Add support for matching from Youtube urls

lib/services/youtube/index.js

@@ -1,5 +1,7 @@
 "use strict";
 var parse = require('url').parse;
+var freebase = require('./freebase');
+var querystring = require('querystring');
 var Promise = require('bluebird');
 var request = require('superagent');
 require('superagent-bluebird-promise');
@@ -19,6 +21,65 @@ var apiRoot = "https://www.googleapis.com/youtube/v3";
 
 module.exports.match = require('./url').match;
 
+module.exports.parseUrl = function(url) {
+  var parsed = parse(url);
+  var query = querystring.parse(parsed.query);
+  var id = query.v;
+  
+  if (!id) {
+    id = parsed.path.substr(1);
+    if (!id) {
+      throw new Error();
+    }
+  }
+  return module.exports.lookupId(id, "track");
+}
+
+module.exports.lookupId = function(id, type) {
+  
+  var path = "/videos?part=snippet%2Cstatus%2CtopicDetails&id=" + id + "&key=" + credentials.key;
+  
+  return request.get(apiRoot + path).promise().then(function(res) {
+    var item = res.body.items[0];
+    if (item.topicDetails.topicIds) {
+      var promises = [];
+      item.topicDetails.topicIds.forEach(function(topicId) {
+        promises.push(freebase.get(topicId).then(function(topic) {
+          return topic.property["/music/recording/song"] ? topic : false;
+        }, function(err) {
+          console.log(err)
+        }));
+      })
+      return Promise.all(promises).then(function(topics) {
+        for (var key in topics) {
+          var topic = topics[key];
+          if (topic) {
+            console.log(topic.property['/music/recording/song'])
+            return {
+              id: id,
+              service: "youtube",
+              type: "track",
+              name: topic.property['/music/recording/song'].values[0].text,
+              artist: {name: topic.property['/music/recording/artist'].values[0].text},
+              album: {name: ""},
+              streamUrl: "https://youtu.be/" + id,
+              purchaseUrl: null,
+              artwork: {
+                small: item.snippet.thumbnails.medium.url,
+                large: item.snippet.thumbnails.high.url,
+              }
+            }
+          }
+        }
+      });
+    } else {
+      return {service: "youtube"};
+    }
+  }, function(res) {
+    return {service: "youtube"};
+  });
+};
+
 module.exports.search = function(data) {
   var query, album;
   var type = data.type;