Remove threshold from growthrate function

Author: szakarias

app/lib/service/download_counts/package_trends.dart

@@ -2,10 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-const minAvgDailyDownloadsThreshold = 1000;
 const analysisWindowDays = 30;
-const weightAge = 0.25;
-const weightGrowthRate = 0.75;
 
 /// Calculates the relative daily growth rate of a package's downloads.
 ///
@@ -14,12 +11,6 @@ const weightGrowthRate = 0.75;
 /// over the last ([analysisWindowDays]) days to determine how fast a package is
 /// growing relative to its own current download volume.
 ///
-/// Returns -double.maxFinite:
-/// - If the [totalDownloads] list has fewer data points than
-///   [analysisWindowDays].
-/// - If the average daily downloads over the [analysisWindowDays] period are
-///   less than [minAvgDailyDownloadsThreshold].
-///
 /// Otherwise, it returns the calculated relative growth rate. A positive value
 /// indicates an upward trend in downloads, while a negative value indicates a
 /// downward trend. The magnitude represents the growth (or decline) rate
@@ -29,21 +20,22 @@ const weightGrowthRate = 0.75;
 /// relative growth) than for a package with 10000 average daily downloads (0.1%
 /// relative growth).
 double computeRelativeGrowthRate(List<int> totalDownloads) {
+  final List<int> data;
   if (totalDownloads.length < analysisWindowDays) {
-    // insufficient data points.
-    return -double.maxFinite;
+    data = [
+      ...totalDownloads,
+      ...List.filled(analysisWindowDays - totalDownloads.length, 0)
+    ];
+  } else {
+    data = totalDownloads;
   }
 
-  final recentDownloads = totalDownloads.sublist(0, analysisWindowDays);
+  final recentDownloads = data.sublist(0, analysisWindowDays);
 
   final averageRecentDownloads =
       recentDownloads.reduce((prev, element) => prev + element) /
           recentDownloads.length;
 
-  if (averageRecentDownloads < minAvgDailyDownloadsThreshold) {
-    // Package does not meet the minimum average download threshold.
-    return -double.maxFinite;
-  }
   // We reverse the recentDownloads list for regression, since the first entry
   // is the newest point in time. By reversing, we pass the data in
   // chronological order.

app/test/service/download_counts/package_trends_test.dart

@@ -20,17 +20,6 @@ void main() {
   });
 
   group('computeRelativeGrowthRate', () {
-    test('returns -double.maxFinite for insufficient data', () {
-      final downloads = List<int>.generate(analysisWindowDays - 1, (i) => 1500);
-      expect(computeRelativeGrowthRate(downloads), -double.maxFinite);
-    });
-
-    test('returns -double.maxFinite for average downloads below threshold', () {
-      final downloads = List<int>.generate(
-          analysisWindowDays, (i) => minAvgDailyDownloadsThreshold - 1);
-      expect(computeRelativeGrowthRate(downloads), -double.maxFinite);
-    });
-
     test('returns 0.0 for stable downloads meeting threshold', () {
       final downloads = List<int>.generate(analysisWindowDays, (i) => 2000);
       expect(computeRelativeGrowthRate(downloads), 0.0);