Add weekly notification

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

lib/service/notifications/scheduler.ex

@@ -7,7 +7,7 @@ defmodule Mobilizon.Service.Notifications.Scheduler do
   alias Mobilizon.Events.{Event, Participant}
   alias Mobilizon.Service.Workers.Notification
   alias Mobilizon.Users
-  alias Mobilizon.Users.Setting
+  alias Mobilizon.Users.{Setting, User}
   require Logger
 
   def before_event_notification(%Participant{
@@ -73,10 +73,75 @@ defmodule Mobilizon.Service.Notifications.Scheduler do
 
   def on_day_notification(_), do: {:ok, nil}
 
+  def weekly_notification(%Participant{
+        event: %Event{begins_on: begins_on},
+        actor: %Actor{user_id: user_id}
+      })
+      when not is_nil(user_id) do
+    %User{settings: settings, locale: locale} = Users.get_user_with_settings!(user_id)
+
+    case settings do
+      %Setting{notification_each_week: true, timezone: timezone} ->
+        %DateTime{} = begins_on_shifted = shift_zone(begins_on, timezone)
+
+        Logger.debug(
+          "Participation event start at #{inspect(begins_on_shifted)} (user timezone is #{
+            timezone
+          })"
+        )
+
+        notification_date =
+          unless begins_on < DateTime.utc_now() do
+            notification_day = calculate_first_day_of_week(DateTime.to_date(begins_on), locale)
+
+            {:ok, %NaiveDateTime{} = notification_date} =
+              notification_day |> NaiveDateTime.new(~T[08:00:00])
+
+            # This is the datetime when the notification should be sent
+            {:ok, %DateTime{} = notification_date} =
+              DateTime.from_naive(notification_date, timezone)
+
+            unless notification_date < DateTime.utc_now() do
+              notification_date
+            else
+              nil
+            end
+          else
+            nil
+          end
+
+        Logger.debug(
+          "Participation notification should be sent at #{inspect(notification_date)} (user timezone)"
+        )
+
+        if is_nil(notification_date) do
+          {:ok, "Too late to send weekly notifications"}
+        else
+          Notification.enqueue(:weekly_notification, %{user_id: user_id},
+            scheduled_at: notification_date
+          )
+        end
+
+      _ ->
+        {:ok, "User has disabled weekly notifications"}
+    end
+  end
+
+  def weekly_notification(_), do: {:ok, nil}
+
   defp shift_zone(datetime, timezone) do
     case DateTime.shift_zone(datetime, timezone) do
       {:ok, shift_datetime} -> shift_datetime
       {:error, _} -> datetime
     end
   end
+
+  defp calculate_first_day_of_week(%Date{} = date, locale) do
+    day_number = Date.day_of_week(date)
+    first_day_number = Cldr.Calendar.first_day_for_locale(locale)
+
+    if day_number == first_day_number,
+      do: date,
+      else: calculate_first_day_of_week(Date.add(date, -1), locale)
+  end
 end