new plus button

lib/utils/dates.dart

@@ -16,5 +16,23 @@ const _months = [
   'Dec',
 ];
 
+const _monthNames = [
+  'January',
+  'February',
+  'March',
+  'April',
+  'May',
+  'June',
+  'July',
+  'August',
+  'September',
+  'October',
+  'November',
+  'December',
+];
+
 String formatDate(DateTime date) =>
     '${date.day} ${_months[date.month - 1]} ${date.year}';
+
+String formatMonthYear(DateTime date) =>
+    '${_monthNames[date.month - 1]} ${date.year}';

lib/utils/shop_calendar.dart

@@ -0,0 +1,48 @@
+/// Month-grid helpers for the shop-log heatmap.
+library;
+
+DateTime dateOnly(DateTime date) => DateTime(date.year, date.month, date.day);
+
+DateTime monthStart(DateTime date) => DateTime(date.year, date.month);
+
+bool isSameDay(DateTime a, DateTime b) =>
+    a.year == b.year && a.month == b.month && a.day == b.day;
+
+bool isSameMonth(DateTime a, DateTime b) =>
+    a.year == b.year && a.month == b.month;
+
+DateTime addMonths(DateTime month, int delta) =>
+    DateTime(month.year, month.month + delta);
+
+/// Monday-first calendar cells for [month], padded with nulls to full weeks.
+List<DateTime?> monthGrid(DateTime month) {
+  final start = DateTime(month.year, month.month, 1);
+  final daysInMonth = DateTime(month.year, month.month + 1, 0).day;
+  final leading = start.weekday - DateTime.monday;
+  final cells = <DateTime?>[
+    ...List<DateTime?>.filled(leading, null),
+    for (var day = 1; day <= daysInMonth; day++)
+      DateTime(month.year, month.month, day),
+  ];
+  while (cells.length % 7 != 0) {
+    cells.add(null);
+  }
+  return cells;
+}
+
+/// How many trips landed on each calendar day.
+Map<DateTime, int> tripCountsByDay(Iterable<DateTime> shoppedAt) {
+  final counts = <DateTime, int>{};
+  for (final date in shoppedAt) {
+    final key = dateOnly(date);
+    counts[key] = (counts[key] ?? 0) + 1;
+  }
+  return counts;
+}
+
+/// GitHub-style 0–4 intensity from a trip count.
+int heatmapLevel(int count) {
+  if (count <= 0) return 0;
+  if (count >= 4) return 4;
+  return count;
+}

lib/utils/shop_log_filter.dart

@@ -0,0 +1,48 @@
+/// Filters shop-log rows by day, tag, and product search.
+library;
+
+import '../models/shop.dart';
+import 'fuzzy.dart';
+import 'shop_calendar.dart';
+
+List<Shop> filterShops({
+  required List<Shop> shops,
+  required Map<int, List<String>> productNames,
+  DateTime? selectedDay,
+  String? tag,
+  String query = '',
+}) {
+  final needle = query.trim();
+  final tagFilter = tag?.trim();
+  return [
+    for (final shop in shops)
+      if (_matches(
+        shop: shop,
+        names: productNames[shop.id] ?? const [],
+        selectedDay: selectedDay,
+        tag: tagFilter,
+        query: needle,
+      ))
+        shop,
+  ];
+}
+
+bool _matches({
+  required Shop shop,
+  required List<String> names,
+  required DateTime? selectedDay,
+  required String? tag,
+  required String query,
+}) {
+  if (selectedDay != null && !isSameDay(shop.shoppedAt, selectedDay)) {
+    return false;
+  }
+  if (tag != null && tag.isNotEmpty) {
+    final wanted = tag.toLowerCase();
+    if (!shop.tags.any((item) => item.toLowerCase() == wanted)) {
+      return false;
+    }
+  }
+  if (query.isEmpty) return true;
+  return names.any((name) => fuzzyScore(query, name) != null);
+}