added ability to delete task

lib/pages/task_edit_page.dart

@@ -1,7 +1,9 @@
 import 'package:flutter/material.dart';
 
 import '../model/callback_models/create_task_request.dart';
+import '../model/extensions/controller_context.dart';
 import '../model/task.dart';
+import '../service/task_controller.dart';
 import '../service/tools.dart';
 import '../service/validators.dart';
 
@@ -14,6 +16,7 @@ class TaskEditPage extends StatefulWidget {
 }
 
 class _TaskEditPageState extends State<TaskEditPage> {
+  Task? task;
   final titleController = TextEditingController();
   final descriptionController = TextEditingController();
   final categoryController = TextEditingController();
@@ -25,17 +28,17 @@ class _TaskEditPageState extends State<TaskEditPage> {
   @override
   void didChangeDependencies() {
     super.didChangeDependencies();
-    final task = ModalRoute.of(context)!.settings.arguments as Task?;
+    task = ModalRoute.of(context)!.settings.arguments as Task?;
     if (task != null) {
-      titleController.text = task.title;
-      descriptionController.text = task.description;
-      categoryController.text = task.category;
-      urlController.text = task.url;
-      dueDateController.text = task.due != null
-          ? getIsoDateString(task.due!)
+      titleController.text = task!.title;
+      descriptionController.text = task!.description;
+      categoryController.text = task!.category;
+      urlController.text = task!.url;
+      dueDateController.text = task!.due != null
+          ? getIsoDateString(task!.due!)
           : '';
-      dueTimeController.text = task.due != null
-          ? TimeOfDay.fromDateTime(task.due!).format(context)
+      dueTimeController.text = task!.due != null
+          ? TimeOfDay.fromDateTime(task!.due!).format(context)
           : '';
     }
     pageTitle = task?.title ?? 'CreateTask';
@@ -44,7 +47,19 @@ class _TaskEditPageState extends State<TaskEditPage> {
   @override
   Widget build(BuildContext context) {
     return Scaffold(
-      appBar: AppBar(title: Text(pageTitle)),
+      appBar: AppBar(
+        title: Text(pageTitle),
+        actions: [
+          if (task != null)
+            IconButton(
+              onPressed: () {
+                context.controller<TaskController>().deleteTask(task!);
+                Navigator.of(context).pop();
+              },
+              icon: Icon(Icons.delete),
+            ),
+        ],
+      ),
       body: Form(
         autovalidateMode: AutovalidateMode.onUnfocus,
         child: Column(