Save trend scores as doubles

app/lib/fake/backend/fake_download_counts.dart

@@ -49,8 +49,8 @@ Future<void> generateFake30DaysTotals(Map<String, int> totals) async {
           downloadCounts30DaysTotalsFileName, jsonUtf8Encoder.convert(totals));
 }
 
-Future<void> generateFakeTrendScores(Map<String, int> totals) async {
+Future<void> generateFakeTrendScores(Map<String, double> trends) async {
   await storageService
       .bucket(activeConfiguration.reportsBucketName!)
-      .writeBytesWithRetry(trendScoreFileName, jsonUtf8Encoder.convert(totals));
+      .writeBytesWithRetry(trendScoreFileName, jsonUtf8Encoder.convert(trends));
 }

app/lib/search/search_service.dart

@@ -79,7 +79,7 @@ class PackageDocument {
   /// The normalized score between [0.0-1.0] (1.0 being the most downloaded package).
   double? downloadScore;
 
-  final int trendScore;
+  final double trendScore;
 
   final int likeCount;
 
@@ -112,7 +112,7 @@ class PackageDocument {
     List<String>? tags,
     int? downloadCount,
     this.downloadScore,
-    int? trendScore,
+    double? trendScore,
     int? likeCount,
     this.likeScore,
     int? grantedPoints,

app/lib/service/download_counts/backend.dart

@@ -31,42 +31,44 @@ class DownloadCountsBackend {
   late CachedValue<Map<String, int>> _thirtyDaysTotals;
   var _lastDownloadsData = (data: <String, int>{}, etag: '');
 
-  late CachedValue<Map<String, int>> _trendScores;
-  var _lastTrendData = (data: <String, int>{}, etag: '');
+  late CachedValue<Map<String, double>> _trendScores;
+  var _lastTrendData = (data: <String, double>{}, etag: '');
 
   DownloadCountsBackend(this._db) {
-    _thirtyDaysTotals = CachedValue(
+    _thirtyDaysTotals = CachedValue<Map<String, int>>(
         name: 'thirtyDaysTotalDownloadCounts',
         maxAge: Duration(days: 14),
         interval: Duration(minutes: 30),
         updateFn: _updateThirtyDaysTotals);
-    _trendScores = CachedValue(
+    _trendScores = CachedValue<Map<String, double>>(
         name: 'trendScores',
         maxAge: Duration(days: 14),
         interval: Duration(minutes: 30),
         updateFn: _updateTrendScores);
   }
 
   Future<Map<String, int>> _updateThirtyDaysTotals() async {
-    return _fetchAndUpdateCachedData(
-        fileName: downloadCounts30DaysTotalsFileName,
-        currentCachedData: _lastDownloadsData,
-        updateCache: (data) => _lastDownloadsData = data,
-        errorContext: '30-days total download counts');
+    return _fetchAndUpdateCachedData<int>(
+      fileName: downloadCounts30DaysTotalsFileName,
+      currentCachedData: _lastDownloadsData,
+      updateCache: (data) => _lastDownloadsData = data,
+      errorContext: '30-days total download counts',
+    );
   }
 
-  Future<Map<String, int>> _updateTrendScores() async {
-    return _fetchAndUpdateCachedData(
-        fileName: trendScoreFileName,
-        currentCachedData: _lastTrendData,
-        updateCache: (data) => _lastTrendData = data,
-        errorContext: 'trend scores');
+  Future<Map<String, double>> _updateTrendScores() async {
+    return _fetchAndUpdateCachedData<double>(
+      fileName: trendScoreFileName,
+      currentCachedData: _lastTrendData,
+      updateCache: (data) => _lastTrendData = data,
+      errorContext: 'trend scores',
+    );
   }
 
-  Future<Map<String, int>> _fetchAndUpdateCachedData({
+  Future<Map<String, V>> _fetchAndUpdateCachedData<V>({
     required String fileName,
-    required ({Map<String, int> data, String etag}) currentCachedData,
-    required void Function(({Map<String, int> data, String etag}) newData)
+    required ({Map<String, V> data, String etag}) currentCachedData,
+    required void Function(({Map<String, V> data, String etag}) newData)
         updateCache,
     required String errorContext,
   }) async {
@@ -89,7 +91,7 @@ class DownloadCountsBackend {
                 .single,
           );
 
-      final data = _parseJsonToMapStringInt(rawData, fileName);
+      final data = _parseJsonToMapStringV<V>(rawData, fileName);
 
       final newData = (data: data, etag: info.etag);
       updateCache(newData);
@@ -109,23 +111,25 @@ class DownloadCountsBackend {
     }
   }
 
-  Map<String, int> _parseJsonToMapStringInt(dynamic rawJson, String fileName) {
+  Map<String, V> _parseJsonToMapStringV<V>(dynamic rawJson, String fileName) {
     if (rawJson is! Map) {
-      throw FormatException(
-          'Expected JSON for $fileName to be a Map, but got ${rawJson.runtimeType}');
+      throw FormatException('Expected JSON for $fileName to be a Map, but got'
+          ' ${rawJson.runtimeType}');
     }
 
-    final Map<String, int> result = {};
+    final Map<String, V> result = {};
     for (final entry in rawJson.entries) {
       if (entry.key is! String) {
         throw FormatException(
-            'Expected map keys for $fileName to be String, but found ${entry.key.runtimeType}');
+            'Expected map keys for $fileName to be String, but found'
+            ' ${entry.key.runtimeType}');
       }
-      if (entry.value is! int) {
+      if (entry.value is! V) {
         throw FormatException(
-            'Expected map value for key "${entry.key}" in $fileName to be int, but got ${entry.value.runtimeType}');
+            'Expected map value for key "${entry.key}" in $fileName to be'
+            ' ${V.runtimeType}, but got ${entry.value.runtimeType}');
       }
-      result[entry.key as String] = entry.value as int;
+      result[entry.key as String] = entry.value as V;
     }
     return result;
   }
@@ -143,7 +147,7 @@ class DownloadCountsBackend {
   int? lookup30DaysTotalCounts(String package) =>
       _thirtyDaysTotals.isAvailable ? _thirtyDaysTotals.value![package] : null;
 
-  int? lookupTrendScore(String package) =>
+  double? lookupTrendScore(String package) =>
       _trendScores.isAvailable ? _trendScores.value![package] : null;
 
   Future<CountData?> lookupDownloadCountData(String pkg) async {

app/test/service/download_counts/computations_test.dart

@@ -339,22 +339,22 @@ void main() {
   });
 
   testWithProfile('cache package trend scores', fn: () async {
-    await generateFakeTrendScores({'foo': 3, 'bar': 1, 'baz': 2});
+    await generateFakeTrendScores({'foo': 3.0, 'bar': 1.0, 'baz': 2.0});
     expect(downloadCountsBackend.lookupTrendScore('foo'), isNull);
     expect(downloadCountsBackend.lookupTrendScore('bar'), isNull);
     expect(downloadCountsBackend.lookupTrendScore('baz'), isNull);
 
     await downloadCountsBackend.start();
-    expect(downloadCountsBackend.lookupTrendScore('foo'), 3);
-    expect(downloadCountsBackend.lookupTrendScore('bar'), 1);
-    expect(downloadCountsBackend.lookupTrendScore('baz'), 2);
+    expect(downloadCountsBackend.lookupTrendScore('foo'), 3.0);
+    expect(downloadCountsBackend.lookupTrendScore('bar'), 1.0);
+    expect(downloadCountsBackend.lookupTrendScore('baz'), 2.0);
     expect(downloadCountsBackend.lookupTrendScore('bax'), isNull);
 
-    await generateFakeTrendScores({'foo': 9, 'bar': 2, 'baz': 5});
+    await generateFakeTrendScores({'foo': 9.0, 'bar': 2.0, 'baz': 5.0});
     await downloadCountsBackend.start();
-    expect(downloadCountsBackend.lookupTrendScore('foo'), 9);
-    expect(downloadCountsBackend.lookupTrendScore('bar'), 2);
-    expect(downloadCountsBackend.lookupTrendScore('baz'), 5);
+    expect(downloadCountsBackend.lookupTrendScore('foo'), 9.0);
+    expect(downloadCountsBackend.lookupTrendScore('bar'), 2.0);
+    expect(downloadCountsBackend.lookupTrendScore('baz'), 5.0);
     expect(downloadCountsBackend.lookupTrendScore('bax'), isNull);
   });
 }