@fontoxml/fontoxml-development-tools/src/ModuleRegistrationApi.js

'use strict';

const ask = require('ask-nicely');
const path = require('path');

const APP = Symbol('app');
const CONTEXTINFORMERS = Symbol('context informers');
const LOCATION = Symbol('location');
const PACKAGEJSON = Symbol('package.json');

/**
 * The unified API for registering module functionality with the FDT instance. The callback exposed
 * by a module will get an instance of ModuleRegistrationApi to register itself with.
 */
class ModuleRegistrationApi {
	/**
	 * Should not be called by a module.
	 *
	 * @param {App}    app            The app.
	 * @param {string} moduleLocation The location of the module that is being registered.
	 *
	 * @constructor
	 */
	constructor(app, moduleLocation) {
		this[APP] = app;

		this[LOCATION] = moduleLocation;

		this[PACKAGEJSON] = require(path.join(this[LOCATION], 'package.json'));

		this[CONTEXTINFORMERS] = [];

		this.hidden = false;

		Object.assign(this, ask);
	}

	/**
	 * Should not be called by a module. Loads and evaluates the Javascript code belonging to a module.
	 *
	 * @param {...*} extra
	 */
	load(...extra) {
		const mod = require(this[LOCATION]);

		if (typeof mod !== 'function') {
			throw new Error(this[PACKAGEJSON].name + ' is not a function.');
		}

		mod(this, ...extra);
	}

	/**
	 * Passes on the information returned by App#getInfo.
	 *
	 * @see App#getInfo
	 *
	 * @return {object} The app information.
	 */
	getAppInfo() {
		return this[APP].getInfo();
	}

	/**
	 * Returns metadata about the module that is being registered.
	 *
	 * @return {{name, version, builtIn, description, path}} The module information.
	 */
	getInfo() {
		return {
			name: this[PACKAGEJSON].name,
			version: this[PACKAGEJSON].version,
			builtIn: this[APP].builtInModules.some(mod => mod === this),
			description: this[PACKAGEJSON].description,
			path: this[LOCATION]
		};
	}

	/**
	 * Adds a command to the root of the FDT instance.
	 *
	 * @see FdtCommand#addCommand
	 *
	 * @param {string} commandName
	 * @param {string|function(AskNicelyRequest, SpeakSoftly)} [controller]
	 *
	 * @return {Command} The command object that was created.
	 */
	registerCommand(commandName, controller) {
		const command = this[APP].cli.addCommand(commandName, controller);
		command._moduleRegistration = this;
		return command;
	}

	/**
	 * Adds a hidden command to the root of the FDT instance.
	 *
	 * @see FdtCommand#addHiddenCommand
	 *
	 * @param {string} commandName
	 * @param {string|function(AskNicelyRequest, SpeakSoftly)} [controller]
	 *
	 * @return {Command} The command object that was created.
	 */
	registerHiddenCommand(commandName, controller) {
		const command = this[APP].cli.addHiddenCommand(commandName, controller);
		command._moduleRegistration = this;
		return command;
	}

	/**
	 * NOTE: Only use this from the module's index.js, not from within commands, or else your config might be overridden.
	 *
	 * @see ConfigManager#registerConfiguration
	 *
	 * @param {string} configName
	 * @param {*}      defaultValue
	 * @param {*|function(config): ?*} [serialize]
	 *
	 * @return {*} The configuration value.
	 */
	registerConfiguration(configName, defaultValue, serialize) {
		return this[APP].config.registerConfig(configName, defaultValue, serialize);
	}

	/**
	 * Get the registered configuration.
	 *
	 * @param {string} configName
	 *
	 * @return {*} The configuration value.
	 */
	getConfiguration(configName) {
		return this[APP].config[configName];
	}

	/**
	 * Register a subcontroller to render additional info provided by a module in the "who" command
	 * provided by FDT.
	 *
	 * @param {function(AskNicelyRequest, SpeakSoftly)} contextInformer
	 *
	 * @return {Object} The context informer.
	 */
	registerContextInformer(contextInformer) {
		this[CONTEXTINFORMERS].push(contextInformer);

		return contextInformer;
	}

	/**
	 * Should not be called by a module. Return the list of context informers registered by this module.
	 *
	 * @return {Array} The context informers.
	 */
	getContextInformers() {
		return this[CONTEXTINFORMERS].slice(0);
	}
}

module.exports = ModuleRegistrationApi;