move add new folder and move to folder into one dialog box

this lets us combine the two actions to create "Move to a new folder".
If the user hits enter rather than clicking a button, there is a hidden
submit button that (for now) prevents them from taking any action.
A future commit will try and understand what the user might be doing
based on which fields are populated/selected.

app/main/forms.py

@@ -3,6 +3,7 @@ from datetime import datetime, timedelta
 from itertools import chain
 
 import pytz
+from flask import request
 from flask_wtf import FlaskForm as Form
 from flask_wtf.file import FileAllowed
 from flask_wtf.file import FileField as FileField_wtf
@@ -1154,11 +1155,33 @@ class TemplateAndFoldersSelectionForm(Form):
 
         self.templates_and_folders.choices = template_list.as_id_and_name
 
+        self.is_move_op = self.is_add_op = False
+
         self.move_to.choices = [
             (item['id'], item['name'])
             for item in ([self.ALL_TEMPLATES_FOLDER] + all_template_folders)
             if item['id'] != str(current_folder_id)
         ]
 
+    def validate(self):
+        op = request.form.get('operation')
+
+        self.is_move_op = op in {'move_to_existing_folder', 'move_to_new_folder'}
+        self.is_add_op = op in {'add_new_folder', 'move_to_new_folder'}
+
+        if not (self.is_add_op or self.is_move_op):
+            return False
+
+        return super().validate()
+
+    def validate_move_to(self, field):
+        if self.is_move_op and not field.data:
+            raise ValidationError('Can’t be empty')
+
+    def validate_new_folder_name(self, field):
+        if self.is_add_op and not field.data:
+            raise ValidationError('Can’t be empty')
+
     templates_and_folders = MultiCheckboxField('Choose templates or folders')
-    move_to = RadioFieldWithNoneOption('Choose a folder')
+    move_to = RadioFieldWithNoneOption('Choose a folder', validators=[Optional()])
+    new_folder_name = StringField('Folder name')

app/main/views/templates.py

@@ -117,24 +117,9 @@ def choose_template(service_id, template_type='all', template_folder_id=None):
         template_type=template_type,
         current_folder_id=template_folder_id,
     )
-    add_folder_form = TemplateFolderForm()
 
-    if is_valid_template_operation('move', templates_and_folders_form):
-        current_service.move_to_folder(
-            ids_to_move=templates_and_folders_form.templates_and_folders.data,
-            move_to=templates_and_folders_form.move_to.data,
-        )
-        return redirect(request.url)
-
-    if is_valid_template_operation('add_new_folder', add_folder_form):
-        template_folder_api_client.create_template_folder(
-            current_service.id,
-            name=add_folder_form.name.data,
-            parent_id=template_folder_id
-        )
-        return redirect(
-            url_for('.choose_template', service_id=service_id, template_folder_id=template_folder_id)
-        )
+    if request.method == 'POST' and can_manage_folders() and templates_and_folders_form.validate_on_submit():
+        return process_folder_management_form(templates_and_folders_form, template_folder_id)
 
     return render_template(
         'views/templates/choose.html',
@@ -150,20 +135,30 @@ def choose_template(service_id, template_type='all', template_folder_id=None):
         template_nav_items=get_template_nav_items(template_folder_id),
         template_type=template_type,
         search_form=SearchTemplatesForm(),
-        templates_and_folders_form=templates_and_folders_form,
-        add_folder_form=add_folder_form,
+        templates_and_folders_form=templates_and_folders_form
     )
 
 
-def is_valid_template_operation(operation_name, form):
+def process_folder_management_form(form, current_folder_id):
+    new_folder_id = None
 
-    if (
-        can_manage_folders() and
-        request.method == 'POST' and
-        request.form.get('operation') == operation_name and
-        form.validate_on_submit()
-    ):
-        return True
+    if form.is_add_op:
+        new_folder_id = template_folder_api_client.create_template_folder(
+            current_service.id,
+            name=form.new_folder_name.data,
+            parent_id=current_folder_id
+        )
+
+    if form.is_move_op:
+        # if we've just made a folder, we also want to move there
+        move_to_id = new_folder_id or form.move_to.data
+
+        current_service.move_to_folder(
+            ids_to_move=form.templates_and_folders.data,
+            move_to=move_to_id
+        )
+
+    return redirect(request.url)
 
 
 def get_template_nav_label(value):

app/templates/views/templates/_move_to.html

@@ -2,6 +2,10 @@
 {% from "components/page-footer.html" import page_footer %}
 
 {% if templates_and_folders_form.move_to.choices and template_list.templates_to_show %}
+  <button type="submit" name="operation" value="unknown" hidden></button>
   {{ radios(templates_and_folders_form.move_to) }}
-  {{ page_footer('Move selected', button_name='operation', button_value='move') }}
+  {{ page_footer('Move', button_name='operation', button_value='move_to_existing_folder') }}
+  {{ textbox(templates_and_folders_form.new_folder_name) }}
+  {{ page_footer('Move to a new folder', button_name='operation', button_value='move_to_new_folder') }}
+  {{ page_footer('New folder', button_name='operation', button_value='add_new_folder') }}
 {% endif %}

app/templates/views/templates/choose.html

@@ -85,11 +85,6 @@
         {% endwith %}
       {% endcall %}
 
-      {% call form_wrapper() %}
-        {{ textbox(add_folder_form.name) }}
-        {{ page_footer('New folder', button_name='operation', button_value='add_new_folder') }}
-      {% endcall %}
-
     {% else %}
       {% include 'views/templates/_template_list.html' %}
     {% endif %}