Use date helper to inflate months and years

Author: pbogut

lib/recurring_events/by_pump.ex

@@ -62,18 +62,25 @@ defmodule RecurringEvents.ByPump do
   defp inflate_week(date, rules) do
     week_start = week_start_date(date, rules)
     week_end = week_end_date(date, rules)
+
     inflate_period(week_start, week_end)
   end
 
   defp inflate_month(date) do
-    month_start = %{date | day: 1}
-    month_end = %{date | day: @date_helper.last_day_of_the_month(date)}
+    start_shift = 1 - date.day
+    end_shift = @date_helper.last_day_of_the_month(date) -1
+
+    month_start = @date_helper.shift_date(date, start_shift, :days)
+    month_end = @date_helper.shift_date(month_start, end_shift, :days)
     inflate_period(month_start, month_end)
   end
 
   defp inflate_year(date) do
-    year_start = %{date | day: 1, month: 1}
-    year_end = %{date | day: 31, month: 12}
+    start_shift = 1 - @date_helper.day_of_the_year(date)
+    end_shift = @date_helper.last_day_of_the_year(date) - 1
+
+    year_start = @date_helper.shift_date(date, start_shift, :days)
+    year_end = @date_helper.shift_date(year_start, end_shift, :days)
     inflate_period(year_start, year_end)
   end
 

test/timezone_test.exs

@@ -1,13 +1,14 @@
 defmodule RecurringEvents.TimezoneTest do
   use ExUnit.Case, async: true
   import RecurringEvents.TestHelper
+  alias RecurringEvents, as: RR
 
   if Code.ensure_loaded?(Timex) do
     test "should handle timezones if Timex available" do
       time = Timex.to_datetime({{2018, 11, 2}, {5, 0, 0}}, "America/Los_Angeles")
 
       result =
-        RecurringEvents.take(
+        RR.take(
           time,
           %{freq: :daily, by_hour: 3, by_minute: 0, by_second: 0},
           5
@@ -20,6 +21,168 @@ defmodule RecurringEvents.TimezoneTest do
                )
     end
 
+    @doc """
+      Every other week - forever
+
+      DTSTART;TZID=US-Eastern:19970902T090000
+      RRULE:FREQ=WEEKLY;INTERVAL=2;WKST=SU
+
+      ==> (1997 9:00 AM EDT)September 2,16,30;October 14
+          (1997 9:00 AM EST)October 28;November 11,25;December 9,23
+          (1998 9:00 AM EST)January 6,20;February
+      ...
+    """
+    test "Every other week - forever" do
+      result =
+        Timex.to_datetime({1997, 9, 2}, "America/Los_Angeles")
+        |> RR.unfold(%{freq: :weekly, interval: 2, week_start: :sunday})
+
+      expect =
+        date_tz_expand(
+          [
+            {1997, 9, [2, 16, 30]},
+            {1997, 10, [14, 28]},
+            {1997, 11, [11, 25]},
+            {1997, 12, [9, 23]},
+            {1998, 1, [6, 20]}
+          ],
+          "America/Los_Angeles"
+        )
+
+      assert expect == result |> Enum.take(expect |> Enum.count())
+    end
+
+    @doc """
+      Every other month on the 1st and last Sunday of the month for 10
+      occurrences:
+
+      DTSTART;TZID=US-Eastern:19970907T090000
+      RRULE:FREQ=MONTHLY;INTERVAL=2;COUNT=10;BYDAY=1SU,-1SU
+
+      ==> (1997 9:00 AM EDT)September 7,28
+          (1997 9:00 AM EST)November 2,30
+          (1998 9:00 AM EST)January 4,25;March 1,29
+          (1998 9:00 AM EDT)May 3,31
+    """
+    test "Every other month on the 1st and last Sunday of the month for 10 occurrences" do
+      result =
+        Timex.to_datetime({1997, 9, 7}, "America/Los_Angeles")
+        |> RR.unfold(%{
+          freq: :monthly,
+          interval: 2,
+          count: 10,
+          by_day: [{1, :sunday}, {-1, :sunday}]
+        })
+
+      expect =
+        date_tz_expand(
+          [
+            {1997, 9, [7, 28]},
+            {1997, 11, [2, 30]},
+            {1998, 1, [4, 25]},
+            {1998, 3, [1, 29]},
+            {1998, 5, [3, 31]}
+          ],
+          "America/Los_Angeles"
+        )
+
+      assert expect == result |> Enum.take(999)
+    end
+
+    @doc """
+      Weekly until December 24, 1997
+
+      DTSTART;TZID=US-Eastern:19970902T090000
+      RRULE:FREQ=WEEKLY;UNTIL=19971224T000000Z
+
+      ==> (1997 9:00 AM EDT)September 2,9,16,23,30;October 7,14,21
+          (1997 9:00 AM EST)October 28;November 4,11,18,25;
+                            December 2,9,16,23
+    """
+    test "Weekly until December 24, 1997" do
+      result =
+        Timex.to_datetime({1997, 9, 2}, "America/Los_Angeles")
+        |> RR.unfold(%{
+          freq: :weekly,
+          until: Timex.to_datetime({1997, 12, 24}, "America/Los_Angeles")
+        })
+
+      expect =
+        date_tz_expand(
+          [
+            {1997, 9, [2, 9, 16, 23, 30]},
+            {1997, 10, [7, 14, 21, 28]},
+            {1997, 11, [4, 11, 18, 25]},
+            {1997, 12, [2, 9, 16, 23]}
+          ],
+          "America/Los_Angeles"
+        )
+
+      assert expect == result |> Enum.take(999)
+    end
+
+    @doc """
+      Weekly for 10 occurrences
+
+      DTSTART;TZID=US-Eastern:19970902T090000
+      RRULE:FREQ=WEEKLY;COUNT=10
+
+      ==> (1997 9:00 AM EDT)September 2,9,16,23,30;October 7,14,21
+          (1997 9:00 AM EST)October 28;November 4
+    """
+    test "Weekly for 10 occurrences" do
+      result =
+        Timex.to_datetime({1997, 9, 2}, "America/Los_Angeles")
+        |> RR.unfold(%{freq: :weekly, count: 10})
+
+      expect =
+        date_tz_expand(
+          [
+            {1997, 9, [2, 9, 16, 23, 30]},
+            {1997, 10, [7, 14, 21, 28]},
+            {1997, 11, 4}
+          ],
+          "America/Los_Angeles"
+        )
+
+      assert expect == result |> Enum.take(999)
+    end
+
+    @doc """
+      Monthly on the first and last day of the month for 10 occurrences
+
+      DTSTART;TZID=US-Eastern:19970930T090000
+      RRULE:FREQ=MONTHLY;COUNT=10;BYMONTHDAY=1,-1
+
+      ==> (1997 9:00 AM EDT)September 30;October 1
+          (1997 9:00 AM EST)October 31;November 1,30;December 1,31
+          (1998 9:00 AM EST)January 1,31;February 1
+    """
+    test "Monthly on the first and last day of the month for 10 occurrences" do
+      result =
+        Timex.to_datetime({1997, 9, 30}, "America/Los_Angeles")
+        |> RR.unfold(%{
+          freq: :monthly,
+          count: 10,
+          by_month_day: [1, -1]
+        })
+
+      expect =
+        date_tz_expand(
+          [
+            {1997, 9, 30},
+            {1997, 10, [1, 31]},
+            {1997, 11, [1, 30]},
+            {1997, 12, [1, 31]},
+            {1998, 1, [1, 31]},
+            {1998, 2, 1}
+          ],
+          "America/Los_Angeles"
+        )
+
+      assert expect == result |> Enum.take(999)
+    end
+
     def date_tz_expand(date_list, time_zone) when is_list(date_list) do
       Enum.flat_map(date_list, fn t -> date_tz_expand(t, time_zone) end)
     end
@@ -33,5 +196,12 @@ defmodule RecurringEvents.TimezoneTest do
           second <- listify(seconds),
           do: Timex.to_datetime({{year, month, day}, {hour, minute, second}}, time_zone)
     end
+
+    def date_tz_expand({years, months, days}, time_zone) do
+      for year <- listify(years),
+          month <- listify(months),
+          day <- listify(days),
+          do: Timex.to_datetime({year, month, day}, time_zone)
+    end
   end
 end