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

/**
 * Migration from v4.0 to v4.1
 *
 * Major changes:
 * 1. Moves thresholds from UPS level to action level
 * 2. Creates default shutdown action for UPS devices that had thresholds
 * 3. Adds empty actions array to UPS devices without actions
 * 4. Adds empty actions array to groups
 *
 * Transforms v4.0 format (with UPS-level thresholds):
 * {
 *   version: "4.0",
 *   upsDevices: [
 *     {
 *       id: "ups-1",
 *       name: "UPS 1",
 *       snmp: {...},
 *       thresholds: { battery: 60, runtime: 20 },  // UPS-level
 *       groups: []
 *     }
 *   ]
 * }
 *
 * To v4.1 format (with action-level thresholds):
 * {
 *   version: "4.1",
 *   upsDevices: [
 *     {
 *       id: "ups-1",
 *       name: "UPS 1",
 *       snmp: {...},
 *       groups: [],
 *       actions: [  // Thresholds moved here
 *         {
 *           type: "shutdown",
 *           thresholds: { battery: 60, runtime: 20 },
 *           triggerMode: "onlyThresholds",
 *           shutdownDelay: 5
 *         }
 *       ]
 *     }
 *   ]
 * }
 */
export class MigrationV4_0ToV4_1 extends BaseMigration {
  readonly fromVersion = '4.0';
  readonly toVersion = '4.1';

  async shouldRun(config: Record<string, unknown>): Promise<boolean> {
    // Run if config is version 4.0
    if (config.version === '4.0') {
      return true;
    }

    // Also run if config has upsDevices with thresholds at UPS level (v4.0 format)
    if (Array.isArray(config.upsDevices) && config.upsDevices.length > 0) {
      const firstDevice = config.upsDevices[0] as Record<string, unknown>;
      // v4.0 has thresholds at UPS level, v4.1 has them in actions
      return firstDevice.thresholds !== undefined;
    }

    return false;
  }

  async migrate(config: Record<string, unknown>): Promise<Record<string, unknown>> {
    logger.info(`${this.getName()}: Migrating v4.0 config to v4.1 format...`);
    logger.dim(`  - Moving thresholds from UPS level to action level`);
    logger.dim(`  - Creating default shutdown actions from existing thresholds`);

    // Migrate UPS devices
    const devices = (config.upsDevices as Array<Record<string, unknown>>) || [];
    const migratedDevices = devices.map((device) => {
      const migrated: Record<string, unknown> = {
        id: device.id,
        name: device.name,
        snmp: device.snmp,
        groups: device.groups || [],
      };

      // If device has thresholds at UPS level, convert to shutdown action
      const deviceThresholds = device.thresholds as { battery: number; runtime: number } | undefined;
      if (deviceThresholds) {
        migrated.actions = [
          {
            type: 'shutdown',
            thresholds: {
              battery: deviceThresholds.battery,
              runtime: deviceThresholds.runtime,
            },
            triggerMode: 'onlyThresholds', // Preserve old behavior (only on threshold violation)
            shutdownDelay: 5, // Default delay
          },
        ];
        logger.dim(
          `    → ${device.name}: Created shutdown action (battery: ${deviceThresholds.battery}%, runtime: ${deviceThresholds.runtime}min)`,
        );
      } else {
        // No thresholds, just add empty actions array
        migrated.actions = device.actions || [];
      }

      return migrated;
    });

    // Add actions to groups
    const groups = (config.groups as Array<Record<string, unknown>>) || [];
    const migratedGroups = groups.map((group) => ({
      ...group,
      actions: group.actions || [],
    }));

    const result = {
      version: this.toVersion,
      upsDevices: migratedDevices,
      groups: migratedGroups,
      checkInterval: config.checkInterval || 30000,
    };

    logger.success(
      `${this.getName()}: Migration complete (${migratedDevices.length} devices, ${migratedGroups.length} groups updated)`,
    );
    return result;
  }
}