'use strict';

const MWBot = require( 'mwbot' );
const Page = require( './Page' );
const MAINPAGE_REQUESTS_MAX_RUNS = 10; // (arbitrary) safe-guard against endless execution

function getJobCount() {
	const bot = new MWBot( {
		apiUrl: `${ browser.config.baseUrl }/api.php`
	} );
	return bot.request( {
		action: 'query',
		meta: 'siteinfo',
		siprop: 'statistics'
	} ).then( ( response ) => response.query.statistics.jobs );
}

function log( message ) {
	process.stdout.write( `RunJobs ${ message }\n` );
}

function runThroughMainPageRequests( runCount = 1 ) {
	const page = new Page();
	log( `through requests to the main page (run ${ runCount }).` );

	return page.openTitle( '' ).then(
		() => getJobCount().then( ( jobCount ) => {
			if ( jobCount === 0 ) {
				log( 'found no more queued jobs.' );
				return;
			}
			log( `detected ${ jobCount } more queued job(s).` );
			if ( runCount >= MAINPAGE_REQUESTS_MAX_RUNS ) {
				log( 'stopping requests to the main page due to reached limit.' );
				return;
			}
			return runThroughMainPageRequests( ++runCount );
		} )
	);
}

/**
 * Trigger the execution of jobs
 *
 * Use RunJobs.run() to ensure that jobs are executed before making assertions that depend on it.
 *
 * Systems that are selenium-tested are usually provisioned for that purpose, see no organic
 * traffic, consequently typical post-send job queue processing rarely happens. Additionally,
 * test set-up is often done through the API, requests to which do not trigger job queue
 * processing at all.
 *
 * This can lead to an accumulation of unprocessed jobs, which in turn would render certain
 * assertions impossible - e.g. checking a page is listed on Special:RecentChanges right
 * after creating it.
 *
 * This class will try to trigger job execution through repeated blunt requests against the
 * wiki's home page to trigger them at a rate of `$wgJobRunRate` per request.
 *
 * See also <https://www.mediawiki.org/wiki/Manual:Job_queue/For_developers#Execution_of_jobs>.
 */
class RunJobs {

	static run() {
		browser.call( () => runThroughMainPageRequests() );
	}
}

module.exports = RunJobs;