Ali Ghassemi | 5b40888 | 2015-01-16 14:58:00 -0800 | [diff] [blame] | 1 | var mercury = require('mercury'); |
| 2 | var EventEmitter = require('events').EventEmitter; |
| 3 | |
| 4 | var freeze = require('../../lib/mercury/freeze'); |
| 5 | |
| 6 | var namespaceService = require('../namespace/service'); |
| 7 | var smartService = require('../smart/service'); |
| 8 | |
| 9 | var log = require('../../lib/log')('services:recommendations:service'); |
| 10 | |
| 11 | var LEARNER_KEY = 'learner-shortcut'; |
| 12 | var MAX_NUM_RECOMMENDATIONS = 10; |
| 13 | |
| 14 | module.exports = { |
| 15 | getAll: getAll |
| 16 | }; |
| 17 | |
| 18 | // Singleton state for all the bookmarks. |
| 19 | var recommendationsObs = mercury.array([]); |
| 20 | |
| 21 | smartService.loadOrCreate( |
| 22 | LEARNER_KEY, |
| 23 | smartService.constants.LEARNER_SHORTCUT, { |
| 24 | k: MAX_NUM_RECOMMENDATIONS |
| 25 | } |
| 26 | ).catch(function(err) { |
| 27 | log.error(err); |
| 28 | }); |
| 29 | |
| 30 | /* |
| 31 | * Gets all the namespace items that are recommended based on our learning agent |
| 32 | * As new recommendations become available/removed the observable array will |
| 33 | * change to reflect the changes. |
| 34 | * |
| 35 | * The observable result has an events property which is an EventEmitter |
| 36 | * and emits 'end', 'itemError' events. |
| 37 | * |
| 38 | * @return {Promise.<mercury.array>} Promise of an observable array |
| 39 | * of recommended items |
| 40 | */ |
| 41 | function getAll() { |
| 42 | |
| 43 | // Empty out the array |
| 44 | recommendationsObs.splice(0, recommendationsObs.getLength()); |
| 45 | var immutableRecommendationsObs = freeze(recommendationsObs); |
| 46 | immutableRecommendationsObs.events = new EventEmitter(); |
| 47 | |
| 48 | return smartService.predict(LEARNER_KEY).then(getRecommendationItems); |
| 49 | |
| 50 | function getRecommendationItems(recs) { |
| 51 | var allItems = recs.map(function(rec) { |
| 52 | var name = rec.item; |
| 53 | return addNamespaceItem(name).catch(function(err) { |
| 54 | immutableRecommendationsObs.events.emit('itemError', { |
| 55 | name: name, |
| 56 | error: err |
| 57 | }); |
| 58 | log.error('Failed to create item for "' + name + '"', err); |
| 59 | }); |
| 60 | }); |
| 61 | |
| 62 | Promise.all(allItems).then(function() { |
| 63 | immutableRecommendationsObs.events.emit('end'); |
| 64 | }).catch(function() { |
| 65 | immutableRecommendationsObs.events.emit('end'); |
| 66 | }); |
| 67 | |
| 68 | return immutableRecommendationsObs; |
| 69 | } |
| 70 | } |
| 71 | |
| 72 | /* |
| 73 | * Gets the namespace items for a name and adds it to the observable array |
| 74 | */ |
| 75 | function addNamespaceItem(name) { |
| 76 | return namespaceService.getNamespaceItem(name) |
| 77 | .then(function(item) { |
| 78 | recommendationsObs.push(item); |
| 79 | }); |
| 80 | } |