/** @module config */
import { ConfigParams } from './ConfigParams';
import { Descriptor } from '../refer/Descriptor';

/**
 * A helper class that allows to extract component name from configuration parameters.
 * The name can be defined in "id", "name" parameters or inside a component descriptor.
 * 
 * ### Example ###
 * 
 *     let config = ConfigParams.fromTuples(
 *         "descriptor", "myservice:connector:aws:connector1:1.0",
 *         "param1", "ABC",
 *         "param2", 123
 *     );
 *     
 *     let name = NameResolver.resolve(config); // Result: connector1
 */
export class NameResolver {

    /**
     * Resolves a component name from configuration parameters.
     * The name can be stored in "id", "name" fields or inside a component descriptor.
     * If name cannot be determined it returns a defaultName.
     * 
     * @param config        configuration parameters that may contain a component name.
     * @param defaultName   (optional) a default component name.
     * @returns             resolved name or default name if the name cannot be determined.
     */
    static resolve(config: ConfigParams, defaultName: string = null): string {
        let name: string = config.getAsNullableString("name") || config.getAsNullableString("id");

        if (name == null) {
            let descriptorStr: string = config.getAsNullableString("descriptor");
            let descriptor: Descriptor = Descriptor.fromString(descriptorStr);
            if (descriptor != null)
                name = descriptor.getName();
        }

        return name || defaultName;
    }
}