Prepare widget with data for versions downloads chart (dart-lang#8360)

app/lib/frontend/handlers/package.dart

@@ -454,7 +454,7 @@ Future<PackagePageData> loadPackagePageData(
   final scoreCardFuture = scoreCardBackend
       .getScoreCardData(packageName, versionName, package: package);
 
-  final weeklyDownloadCountsFuture = getWeeklyDownloads(package.name!);
+  final weeklyDownloadCountsFuture = getWeeklyTotalDownloads(package.name!);
 
   await Future.wait([
     latestReleasesFuture,

app/lib/frontend/templates/views/pkg/score_tab.dart

@@ -2,8 +2,10 @@
 // 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.
 
+import 'package:_pub_shared/format/encoding.dart';
 import 'package:_pub_shared/format/number_format.dart';
 import 'package:pana/models.dart';
+import 'package:pub_dev/service/download_counts/download_counts.dart';
 import 'package:pub_dev/shared/popularity_storage.dart';
 
 import '../../../../scorecard/models.dart' hide ReportStatus;
@@ -77,6 +79,8 @@ d.Node scoreTabNode({
           ],
         ),
         _reportNode(report),
+        if (card.weeklyVersionsDownloads != null)
+          _versionDownloadsChart(card.weeklyVersionsDownloads!),
         if (toolEnvInfo != null) toolEnvInfo,
       ]),
     if (!showPending)
@@ -173,6 +177,39 @@ d.Node _section(ReportSection section) {
   ]);
 }
 
+d.Node _versionDownloadsChart(
+    WeeklyVersionsDownloadCounts weeklyVersionsDownloads) {
+  return d.div(
+    classes: ['versions-downloads-chart'],
+    id: '-versions-downloads-chart',
+    attributes: {
+      'data-widget': 'versions-downloads-chart',
+      'data-versions-downloads-chart':
+          _encodeForVersionsChart(weeklyVersionsDownloads)
+    },
+  );
+}
+
+String _encodeForVersionsChart(WeeklyVersionsDownloadCounts wvcd) {
+  final date = wvcd.newestDate.toUtc().millisecondsSinceEpoch ~/ 1000;
+
+  final allCounts = <int>[];
+  final allRanges = <String>[];
+  wvcd.majorRangeWeeklyDownloads.forEach((e) => allCounts.addAll(e.counts));
+  wvcd.minorRangeWeeklyDownloads.forEach((e) => allCounts.addAll(e.counts));
+  wvcd.patchRangeWeeklyDownloads.forEach((e) => allCounts.addAll(e.counts));
+  allCounts.addAll(wvcd.totalWeeklyDownloads);
+
+  wvcd.majorRangeWeeklyDownloads.forEach((e) => allRanges.add(e.versionRange));
+  wvcd.minorRangeWeeklyDownloads.forEach((e) => allRanges.add(e.versionRange));
+  wvcd.patchRangeWeeklyDownloads.forEach((e) => allRanges.add(e.versionRange));
+
+  return [
+    encodeIntsAsLittleEndianBase64String([date, ...allCounts]),
+    allRanges
+  ].join(',');
+}
+
 final _statusIconUrls = {
   ReportStatus.passed:
       staticUrls.getAssetUrl('/static/img/report-ok-icon-green.svg'),

app/lib/scorecard/backend.dart

@@ -10,6 +10,7 @@ import 'package:logging/logging.dart';
 import 'package:meta/meta.dart';
 import 'package:pool/pool.dart';
 import 'package:pub_dev/service/download_counts/backend.dart';
+import 'package:pub_dev/service/download_counts/computations.dart';
 import 'package:pub_dev/shared/exceptions.dart';
 import 'package:pub_dev/shared/popularity_storage.dart';
 import 'package:pub_dev/task/backend.dart';
@@ -162,6 +163,9 @@ class ScoreCardBackend {
       taskStatus = PackageVersionStatus.pending;
     }
 
+    final weeklyVersionsDownloads =
+        await getWeeklyVersionsDownloads(packageName);
+
     final data = ScoreCardData(
       packageName: packageName,
       packageVersion: packageVersion,
@@ -173,6 +177,7 @@ class ScoreCardBackend {
       ),
       panaReport: PanaReport.fromSummary(summary, packageStatus: status),
       taskStatus: taskStatus,
+      weeklyVersionsDownloads: weeklyVersionsDownloads,
     );
     await cacheEntry.set(data);
     return data;

app/lib/scorecard/models.dart

@@ -8,6 +8,7 @@ import 'package:_pub_shared/search/tags.dart';
 import 'package:json_annotation/json_annotation.dart';
 import 'package:pana/models.dart';
 import 'package:pub_dev/service/download_counts/backend.dart';
+import 'package:pub_dev/service/download_counts/download_counts.dart';
 import 'package:pub_dev/task/models.dart';
 
 import '../scorecard/backend.dart';
@@ -33,6 +34,7 @@ class ScoreCardData {
   final DartdocReport? dartdocReport;
   final PanaReport? panaReport;
   final PackageVersionStatus? taskStatus;
+  final WeeklyVersionsDownloadCounts? weeklyVersionsDownloads;
 
   ScoreCardData({
     this.packageName,
@@ -42,6 +44,7 @@ class ScoreCardData {
     this.dartdocReport,
     this.panaReport,
     this.taskStatus,
+    this.weeklyVersionsDownloads,
   });
 
   factory ScoreCardData.fromJson(Map<String, dynamic> json) =>

app/lib/service/download_counts/computations.dart

@@ -46,42 +46,89 @@ Future<void> upload30DaysTotal(Map<String, int> counts) async {
       jsonUtf8Encoder.convert(counts));
 }
 
-Future<WeeklyDownloadCounts?> getWeeklyDownloads(String package) async {
+Future<WeeklyDownloadCounts?> getWeeklyTotalDownloads(String package) async {
   return (await cache.weeklyDownloadCounts(package).get(() async {
-    final wdc = await computeWeeklyDownloads(package);
-    if (wdc.newestDate == null) {
-      return null;
-    }
-    return WeeklyDownloadCounts(
-        weeklyDownloads: wdc.weeklyDownloads, newestDate: wdc.newestDate!);
+    return computeWeeklyTotalDownloads(package);
+  }));
+}
+
+Future<WeeklyVersionsDownloadCounts?> getWeeklyVersionsDownloads(
+    String package) async {
+  return (await cache.weeklyVersionsDownloadCounts(package).get(() async {
+    return computeWeeklyVersionsDownloads(package);
   }));
 }
 
-/// Computes `weeklyDownloads` starting from `newestDate` for [package].
+/// Computes weekly downloads starting from `newestDate` for [package] and 52
+/// weeks back.
 ///
-/// Each number in `weeklyDownloads` is the total number of downloads for
+/// Each number in weeklyDownloads` is the total number of downloads for
 /// a given 7 day period starting from the newest date with download counts
 /// data available.
-Future<({List<int> weeklyDownloads, DateTime? newestDate})>
-    computeWeeklyDownloads(String package) async {
-  final weeklyDownloads = List.filled(52, 0);
+Future<WeeklyDownloadCounts?> computeWeeklyTotalDownloads(
+    String package) async {
   final countData =
       await downloadCountsBackend.lookupDownloadCountData(package);
   if (countData == null) {
-    return (weeklyDownloads: <int>[], newestDate: null);
+    return null;
   }
 
-  final totals = countData.totalCounts;
+  return WeeklyDownloadCounts(
+      weeklyDownloads: _computeWeeklyCounts(countData.totalCounts),
+      newestDate: countData.newestDate!);
+}
 
+/// Computes weekly downloads starting from `newestDate` for [package] and 52
+/// weeks back for all stored major, minor, and patch version ranges and total
+/// downloads.
+Future<WeeklyVersionsDownloadCounts?> computeWeeklyVersionsDownloads(
+    String package) async {
+  final countData =
+      await downloadCountsBackend.lookupDownloadCountData(package);
+  if (countData == null) return null;
+
+  final majorRangeWeeklyCounts = <VersionRangeCount>[];
+  countData.majorRangeCounts.forEach((vrc) {
+    majorRangeWeeklyCounts.add((
+      counts: _computeWeeklyCounts(vrc.counts),
+      versionRange: vrc.versionRange
+    ));
+  });
+  final minorRangeWeeklyCounts = <VersionRangeCount>[];
+  countData.minorRangeCounts.forEach((vrc) {
+    minorRangeWeeklyCounts.add((
+      counts: _computeWeeklyCounts(vrc.counts),
+      versionRange: vrc.versionRange
+    ));
+  });
+  final patchRangeWeeklyCounts = <VersionRangeCount>[];
+  countData.patchRangeCounts.forEach((vrc) {
+    patchRangeWeeklyCounts.add((
+      counts: _computeWeeklyCounts(vrc.counts),
+      versionRange: vrc.versionRange
+    ));
+  });
+
+  final weeklyTotalCounts = _computeWeeklyCounts(countData.totalCounts);
+
+  return WeeklyVersionsDownloadCounts(
+      newestDate: countData.newestDate!,
+      majorRangeWeeklyDownloads: majorRangeWeeklyCounts,
+      minorRangeWeeklyDownloads: minorRangeWeeklyCounts,
+      patchRangeWeeklyDownloads: patchRangeWeeklyCounts,
+      totalWeeklyDownloads: weeklyTotalCounts);
+}
+
+List<int> _computeWeeklyCounts(List<int> dailyCounts) {
+  final weeklyCounts = List.filled(52, 0);
   for (int w = 0; w < 52; w++) {
     var sum = 0;
     for (int d = 0; d < 7; d++) {
-      if (totals[w * 7 + d] > 0) {
-        sum += totals[w * 7 + d];
+      if (dailyCounts[w * 7 + d] > 0) {
+        sum += dailyCounts[w * 7 + d];
       }
     }
-    weeklyDownloads[w] = sum;
+    weeklyCounts[w] = sum;
   }
-
-  return (weeklyDownloads: weeklyDownloads, newestDate: countData.newestDate!);
+  return weeklyCounts;
 }

app/lib/service/download_counts/download_counts.dart

@@ -8,11 +8,19 @@ import 'package:json_annotation/json_annotation.dart';
 import 'package:pub_semver/pub_semver.dart';
 part 'download_counts.g.dart';
 
-/// A tuple containing a string describing a `versionRange`, for instance
-/// '>=1.0.0-0 <2.0.0', and a list of integers with a count for each day.
-/// The `counts` list contains at most [maxAge] entries. The first entry
-/// represents the number of downloads on `newestDate` followed by the
-/// downloads on `newestDate` - 1 and so on. E.g.
+/// A [VersionRangeCount] is a tuple containing a version range and a list of
+/// download counts for periods of same length.
+///
+/// The first entry in the tuple is a string describing the `versionRange`, for
+/// instance '>=1.0.0-0 <2.0.0'.
+///
+/// The second entry in the tuple is an integer list of `counts` with download
+/// counts for each period. A period could for instance be a day, or a week etc.
+/// The `counts` list contains at most [maxAge] entries.
+///
+/// Consider the example of period being one day. The first count represents the
+/// number of downloads on `newestDate` followed by the downloads on
+/// `newestDate` - 1 and so on. E.g.
 ///
 ///  counts = [ 42, 21, 55 ]
 ///              ▲   ▲   ▲
@@ -218,7 +226,11 @@ class CountData {
 
 @JsonSerializable(includeIfNull: false)
 class WeeklyDownloadCounts {
+  /// Each number in [weeklyDownloads] is the total number of downloads for
+  /// a given 7 day period starting from [newestDate].
   final List<int> weeklyDownloads;
+
+  /// The newest date with download counts data available.
   final DateTime newestDate;
 
   WeeklyDownloadCounts({
@@ -230,3 +242,46 @@ class WeeklyDownloadCounts {
       _$WeeklyDownloadCountsFromJson(json);
   Map<String, dynamic> toJson() => _$WeeklyDownloadCountsToJson(this);
 }
+
+@JsonSerializable(includeIfNull: false)
+class WeeklyVersionsDownloadCounts {
+  /// An integer list where each number is the total number of downloads for a
+  /// given 7 day period starting from [newestDate].
+  final List<int> totalWeeklyDownloads;
+
+  /// A list of [VersionRangeCount] with major version ranges and weekly
+  /// downloads for these ranges.
+  ///
+  /// E.g. each number in the `counts` list is the total number of downloads for
+  /// the range in a 7 day period starting from [newestDate].
+  final List<VersionRangeCount> majorRangeWeeklyDownloads;
+
+  /// A list of [VersionRangeCount] with minor version ranges and weekly
+  /// downloads for these ranges.
+  ///
+  /// E.g. each number in the `counts` list is the total number of downloads for
+  /// the range in a 7 day period starting from [newestDate].
+  final List<VersionRangeCount> minorRangeWeeklyDownloads;
+
+  /// A list of [VersionRangeCount] with patch version ranges and weekly
+  /// downloads for these ranges.
+  ///
+  /// E.g. each number in the `counts` list is the total number of downloads for
+  /// the range in a 7 day period starting from [newestDate].
+  final List<VersionRangeCount> patchRangeWeeklyDownloads;
+
+  /// The newest date with download counts data available.
+  final DateTime newestDate;
+
+  WeeklyVersionsDownloadCounts({
+    required this.newestDate,
+    required this.majorRangeWeeklyDownloads,
+    required this.minorRangeWeeklyDownloads,
+    required this.patchRangeWeeklyDownloads,
+    required this.totalWeeklyDownloads,
+  });
+
+  factory WeeklyVersionsDownloadCounts.fromJson(Map<String, dynamic> json) =>
+      _$WeeklyVersionsDownloadCountsFromJson(json);
+  Map<String, dynamic> toJson() => _$WeeklyVersionsDownloadCountsToJson(this);
+}