var mubsub = require('mubsub');

var debug = require('debug')('feathers-sync');

var omit = require('lodash').omit;

module.exports = function (config) {

debug('setting up database %s', config.db);

var client = mubsub(config.db, config.mubsub);

var channel = client.channel(config.collection || 'events', omit(config, ['mubsub', 'db', 'collection']));

return function () {

var oldSetup = this.setup;

this.setup = function () {

var result = oldSetup.apply(this, arguments);

var services = this.services;

Object.keys(services).forEach(function (path) {

var service = services[path];

service._serviceEvents.forEach(function (event) {

var ev = path + ' ' + event;

debug('subscribing to handler %s', ev);

channel.subscribe(ev, function (data) {

debug('got event, calling old emit %s', ev);

service._emit.call(service, event, data); // eslint-disable-line no-useless-call

});

});

});

return result;

};

function configurePlugin (service, path) {

if (typeof service.emit !== 'function' || typeof service.on !== 'function') {

return;

}

// Store the old emit method

service._emit = service.emit;

// Override an emit that publishes to the hub

service.mixin({

emit: function (ev, data) {

var event = path + ' ' + ev;

debug('emitting event to channel %s', event);

return channel.publish(event, data);

}

});

}

if (this.version && parseInt(this.version, 10) >= 3) {

this.mixins.push(configurePlugin);

}

else {

this.providers.push((path, service) => configurePlugin(service, path));

}

if (typeof config.connect === 'function') {

channel.connection.once('connect', config.connect);

}

};

};