import * as plugins from '../plugins.js';
import { EsclProtocol } from '../scanner/scanner.classes.esclprotocol.js';
import { IppProtocol } from '../printer/printer.classes.ippprotocol.js';
import {
  cidrToIps,
  ipRangeToIps,
  isValidIp,
} from '../helpers/helpers.iprange.js';
import type {
  INetworkScanOptions,
  INetworkScanResult,
  INetworkScanDevice,
  INetworkScanProgress,
} from '../interfaces/index.js';

/**
 * Default ports to probe for device discovery
 */
const DEFAULT_PORTS = [631, 80, 443, 6566, 9100];

/**
 * Default scan options
 */
const DEFAULT_OPTIONS: Required<Omit<INetworkScanOptions, 'ipRange' | 'startIp' | 'endIp'>> = {
  concurrency: 50,
  timeout: 2000,
  ports: DEFAULT_PORTS,
  probeEscl: true,
  probeIpp: true,
  probeSane: true,
};

/**
 * Simple concurrency limiter
 */
class ConcurrencyLimiter {
  private running = 0;
  private queue: (() => void)[] = [];

  constructor(private limit: number) {}

  async run<T>(fn: () => Promise<T>): Promise<T> {
    while (this.running >= this.limit) {
      await new Promise<void>((resolve) => this.queue.push(resolve));
    }

    this.running++;
    try {
      return await fn();
    } finally {
      this.running--;
      const next = this.queue.shift();
      if (next) next();
    }
  }
}

/**
 * Network Scanner - scans IP ranges for scanners and printers
 */
export class NetworkScanner extends plugins.events.EventEmitter {
  private cancelled = false;
  private scanning = false;

  /**
   * Check if a scan is currently in progress
   */
  public get isScanning(): boolean {
    return this.scanning;
  }

  /**
   * Scan a network range for devices
   */
  public async scan(options: INetworkScanOptions): Promise<INetworkScanResult[]> {
    if (this.scanning) {
      throw new Error('A scan is already in progress');
    }

    this.cancelled = false;
    this.scanning = true;

    const opts = { ...DEFAULT_OPTIONS, ...options };
    const results: INetworkScanResult[] = [];

    try {
      // Get list of IPs to scan
      const ips = this.resolveIps(options);

      if (ips.length === 0) {
        throw new Error('No IPs to scan. Provide ipRange, or startIp and endIp.');
      }

      const limiter = new ConcurrencyLimiter(opts.concurrency);
      let scanned = 0;

      // Progress tracking
      const emitProgress = (currentIp?: string) => {
        const progress: INetworkScanProgress = {
          total: ips.length,
          scanned,
          percentage: Math.round((scanned / ips.length) * 100),
          currentIp,
          devicesFound: results.reduce((sum, r) => sum + r.devices.length, 0),
        };
        this.emit('progress', progress);
      };

      emitProgress();

      // Scan all IPs with concurrency limit
      const scanPromises = ips.map((ip) =>
        limiter.run(async () => {
          if (this.cancelled) return;

          const devices = await this.probeIp(ip, opts);
          scanned++;

          if (devices.length > 0) {
            const result: INetworkScanResult = { address: ip, devices };
            results.push(result);
            this.emit('device:found', result);
          }

          emitProgress(ip);
        })
      );

      await Promise.all(scanPromises);

      if (this.cancelled) {
        this.emit('cancelled');
      } else {
        this.emit('complete', results);
      }

      return results;
    } finally {
      this.scanning = false;
    }
  }

  /**
   * Cancel an ongoing scan
   */
  public async cancel(): Promise<void> {
    if (this.scanning) {
      this.cancelled = true;
    }
  }

  /**
   * Resolve IPs from options (CIDR or start/end range)
   */
  private resolveIps(options: INetworkScanOptions): string[] {
    if (options.ipRange) {
      return cidrToIps(options.ipRange);
    }

    if (options.startIp && options.endIp) {
      return ipRangeToIps(options.startIp, options.endIp);
    }

    if (options.startIp && !options.endIp) {
      // Single IP
      if (isValidIp(options.startIp)) {
        return [options.startIp];
      }
    }

    return [];
  }

  /**
   * Probe a single IP address for devices
   */
  private async probeIp(
    ip: string,
    opts: Required<Omit<INetworkScanOptions, 'ipRange' | 'startIp' | 'endIp'>>
  ): Promise<INetworkScanDevice[]> {
    const devices: INetworkScanDevice[] = [];
    const timeout = opts.timeout;

    // First, do a quick port scan to see which ports are open
    const openPorts = await this.scanPorts(ip, opts.ports, timeout / 2);

    if (openPorts.length === 0 || this.cancelled) {
      return devices;
    }

    // Probe each open port for specific protocols
    const probePromises: Promise<void>[] = [];

    for (const port of openPorts) {
      // IPP probe (port 631)
      if (opts.probeIpp && port === 631) {
        probePromises.push(
          this.probeIpp(ip, port, timeout).then((device) => {
            if (device) devices.push(device);
          })
        );
      }

      // eSCL probe (ports 80, 443)
      if (opts.probeEscl && (port === 80 || port === 443)) {
        probePromises.push(
          this.probeEscl(ip, port, timeout).then((device) => {
            if (device) devices.push(device);
          })
        );
      }

      // SANE probe (port 6566)
      if (opts.probeSane && port === 6566) {
        probePromises.push(
          this.probeSane(ip, port, timeout).then((device) => {
            if (device) devices.push(device);
          })
        );
      }

      // JetDirect probe (port 9100) - just mark as raw printer
      if (port === 9100) {
        devices.push({
          type: 'printer',
          protocol: 'jetdirect',
          port: 9100,
          name: `Raw Printer at ${ip}`,
        });
      }
    }

    await Promise.all(probePromises);

    return devices;
  }

  /**
   * Quick TCP port scan
   */
  private async scanPorts(ip: string, ports: number[], timeout: number): Promise<number[]> {
    const openPorts: number[] = [];

    const scanPromises = ports.map(async (port) => {
      const isOpen = await this.isPortOpen(ip, port, timeout);
      if (isOpen) {
        openPorts.push(port);
      }
    });

    await Promise.all(scanPromises);
    return openPorts;
  }

  /**
   * Check if a TCP port is open
   */
  private isPortOpen(ip: string, port: number, timeout: number): Promise<boolean> {
    return new Promise((resolve) => {
      const socket = new plugins.net.Socket();

      const timer = setTimeout(() => {
        socket.destroy();
        resolve(false);
      }, timeout);

      socket.on('connect', () => {
        clearTimeout(timer);
        socket.destroy();
        resolve(true);
      });

      socket.on('error', () => {
        clearTimeout(timer);
        socket.destroy();
        resolve(false);
      });

      socket.connect(port, ip);
    });
  }

  /**
   * Probe for IPP printer
   */
  private async probeIpp(
    ip: string,
    port: number,
    timeout: number
  ): Promise<INetworkScanDevice | null> {
    try {
      const ipp = new IppProtocol(ip, port);
      const attrs = await Promise.race([
        ipp.getAttributes(),
        new Promise<null>((_, reject) =>
          setTimeout(() => reject(new Error('Timeout')), timeout)
        ),
      ]);

      if (attrs) {
        return {
          type: 'printer',
          protocol: 'ipp',
          port,
          name: `IPP Printer at ${ip}`,
          model: undefined,
        };
      }
    } catch {
      // Not an IPP printer
    }

    return null;
  }

  /**
   * Probe for eSCL scanner
   */
  private async probeEscl(
    ip: string,
    port: number,
    timeout: number
  ): Promise<INetworkScanDevice | null> {
    try {
      const secure = port === 443;
      const escl = new EsclProtocol(ip, port, secure);

      const caps = await Promise.race([
        escl.getCapabilities(),
        new Promise<null>((_, reject) =>
          setTimeout(() => reject(new Error('Timeout')), timeout)
        ),
      ]);

      if (caps) {
        return {
          type: 'scanner',
          protocol: 'escl',
          port,
          name: caps.makeAndModel || `eSCL Scanner at ${ip}`,
          model: caps.makeAndModel,
        };
      }
    } catch {
      // Not an eSCL scanner
    }

    return null;
  }

  /**
   * Probe for SANE scanner (quick check)
   */
  private async probeSane(
    ip: string,
    port: number,
    timeout: number
  ): Promise<INetworkScanDevice | null> {
    // SANE probing requires full protocol implementation
    // For now, just check if port is open and assume it's SANE
    // A more thorough implementation would send SANE_NET_INIT
    try {
      const isOpen = await this.isPortOpen(ip, port, timeout);
      if (isOpen) {
        return {
          type: 'scanner',
          protocol: 'sane',
          port,
          name: `SANE Scanner at ${ip}`,
        };
      }
    } catch {
      // Not a SANE scanner
    }

    return null;
  }
}