import { CreateConnectionString, IConnectionOptions } from "./Utils";
import { Observable, BehaviorSubject } from "rxjs";

// MongoDB
import { MongoClient, Db, MongoError } from "mongodb";

export class MongoConnection
{
    protected _OnConnectedSubject: BehaviorSubject<boolean> = new BehaviorSubject<boolean>(null);
	protected _db: Db = null;
    protected _mongoClient: MongoClient;
	constructor(private options: IConnectionOptions)
	{
	}

    OnConnect(): Observable<boolean>
	{
		return this._OnConnectedSubject.asObservable();
	}

    protected async _connected()
    {

    }

	connect(options?: IConnectionOptions): Promise<any>
	{
        if(!options)
        {
            options = this.options;
        }
		let connectionString = CreateConnectionString(options);
		return MongoClient.connect(connectionString, {
			autoReconnect: true,
		}).then(async (client: MongoClient) => {
            this._db = client.db(options.Database);
            this._mongoClient = client;

            await this._connected();

            this._OnConnectedSubject.next(true);
            return client;
		});
	}

	// Closes the mongo connection
	close(forceClose: boolean = false): Promise<void>
	{
		if(!this._db)
		{
			throw Error("Not connected.");
		}
        return this._mongoClient.close(forceClose);
	}
};