provider.mongodb.ts

import { Collection, Db, MongoClient, ObjectID } from 'mongodb';

import { environment } from './environment';

export class MongoDbProvider {
  private database?: Db;
  private mongoClient: MongoClient;

  constructor(url: string) {
    this.mongoClient = new MongoClient(url) // , { useUnifiedTopology: true });
  }

  get validatorsCollection(): Collection {
    const validatorsCollection = this.getCollection('w3f_validator');
    if (!validatorsCollection) {
      throw new Error('Validator collection is undefined');
    }
    return validatorsCollection;
  }

  get postsCollection(): Collection {
    const postsCollection = this.getCollection('posts');
    if (!postsCollection) {
      throw new Error('Posts collection is undefined');
    }
    return postsCollection;
  }

  get usersCollection(): Collection {
    const usersCollection = this.getCollection('users');
    if (!usersCollection) {
      throw new Error('Users collection is undefined');
    }
    return usersCollection;
  }

  /**
   * Connect to MongoDB.
   * @async
   * @param databaseName - Database name.
   */
  async connectAsync(databaseName: string): Promise<void> {
    await this.mongoClient.connect();
    this.database = this.mongoClient.db(databaseName);
  }

  /**
   * Close the database and its underlying connections.
   */
  async closeAsync(): Promise<void> {
    await this.mongoClient.close();
  }

  /**
   * Fetch a specific collection.
   * @private
   * @param collectionName - Collection name.
   * @returns The collection instance.
   */
  private getCollection(collectionName: string): Collection {
    if (!this.database) {
      throw new Error('Database is undefined.');
    }

    return this.database.collection(collectionName);
  }
}

export const mongoDbProvider = new MongoDbProvider(environment.mongoDb.url);

/**
 * Add mock users if `users` collection is empty.
 * TODO: Remove in Production.
 */
// export async function addMockUsersAsync(): Promise<void> {
//   const usersCount = await mongoDbProvider.usersCollection.countDocuments();

//   if (usersCount === 0) {
//     await mongoDbProvider.usersCollection.insertMany([
//       {
//         _id: new ObjectID('0123456789abcdef01234567'),
//         firstName: 'Test',
//         lastName: 'User 1',
//         email: 'test.user1@test.com',
//       },
//       {
//         _id: new ObjectID('fedcba987654321098765432'),
//         firstName: 'Test',
//         lastName: 'User 2',
//         email: 'test.user2@test.com',
//         following: [new ObjectID('0123456789abcdef01234567')],
//       },
//     ]);
//   }
// }