import * as plugins from '../../plugins.js';
import { IncomingMessage, ServerResponse } from 'http';
import {
  CertificateEvents
} from '../../certificate/events/certificate-events.js';
import type {
  CertificateData,
  CertificateFailure,
  CertificateExpiring
} from '../../certificate/models/certificate-types.js';
import type {
  SmartAcme,
  SmartAcmeCert,
  SmartAcmeOptions,
  Http01MemoryHandler
} from './acme-interfaces.js';

/**
 * ChallengeResponder handles ACME HTTP-01 challenges by leveraging SmartAcme
 * It acts as a bridge between the HTTP server and the ACME challenge verification process
 */
export class ChallengeResponder extends plugins.EventEmitter {
  private smartAcme: SmartAcme | null = null;
  private http01Handler: Http01MemoryHandler | null = null;

  /**
   * Creates a new challenge responder
   * @param useProduction Whether to use production ACME servers
   * @param email Account email for ACME
   * @param certificateStore Directory to store certificates
   */
  constructor(
    private readonly useProduction: boolean = false,
    private readonly email: string = 'admin@example.com',
    private readonly certificateStore: string = './certs'
  ) {
    super();
  }

  /**
   * Initialize the ACME client
   */
  public async initialize(): Promise<void> {
    try {
      // Create the HTTP-01 memory handler from SmartACME
      this.http01Handler = new plugins.smartacme.handlers.Http01MemoryHandler();

      // Ensure certificate store directory exists
      await this.ensureCertificateStore();

      // Create a MemoryCertManager for certificate storage
      const certManager = new plugins.smartacme.certmanagers.MemoryCertManager();

      // Initialize the SmartACME client with appropriate options
      this.smartAcme = new plugins.smartacme.SmartAcme({
        accountEmail: this.email,
        certManager: certManager,
        environment: this.useProduction ? 'production' : 'integration',
        challengeHandlers: [this.http01Handler],
        challengePriority: ['http-01']
      });

      // Set up event forwarding from SmartAcme
      this.setupEventListeners();

      // Start the SmartACME client
      await this.smartAcme.start();
      console.log('ACME client initialized successfully');
    } catch (error) {
      const errorMessage = error instanceof Error ? error.message : String(error);
      throw new Error(`Failed to initialize ACME client: ${errorMessage}`);
    }
  }

  /**
   * Ensure the certificate store directory exists
   */
  private async ensureCertificateStore(): Promise<void> {
    try {
      await plugins.fs.promises.mkdir(this.certificateStore, { recursive: true });
    } catch (error) {
      const errorMessage = error instanceof Error ? error.message : String(error);
      throw new Error(`Failed to create certificate store: ${errorMessage}`);
    }
  }

  /**
   * Setup event listeners to forward SmartACME events to our own event emitter
   */
  private setupEventListeners(): void {
    if (!this.smartAcme) return;

    const setupEvents = (emitter: { on: (event: string, listener: (data: any) => void) => void }) => {
      // Forward certificate events
      emitter.on('certificate', (data: any) => {
        const isRenewal = !!data.isRenewal;

        const certData: CertificateData = {
          domain: data.domainName || data.domain,
          certificate: data.publicKey || data.cert,
          privateKey: data.privateKey || data.key,
          expiryDate: new Date(data.validUntil || data.expiryDate || Date.now()),
          source: 'http01',
          isRenewal
        };

        const eventType = isRenewal
          ? CertificateEvents.CERTIFICATE_RENEWED
          : CertificateEvents.CERTIFICATE_ISSUED;

        this.emit(eventType, certData);
      });

      // Forward error events
      emitter.on('error', (error: any) => {
        const domain = error.domainName || error.domain || 'unknown';
        const failureData: CertificateFailure = {
          domain,
          error: error.message || String(error),
          isRenewal: !!error.isRenewal
        };

        this.emit(CertificateEvents.CERTIFICATE_FAILED, failureData);
      });
    };

    // Check for direct event methods on SmartAcme
    if (typeof this.smartAcme.on === 'function') {
      setupEvents(this.smartAcme as any);
    }
    // Check for eventEmitter property
    else if (this.smartAcme.eventEmitter) {
      setupEvents(this.smartAcme.eventEmitter);
    }
    // If no proper event handling, log a warning
    else {
      console.warn('SmartAcme instance does not support expected event interface - events may not be forwarded');
    }
  }

  /**
   * Handle HTTP request by checking if it's an ACME challenge
   * @param req HTTP request object
   * @param res HTTP response object
   * @returns true if the request was handled, false otherwise
   */
  public handleRequest(req: IncomingMessage, res: ServerResponse): boolean {
    if (!this.http01Handler) return false;

    // Check if this is an ACME challenge request (/.well-known/acme-challenge/*)
    const url = req.url || '';
    if (url.startsWith('/.well-known/acme-challenge/')) {
      try {
        // Delegate to the HTTP-01 memory handler, which knows how to serve challenges
        this.http01Handler.handleRequest(req, res);
        return true;
      } catch (error) {
        console.error('Error handling ACME challenge:', error);
        // If there was an error, send a 404 response
        res.writeHead(404);
        res.end('Not found');
        return true;
      }
    }
    
    return false;
  }

  /**
   * Request a certificate for a domain
   * @param domain Domain name to request a certificate for
   * @param isRenewal Whether this is a renewal request
   */
  public async requestCertificate(domain: string, isRenewal: boolean = false): Promise<CertificateData> {
    if (!this.smartAcme) {
      throw new Error('ACME client not initialized');
    }

    try {
      // Request certificate using SmartACME
      const certObj = await this.smartAcme.getCertificateForDomain(domain);
      
      // Convert the certificate object to our CertificateData format
      const certData: CertificateData = {
        domain,
        certificate: certObj.publicKey,
        privateKey: certObj.privateKey,
        expiryDate: new Date(certObj.validUntil),
        source: 'http01',
        isRenewal
      };
      
      return certData;
    } catch (error) {
      // Create failure object
      const failure: CertificateFailure = {
        domain,
        error: error instanceof Error ? error.message : String(error),
        isRenewal
      };
      
      // Emit failure event
      this.emit(CertificateEvents.CERTIFICATE_FAILED, failure);
      
      // Rethrow with more context
      throw new Error(`Failed to ${isRenewal ? 'renew' : 'obtain'} certificate for ${domain}: ${
        error instanceof Error ? error.message : String(error)
      }`);
    }
  }

  /**
   * Check if a certificate is expiring soon and trigger renewal if needed
   * @param domain Domain name
   * @param certificate Certificate data
   * @param thresholdDays Days before expiry to trigger renewal
   */
  public checkCertificateExpiry(
    domain: string,
    certificate: CertificateData,
    thresholdDays: number = 30
  ): void {
    if (!certificate.expiryDate) return;
    
    const now = new Date();
    const expiryDate = certificate.expiryDate;
    const daysDifference = Math.floor((expiryDate.getTime() - now.getTime()) / (1000 * 60 * 60 * 24));
    
    if (daysDifference <= thresholdDays) {
      const expiryInfo: CertificateExpiring = {
        domain,
        expiryDate,
        daysRemaining: daysDifference
      };
      
      this.emit(CertificateEvents.CERTIFICATE_EXPIRING, expiryInfo);
      
      // Automatically attempt renewal if expiring
      if (this.smartAcme) {
        this.requestCertificate(domain, true).catch(error => {
          console.error(`Failed to auto-renew certificate for ${domain}:`, error);
        });
      }
    }
  }
}