Prepare data for downloads chart

pkg/web_app/lib/src/widget/downloads_chart/computations.dart

@@ -0,0 +1,36 @@
+// Copyright (c) 2024, the Dart project authors.  Please see the AUTHORS file
+// 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/data/download_counts_data.dart';
+
+Iterable<String> prepareRanges(List<VersionRangeCount> rangeDownloads) {
+  return rangeDownloads.map((e) => e.versionRange);
+}
+
+/// Returns an iterable containing data to be shown in a chart displaying the
+/// ranges in [rangeDownloads].
+///
+/// The 'i'th entry in the iterable is a list of the download values
+/// (y coordinates) for the 'i'th week (x coordinate).
+Iterable<List<int>> prepareWeekLists(
+  List<int> totals,
+  List<VersionRangeCount> rangeDownloads,
+  int displayLength,
+) {
+  final result = <List<int>>[];
+
+  final showOther =
+      totals[0] > rangeDownloads.fold(0, (sum, d) => sum + d.counts[0]);
+
+  for (int week = 0; week < displayLength; week++) {
+    final weekList = <int>[];
+    if (showOther) {
+      weekList.add(totals[week] -
+          rangeDownloads.fold(0, (sum, d) => sum + d.counts[week]));
+    }
+    rangeDownloads.forEach((d) => weekList.add(d.counts[week]));
+    result.add(weekList);
+  }
+  return result.reversed;
+}

pkg/web_app/lib/src/widget/downloads_chart/widget.dart

@@ -7,6 +7,8 @@ import 'dart:convert';
 import 'package:_pub_shared/data/download_counts_data.dart';
 import 'package:web/web.dart';
 
+import 'computations.dart';
+
 void create(HTMLElement element, Map<String, String> options) {
   final dataPoints = options['points'];
   if (dataPoints == null) {
@@ -18,7 +20,35 @@ void create(HTMLElement element, Map<String, String> options) {
   final data = WeeklyVersionDownloadCounts.fromJson((utf8.decoder
       .fuse(json.decoder)
       .convert(base64Decode(dataPoints)) as Map<String, dynamic>));
-  drawChart(svg, data);
+
+  final weeksToDisplay = data.totalWeeklyDownloads.length > 28
+      ? 28
+      : data.totalWeeklyDownloads.length;
+
+  final majorDisplayLists = prepareWeekLists(
+    data.totalWeeklyDownloads,
+    data.majorRangeWeeklyDownloads,
+    weeksToDisplay,
+  );
+  final majorRanges = data.majorRangeWeeklyDownloads.map((e) => e.versionRange);
+
+  // final minorDisplayLists = prepareWeekLists(
+  //   data.totalWeeklyDownloads,
+  //   data.minorRangeWeeklyDownloads,
+  //   weeksToDisplay,
+  // );
+  // final minorRanges = data.minorRangeWeeklyDownloads.map((e) => e.versionRange);
+
+  // final patchDisplayLists = prepareWeekLists(
+  //   data.totalWeeklyDownloads,
+  //   data.patchRangeWeeklyDownloads,
+  //   weeksToDisplay,
+  // );
+  // final patchRanges = data.patchRangeWeeklyDownloads.map((e) => e.versionRange);
+
+  drawChart(svg, majorRanges, majorDisplayLists, data.newestDate);
 }
 
-void drawChart(Element svg, WeeklyVersionDownloadCounts data) {}
+void drawChart(Element svg, Iterable<String> ranges, Iterable<List<int>> values,
+    DateTime newestData,
+    {bool stacked = true}) {}

pkg/web_app/test/widget/downloads_chart/downloads_chart_test.dart

@@ -0,0 +1,81 @@
+// Copyright (c) 2024, the Dart project authors.  Please see the AUTHORS file
+// 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:test/test.dart';
+import 'package:web_app/src/widget/downloads_chart/computations.dart';
+// import 'package:web_app/src/widget/downloads_chart/widget.dart';
+
+void main() {
+  test('week lists - simpler', () {
+    final List<int> l1 = List.from(List.filled(10, 10))
+      ..addAll(List.filled(10, 20))
+      ..add(2)
+      ..addAll(List.filled(31, 0));
+
+    final List<int> l2 = List.from(List.filled(10, 20))
+      ..addAll(List.filled(10, 40))
+      ..add(4)
+      ..addAll(List.filled(31, 0));
+
+    final List<int> l3 = List.from(List.filled(10, 70))
+      ..addAll(List.filled(10, 140))
+      ..add(14)
+      ..addAll(List.filled(31, 0));
+
+    final totals = List<int>.from(List.filled(10, 110))
+      ..addAll(List.filled(10, 220))
+      ..add(22)
+      ..addAll(List.filled(31, 0));
+
+    final patchRangeDownloads = [
+      (counts: l1, versionRange: '>=6.2.0-0 <6.2.1'),
+      (counts: l1, versionRange: '>=6.2.1-0 <6.2.2'),
+      (counts: l1, versionRange: '>=6.3.1-0 <6.3.2'),
+      (counts: l1, versionRange: '>=6.4.0-0 <6.4.1'),
+      (counts: l1, versionRange: '>=6.6.1-0 <6.6.2'),
+    ];
+
+    final minorRangeDownloads = [
+      (counts: l1, versionRange: '>=6.1.0-0 <6.2.0'),
+      (counts: l2, versionRange: '>=6.2.0-0 <6.3.0'),
+      (counts: l1, versionRange: '>=6.3.0-0 <6.4.0'),
+      (counts: l1, versionRange: '>=6.4.0-0 <6.5.0'),
+      (counts: l1, versionRange: '>=6.6.0-0 <6.7.0')
+    ];
+
+    final majorRangeDownloads = [
+      (counts: l1, versionRange: '>=1.0.0-0 <2.0.0'),
+      (counts: l1, versionRange: '>=2.0.0-0 <3.0.0'),
+      (counts: l1, versionRange: '>=3.0.0-0 <4.0.0'),
+      (counts: l1, versionRange: '>=4.0.0-0 <5.0.0'),
+      (counts: l3, versionRange: '>=6.0.0-0 <7.0.0')
+    ];
+
+    final w1 = prepareWeekLists(totals, majorRangeDownloads, 52).toList();
+    final w2 = prepareWeekLists(totals, minorRangeDownloads, 52).toList();
+    final w3 = prepareWeekLists(totals, patchRangeDownloads, 52).toList();
+
+    for (int i = 42; i < 52; i++) {
+      expect(w1[i], [10, 10, 10, 10, 70]);
+      expect(w2[i], [50, 10, 20, 10, 10, 10]);
+      expect(w3[i], [60, 10, 10, 10, 10, 10]);
+    }
+
+    for (int i = 32; i < 42; i++) {
+      expect(w1[i], [20, 20, 20, 20, 140]);
+      expect(w2[i], [100, 20, 40, 20, 20, 20]);
+      expect(w3[i], [120, 20, 20, 20, 20, 20]);
+    }
+
+    expect(w1[31], [2, 2, 2, 2, 14]);
+    expect(w2[31], [10, 2, 4, 2, 2, 2]);
+    expect(w3[31], [12, 2, 2, 2, 2, 2]);
+
+    for (int i = 0; i < 31; i++) {
+      expect(w1[i], [0, 0, 0, 0, 0]);
+      expect(w2[i], [0, 0, 0, 0, 0, 0]);
+      expect(w3[i], [0, 0, 0, 0, 0, 0]);
+    }
+  });
+}