/**
 * SNMP Feature
 * Provides SNMP query capability for network management
 */

import { Feature, type TDeviceReference } from './feature.abstract.js';
import type {
  TSnmpVersion,
  ISnmpVarbind,
  ISnmpFeatureInfo,
  IFeatureOptions,
} from '../interfaces/feature.interfaces.js';

/**
 * Options for creating an SnmpFeature
 */
export interface ISnmpFeatureOptions extends IFeatureOptions {
  version?: TSnmpVersion;
  community?: string;
  // SNMPv3 options
  username?: string;
  authProtocol?: 'md5' | 'sha';
  authKey?: string;
  privProtocol?: 'des' | 'aes';
  privKey?: string;
}

/**
 * SNMP Feature - provides SNMP query capability
 *
 * Allows querying devices via SNMP for monitoring and management.
 * Many network devices (printers, switches, UPS) support SNMP.
 *
 * @example
 * ```typescript
 * const snmp = device.getFeature<SnmpFeature>('snmp');
 * if (snmp) {
 *   const sysDescr = await snmp.get('1.3.6.1.2.1.1.1.0');
 *   console.log(`System: ${sysDescr.value}`);
 *
 *   const interfaces = await snmp.walk('1.3.6.1.2.1.2.2.1');
 *   console.log(`Found ${interfaces.length} interface entries`);
 * }
 * ```
 */
export class SnmpFeature extends Feature {
  public readonly type = 'snmp' as const;
  public readonly protocol = 'snmp';

  // Configuration
  public readonly version: TSnmpVersion;
  public readonly community: string;

  // System info (populated after connect)
  public sysDescr?: string;
  public sysObjectId?: string;
  public sysName?: string;
  public sysLocation?: string;
  public sysContact?: string;
  public sysUpTime?: number;

  constructor(
    device: TDeviceReference,
    port: number,
    options?: ISnmpFeatureOptions
  ) {
    super(device, port ?? 161, options);
    this.version = options?.version ?? 'v2c';
    this.community = options?.community ?? 'public';
  }

  // ============================================================================
  // Connection
  // ============================================================================

  protected async doConnect(): Promise<void> {
    // Test connection by getting system description
    try {
      const result = await this.get('1.3.6.1.2.1.1.1.0'); // sysDescr
      if (result) {
        this.sysDescr = String(result.value);
      }
    } catch {
      // Connection test failed
      throw new Error('SNMP connection failed');
    }
  }

  protected async doDisconnect(): Promise<void> {
    // SNMP is connectionless, nothing to disconnect
  }

  // ============================================================================
  // SNMP Operations
  // ============================================================================

  /**
   * Get a single OID value
   */
  public async get(oid: string): Promise<ISnmpVarbind> {
    // This would use the SNMP library to perform the query
    // Placeholder implementation
    return {
      oid,
      type: 0,
      value: null,
    };
  }

  /**
   * Get multiple OID values
   */
  public async getMultiple(oids: string[]): Promise<ISnmpVarbind[]> {
    const results: ISnmpVarbind[] = [];
    for (const oid of oids) {
      results.push(await this.get(oid));
    }
    return results;
  }

  /**
   * Get next OID in MIB tree
   */
  public async getNext(oid: string): Promise<ISnmpVarbind> {
    // Placeholder
    return {
      oid,
      type: 0,
      value: null,
    };
  }

  /**
   * Walk a subtree of the MIB
   */
  public async walk(baseOid: string): Promise<ISnmpVarbind[]> {
    const results: ISnmpVarbind[] = [];
    // This would iterate through the MIB tree using getNext
    return results;
  }

  /**
   * Bulk get (SNMPv2c/v3)
   */
  public async getBulk(
    oids: string[],
    nonRepeaters: number = 0,
    maxRepetitions: number = 10
  ): Promise<ISnmpVarbind[]> {
    if (this.version === 'v1') {
      throw new Error('getBulk not supported in SNMPv1');
    }
    // Placeholder
    return [];
  }

  /**
   * Set an OID value
   */
  public async set(oid: string, type: number, value: unknown): Promise<ISnmpVarbind> {
    // Placeholder
    return {
      oid,
      type,
      value,
    };
  }

  // ============================================================================
  // System Info
  // ============================================================================

  /**
   * Get all system info OIDs
   */
  public async getSystemInfo(): Promise<{
    sysDescr?: string;
    sysObjectId?: string;
    sysName?: string;
    sysLocation?: string;
    sysContact?: string;
    sysUpTime?: number;
  }> {
    const oids = [
      '1.3.6.1.2.1.1.1.0',  // sysDescr
      '1.3.6.1.2.1.1.2.0',  // sysObjectID
      '1.3.6.1.2.1.1.3.0',  // sysUpTime
      '1.3.6.1.2.1.1.4.0',  // sysContact
      '1.3.6.1.2.1.1.5.0',  // sysName
      '1.3.6.1.2.1.1.6.0',  // sysLocation
    ];

    const results = await this.getMultiple(oids);

    return {
      sysDescr: results[0]?.value as string,
      sysObjectId: results[1]?.value as string,
      sysUpTime: results[2]?.value as number,
      sysContact: results[3]?.value as string,
      sysName: results[4]?.value as string,
      sysLocation: results[5]?.value as string,
    };
  }

  // ============================================================================
  // Serialization
  // ============================================================================

  public getFeatureInfo(): ISnmpFeatureInfo {
    return {
      ...this.getBaseFeatureInfo(),
      type: 'snmp',
      version: this.version,
      community: this.version !== 'v3' ? this.community : undefined,
      sysDescr: this.sysDescr,
      sysName: this.sysName,
      sysLocation: this.sysLocation,
    };
  }

  // ============================================================================
  // Static Factory
  // ============================================================================

  public static fromDiscovery(
    device: TDeviceReference,
    port: number,
    metadata: Record<string, unknown>
  ): SnmpFeature {
    return new SnmpFeature(device, port ?? 161, {
      version: metadata.version as TSnmpVersion ?? 'v2c',
      community: metadata.community as string ?? 'public',
    });
  }
}