Move widgets for quickly creating lessons to own file. (#1787)

Move `TimetableQuickCreateDialog` to
`timetable_quick_create_dialog.dart` and delete some unused code.

app/lib/timetable/src/widgets/quick_create/timetable_quick_create_dialog.dart

@@ -0,0 +1,210 @@
+// Copyright (c) 2024 Sharezone UG (haftungsbeschränkt)
+// Licensed under the EUPL-1.2-or-later.
+//
+// You may obtain a copy of the Licence at:
+// https://joinup.ec.europa.eu/software/page/eupl
+//
+// SPDX-License-Identifier: EUPL-1.2
+
+import 'package:bloc_provider/bloc_provider.dart';
+import 'package:flutter/material.dart';
+import 'package:group_domain_models/group_domain_models.dart';
+import 'package:sharezone/groups/group_join/group_join_page.dart';
+import 'package:sharezone/groups/group_permission.dart';
+import 'package:sharezone/groups/src/pages/course/course_card.dart';
+import 'package:sharezone/groups/src/pages/course/create/pages/course_template_page.dart';
+import 'package:sharezone/main/application_bloc.dart';
+import 'package:sharezone/timetable/timetable_add/timetable_add_page.dart';
+import 'package:sharezone_widgets/sharezone_widgets.dart';
+
+import '../../bloc/timetable_selection_bloc.dart';
+
+class TimetableQuickCreateDialog extends StatelessWidget {
+  final EmptyPeriodSelection periodSelection;
+  final TimetableSelectionBloc selectionBloc;
+
+  const TimetableQuickCreateDialog({
+    super.key,
+    required this.periodSelection,
+    required this.selectionBloc,
+  });
+
+  @override
+  Widget build(BuildContext context) {
+    final height = MediaQuery.of(context).size.height;
+    return SizedBox(
+      height: height - (height / 5),
+      child: StreamBuilder<List<Course>>(
+        stream: BlocProvider.of<SharezoneContext>(context)
+            .api
+            .course
+            .streamCourses(),
+        builder: (context, snapshot) {
+          final courses = snapshot.data ?? [];
+          final isCourseListEmpty = courses.isEmpty;
+          _sortCoursesByAlphabet(courses);
+          return CustomScrollView(
+            slivers: <Widget>[
+              _AppBar(),
+              SliverToBoxAdapter(
+                child: SafeArea(
+                  child: isCourseListEmpty
+                      ? _EmptyCourseList()
+                      : Column(
+                          mainAxisSize: MainAxisSize.min,
+                          children: courses
+                              .map((course) => _QuickCreateCourseTile(
+                                    course: course,
+                                    selectionBloc: selectionBloc,
+                                    periodSelection: periodSelection,
+                                  ))
+                              .toList(),
+                        ),
+                ),
+              )
+            ],
+          );
+        },
+      ),
+    );
+  }
+
+  void _sortCoursesByAlphabet(List<Course> courses) {
+    courses.sort((a, b) => a.name.compareTo(b.name));
+  }
+}
+
+class _AppBar extends StatelessWidget {
+  @override
+  Widget build(BuildContext context) {
+    return SliverAppBar(
+      pinned: true,
+      backgroundColor: Theme.of(context).isDarkTheme ? null : Colors.white,
+      centerTitle: false,
+      forceElevated: true,
+      automaticallyImplyLeading: false,
+      elevation: 0,
+      actions: <Widget>[
+        const _CreateCourseIconButton(),
+        const _JoinGroupIconButton(),
+        CloseIconButton(color: _getIconColor(context)),
+      ],
+      title: Text("Stunde hinzufügen",
+          style: Theme.of(context).textTheme.titleLarge),
+    );
+  }
+}
+
+class _JoinGroupIconButton extends StatelessWidget {
+  const _JoinGroupIconButton();
+
+  @override
+  Widget build(BuildContext context) {
+    return IconButton(
+      icon: const Icon(Icons.vpn_key),
+      tooltip: 'Kurs/Klasse beitreten',
+      color: _getIconColor(context),
+      onPressed: () => openGroupJoinPage(context),
+    );
+  }
+}
+
+class _CreateCourseIconButton extends StatelessWidget {
+  const _CreateCourseIconButton();
+
+  @override
+  Widget build(BuildContext context) {
+    return IconButton(
+      icon: const Icon(Icons.add),
+      tooltip: 'Kurs erstellen',
+      color: _getIconColor(context),
+      onPressed: () => Navigator.pushNamed(context, CourseTemplatePage.tag),
+    );
+  }
+}
+
+class _EmptyCourseList extends StatelessWidget {
+  @override
+  Widget build(BuildContext context) {
+    final height = MediaQuery.of(context).size.height;
+    final modalSheetHeight = height - (height / 5);
+    const appBarHeight = 56.0;
+    return Material(
+      color: Theme.of(context).isDarkTheme
+          ? Theme.of(context).scaffoldBackgroundColor
+          : Colors.white,
+      child: SizedBox(
+        height: modalSheetHeight - appBarHeight,
+        child: Center(
+          child: PlaceholderModel(
+            iconSize: const Size(175, 175),
+            title: "Du bist noch keinem Kurs, bzw. keiner Klasse beigetreten!",
+            svgPath: 'assets/icons/ghost.svg',
+            animateSVG: true,
+            subtitle: Padding(
+              padding: const EdgeInsets.only(top: 12),
+              child: Row(
+                children: <Widget>[
+                  Expanded(
+                    child: CourseManagementButton(
+                      iconData: Icons.add,
+                      title: "Kurs erstellen",
+                      onTap: () =>
+                          Navigator.pushNamed(context, CourseTemplatePage.tag),
+                    ),
+                  ),
+                  const SizedBox(width: 12),
+                  Expanded(
+                    child: CourseManagementButton(
+                      iconData: Icons.vpn_key,
+                      title: "Kurs beitreten",
+                      onTap: () => openGroupJoinPage(context),
+                    ),
+                  ),
+                ],
+              ),
+            ),
+          ),
+        ),
+      ),
+    );
+  }
+}
+
+class _QuickCreateCourseTile extends StatelessWidget {
+  const _QuickCreateCourseTile({
+    required this.course,
+    required this.selectionBloc,
+    required this.periodSelection,
+  });
+
+  final Course course;
+  final TimetableSelectionBloc selectionBloc;
+  final EmptyPeriodSelection periodSelection;
+
+  @override
+  Widget build(BuildContext context) {
+    final hasCreatorPermissions =
+        course.myRole.hasPermission(GroupPermission.contentCreation);
+    return ListTile(
+      enabled: hasCreatorPermissions,
+      title: Text(course.name),
+      leading: CourseCircleAvatar(
+        courseId: course.id,
+        abbreviation: course.abbreviation,
+      ),
+      trailing: !hasCreatorPermissions ? const Icon(Icons.lock) : null,
+      onTap: () {
+        selectionBloc.createLesson(
+          BlocProvider.of<SharezoneContext>(context).api.timetable,
+          periodSelection,
+          course,
+        );
+        Navigator.pop(context, course);
+      },
+    );
+  }
+}
+
+Color? _getIconColor(BuildContext context) =>
+    Theme.of(context).isDarkTheme ? Colors.grey : Colors.grey[600];