Set Consolidated View's timezone to what majority of sites has (#5834)

* Set Consolidated View's timezone to what majority of sites has

* clean up

extra/lib/plausible/consolidated_view.ex

@@ -26,6 +26,7 @@ defmodule Plausible.ConsolidatedView do
         if has_sites_to_consolidate?(team) do
           consolidated_view
           |> change_stats_dates(team)
+          |> change_timezone(majority_sites_timezone(team))
           |> bump_updated_at()
           |> Repo.update!()
         else
@@ -110,6 +111,10 @@ defmodule Plausible.ConsolidatedView do
     end
   end
 
+  defp change_timezone(site_or_changeset, timezone) do
+    Ecto.Changeset.change(site_or_changeset, timezone: timezone)
+  end
+
   defp bump_updated_at(struct_or_changeset) do
     Ecto.Changeset.change(struct_or_changeset, updated_at: NaiveDateTime.utc_now(:second))
   end
@@ -119,7 +124,11 @@ defmodule Plausible.ConsolidatedView do
       nil ->
         {:ok, consolidated_view} =
           team
-          |> Site.new_for_team(%{consolidated: true, domain: make_id(team)})
+          |> Site.new_for_team(%{
+            consolidated: true,
+            domain: make_id(team)
+          })
+          |> change_timezone(majority_sites_timezone(team))
           |> change_stats_dates(team)
           |> Repo.insert()
 
@@ -160,4 +169,21 @@ defmodule Plausible.ConsolidatedView do
   defp has_sites_to_consolidate?(%Team{} = team) do
     Teams.owned_sites_count(team) > 0
   end
+
+  defp majority_sites_timezone(%Team{} = team) do
+    q =
+      from(sr in Site.regular(),
+        where: sr.team_id == ^team.id,
+        group_by: sr.timezone,
+        select: {sr.timezone, count(sr.id)},
+        order_by: [desc: count(sr.id), asc: sr.timezone],
+        limit: 1
+      )
+
+    case Repo.one(q) do
+      {"UTC", _count} -> "Etc/UTC"
+      {timezone, _count} -> timezone
+      nil -> "Etc/UTC"
+    end
+  end
 end

test/plausible/consolidated_view_test.exs

@@ -72,6 +72,34 @@ defmodule Plausible.ConsolidatedViewTest do
                  {ConsolidatedView.Cache.get(team.identifier) == [site.id], :ok}
                end)
       end
+
+      test "sets Etc/UTC by default", %{team: team} do
+        new_site(team: team)
+        team = Teams.complete_setup(team)
+
+        assert {:ok, %Plausible.Site{timezone: "Etc/UTC"}} =
+                 ConsolidatedView.enable(team)
+      end
+
+      test "sets Etc/UTC for UTC sites", %{team: team} do
+        new_site(team: team, timezone: "UTC")
+        team = Teams.complete_setup(team)
+
+        assert {:ok, %Plausible.Site{timezone: "Etc/UTC"}} =
+                 ConsolidatedView.enable(team)
+      end
+
+      test "sets majority timezone by default", %{team: team} do
+        new_site(team: team, timezone: "Etc/UTC")
+        new_site(team: team, timezone: "Europe/Tallinn")
+        new_site(team: team, timezone: "Europe/Warsaw")
+        new_site(team: team, timezone: "Europe/Tallinn")
+
+        team = Teams.complete_setup(team)
+
+        assert {:ok, %Plausible.Site{timezone: "Europe/Tallinn"}} =
+                 ConsolidatedView.enable(team)
+      end
     end
 
     describe "disable/1" do
@@ -174,12 +202,23 @@ defmodule Plausible.ConsolidatedViewTest do
 
       @tag :slow
       test "re-enables", %{team: team} do
-        _site = new_site(team: team, native_stats_start_at: ~N[2024-01-01 12:00:00])
+        _site =
+          new_site(
+            team: team,
+            native_stats_start_at: ~N[2024-01-01 12:00:00],
+            timezone: "Europe/Warsaw"
+          )
+
         team = Teams.complete_setup(team)
 
         {:ok, first_enable} = ConsolidatedView.enable(team)
 
-        another_site = new_site(team: team, native_stats_start_at: ~N[2024-01-01 10:00:00])
+        another_site =
+          new_site(
+            team: team,
+            native_stats_start_at: ~N[2024-01-01 10:00:00],
+            timezone: "Europe/Tallinn"
+          )
 
         Process.sleep(1_000)
 
@@ -189,6 +228,7 @@ defmodule Plausible.ConsolidatedViewTest do
         consolidated_view = ConsolidatedView.get(team)
         assert consolidated_view.native_stats_start_at == another_site.native_stats_start_at
         assert NaiveDateTime.after?(consolidated_view.updated_at, first_enable.updated_at)
+        assert consolidated_view.timezone == "Europe/Tallinn"
       end
     end
   end