added some missing files.

batch.js

@@ -0,0 +1,32 @@
+var Promise = require('promise');
+
+//fun = [1,2,3] -> Promise({1: {}, 2: {}, 3: {}})
+module.exports = function batch(fun) {
+	var batches = {};
+	var result = null;
+
+	return function(ids) {
+
+		if (!Object.keys(batches).length) {	
+			result = 
+				Promise.
+					resolve().
+					then(function() {
+						var keys = Object.keys(batches);
+						batches = {};
+						return fun(keys);
+					});
+		}
+		ids.forEach(function(id) {
+			batches[id] = true;
+		});
+
+		return result.then(function(results) {
+			var prunedResults = {};
+			ids.forEach(function(id) {
+				prunedResults[id] = results[id];
+			});
+			return prunedResults;
+		});
+	};
+};

cache.js

@@ -0,0 +1,32 @@
+var Promise = require('promise');
+
+//fun = [1,2,3] -> Promise({1: {}, 2: {}, 3: {}})
+module.exports = function cache(fun) {
+	var cache = {};
+
+	return function(ids) {
+
+		var assemble = function(results) {
+			//put new results in cache:
+			Object.keys(results).forEach(function(id) {
+				cache[id] = results[id];
+			});
+			//grab cached results:
+			ids.forEach(function(id) {
+				results[id] = cache[id];
+			});
+
+			return results;
+		};
+
+		var culledIds = ids.filter(function(id) {
+			return !cache[id];
+		});
+
+		if (culledIds.length) {			
+			return fun(culledIds).then(assemble);
+		} else {
+			return Promise.resolve(assemble({}));
+		}
+	};
+};

rating-service.js

@@ -0,0 +1,112 @@
+var Promise = require('promise')
+var PouchDB = require('pouchdb')
+var ratingsDB = new PouchDB('ratings_db')
+var batch = require('./batch')
+var cache = require('./cache')
+
+var jlog = function(x) { console.log(JSON.stringify(x, null, 3)) }
+
+// ratings service
+function RatingService() {}
+RatingService.prototype = {
+
+    getRatings: function(userId, titleIds) {
+        jlog("getRatings(" + userId + ", [" + titleIds + "])")
+
+        return ratingsDB.allDocs({
+            keys: titleIds.map(function(id) {
+                return userId + "," + id;
+            }),
+            include_docs: true
+        }).then(function(dbResponse) {
+            var ratings = {}
+            dbResponse.rows.forEach(function(row) {
+                ratings[row.key.substr((userId + ",").length)] = row
+            })
+            return ratings
+        });
+	},
+
+    setRatings: function(userId, titlesIdsAndRating) {
+        jlog("setRatings(" + userId + ", {" + JSON.stringify(titlesIdsAndRating) + "})")        
+
+        function coerce(rating) {
+                if (rating > 5)
+                	return 5
+                else if (rating < 1)
+                	return 1
+                else
+                	return rating
+        }
+
+        var ids = Object.keys(titlesIdsAndRating)
+
+        //test:
+        // return Promise.resolve({
+        //     9: {
+        //         doc: {rating: 69}
+
+        //     },
+        //     10: {
+        //         doc: {rating: 69}
+        //     }
+        // })
+
+        return ratingsDB.allDocs({
+            keys: ids.map(function(id) {
+                return userId + "," + id;
+            }),
+            include_docs: true
+        }).then(function(getResponse) {
+            //jlog(getResponse)
+            return ratingsDB.bulkDocs(ids.map(function(id, index) {
+                // jlog("=============")
+                // jlog(titlesIdsAndRating[id].userRating)
+                return {
+                    _id: userId + "," + id,
+                    _rev: (!getResponse.rows[index].error ? getResponse.rows[index].value.rev : undefined),
+                    rating: coerce(titlesIdsAndRating[id].userRating)
+                };
+            })).then(function(setResponse) {
+                var results = {}
+                getResponse.rows.forEach(function(response, index) {
+                    if (setResponse[index].ok) {
+                        if (getResponse.rows[index].error) {
+                            results[response.key.substr((userId + ",").length)] = {
+                              id: setResponse[index].id,
+                              key: setResponse[index].id,
+                              value: {
+                                 rev: setResponse[index].rev
+                              },
+                              doc: {
+                                 rating: coerce(titlesIdsAndRating[response.key.substr((userId + ",").length)].userRating),
+                                 _id: setResponse[index].id,
+                                 _rev: setResponse[index].rev
+                              }
+                           }
+                        } else {
+                            results[response.key.substr((userId + ",").length)] = response
+                        }
+                    } else {
+                        results[response.key.substr((userId + ",").length)] = setResponse[index]
+                    }
+                })
+                return results
+            })
+        });	
+	}
+}
+
+module.exports = new RatingService()
+
+// module.exports.getRatings(1, [3,4,5]).then(jlog, jlog)
+// module.exports.getRatings(1, [1,2,3]).then(jlog, jlog)
+
+// //example:
+// module.exports.getRatings(1, [11]).then(jlog)
+// module.exports.getRatings(1, [11]).then(function(x) {
+// 	jlog(x)
+// 	module.exports.getRatings(1, [11]).then(jlog)
+// 	module.exports.getRatings(1, [11]).then(jlog)
+// })
+// jlog("-----------------------------------")

recommendation-service.js

@@ -0,0 +1,74 @@
+var Promise = require('promise')
+
+var PouchDB = require('pouchdb')
+var recommendationsDB = new PouchDB('recommendations_db')
+
+var log = console.log.bind(console)
+var jlog = function(x) { console.log(JSON.stringify(x, null, 3)) }
+
+// genrelist service
+function RecommendationsService() {}
+RecommendationsService.prototype = {
+	getGenreList: function(userId) {
+		var self = this
+		if (self.cache) {
+			return Promise.resolve(self.cache)
+		} else {
+	        return recommendationsDB.get((userId || 'all').toString())
+	            .then(function(response) {
+					self.cache = response.recommendations
+	                return response.recommendations
+	            })
+		}
+	},
+	addTitleToGenreList: function(userId, genreIndex, titles) {
+
+        return recommendationsDB.get(userId)
+            .then(function(response) {
+                var titlesLength = response.recommendations[genreIndex].titles.push(titles);
+                return recommendationsDB.put({
+                    _id: userId,
+                    _rev: response._rev,
+                    recommendations: response.recommendations                     
+                }).then(function(a) {
+                    return [
+                        {
+                            path: ['genrelist', genreIndex, 'titles', titlesLength - 1],
+                            value: titles
+                        },
+                        {
+                            path: ['genrelist', genreIndex, 'titles', 'length'],
+                            value: titlesLength
+                        }
+                    ];
+                });
+            });		
+	},
+
+    //@TODO: untested.
+    //[].splice(index, howMany, replce, replce, replce) takes unlimited number of the final argument
+    spliceTitleFromGenreList: function(userId, a, b, c) {
+        return recommendationsDB.get(userId)
+            .then(function(response) {
+                var titlesLength = response.recommendations[genreIndex].titles.splice(a, b, c);
+                return recommendationsDB.put({
+                    _id: userId,
+                    _rev: response._rev,
+                    recommendations: response.recommendations                     
+                }).then(function() {
+                    return [
+                        {
+                            path: ['genrelist', genreIndex, 'titles', titlesLength - 1],
+                            value: titles
+                        },
+                        {
+                            path: ['genrelist', genreIndex, 'titles', 'length'],
+                            value: titlesLength
+                        }
+                    ];
+                });
+            });
+    }    
+}
+
+module.exports = new RecommendationsService()

title-service.js

@@ -0,0 +1,36 @@
+var PouchDB = require('pouchdb')
+var titlesDB = new PouchDB('titles_db')
+var batch = require('./batch')
+var cache = require('./cache')
+
+var jlog = function(x) { console.log(JSON.stringify(x, null, 3)) }
+
+// titles service
+function TitleService() {}
+TitleService.prototype = {
+	getTitles: function(titleIds) {
+		jlog("getTitles([" + titleIds + "])")
+
+        return titlesDB.allDocs({
+            keys: titleIds,
+            include_docs: true
+        }).then(function(dbResponse) {
+			var titles = {}
+			dbResponse.rows.forEach(function (row) {
+				titles[row.key] = row	
+			})
+			return titles
+		})
+	}
+}
+
+module.exports = new TitleService()
+
+//example:
+// module.exports.getTitles([12]).then(jlog)
+// module.exports.getTitles([12]).then(function(x) {
+// 	jlog(x)
+// 	module.exports.getTitles([13]).then(jlog)
+// 	module.exports.getTitles([12,13]).then(jlog)
+// })
+// jlog("-----------------------------------")