refactored data providers with centralized cache resolution, unified UI using custom dialogs and bottom sheets, and enhanced network error handling for Dio and TLS errors

lib/view/pages/timetable/widgets/appointment_tile.dart

@@ -2,14 +2,11 @@ import 'package:flutter/material.dart';
 import 'package:syncfusion_flutter_calendar/calendar.dart';
 
 import '../data/arbitrary_appointment.dart';
+import '../data/calendar_layout.dart';
 import 'cross_painter.dart';
 
 class AppointmentTile extends StatelessWidget {
   static const _radius = BorderRadius.all(Radius.circular(7));
-  static const _titleFontSize = 15.0;
-  static const _titleMinFontSize = 11.0;
-  static const _bodyFontSize = 10.0;
-  static const _bodyLineHeight = 1.15;
 
   final Appointment appointment;
   final bool crossedOut;
@@ -42,8 +39,8 @@ class AppointmentTile extends StatelessWidget {
                 children: [
                   _AdaptiveTitle(
                     text: appointment.subject,
-                    fontSize: _titleFontSize,
-                    minFontSize: _titleMinFontSize,
+                    fontSize: kAppointmentTitleFontSize,
+                    minFontSize: kAppointmentTitleMinFontSize,
                     fontWeight: FontWeight.w500,
                   ),
                   if (isCustom) ...[
@@ -53,8 +50,8 @@ class AppointmentTile extends StatelessWidget {
                           padding: const EdgeInsets.only(top: 1),
                           child: _WrappingBody(
                             text: description,
-                            fontSize: _bodyFontSize,
-                            lineHeight: _bodyLineHeight,
+                            fontSize: kAppointmentBodyFontSize,
+                            lineHeight: kAppointmentBodyLineHeight,
                           ),
                         ),
                       ),
@@ -63,7 +60,7 @@ class AppointmentTile extends StatelessWidget {
                         .split('\n')
                         .where((p) => p.isNotEmpty)
                         .take(2))
-                      _ScaledLine(text: line, fontSize: _bodyFontSize),
+                      _ScaledLine(text: line, fontSize: kAppointmentBodyFontSize),
                   ],
                 ],
               ),

lib/view/pages/timetable/widgets/calendar/outside_chips.dart

@@ -1,11 +1,6 @@
 part of '../custom_workweek_calendar.dart';
 
 class _OutsideHoursStrip extends StatelessWidget {
-  static const int _maxVisibleChips = 2;
-  static const double _chipHeight = 22;
-  static const double _chipSpacing = 3;
-  static const double _verticalPadding = 3;
-
   final DateTime weekStart;
   final List<Appointment> appointments;
   final double rulerWidth;
@@ -28,17 +23,17 @@ class _OutsideHoursStrip extends StatelessWidget {
 
     final theme = Theme.of(context);
     final maxChipsPerDay = outside
-        .map((day) => day.length > _maxVisibleChips ? _maxVisibleChips : day.length)
+        .map((day) => day.length > kOutsideChipsMaxVisible ? kOutsideChipsMaxVisible : day.length)
         .fold<int>(0, (m, c) => c > m ? c : m);
-    final stripHeight = _verticalPadding * 2 +
-        maxChipsPerDay * _chipHeight +
-        (maxChipsPerDay > 1 ? (maxChipsPerDay - 1) * _chipSpacing : 0);
+    final stripHeight = kOutsideStripVerticalPadding * 2 +
+        maxChipsPerDay * kOutsideChipHeight +
+        (maxChipsPerDay > 1 ? (maxChipsPerDay - 1) * kOutsideChipSpacing : 0);
 
     return Container(
       color: theme.colorScheme.surfaceContainerLowest,
-      padding: const EdgeInsets.symmetric(vertical: _verticalPadding),
+      padding: const EdgeInsets.symmetric(vertical: kOutsideStripVerticalPadding),
       child: SizedBox(
-        height: stripHeight - _verticalPadding * 2,
+        height: stripHeight - kOutsideStripVerticalPadding * 2,
         child: Row(
           crossAxisAlignment: CrossAxisAlignment.start,
           children: [
@@ -47,9 +42,6 @@ class _OutsideHoursStrip extends StatelessWidget {
               Expanded(
                 child: _OutsideDayColumn(
                   appointments: outside[d],
-                  maxVisible: _maxVisibleChips,
-                  chipHeight: _chipHeight,
-                  chipSpacing: _chipSpacing,
                   onAppointmentTap: onAppointmentTap,
                   isCrossedOut: isCrossedOut,
                 ),
@@ -63,17 +55,11 @@ class _OutsideHoursStrip extends StatelessWidget {
 
 class _OutsideDayColumn extends StatelessWidget {
   final List<Appointment> appointments;
-  final int maxVisible;
-  final double chipHeight;
-  final double chipSpacing;
   final void Function(Appointment) onAppointmentTap;
   final bool Function(Appointment) isCrossedOut;
 
   const _OutsideDayColumn({
     required this.appointments,
-    required this.maxVisible,
-    required this.chipHeight,
-    required this.chipSpacing,
     required this.onAppointmentTap,
     required this.isCrossedOut,
   });
@@ -132,11 +118,12 @@ class _OutsideDayColumn extends StatelessWidget {
         if (!aLike && bLike) return 1;
         return a.startTime.compareTo(b.startTime);
       });
-    final visible = sorted.length <= maxVisible
+    final visible = sorted.length <= kOutsideChipsMaxVisible
         ? sorted
-        : sorted.take(maxVisible - 1).toList();
-    final overflow =
-        sorted.length <= maxVisible ? const <Appointment>[] : sorted.skip(maxVisible - 1).toList();
+        : sorted.take(kOutsideChipsMaxVisible - 1).toList();
+    final overflow = sorted.length <= kOutsideChipsMaxVisible
+        ? const <Appointment>[]
+        : sorted.skip(kOutsideChipsMaxVisible - 1).toList();
 
     return Padding(
       padding: const EdgeInsets.symmetric(horizontal: 2),
@@ -145,9 +132,9 @@ class _OutsideDayColumn extends StatelessWidget {
         crossAxisAlignment: CrossAxisAlignment.stretch,
         children: [
           for (var i = 0; i < visible.length; i++) ...[
-            if (i > 0) SizedBox(height: chipSpacing),
+            if (i > 0) const SizedBox(height: kOutsideChipSpacing),
             SizedBox(
-              height: chipHeight,
+              height: kOutsideChipHeight,
               child: _OutsideChip(
                 appointment: visible[i],
                 onTap: () => onAppointmentTap(visible[i]),
@@ -155,9 +142,9 @@ class _OutsideDayColumn extends StatelessWidget {
             ),
           ],
           if (overflow.isNotEmpty) ...[
-            SizedBox(height: chipSpacing),
+            const SizedBox(height: kOutsideChipSpacing),
             SizedBox(
-              height: chipHeight,
+              height: kOutsideChipHeight,
               child: _OutsideOverflowChip(
                 count: overflow.length,
                 onTap: () => _showOverflow(context, overflow),

lib/view/pages/timetable/widgets/calendar/week_grid.dart

@@ -429,8 +429,7 @@ class _OverflowTile extends StatelessWidget {
       padding: const EdgeInsets.all(1),
       child: Stack(
         children: [
-          // Card peeking out at the bottom — visual hint that more cards lie
-          // underneath the visible one.
+          // Stacked-cards effect: a darker layer peeks out below the front card.
           Positioned(
             top: 4,
             left: 2,
@@ -443,7 +442,6 @@ class _OverflowTile extends StatelessWidget {
               ),
             ),
           ),
-          // Front card with the "+N" indicator.
           Positioned(
             top: 0,
             left: 0,