Add BillingIndexView to render current usage (partial)

ereuse_devicehub/billing/templates/billing/home.html

@@ -0,0 +1,38 @@
+{% extends "ereuse_devicehub/base_site.html" %}
+{% block main %}
+
+<div class="pagetitle">
+  <h1>Billing</h1>
+  <nav>
+    <ol class="breadcrumb">
+      <li class="breadcrumb-item active">{{ page_title }}</li>
+    </ol>
+  </nav>
+</div><!-- End Page Title -->
+
+<section class="section">
+  Current usage
+
+  <table class="table table-striped">
+    <thead>
+      <tr>
+        <th scope="col">Year</th>
+        <th scope="col">Month</th>
+        <th scope="col">Snapshot (register)</th>
+        <th scope="col">Snapshot (update)</th>
+        <th scope="col">Drives Erasure (uniques)</th>
+      </tr>
+    </thead>
+    <tbody>
+      <tr>
+        <th scope="row">{{ current_month_usage.year }}</th>
+        <th scope="row">{{ current_month_usage.month }}</th>
+        <td>{{ current_month_usage.snapshot_register }}</td>
+        <td>{{ current_month_usage.snapshot_update }}</td>
+        <td>{{ current_month_usage.drives_erasure }}</td>
+      </tr>
+    </tbody>
+  </table>
+
+</section>
+{% endblock main %}

ereuse_devicehub/billing/views.py

@@ -1,7 +1,57 @@
 import logging
 
+import flask
 from flask import Blueprint
+from flask.views import View
+from flask_login import current_user, login_required
+from sqlalchemy.sql import extract
 
-billing = Blueprint('billing', __name__, url_prefix='/billing')
+from ereuse_devicehub import __version__
+from ereuse_devicehub.resources.action.models import Snapshot
+
+billing = Blueprint(
+    "billing", __name__, url_prefix="/billing", template_folder="templates"
+)
 
 logger = logging.getLogger(__name__)
+
+
+class BillingIndexView(View):
+    methods = ["GET"]
+    decorators = [login_required]
+    template_name = "billing/home.html"
+
+    def dispatch_request(self):
+        # TODO (@slamora): replace hardcoded and get current time
+        year = 2022
+        month = 9
+        snapshot_register, snapshot_update = self.count_snapshot(year, month)
+
+        current_month_usage = {
+            "year": year,
+            "month": month,
+            "snapshot_register": snapshot_register,
+            "snapshot_update": snapshot_update,
+        }
+        context = {
+            "current_month_usage": current_month_usage,
+            "page_title": "Billing",
+            "version": __version__,
+        }
+        return flask.render_template(self.template_name, **context)
+
+    def count_snapshot(self, year, month):
+        query = Snapshot.query.filter(
+            Snapshot.author_id == current_user.id,
+            extract('year', Snapshot.created) == year,
+            extract('month', Snapshot.created) == month,
+        )
+
+        all = query.count()
+        register = query.distinct(Snapshot.device_id).count()
+        update = all - register
+
+        return (register, update)
+
+
+billing.add_url_rule("/", view_func=BillingIndexView.as_view("billing_index"))