Add "Delete center" action

Creates "delete center" form with a select to choose a center to delete.

Adds a new button in the scopes view. Because scopes checkboxes values
maps to ips the only way to specify the center to delete is in the delete
center form itself, using a select input.

ogcp/forms/action_forms.py

@@ -109,6 +109,11 @@ class CenterForm(FlaskForm):
     comment = StringField(label=_('Comment'))
     submit = SubmitField(label=_('Submit'))
 
+class DeleteCenterForm(FlaskForm):
+    center = SelectField(label=_('Center'),
+                         validators=[InputRequired()])
+    submit = SubmitField(label=_('Submit'))
+
 class RoomForm(FlaskForm):
     center = SelectField(label=_('Center'),
                          validators=[InputRequired()])

ogcp/templates/scopes.html

@@ -26,4 +26,6 @@
          form="scopesForm" formaction="{{ url_for('action_client_delete') }}" formmethod="post">
   <input class="btn btn-light" type="submit" value="{{ _('Delete room') }}"
          form="scopesForm" formaction="{{ url_for('action_room_delete') }}" formmethod="get">
+  <input class="btn btn-light" type="submit" value="{{ _('Delete center') }}"
+         form="scopesForm" formaction="{{ url_for('action_center_delete') }}" formmethod="get">
 {% endblock %}

ogcp/views.py

@@ -11,7 +11,7 @@ from flask import (
 from ogcp.forms.action_forms import (
     WOLForm, SetupForm, ClientDetailsForm, HardwareForm,
     SessionForm, ImageRestoreForm, ImageCreateForm, SoftwareForm, BootModeForm,
-    RoomForm, DeleteRoomForm, CenterForm
+    RoomForm, DeleteRoomForm, CenterForm, DeleteCenterForm
 )
 from flask_login import (
     current_user, LoginManager,
@@ -681,6 +681,26 @@ def action_center_add():
     else:
         return render_template('actions/add_center.html', form=form)
 
+@app.route('/action/center/delete', methods=['GET', 'POST'])
+@login_required
+def action_center_delete():
+    form = DeleteCenterForm(request.form)
+    if request.method == 'POST':
+        payload = {"id": form.center.data}
+        r = g.server.post('/center/delete', payload)
+        if r.status_code != requests.codes.ok:
+            flash(_('Server replied with error code when deleting the center'),
+                  category='error')
+        else:
+            flash(_('Center deleted successfully'), category='info')
+        return redirect(url_for("scopes"))
+    else:
+        r = g.server.get('/scopes')
+        centers = parse_scopes_from_tree(r.json(), 'center')
+        centers = [(center['id'], center['name']) for center in centers]
+        form.center.choices = list(centers)
+        return render_template('actions/delete_center.html', form=form)
+
 @app.route('/action/room/add', methods=['GET', 'POST'])
 @login_required
 def action_room_add():