import { DataSource } from '../data-source/DataSource';
import { ConnectionNotFoundError } from '../error/ConnectionNotFoundError';
import { DataSourceOptions } from '../data-source/DataSourceOptions';
import { AlreadyHasActiveConnectionError } from '../error/AlreadyHasActiveConnectionError';

/**
 * ConnectionManager is used to store and manage multiple orm connections.
 * It also provides useful factory methods to simplify connection creation.
 *
 * @deprecated
 */
export class ConnectionManager {
	/**
	 * List of connections registered in this connection manager.
	 */
	get connections(): DataSource[] {
		return Array.from(this.connectionMap.values());
	}

	/**
	 * Internal lookup to quickly get from a connection name to the Connection object.
	 */
	private readonly connectionMap: Map<string, DataSource> = new Map();

	// -------------------------------------------------------------------------
	// Public Methods
	// -------------------------------------------------------------------------

	/**
	 * Checks if connection with the given name exist in the manager.
	 */
	has(name: string): boolean {
		return this.connectionMap.has(name);
	}

	/**
	 * Gets registered connection with the given name.
	 * If connection name is not given then it will get a default connection.
	 * Throws error if connection with the given name was not found.
	 */
	get(name: string = 'default'): DataSource {
		const connection = this.connectionMap.get(name);
		if (!connection) throw new ConnectionNotFoundError(name);

		return connection;
	}

	/**
	 * Creates a new connection based on the given connection options and registers it in the manager.
	 * Connection won't be established, you'll need to manually call connect method to establish connection.
	 */
	create(options: DataSourceOptions): DataSource {
		// check if such connection is already registered
		const existConnection = this.connectionMap.get(options.name || 'default');
		if (existConnection) {
			// if connection is registered and its not closed then throw an error
			if (existConnection.isInitialized)
				throw new AlreadyHasActiveConnectionError(options.name || 'default');
		}

		// create a new connection
		const connection = new DataSource(options);
		this.connectionMap.set(connection.name, connection);
		return connection;
	}
}