/* Contents of index.js */

// Import the HubManager from jobhub
var HubManager = require('jobhub').HubManager;

// Create a new instance of the HubManager, configured to load your jobs from jobs.js
var hub = new HubManager({
	jobsModulePath: require('path').resolve(__dirname, 'jobs.js')
});

// Startup the hub manager, which will import and register the jobs from jobsModulePath.
hub.start();

/* Contents of jobs.js */

// The simplest form of a job is a function, which is executed in the child process.
exports.feedGremlins = function(job) {
	var numberOfGremlins = job.params.numberOfGremlins;
	if (numberOfGremlins < 1) {
		job.resolve('No gremlins to feed, which is probably for the best.');
	}
	else {
		var hour = new Date().getHours();
		if (hour >= 0 && hour < 5) { // Assumes okay to feed after 6am
			job.reject(new Error('Never feed after midnight!'));
		}
		else {
			job.sendProgress({
				message: 'Feeding has begun!'
			});

			setTimeout(function() {
				job.sendProgress({
					message: 'Still feeding...'
				});
			}, 2500);

			// TODO: Yikes! What if it goes past midnight while we're feeding?

			setTimeout(function() {
				job.resolve({
					numberOfGremlins: numberOfGremlins,
					message: numberOfGremlins === 1
						? 'Fed the gremlin!'
						: 'Fed all ' + numberOfGremlins + ' gremlins! Wait, where did the other ones come from?'
				});
			}, 5000);
		}
	}
};

// If a job is an object, we can add additional configuration.
exports.geGremlinsWet = {
	// For example, let's validate the params.
	// The validation is performed in both the parent and child process.
	validate: function(params, InvalidJobParamError) {
		if (params.numberOfGremlins === 0) {
			throw new InvalidJobParamError('No gremlins to get wet!');
		}
	},

	// At a minimum you must include a "run" function, which is executed in the child process.
	run: function(job) {
		job.resolve({
			message: job.params.numberOfGremlins === 1
				? 'Washed that dirty gremlin!'
				: 'Washed those dirty gremlins!',
			numberOfGremlins: job.params.numberOfGremlins * 2
		});
	}
};

/* Add to the end of index.js */

// Queue a job to be run, which returns an object that lets us track the job.
var trackedJob = hub.queueJob('feedGremlins', { numberOfGremlins: 1 });

// We can listen for events, such as when a progress message is received. 
trackedJob.on('jobProgress', function(progress) {
	console.log('[progress update]: ' + progress.message);
});

// TrackedJob instances include then/catch to be Promise-like
trackedJob
	.then(function(feedingResult) {
		console.log('[first feeding result] ' + feedingResult.message);
		return hub.queueJob('getGremlinsWet', { numberOfGremlins: feedingResult.numberOfGremlins });
	})
	.then(function(washingResult) {
		console.log('[washing result] ' + washingResult.message);
		return hub.queueJob('feedGremlins', { numberOfGremlins: washingResult.numberOfGremlins });
	})
	.then(function(feedingResult) {
		console.log('[second feeding result] ' + feedingResult.message);
	}, function(err) {
		console.error('Something went wrong: ' + err.stack);
	});

/* Contents of index.js */

var express = require('express');
var HubManager = require('jobhub').HubManager;

var hub = new HubManager({
	jobsModulePath: require('path').resolve(__dirname, 'jobs.js')
}).start();

// Listen to job lifecycle events.
hub.on('jobCreated', function(trackedJob) {
	console.log('[JOB CREATED] name:' + trackedJob.jobConfig.jobName + ' id:' + trackedJob.jobId);
}).on('jobSuccess', function(trackedJob, result) {
	console.log('[JOB SUCCESS] name:' + trackedJob.jobConfig.jobName + ' id:' + trackedJob.jobId + ' result:' + JSON.stringify(result));
}).on('jobFailure', function(trackedJob, err) {
	console.log('[JOB FAILURE] name:' + trackedJob.jobConfig.jobName + ' id:' + trackedJob.jobId + ' err:' + err.stack);
});

var app = express();

app.get('/is-big-daily-load-running', function(req, res) {
	res.json({
		isRunning: !!hub.findUniqueTrackedJob('big-daily-data-load')
	});
});

app.get('/big-daily-data-load', function(req, res) {
	var trackedJob = hub.queueJob('big-daily-data-load');

	// Since this job is flagged as "unique", repeated attempts to queue
	// this job will return the same TrackedJob instance, allowing all
	// of the requests to wait on the same job.
	console.log('[Load request] jobId:' + trackedJob.jobId);

	trackedJob.then(function(result) {
		res.json(result);
	}).catch(function(err) {
		res.json({
			error: err.message,
			stack: err.stack
		});
	});
});

app.on('error', function(err) {
	console.error('Failed to listen to port 3000: ' + err.message);
}).listen(3000, function() {
	console.log('Listening on port 3000!');
});

/* Contents of jobs.js */

exports['big-daily-data-load'] = {
	// Make sure only one instance runs at a time.
	unique: true,

	run: function(job) {
		setTimeout(function() {
			job.resolve({
				recordsLoaded: 5000000
			});
		}, 15000);
	}
};

/* Contents of client.js */

var http = require('http');

fetch('http://localhost:3000/is-big-daily-load-running', function(err, body) {
	if (err) console.log('[isRunning failed] ' + err.message);
	else console.log('[isRunning success] ' + body);
});

fetch('http://localhost:3000/big-daily-data-load', function(err, body) {
	if (err) console.log('[dataLoad failed] ' + err.message);
	else console.log('[dataLoad success] ' + body);
});

fetch('http://localhost:3000/is-big-daily-load-running', function(err, body) {
	if (err) console.log('[isRunning failed] ' + err.message);
	else console.log('[isRunning success] ' + body);
});

fetch('http://localhost:3000/big-daily-data-load', function(err, body) {
	if (err) console.log('[dataLoad failed] ' + err.message);
	else console.log('[dataLoad success] ' + body);
});

function fetch(url, cb) {
	http.get(url, function(res) {
		readData(res, cb);
	}).on('error', cb);
}

function readData(stream, cb) {
	var body = '';
	stream.on('data', function(d) {
		body += d;
	}).on('end', function() {
		cb(null, body);
	}).on('error', cb);
}