From 0ae0364497cd203005e681d223d990e608af61fb Mon Sep 17 00:00:00 2001
From: Tom Owers <tom@posthog.com>
Date: Fri, 5 Jan 2024 16:51:01 +0000
Subject: [PATCH] feat(trends): Added smoothing to new trends query runner
 (#19578)

* Added smoothing to new trends query runner

* Update query snapshots

* Update query snapshots

* Fixed tests

* Update query snapshots

* Updated the name to rolling average

* Fixed snaoshots

* Update query snapshots

---------

Co-authored-by: github-actions <41898282+github-actions[bot]@users.noreply.github.com>
---
 .../insights/trends/query_builder.py          | 28 +++++++++++++++++++
 .../trends/test/test_trends_query_runner.py   | 14 ++++++++++
 2 files changed, 42 insertions(+)

diff --git a/posthog/hogql_queries/insights/trends/query_builder.py b/posthog/hogql_queries/insights/trends/query_builder.py
index 26c287600e4553..7733bdfd41dcb6 100644
--- a/posthog/hogql_queries/insights/trends/query_builder.py
+++ b/posthog/hogql_queries/insights/trends/query_builder.py
@@ -300,6 +300,34 @@ def _inner_select_query(self, inner_query: ast.SelectQuery | ast.SelectUnionQuer
             ),
         )
 
+        if (
+            self.query.trendsFilter is not None
+            and self.query.trendsFilter.smoothing_intervals is not None
+            and self.query.trendsFilter.smoothing_intervals > 1
+        ):
+            rolling_average = ast.Alias(
+                alias="count",
+                expr=ast.Call(
+                    name="floor",
+                    args=[
+                        ast.WindowFunction(
+                            name="avg",
+                            args=[ast.Call(name="sum", args=[ast.Field(chain=["total"])])],
+                            over_expr=ast.WindowExpr(
+                                order_by=[ast.OrderExpr(expr=ast.Field(chain=["day_start"]), order="ASC")],
+                                frame_method="ROWS",
+                                frame_start=ast.WindowFrameExpr(
+                                    frame_type="PRECEDING",
+                                    frame_value=int(self.query.trendsFilter.smoothing_intervals - 1),
+                                ),
+                                frame_end=ast.WindowFrameExpr(frame_type="CURRENT ROW"),
+                            ),
+                        )
+                    ],
+                ),
+            )
+            query.select = [rolling_average]
+
         query.group_by = []
         query.order_by = []
 
diff --git a/posthog/hogql_queries/insights/trends/test/test_trends_query_runner.py b/posthog/hogql_queries/insights/trends/test/test_trends_query_runner.py
index a8e966d3ccbb0a..b54d4ca1470153 100644
--- a/posthog/hogql_queries/insights/trends/test/test_trends_query_runner.py
+++ b/posthog/hogql_queries/insights/trends/test/test_trends_query_runner.py
@@ -1144,3 +1144,17 @@ def test_properties_filtering_with_materialized_columns_and_empty_string_as_prop
         )
 
         assert response.results[0]["data"] == [1]
+
+    def test_smoothing(self):
+        self._create_test_events()
+
+        response = self._run_trends_query(
+            "2020-01-09",
+            "2020-01-20",
+            IntervalType.day,
+            [EventsNode(event="$pageview")],
+            TrendsFilter(smoothing_intervals=7),
+            None,
+        )
+
+        assert response.results[0]["data"] == [1, 0, 0, 1, 1, 1, 1, 1, 1, 1, 0, 0]