Add mark all read button to unread notifications

This will only mark notifications upto the timestamp of the last one shown on
the unread_notifications page where it was clicked

tildes/tildes/templates/notifications_unread.jinja2

@@ -5,7 +5,20 @@
 
 {% block title %}Unread notifications{% endblock %}
 
-{% block main_heading %}Unread notifications{% endblock %}
+{% block main_heading %}Unread notifications
+  {% if notifications and not request.user.auto_mark_notifications_read %}
+      <button
+        class="btn btn-link-minimal ml-2"
+        data-ic-put-to="{{ request.route_url(
+            'ic_comment_mark_read',
+            comment_id36=notifications[0].comment.comment_id36,
+            _query={"mark_all_previous": "true"},
+        )}}",
+        data-ic-target="closest main"
+      >Mark all read</button>
+  {% endif %}
+
+{% endblock %}
 
 {% block content %}
 {% if notifications %}

tildes/tildes/views/api/web/comment.py

@@ -1,9 +1,12 @@
 """Web API endpoints related to comments."""
 
+from marshmallow.fields import String
+from marshmallow.validate import OneOf
 from pyramid.request import Request
 from pyramid.response import Response
 from sqlalchemy.dialects.postgresql import insert
 from sqlalchemy.exc import IntegrityError
+from sqlalchemy.orm import joinedload
 from sqlalchemy.orm.exc import FlushError
 from webargs.pyramidparser import use_kwargs
 from zope.sqlalchemy import mark_changed
@@ -22,6 +25,40 @@ from tildes.views import IC_NOOP
 from tildes.views.decorators import ic_view_config
 
 
+def _increment_topic_comments_seen(
+      request: Request,
+      comment: Comment,
+) -> None:
+    """If the user has the "track comment visits" feature enabled, we want to
+    increment the number of comments they've seen in the thread that the
+    comment came from, so that they don't *both* get a notification as well as
+    have the thread highlight with "(1 new)". This should only happen if their
+    last visit was before the comment was posted, however.  Below, this is
+    implemented as a INSERT ... ON CONFLICT DO UPDATE so that it will insert
+    a new topic visit with 1 comment if they didn't previously have one at
+    all. """
+    if request.user.track_comment_visits:
+        statement = (
+            insert(TopicVisit.__table__)
+            .values(
+                user_id=request.user.user_id,
+                topic_id=comment.topic_id,
+                visit_time=utc_now(),
+                num_comments=1,
+            )
+            .on_conflict_do_update(
+                constraint=TopicVisit.__table__.primary_key,
+                set_={'num_comments': TopicVisit.num_comments + 1},
+                where=TopicVisit.visit_time < comment.created_time,
+            )
+        )
+
+        request.db_session.execute(statement)
+        mark_changed(request.db_session)
+
+    return
+
+
 @ic_view_config(
     route_name='topic_comments',
     request_method='POST',
@@ -287,41 +324,52 @@ def untag_comment(request: Request, name: CommentTagOption) -> Response:
     request_method='PUT',
     permission='mark_read',
 )
-def mark_read_comment(request: Request) -> Response:
+@use_kwargs({
+    'clear_all_previous': String(
+        load_from='mark_all_previous',
+        validate=OneOf(('true', 'false')),
+    ),
+})
+def put_mark_comments_read(
+        request: Request,
+        clear_all_previous: str = 'false'
+) -> Response:
     """Mark a comment read (clear all notifications)."""
     comment = request.context
 
-    request.query(CommentNotification).filter(
-        CommentNotification.user == request.user,
-        CommentNotification.comment == comment,
-    ).update(
-        {CommentNotification.is_unread: False}, synchronize_session=False)
-
-    # If the user has the "track comment visits" feature enabled, we want to
-    # increment the number of comments they've seen in the thread that the
-    # comment came from, so that they don't *both* get a notification as well
-    # as have the thread highlight with "(1 new)". This should only happen if
-    # their last visit was before the comment was posted, however.
-    # Below, this is implemented as a INSERT ... ON CONFLICT DO UPDATE so that
-    # it will insert a new topic visit with 1 comment if they didn't previously
-    # have one at all.
-    if request.user.track_comment_visits:
-        statement = (
-            insert(TopicVisit.__table__)
-            .values(
-                user_id=request.user.user_id,
-                topic_id=comment.topic_id,
-                visit_time=utc_now(),
-                num_comments=1,
-            )
-            .on_conflict_do_update(
-                constraint=TopicVisit.__table__.primary_key,
-                set_={'num_comments': TopicVisit.num_comments + 1},
-                where=TopicVisit.visit_time < comment.created_time,
+    if clear_all_previous == 'true':
+
+        prev_notifications = (
+
+            request.query(CommentNotification).filter(
+                CommentNotification.is_unread == True, #noqa
+                CommentNotification.created_time <=
+                request.db_session.query(CommentNotification.created_time)
+                .filter(
+                    CommentNotification.user == request.user,
+                    CommentNotification.comment_id == comment.comment_id,
+                )
+                .as_scalar()
             )
+            .options(joinedload(CommentNotification.comment))
+            .all()
         )
 
-        request.db_session.execute(statement)
-        mark_changed(request.db_session)
+        for notification in prev_notifications:
+          notification.is_unread = False
+          _increment_topic_comments_seen(request, notification.comment)
+
+
+        return Response('Your comment notifications have been cleared.')
+
+    else:
+
+        request.query(CommentNotification).filter(
+            CommentNotification.user == request.user,
+            CommentNotification.comment == comment,
+        ).update(
+            {CommentNotification.is_unread: False}, synchronize_session=False)
+
+        _increment_topic_comments_seen(request, comment)
 
-    return IC_NOOP
+        return IC_NOOP