(key, value);
  }

  /**
   * Get metadata
   */
  getMetadata(key: string): string | null {
    return this.metadata.has(key) ? this.metadata.get(key) : null;
  }
}

/**
 * Quantum authenticator for advanced security
 */
export class QuantumAuthenticator {
  private challenges: Map<string, AuthChallenge>;
  private sessions: Map<string, AuthSession>;

  constructor() {
    this.challenges = new Map<string, AuthChallenge>();
    this.sessions = new Map<string, AuthSession>();
  }

  /**
   * Create authentication challenge
   */
  createChallenge(method: AuthMethod): AuthChallenge {
    // Generate challenge based on method
    let challengeData = "";
    switch (method) {
      case AuthMethod.PASSWORD:
        challengeData = "password_challenge";
        break;
      case AuthMethod.BIOMETRIC:
        challengeData = "biometric_challenge";
        break;
      case AuthMethod.HARDWARE_KEY:
        challengeData = "hardware_key_challenge";
        break;
      case AuthMethod.QUANTUM_SIGNATURE:
        challengeData = "quantum_signature_challenge";
        break;
      case AuthMethod.MULTI_FACTOR:
        challengeData = "multi_factor_challenge";
        break;
    }

    const challenge = new AuthChallenge(method, challengeData);
    this.challenges.set(challenge.id, challenge);
    return challenge;
  }

  /**
   * Verify authentication challenge
   */
  verifyChallenge(challengeId: string, response: string): boolean {
    const challenge = this.challenges.get(challengeId);
    if (!challenge) {
      return false;
    }

    const isValid = challenge.verify(response);
    
    if (!challenge.isValid()) {
      this.challenges.delete(challengeId);
    }

    return isValid;
  }

  /**
   * Create authenticated session
   */
  createSession(
    identityId: IdentityId,
    method: AuthMethod,
    ipAddress: string = "",
    userAgent: string = ""
  ): AuthSession {
    const session = new AuthSession(identityId, method, 3600000, ipAddress, userAgent);
    this.sessions.set(session.id, session);
    
    // Log session creation
    globalAuditTrail.logEvent(
      AuditEventType.IDENTITY_AUTHENTICATED,
      identityId,
      "session",
      session.id,
      "Authentication session created",
      AuditSeverity.INFO
    );
    
    return session;
  }

  /**
   * Validate session
   */
  validateSession(sessionId: string): AuthSession | null {
    const session = this.sessions.get(sessionId);
    if (!session || !session.isValid()) {
      return null;
    }

    session.refresh();
    return session;
  }

  /**
   * Revoke session
   */
  revokeSession(sessionId: string): void {
    const session = this.sessions.get(sessionId);
    if (session) {
      session.revoke();
      
      // Log session revocation
      globalAuditTrail.logEvent(
        AuditEventType.IDENTITY_DEAUTHENTICATED,
        session.identityId,
        "session",
        sessionId,
        "Authentication session revoked",
        AuditSeverity.INFO
      );
    }
  }

  /**
   * Clean up expired sessions and challenges
   */
  cleanup(): void {
    // Clean up expired challenges
    const challengeIds = this.challenges.keys();
    for (let i = 0; i < challengeIds.length; i++) {
      const challenge = this.challenges.get(challengeIds[i]);
      if (challenge && challenge.isExpired()) {
        this.challenges.delete(challengeIds[i]);
      }
    }

    // Clean up expired sessions
    const sessionIds = this.sessions.keys();
    for (let i = 0; i < sessionIds.length; i++) {
      const session = this.sessions.get(sessionIds[i]);
      if (session && session.isExpired()) {
        session.status = SessionStatus.EXPIRED;
      }
    }
  }
}

/**
 * Main authentication manager
 */
export class AuthenticationManager {
  private authenticator: QuantumAuthenticator;
  private identityStore: Map<IdentityId, IIdentity>;

  constructor(identityStore: Map<IdentityId, IIdentity>) {
    this.authenticator = new QuantumAuthenticator();
    this.identityStore = identityStore;
  }

  /**
   * Authenticate an identity
   */
  authenticate(
    identityId: IdentityId,
    method: AuthMethod,
    credentials: string,
    ipAddress: string = "",
    userAgent: string = ""
  ): AuthSession | null {
    const identity = this.identityStore.get(identityId);
    if (!identity) {
      return null;
    }

    // Create challenge
    const challenge = this.authenticator.createChallenge(method);
    
    // Verify credentials against challenge
    if (!this.authenticator.verifyChallenge(challenge.id, credentials)) {
      return null;
    }

    // Create session
    return this.authenticator.createSession(identityId, method, ipAddress, userAgent);
  }

  /**
   * Validate session
   */
  validateSession(sessionId: string): AuthSession | null {
    return this.authenticator.validateSession(sessionId);
  }

  /**
   * Revoke session
   */
  revokeSession(sessionId: string): void {
    this.authenticator.revokeSession(sessionId);
  }

  /**
   * Cleanup expired sessions
   */
  cleanup(): void {
    this.authenticator.cleanup();
  }
}

/**
 * Global authentication manager
 */
export const globalAuthManager = new AuthenticationManager(new Map<IdentityId, IIdentity>());