import { Injectable, OnModuleInit } from '@nestjs/common';
import { MongoCoreService } from 'src/mongo/mongo-core.service';
import { FFBProductionRepository } from 'src/FFB/mongo-ffb-production.repository';
import { FFBProduction } from '../ffb-production.schema';
import { GeminiEmbeddingService } from '../gemini-embedding.service';

@Injectable()
export class FFBVectorService implements OnModuleInit {
  private repo: FFBProductionRepository;

  constructor(
    private readonly mongoCore: MongoCoreService,
    private readonly embeddingService: GeminiEmbeddingService
  ) { }

  async onModuleInit() {
    // Initialize Mongo repository
    const db = await this.mongoCore.getDb();
    this.repo = new FFBProductionRepository(db);
    await this.repo.init();

    console.log('✅ Gemini embedding service ready. Repository initialized.');
  }

  /** Convert a record to a string suitable for embedding */
  private recordToText(record: FFBProduction): string {
    return `Production on ${new Date(record.productionDate).toISOString()} at ${record.site} in ${record.phase} ${record.block} produced ${record.quantity} ${record.quantityUom} with a total weight of ${record.weight} ${record.weightUom}.`;
  }

  /** Insert a single record with embedding vector */
  async insertWithVector(record: FFBProduction) {
    const text = this.recordToText(record);
    const vector = await this.embeddingService.embedText(text);

    const data: FFBProduction & { vector: number[] } = { ...record, vector };
    return this.repo.create(data);
  }

  /** Search for top-k similar records using a text query */
  async vectorSearch(query: string, k = 5, filter: Record<string, any> = {}) {
    if (!query) throw new Error('Query string cannot be empty');

    const vector = await this.embeddingService.embedText(query);
    const results = await this.repo.vectorSearch(vector, k, 50, filter);

    return results.map((r) => ({
      ...r,
      _id: r._id.toString(),
      score: r.score,
    }));
  }

  /* For traditional operation that requires arithematic operations. */
  async aggregate(pipeline: Array<Record<string, any>>): Promise<any[]> {
    return this.repo.aggregate(pipeline);
  }

}