added dialog to create a bookmark manually

lib/widgets/create_bookmark_dialog.dart

@@ -0,0 +1,102 @@
+import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
+
+import '../model/bookmark.dart';
+
+class CreateBookmarkDialog extends StatelessWidget {
+  const CreateBookmarkDialog({
+    super.key,
+    required this.collectionId,
+    required this.onSavePressed,
+    this.selectedBookmark,
+  });
+  final void Function(Bookmark bookmark) onSavePressed;
+  final int collectionId;
+  final Bookmark? selectedBookmark;
+
+  @override
+  Widget build(BuildContext context) {
+    final nameController = TextEditingController();
+    final linkController = TextEditingController();
+    final descriptionController = TextEditingController();
+
+    return AlertDialog(
+      title: Text('Create Bookmark'),
+      content: SingleChildScrollView(
+        child: Column(
+          children: [
+            Padding(padding: EdgeInsetsGeometry.only(top: 10)),
+            TextField(
+              controller: nameController,
+              autofocus: true,
+              maxLines: 1,
+              maxLength: 50,
+              inputFormatters: [
+                FilteringTextInputFormatter.allow(
+                  RegExp(r'[a-zA-Z0-9äöüÄÖÜß\s]'),
+                ),
+                FilteringTextInputFormatter.deny(RegExp(r'\s\s+')),
+              ],
+              decoration: InputDecoration(
+                labelText: 'Bookmark Title',
+                border: OutlineInputBorder(
+                  borderRadius: BorderRadius.circular(10),
+                ),
+              ),
+            ),
+            TextField(
+              controller: linkController,
+              maxLines: 1,
+              maxLength: 50,
+              inputFormatters: [
+                FilteringTextInputFormatter.allow(
+                  RegExp(r'[a-zA-Z0-9äöüÄÖÜß\s]'),
+                ),
+                FilteringTextInputFormatter.deny(RegExp(r'\s\s+')),
+              ],
+              decoration: InputDecoration(
+                labelText: 'Url',
+                border: OutlineInputBorder(
+                  borderRadius: BorderRadius.circular(10),
+                ),
+              ),
+            ),
+            TextField(
+              controller: descriptionController,
+              maxLines: 3,
+              maxLength: 300,
+              inputFormatters: [
+                FilteringTextInputFormatter.allow(
+                  RegExp(r'[a-zA-Z0-9äöüÄÖÜß\s]'),
+                ),
+                FilteringTextInputFormatter.deny(RegExp(r'\s\s+')),
+              ],
+              decoration: InputDecoration(
+                labelText: 'Description',
+                border: OutlineInputBorder(
+                  borderRadius: BorderRadius.circular(10),
+                ),
+              ),
+            ),
+          ],
+        ),
+      ),
+      actions: [
+        FloatingActionButton(
+          onPressed: () {
+            onSavePressed(
+              Bookmark(
+                collectionId: collectionId,
+                name: nameController.text,
+                link: linkController.text,
+                description: descriptionController.text,
+              ),
+            );
+            Navigator.of(context).pop();
+          },
+          child: Icon(Icons.save),
+        ),
+      ],
+    );
+  }
+}