/// <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>;
}

async function migrateTargetProfileTargetHosts(ctx: {
  mongo?: { collection: (name: string) => any };
  log: { log: (level: 'info', message: string) => void };
}): Promise<void> {
  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((target: any) => {
      if (target && typeof target === 'object' && 'host' in target && !('ip' in target)) {
        const { host, ...rest } = target;
        return { ...rest, ip: host };
      }
      return target;
    });

    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)`);
}

/**
 * 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) => migrateTargetProfileTargetHosts(ctx))
    .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)`,
      );
    })
    .step('unify-routes-rename-collection')
    .from('13.8.2').to('13.16.0')
    .description('Rename StoredRouteDoc → RouteDoc, add origin field, drop RouteOverrideDoc')
    .up(async (ctx) => {
      const db = ctx.mongo!;

      // 1. Rename StoredRouteDoc → RouteDoc (smartdata uses exact class names)
      const collections = await db.listCollections({ name: 'StoredRouteDoc' }).toArray();
      if (collections.length > 0) {
        await db.renameCollection('StoredRouteDoc', 'RouteDoc');
        ctx.log.log('info', 'Renamed StoredRouteDoc → RouteDoc');
      }

      // 2. Set origin='api' on all migrated docs (they were API-created)
      const routeCol = db.collection('RouteDoc');
      const result = await routeCol.updateMany(
        { origin: { $exists: false } },
        { $set: { origin: 'api' } },
      );
      ctx.log.log('info', `Set origin='api' on ${result.modifiedCount} migrated route(s)`);

      // 3. Drop RouteOverrideDoc collection
      const overrideCollections = await db.listCollections({ name: 'RouteOverrideDoc' }).toArray();
      if (overrideCollections.length > 0) {
        await db.collection('RouteOverrideDoc').drop();
        ctx.log.log('info', 'Dropped RouteOverrideDoc collection');
      }
    })
    .step('repair-target-profile-ip-migration')
    .from('13.16.0').to('13.17.4')
    .description('Repair TargetProfileDoc.targets host→ip migration for already-upgraded installs')
    .up(async (ctx) => {
      await migrateTargetProfileTargetHosts(ctx);
    });

  return migration;
}