Experimental: use trend scores in search and sorting

Author: szakarias

app/lib/frontend/templates/_consts.dart

@@ -3,6 +3,7 @@
 // BSD-style license that can be found in the LICENSE file.
 
 import 'package:_pub_shared/search/tags.dart';
+import 'package:pub_dev/frontend/request_context.dart';
 
 import '../dom/dom.dart' as d;
 
@@ -124,5 +125,10 @@ List<SortDict> getSortDicts(bool isSearch) {
   final removeId = isSearch ? 'listing_relevance' : 'search_relevance';
   return <SortDict>[
     ..._sortDicts.where((d) => d.id != removeId),
+    if (requestContext.experimentalFlags.showTrending)
+      SortDict(
+          id: 'trending',
+          label: 'trendin',
+          tooltip: 'Packages are sorted by trending.'),
   ];
 }

app/lib/search/backend.dart

@@ -372,6 +372,7 @@ class SearchBackend {
       updated: p.lastVersionPublished!,
       readme: compactReadme(readmeAsset?.textContent),
       downloadCount: downloadCountsBackend.lookup30DaysTotalCounts(pv.package),
+      trendScore: downloadCountsBackend.lookupTrendScore(pv.package),
       likeCount: p.likes,
       grantedPoints: scoreCard.grantedPubPoints,
       maxPoints: scoreCard.maxPubPoints,

app/lib/search/mem_index.dart

@@ -43,6 +43,7 @@ class InMemoryPackageIndex {
   late final List<IndexedPackageHit> _downloadsOrderedHits;
   late final List<IndexedPackageHit> _likesOrderedHits;
   late final List<IndexedPackageHit> _pointsOrderedHits;
+  late final List<IndexedPackageHit> _trendingOrderedHits;
 
   // Contains all of the topics the index had seen so far.
   // TODO: consider moving this into a separate index
@@ -121,6 +122,8 @@ class InMemoryPackageIndex {
         score: (doc) => doc.likeCount.toDouble());
     _pointsOrderedHits = _rankWithComparator(_comparePoints,
         score: (doc) => doc.grantedPoints.toDouble());
+    _trendingOrderedHits = _rankWithComparator(_compareTrending,
+        score: (doc) => doc.trendScore.toDouble());
   }
 
   IndexInfo indexInfo() {
@@ -289,6 +292,9 @@ class InMemoryPackageIndex {
       case SearchOrder.points:
         indexedHits = _pointsOrderedHits.whereInScores(packageScores);
         break;
+      case SearchOrder.trending:
+        indexedHits = _trendingOrderedHits.whereInScores(packageScores);
+        break;
     }
 
     // bound by offset and limit (or randomize items)
@@ -532,6 +538,12 @@ class InMemoryPackageIndex {
     if (x != 0) return x;
     return _compareUpdated(a, b);
   }
+
+  int _compareTrending(PackageDocument a, PackageDocument b) {
+    final x = -a.trendScore.compareTo(b.trendScore);
+    if (x != 0) return x;
+    return _compareUpdated(a, b);
+  }
 }
 
 class _TextResults {

app/lib/search/search_service.dart

@@ -79,6 +79,8 @@ class PackageDocument {
   /// The normalized score between [0.0-1.0] (1.0 being the most downloaded package).
   double? downloadScore;
 
+  final int trendScore;
+
   final int likeCount;
 
   /// The normalized score between [0.0-1.0] (1.0 being the most liked package).
@@ -110,6 +112,7 @@ class PackageDocument {
     List<String>? tags,
     int? downloadCount,
     this.downloadScore,
+    int? trendScore,
     int? likeCount,
     this.likeScore,
     int? grantedPoints,
@@ -121,6 +124,7 @@ class PackageDocument {
   })  : created = created ?? clock.now(),
         updated = updated ?? clock.now(),
         downloadCount = downloadCount ?? 0,
+        trendScore = trendScore ?? 0,
         likeCount = likeCount ?? 0,
         grantedPoints = grantedPoints ?? 0,
         maxPoints = maxPoints ?? 0,

app/lib/search/search_service.g.dart

@@ -64,6 +64,9 @@ enum SearchOrder {
 
   /// Search order should be in decreasing pub points.
   points,
+
+  /// Search order should be in decreasing trend score.
+  trending,
 }
 
 /// Returns null if [value] is not a recognized search order.