import { ICollection, IDb, WithId } from '@p81-common/p81-mongo-client';
import { UrlCategories, UrlCategoriesMetadata } from '@p81-common/p81-mongo-validation-schemas';

export default class CategoriesService {
  readonly categoryMap: Map<string, WithId<UrlCategories>>;

  categories!: ICollection<UrlCategories>;

  constructor(protected db: IDb) {
    this.categories = db.collection<UrlCategories>(UrlCategoriesMetadata);
    this.categoryMap = new Map();
  }

  private setCategories(categories: WithId<UrlCategories>[]) {
    for (const category of categories) {
      for (const code of category.codes) {
        this.categoryMap.set(code, category);
      }
    }
  }

  async init() {
    const categories = await this.categories.find({}).toArray();
    this.setCategories(categories);
  }

  async findByIds(categoryIds: string[]): Promise<string[]> {
    if (this.categoryMap.size === 0) {
      await this.init();
    }
    let result: string[] = [];
    for (const categoryId of categoryIds) {
      const category: WithId<UrlCategories> | undefined = this.getById(categoryId);
      if (category) {
        result = [...result, ...category.codes];
      }
    }
    return result;
  }

  getById(categoryId: string): WithId<UrlCategories> | undefined {
    return this.categoryMap.get(categoryId);
  }
}