import { BaseMigration } from './base-migration.ts';
import { logger } from '../logger.ts';

/**
 * Migration from v3 (upsList) to v4 (upsDevices)
 *
 * Transforms v3 format with flat SNMP config:
 * {
 *   upsList: [
 *     {
 *       id: "ups-1",
 *       name: "UPS 1",
 *       host: "192.168.1.1",
 *       port: 161,
 *       community: "public",
 *       version: "1"  // string
 *     }
 *   ]
 * }
 *
 * To v4 format with nested SNMP config:
 * {
 *   version: "4.0",
 *   upsDevices: [
 *     {
 *       id: "ups-1",
 *       name: "UPS 1",
 *       snmp: {
 *         host: "192.168.1.1",
 *         port: 161,
 *         community: "public",
 *         version: 1,  // number
 *         timeout: 5000
 *       },
 *       thresholds: { battery: 60, runtime: 20 },
 *       groups: []
 *     }
 *   ]
 * }
 */
export class MigrationV3ToV4 extends BaseMigration {
  readonly order = 4;
  readonly fromVersion = '3.x';
  readonly toVersion = '4.0';

  async shouldRun(config: any): Promise<boolean> {
    // V3 format has upsList instead of upsDevices
    return !!config.upsList && !config.upsDevices;
  }

  async migrate(config: any): Promise<any> {
    logger.info(`${this.getName()}: Migrating v3 config to v4 format...`);
    logger.dim(`  - Renaming upsList → upsDevices`);
    logger.dim(`  - Restructuring UPS devices (flat → nested snmp config)`);

    // Transform each UPS device from v3 flat structure to v4 nested structure
    const transformedDevices = config.upsList.map((device: any) => {
      // Build SNMP config object
      const snmpConfig: any = {
        host: device.host,
        port: device.port || 161,
        version: typeof device.version === 'string' ? parseInt(device.version, 10) : device.version,
        timeout: device.timeout || 5000,
      };

      // Add SNMPv1/v2c fields
      if (device.community) {
        snmpConfig.community = device.community;
      }

      // Add SNMPv3 fields
      if (device.securityLevel) snmpConfig.securityLevel = device.securityLevel;
      if (device.username) snmpConfig.username = device.username;
      if (device.authProtocol) snmpConfig.authProtocol = device.authProtocol;
      if (device.authKey) snmpConfig.authKey = device.authKey;
      if (device.privProtocol) snmpConfig.privProtocol = device.privProtocol;
      if (device.privKey) snmpConfig.privKey = device.privKey;

      // Add UPS model if present
      if (device.upsModel) snmpConfig.upsModel = device.upsModel;
      if (device.customOIDs) snmpConfig.customOIDs = device.customOIDs;

      // Return v4 format with nested structure
      return {
        id: device.id,
        name: device.name,
        snmp: snmpConfig,
        thresholds: device.thresholds || {
          battery: 60,
          runtime: 20,
        },
        groups: device.groups || [],
      };
    });

    const migrated = {
      version: this.toVersion,
      upsDevices: transformedDevices,
      groups: config.groups || [],
      checkInterval: config.checkInterval || 30000,
    };

    logger.success(`${this.getName()}: Migration complete (${transformedDevices.length} devices transformed)`);
    return migrated;
  }
}