From 30cfd6260b37b9af793128456f5be02b51e052cf Mon Sep 17 00:00:00 2001
From: Thomas Sileo <t@a4.io>
Date: Thu, 25 Aug 2022 08:45:07 +0200
Subject: [PATCH] Pagination for the notifications page

---
 app/admin.py                     | 40 +++++++++++++++++++++++++++++++-
 app/templates/notifications.html | 11 +++++++++
 2 files changed, 50 insertions(+), 1 deletion(-)

diff --git a/app/admin.py b/app/admin.py
index c847f62..4300613 100644
--- a/app/admin.py
+++ b/app/admin.py
@@ -211,6 +211,7 @@ async def admin_bookmarks(
     request: Request,
     db_session: AsyncSession = Depends(get_db_session),
 ) -> templates.TemplateResponse:
+    # TODO: support pagination
     stream = (
         (
             await db_session.scalars(
@@ -667,12 +668,25 @@ async def admin_outbox(
 
 @router.get("/notifications")
 async def get_notifications(
-    request: Request, db_session: AsyncSession = Depends(get_db_session)
+    request: Request,
+    db_session: AsyncSession = Depends(get_db_session),
+    cursor: str | None = None,
 ) -> templates.TemplateResponse:
+    where = []
+    if cursor:
+        decoded_cursor = pagination.decode_cursor(cursor)
+        where.append(models.Notification.created_at < decoded_cursor)
+
+    page_size = 20
+    remaining_count = await db_session.scalar(
+        select(func.count(models.Notification.id)).where(*where)
+    )
+
     notifications = (
         (
             await db_session.scalars(
                 select(models.Notification)
+                .where(*where)
                 .options(
                     joinedload(models.Notification.actor),
                     joinedload(models.Notification.inbox_object),
@@ -684,6 +698,7 @@ async def get_notifications(
                     joinedload(models.Notification.webmention),
                 )
                 .order_by(models.Notification.created_at.desc())
+                .limit(page_size)
             )
         )
         .unique()
@@ -697,6 +712,27 @@ async def get_notifications(
         notif.is_new = False
     await db_session.commit()
 
+    next_cursor = (
+        pagination.encode_cursor(notifications[-1].created_at)
+        if notifications and remaining_count > page_size
+        else None
+    )
+
+    more_unread_count = 0
+    next_cursor = None
+    if notifications and remaining_count > page_size:
+        decoded_next_cursor = notifications[-1].created_at
+        next_cursor = pagination.encode_cursor(decoded_next_cursor)
+
+        # If on the "see more" page there's more unread notification, we want
+        # to display it next to the link
+        more_unread_count = await db_session.scalar(
+            select(func.count(models.Notification.id)).where(
+                models.Notification.is_new.is_(True),
+                models.Notification.created_at < decoded_next_cursor,
+            )
+        )
+
     return await templates.render_template(
         db_session,
         request,
@@ -704,6 +740,8 @@ async def get_notifications(
         {
             "notifications": notifications,
             "actors_metadata": actors_metadata,
+            "next_cursor": next_cursor,
+            "more_unread_count": more_unread_count,
         },
     )
 
diff --git a/app/templates/notifications.html b/app/templates/notifications.html
index 3f35fe8..6a4c085 100644
--- a/app/templates/notifications.html
+++ b/app/templates/notifications.html
@@ -88,4 +88,15 @@
     </div>
     {%- endfor %}
     </div>
+
+{% if next_cursor %}
+<div class="box">
+    <p>
+        <a href="{{ request.url._path }}?cursor={{ next_cursor }}">
+            See more{% if more_unread_count %}({{ more_unread_count }} unread left){% endif %}
+        </a>
+    </p>
+</div>
+{% endif %}
+
 {% endblock %}