Fix shift_day/4 and add Julian variants

Author: kipcole9

mix/julian_calendars/julian_dec_25.ex renamed to lib/cldr/calendar/calendars/julian/julian_dec_25.ex

@@ -17,10 +17,17 @@ defmodule Cldr.Calendar.Julian.Compiler do
       @new_year_starting_day start_day
 
       @quarters_in_year 4
+      @months_in_quarter 3
       @months_in_year Cldr.Calendar.Julian.months_in_year(0)
       @last_month_of_year rem(start_month + (@months_in_year - 1), @months_in_year)
 
-      defguard year_rollover(month, day) when month <= @new_year_starting_month and day < @new_year_starting_day
+      @doc """
+      These dates belong to the prior Julian year
+
+      """
+      defguard year_rollover(month, day)
+        when month < @new_year_starting_month
+          or (month == @new_year_starting_month and day < @new_year_starting_day)
 
       # Adjust the year to be a Jan 1st starting year and carry
       # on
@@ -33,26 +40,76 @@ defmodule Cldr.Calendar.Julian.Compiler do
         Cldr.Calendar.Julian.date_to_iso_days(year, month, day)
       end
 
-      def naive_datetime_to_iso_days(year, month, day, 0, 0, 0, {0, 0}) do
-        {date_to_iso_days(year, month, day), {0, 6}}
-      end
-
       # Adjust the year to be this calendars starting year
       def date_from_iso_days(iso_days) do
         {year, month, day} = Cldr.Calendar.Julian.date_from_iso_days(iso_days)
+        date_from_julian_date(year, month, day)
+      end
 
-        if month <= @new_year_starting_month and day < @new_year_starting_day do
-          {year - 1, month, day}
-        else
-          {year, month, day}
-        end
+      def date_from_julian_date(year, month, day) when year_rollover(month, day) do
+        {year - 1, month, day}
+      end
+
+      def date_from_julian_date(year, month, day) do
+        {year, month, day}
+      end
+
+      def naive_datetime_to_iso_days(year, month, day, 0, 0, 0, {0, 0}) do
+        {date_to_iso_days(year, month, day), {0, 6}}
       end
 
       def naive_datetime_from_iso_days({iso_days, _}) do
         {year, month, day} = date_from_iso_days(iso_days)
         {year, month, day, 0, 0, 0, {0, 6}}
       end
 
+      def shift_date(year, month, day, duration) do
+        Cldr.Calendar.shift_date(year, month, day, __MODULE__, duration)
+      end
+
+      def plus(year, month, day, date_part, increment, options \\ [])
+
+      def plus(year, month, day, :years, years, options) do
+        new_year =
+          year + years
+
+        new_day =
+          if Keyword.get(options, :coerce, false) do
+            max_new_day = days_in_month(new_year, month)
+            min(day, max_new_day)
+          else
+            day
+          end
+
+        {year + years, month, new_day}
+      end
+
+      def plus(year, month, day, :quarters, quarters, options) do
+        months = quarters * @months_in_quarter
+        plus(year, month, day, :months, months, options)
+      end
+
+      def plus(year, month, day, :months, months, options) do
+        months_in_year = months_in_year(year)
+        {year_increment, new_month} = Cldr.Math.div_amod(month + months, months_in_year)
+        new_year = year + year_increment
+
+        new_day =
+          if Keyword.get(options, :coerce, false) do
+            max_new_day = days_in_month(new_year, new_month)
+            min(day, max_new_day)
+          else
+            day
+          end
+
+        {new_year, new_month, new_day}
+      end
+
+      def plus(year, month, day, :days, days, _options) do
+        iso_days = date_to_iso_days(year, month, day) + days
+        date_from_iso_days(iso_days)
+      end
+
       def days_in_year(year) do
         first_day = date_to_iso_days(year, @new_year_starting_month, @new_year_starting_day)
         first_day_next_year = date_to_iso_days(year + 1, @new_year_starting_month, @new_year_starting_day)
@@ -184,7 +241,6 @@ defmodule Cldr.Calendar.Julian.Compiler do
 
       defdelegate valid_date?(year, month, day), to: Cldr.Calendar.Julian
       defdelegate leap_year?(year), to: Cldr.Calendar.Julian
-      defdelegate plus(year, month, day, part, years, options), to: Cldr.Calendar.Julian
       defdelegate week(year, week), to: Cldr.Calendar.Julian
       defdelegate weeks_in_year(year), to: Cldr.Calendar.Julian
       defdelegate months_in_year(year), to: Cldr.Calendar.Julian
@@ -204,7 +260,6 @@ defmodule Cldr.Calendar.Julian.Compiler do
       defdelegate time_to_day_fraction(hour, minute, second, millisecond), to: Cldr.Calendar.Julian
       defdelegate time_from_day_fraction(fraction), to: Cldr.Calendar.Julian
       defdelegate shift_time(hour, minute, second, millisecond, duration), to: Cldr.Calendar.Julian
-      defdelegate shift_date(year, month, day, duration), to: Cldr.Calendar.Julian
       defdelegate shift_naive_datetime(year, month, day, hour, minute, second, millisecond, duration), to: Cldr.Calendar.Julian
       defdelegate iso_days_to_end_of_day(iso_days), to: Cldr.Calendar.Julian
       defdelegate iso_days_to_beginning_of_day(iso_days), to: Cldr.Calendar.Julian

mix/julian_calendars/julian_jan_1.ex renamed to lib/cldr/calendar/calendars/julian/julian_jan_1.ex

@@ -88,7 +88,7 @@ defmodule Cldr.Calendar.RoundTrip.Test do
   end
 
   test "that Cldr.Calendar.Julian.March25 dates all round trip" do
-    for year <- 0001..1800,
+    for year <- 0001..2200,
         month <- 1..12,
         day <- 1..28 do
       {:ok, julian} = Date.new(year, month, day, Cldr.Calendar.Julian.March25)
@@ -98,6 +98,28 @@ defmodule Cldr.Calendar.RoundTrip.Test do
     end
   end
 
+  test "that Cldr.Calendar.Julian.Jan1 dates all round trip" do
+    for year <- 0001..2200,
+        month <- 1..12,
+        day <- 1..Cldr.Calendar.Julian.days_in_month(year, month) do
+      {:ok, julian} = Date.new(year, month, day, Cldr.Calendar.Julian.Jan1)
+      {:ok, iso} = Date.convert(julian, Calendar.ISO)
+      {:ok, converted} = Date.convert(iso, Cldr.Calendar.Julian.Jan1)
+      assert Date.compare(julian, converted) == :eq
+    end
+  end
+
+  test "that Cldr.Calendar.Julian.Jan1 dates are the same as Cldr.Calendar.Julian dates" do
+    for year <- 0001..2200,
+        month <- 1..12,
+        day <- 1..Cldr.Calendar.Julian.days_in_month(year, month) do
+      {:ok, julian_jan1} = Date.new(year, month, day, Cldr.Calendar.Julian.Jan1)
+      {:ok, julian} = Date.convert(julian_jan1, Cldr.Calendar.Julian)
+      {:ok, converted} = Date.convert(julian, Cldr.Calendar.Julian.Jan1)
+      assert Date.compare(julian_jan1, converted) == :eq
+    end
+  end
+
   if function_exported?(Code, :fetch_docs, 1) do
     test "that no module docs are generated for a backend" do
       assert {:docs_v1, _, :elixir, _, :hidden, %{}, _} = Code.fetch_docs(NoDocs.Cldr.Calendar)