const path = require('path');
const chokidar = require('chokidar');

const { FS_EVENT_ADD: EVENT_ADD, FS_EVENT_UNLINK: EVENT_UNLINK, FS_EVENT_CHANGE: EVENT_CHANGE } = require('../libs/constants.js');

class Watcher {

    constructor() {
        this.#initialize();
    }

    #initialize() {
        if (config?.library === undefined) {
            throw new Error('library not defined');
        }
        if (config?.library?.sources === undefined || config?.library?.sources.length === 0) {
            throw new Error('no library sources defined');
        }
        for (let index = 0; index < config.library.sources.length; index++) {
            const directory = path.resolve(config.library.sources[index]);
            logger.debug('watching directory \'' + directory + '\'...');
            this.#handleEvents(chokidar.watch(directory));
        }
    }

    #handleEvents(watcher) {
        if (watcher === undefined) {
            return;
        }
        watcher.on(EVENT_ADD, (file, stats) => {
            queue.add(EVENT_ADD, file, stats);
        });
        watcher.on(EVENT_UNLINK, (file, stats) => {
            queue.add(EVENT_UNLINK, file, stats);
        });
        watcher.on(EVENT_CHANGE, (file, stats) => {
            queue.add(EVENT_CHANGE, file, stats);
        });
    }
}

module.exports = Watcher, EVENT_ADD, EVENT_UNLINK;