/// <reference types="node" />

/**
 * dcrouter migration runner.
 *
 * Uses @push.rocks/smartmigration via dynamic import so smartmigration's type
 * chain (which pulls in mongodb 7.x and related types) doesn't leak into
 * compile-time type checking for this folder.
 */

/** Matches the subset of IMigrationRunResult we actually log. */
export interface IMigrationRunResult {
  stepsApplied: Array<unknown>;
  wasFreshInstall: boolean;
  currentVersionBefore: string | null;
  currentVersionAfter: string;
  totalDurationMs: number;
}

export interface IMigrationRunner {
  run(): Promise<IMigrationRunResult>;
}

/**
 * Create a configured SmartMigration runner with all dcrouter migration steps registered.
 *
 * Call `.run()` on the returned instance at startup (after DcRouterDb is ready,
 * before any service that reads migrated collections).
 *
 * @param db - The initialized SmartdataDb instance from DcRouterDb.getDb()
 * @param targetVersion - The current app version (from commitinfo.version)
 */
export async function createMigrationRunner(
  db: unknown,
  targetVersion: string,
): Promise<IMigrationRunner> {
  const sm = await import('@push.rocks/smartmigration');
  const migration = new sm.SmartMigration({
    targetVersion,
    db: db as any,
    // Brand-new installs skip all migrations and stamp directly to the current version.
    freshInstallVersion: targetVersion,
  });

  // Register steps in execution order. Each step's .from() must match the
  // previous step's .to() to form a contiguous chain.
  migration
    .step('rename-target-profile-host-to-ip')
    .from('13.0.11').to('13.1.0')
    .description('Rename ITargetProfileTarget.host → ip on all target profiles')
    .up(async (ctx) => {
      const collection = ctx.mongo!.collection('targetprofiledoc');
      const cursor = collection.find({ 'targets.host': { $exists: true } });
      let migrated = 0;
      for await (const doc of cursor) {
        const targets = ((doc as any).targets || []).map((t: any) => {
          if (t && typeof t === 'object' && 'host' in t && !('ip' in t)) {
            const { host, ...rest } = t;
            return { ...rest, ip: host };
          }
          return t;
        });
        await collection.updateOne({ _id: (doc as any)._id }, { $set: { targets } });
        migrated++;
      }
      ctx.log.log('info', `rename-target-profile-host-to-ip: migrated ${migrated} profile(s)`);
    })
    .step('rename-domain-source-manual-to-dcrouter')
    .from('13.1.0').to('13.8.1')
    .description('Rename DomainDoc.source value from "manual" to "dcrouter"')
    .up(async (ctx) => {
      const collection = ctx.mongo!.collection('domaindoc');
      const result = await collection.updateMany(
        { source: 'manual' },
        { $set: { source: 'dcrouter' } },
      );
      ctx.log.log(
        'info',
        `rename-domain-source-manual-to-dcrouter: migrated ${result.modifiedCount} domain(s)`,
      );
    })
    .step('rename-record-source-manual-to-local')
    .from('13.8.1').to('13.8.2')
    .description('Rename DnsRecordDoc.source value from "manual" to "local"')
    .up(async (ctx) => {
      const collection = ctx.mongo!.collection('dnsrecorddoc');
      const result = await collection.updateMany(
        { source: 'manual' },
        { $set: { source: 'local' } },
      );
      ctx.log.log(
        'info',
        `rename-record-source-manual-to-local: migrated ${result.modifiedCount} record(s)`,
      );
    });

  return migration;
}