Put usage summary back on the dashboard

This reverts 1b1839ad30, which removed
the usage from the dashboard because it was causing performance
problems:

> **The yearly usage section on the dashboard page takes too log as a
> result services with large yearly stats are timing out.**
>
> As a short term fix we have taken the yearly stats off the dashboard.
>
> There is a plan to create permanent statistic tables to warehouse the
> data.

The long term fix (the fact tables) is now in place, so it should be OK
to bring this back.

This is part of a wider piece of work to refresh the dashboard page now
that jobs are moving to their own page.

app/main/views/dashboard.py

@@ -299,7 +299,14 @@ def get_dashboard_partials(service_id):
         )
         for key, value in dashboard_totals[0].items()
     )
-
+    free_sms_allowance = billing_api_client.get_free_sms_fragment_limit_for_year(
+        current_service.id,
+        get_current_financial_year(),
+    )
+    yearly_usage = billing_api_client.get_service_usage(
+        service_id,
+        get_current_financial_year(),
+    )
     return {
         'upcoming': render_template(
             'views/dashboard/_upcoming.html',
@@ -332,7 +339,12 @@ def get_dashboard_partials(service_id):
             'views/dashboard/_jobs.html',
             jobs=immediate_jobs
         ),
-        'has_jobs': bool(immediate_jobs)
+        'has_jobs': bool(immediate_jobs),
+        'usage': render_template(
+            'views/dashboard/_usage.html',
+            column_width=column_width,
+            **calculate_usage(yearly_usage, free_sms_allowance),
+        ),
     }
 
 

app/templates/views/dashboard/_usage.html

@@ -1,16 +1,16 @@
 {% from "components/big-number.html" import big_number %}
 
 <div class='grid-row ajax-block-container'>
-  <div class='column-half'>
+  <div class='{{ column_width }}'>
     <div class="keyline-block">
       {{ big_number("Unlimited", 'free email allowance', smaller=True) }}
     </div>
   </div>
-  <div class='column-half'>
+  <div class='{{ column_width }}'>
     <div class="keyline-block">
       {% if sms_chargeable %}
         {{ big_number(
-          total_sms_cost,
+          sms_chargeable * sms_rate,
           'spent on text messages',
           currency="£",
           smaller=True
@@ -20,4 +20,14 @@
       {% endif %}
     </div>
   </div>
+  <div class='{{ column_width }}'>
+    <div class="keyline-block">
+      {{ big_number(
+        letter_cost,
+        'spent on letters',
+        currency="£",
+        smaller=True
+      ) }}
+    </div>
+  </div>
 </div>

app/templates/views/dashboard/dashboard.html

@@ -43,6 +43,15 @@
       ) }}
     {% endif %}
 
+    {% if current_user.has_permissions('manage_service') %}
+      <h2 class='heading-medium'>This year</h2>
+      {{ ajax_block(partials, updates_url, 'usage') }}
+      {{ show_more(
+        url_for(".usage", service_id=current_service['id']),
+        'See usage'
+      ) }}
+    {% endif %}
+
   </div>
 
 {% endblock %}