Add page to change SMS allowance

There may be exceptions to the rule, so we should have a way of
overriding this manually.

app/main/forms.py

@@ -246,6 +246,15 @@ class OrganisationTypeForm(Form):
     organisation_type = organisation_type()
 
 
+class FreeSMSAllowance(Form):
+    free_sms_allowance = IntegerField(
+        'Numbers of text message fragments per year',
+        validators=[
+            DataRequired(message='Can’t be empty')
+        ]
+    )
+
+
 class ConfirmPasswordForm(Form):
     def __init__(self, validate_password_func, *args, **kwargs):
         self.validate_password_func = validate_password_func

app/main/views/service_settings.py

@@ -35,6 +35,7 @@ from app.main.forms import (
     ServiceInboundApiForm,
     InternationalSMSForm,
     OrganisationTypeForm,
+    FreeSMSAllowance,
 )
 from app import user_api_client, current_service, organisations_client, inbound_number_client
 from notifications_utils.formatters import formatted_list
@@ -589,14 +590,32 @@ def set_organisation_type(service_id):
         )
         return redirect(url_for('.service_settings', service_id=service_id))
 
-    form.organisation_type.data = current_service.get('organisation_type')
-
     return render_template(
         'views/service-settings/set-organisation-type.html',
         form=form,
     )
 
 
+@main.route("/services/<service_id>/service-settings/set-free-sms-allowance", methods=['GET', 'POST'])
+@login_required
+@user_has_permissions(admin_override=True)
+def set_free_sms_allowance(service_id):
+
+    form = FreeSMSAllowance(free_sms_allowance=current_service['free_sms_fragment_limit'])
+
+    if form.validate_on_submit():
+        service_api_client.update_service(
+            service_id,
+            free_sms_fragment_limit=form.free_sms_allowance.data,
+        )
+        return redirect(url_for('.service_settings', service_id=service_id))
+
+    return render_template(
+        'views/service-settings/set-free-sms-allowance.html',
+        form=form,
+    )
+
+
 @main.route("/services/<service_id>/service-settings/set-branding-and-org", methods=['GET', 'POST'])
 @login_required
 @user_has_permissions(admin_override=True)

app/notify_client/service_api_client.py

@@ -104,7 +104,9 @@ class ServiceAPIClient(NotifyAdminAPIClient):
             'organisation',
             'letter_contact_block',
             'dvla_organisation',
-            'permissions'
+            'permissions',
+            'organisation_type',
+            'free_sms_fragment_limit',
         }
         if disallowed_attributes:
             raise TypeError('Not allowed to update service attributes: {}'.format(

app/templates/views/service-settings.html

@@ -198,7 +198,7 @@
         {% call row() %}
           {{ text_field('Free text message allowance')}}
           {{ text_field('{:,}'.format(current_service.free_sms_fragment_limit)) }}
-          {{ text_field() }}
+          {{ edit_field('Change', url_for('.set_free_sms_allowance', service_id=current_service.id)) }}
         {% endcall %}
         {% call row() %}
           {{ text_field('Email branding' )}}

app/templates/views/service-settings/set-free-sms-allowance.html

@@ -0,0 +1,21 @@
+{% extends "withnav_template.html" %}
+{% from "components/textbox.html" import textbox %}
+{% from "components/page-footer.html" import page_footer %}
+
+{% block service_page_title %}
+  Emails
+{% endblock %}
+
+{% block maincolumn_content %}
+
+  <form method="post">
+    <h1 class="heading-large">Free text message allowance</h1>
+    {{ textbox(form.free_sms_allowance) }}
+    {{ page_footer(
+      'Save',
+      back_link=url_for('.service_settings', service_id=current_service.id),
+      back_link_text='Back to settings'
+    ) }}
+  </form>
+
+{% endblock %}