Restore message in a form if it's incorrect.

Simplify controller a bit.

Author: VorontsovIE

ennead/templates/dialogue.html

@@ -1,5 +1,6 @@
 {% extends 'base.html' %}
-
+{% set task=thread.task %}
+{% set student=thread.student %}
 {% block title %}{{task.order_num}}. {{ task.name }}{% endblock %}
 
 {% block body %}
@@ -58,7 +59,7 @@ <h5 class="card-header">Критерии проверки</h5>
         <div class="col-9 offset-1">
             <hr/>
             <form id="post-form" action="{{ url_for('post_to_thread', task_id=task.id, student_id=student.id) }}" method="POST">
-                {{ markdown_editor(text='', name='text', id='post-textarea') }}
+                {{ markdown_editor(text=msg_value, name='text', id='post-textarea') }}
                 {% if g.user.is_teacher %}
                     <div class="form-check">
                       <input class="form-check-input" type="checkbox" name="hide_from_student" value="hide_from_student" id="hide_from_student">
@@ -69,7 +70,7 @@ <h5 class="card-header">Критерии проверки</h5>
                     <div class="form-group row">
                         <label for="score-setter" class="col-form-label col-2">Балл:</label>
                         <div class="col-5">
-                            <input type="number" step="any" name="score" value={{ thread.score }} class="form-control" id="score-setter">
+                            <input type="number" step="any" name="score" value={{ score_value }} class="form-control" id="score-setter">
                         </div>
                     </div>
                 {% endif %}

ennead/views/dialogue.py

@@ -47,8 +47,8 @@ def thread_page(task_id: int, student_id: int) -> Response:
         return redirect(url_for('index'))
     thread = get_thread(task_id, student_id)
     posts = thread.ordered_posts(show_hidden=g.user.is_teacher)
-    return render_template('dialogue.html', thread=thread, task=thread.task,
-                           student=thread.student, posts=posts)
+    return render_template('dialogue.html', thread=thread, posts=posts,
+                           msg_value='', score_value=thread.score)
 
 
 @require_logged_in
@@ -67,8 +67,11 @@ def post_to_thread(task_id: int, student_id: int) -> Response:
                     author=g.user, thread=thread,
                     hide_from_student=hide_from_student)
     else:
-        # TODO: redirect back to a dialogue, restoring a message draft not to lose it
-        pass
+        # Right now, unnecessary because only empty message can be incorrect
+        posts = thread.ordered_posts(show_hidden=g.user.is_teacher)
+        return render_template('dialogue.html', thread=thread, posts=posts,
+                               msg_value=request.form.get('text'),
+                               score_value=request.form.get('score'))
 
     if g.user.is_teacher:
         score = float(request.form.get('score'))