import {
  MongoClient,
  Db,
  Collection,
  Document,
  UpdateResult,
  DeleteResult,
} from 'mongodb';
import config from '../../../config';

let client: MongoClient;
let database: Db;
let collection: Collection<Document>;

async function initializeDbConnection() {
  if (!client) {
    client = new MongoClient(config.mongodbUri);
    await client.connect();
    database = client.db('butler_db');
    collection = database.collection('GameFeatures');
  }
}

/**
 * Retrieves a list of game names from the database.
 *
 * @returns An array of game objects containing game names.
 */
export async function listGameNames(): Promise<any[]> {
  await initializeDbConnection();
  return collection.find({}, { projection: { game: 1 } }).toArray();
}

/**
 * Retrieves a specific game by its name from the database.
 *
 * @param game - The name of the game to retrieve.
 * @returns The game object if found, or null if not found.
 */
export async function getGame(game: string): Promise<any | null> {
  await initializeDbConnection();
  return collection.findOne({ game });
}

/**
 * Sets a key-value pair for a specific game in the database.
 * If the game does not exist, it will be created.
 *
 * @param game - The name of the game to update or create.
 * @param key - The key to set or update in the game object.
 * @param value - The value to set for the specified key.
 * @returns The result of the update operation.
 */
export async function setGame(
  game: string,
  key: string,
  value: any
): Promise<UpdateResult> {
  await initializeDbConnection();
  return collection.updateOne(
    { game },
    { $set: { game, [key]: value } },
    { upsert: true }
  );
}

/**
 * Deletes a game from the database by its name.
 *
 * @param game - The name of the game to delete.
 * @returns The result of the delete operation.
 */
export async function deleteGame(game: string): Promise<DeleteResult> {
  await initializeDbConnection();
  return collection.deleteOne({ game });
}

/**
 * Deletes a specific field from a game object in the database.
 *
 * @param game - The name of the game to update.
 * @param key - The field key to remove from the game object.
 * @returns The result of the update operation.
 */
export async function deleteField(
  game: string,
  key: string
): Promise<UpdateResult> {
  await initializeDbConnection();
  return collection.updateOne({ game }, { $unset: { [key]: '' } });
}