[addon] adds sorting and limit options

addon/lib/sort.js

@@ -0,0 +1,62 @@
+const HEALTHY_SEEDERS = 5;
+const SEEDED_SEEDERS = 1;
+const MIN_HEALTHY_COUNT = 10;
+const MAX_UNHEALTHY_COUNT = 5;
+
+const SortType = {
+  QUALITY: 'quality',
+  SEEDERS: 'seeders',
+};
+
+function sortStreams(streams, config) {
+  const sort = config.sort && config.sort.toLowerCase() || undefined;
+  const limit = /^[1-9][0-9]*$/.test(config.limit) && parseInt(config.limit) || undefined;
+  if (sort === SortType.SEEDERS) {
+    return sortBySeeders(streams).slice(0, limit)
+  }
+  return sortByVideoQuality(streams, limit)
+}
+
+function sortBySeeders(streams) {
+  const sortedStreams = streams
+      .sort((a, b) => b.filters.seeders - a.filters.seeders || b.filters.uploadDate - a.filters.uploadDate);
+  const healthy = sortedStreams.filter(stream => stream.filters.seeders >= HEALTHY_SEEDERS);
+  const seeded = sortedStreams.filter(stream => stream.filters.seeders >= SEEDED_SEEDERS);
+
+  if (healthy.length >= MIN_HEALTHY_COUNT) {
+    return healthy;
+  } else if (seeded.length >= MAX_UNHEALTHY_COUNT) {
+    return seeded.slice(0, MIN_HEALTHY_COUNT);
+  }
+  return sortedStreams.slice(0, MAX_UNHEALTHY_COUNT);
+}
+
+function sortByVideoQuality(streams, limit) {
+  const qualityMap = sortBySeeders(streams)
+      .reduce((map, stream) => {
+        const quality = stream.filters.quality;
+        map[quality] = (map[quality] || []).concat(stream);
+        return map;
+      }, {});
+  const sortedQualities = Object.keys(qualityMap)
+      .sort((a, b) => {
+        const aQuality = a === '4k' ? '2160p' : a;
+        const bQuality = b === '4k' ? '2160p' : b;
+        const aResolution = aQuality && aQuality.match(/\d+p/) && parseInt(aQuality, 10);
+        const bResolution = bQuality && bQuality.match(/\d+p/) && parseInt(bQuality, 10);
+        if (aResolution && bResolution) {
+          return bResolution - aResolution; // higher resolution first;
+        } else if (aResolution) {
+          return -1;
+        } else if (bResolution) {
+          return 1;
+        }
+        return a < b ? -1 : b < a ? 1 : 0;
+      });
+  return sortedQualities
+      .map(quality => qualityMap[quality].slice(0, limit))
+      .reduce((a, b) => a.concat(b), []);
+}
+
+module.exports = sortStreams;
+module.exports.SortType = SortType;