defmodule Cldr.Calendar.Julian do
@behaviour Calendar
@behaviour Cldr.Calendar
@type year :: -9999..-1 | 1..9999
@type month :: 1..12
@type day :: 1..31
@quarters_in_year 4
@months_in_year 12
@months_in_quarter 3
@days_in_week 7
@doc """
Defines the CLDR calendar type for this calendar.
This type is used in support of `Cldr.Calendar.localize/3`.
Currently only `:gregorian` is supported.
"""
@impl Cldr.Calendar
def cldr_calendar_type do
:gregorian
end
@doc """
Identifies that this calendar is month based.
"""
@impl Cldr.Calendar
def calendar_base do
:month
end
@epoch Cldr.Calendar.Gregorian.date_to_iso_days(0, 12, 30)
def epoch do
@epoch
end
@doc """
Determines if the date given is valid according to this calendar.
"""
@impl Calendar
def valid_date?(0, _month, _day) do
false
end
@months_with_30_days [4, 6, 9, 11]
def valid_date?(_year, month, day) when month in @months_with_30_days and day in 1..30 do
true
end
@months_with_31_days [1, 3, 5, 7, 8, 10, 12]
def valid_date?(_year, month, day) when month in @months_with_31_days and day in 1..31 do
true
end
def valid_date?(year, 2, 29) do
if leap_year?(year), do: true, else: false
end
def valid_date?(_year, 2, day) when day in 1..28 do
true
end
def valid_date?(_year, _month, _day) do
false
end
@doc """
Calculates the year and era from the given `year`.
The ISO calendar has two eras: the current era which
starts in year 1 and is defined as era "1". And a
second era for those years less than 1 defined as
era "0".
"""
@spec year_of_era(year) :: {year, era :: 0..1}
unless Code.ensure_loaded?(Calendar.ISO) && function_exported?(Calendar.ISO, :year_of_era, 3) do
@impl Cldr.Calendar
end
def year_of_era(year) when year > 0 do
{year, 1}
end
def year_of_era(year) when year <= 0 do
{abs(year), 0}
end
@doc """
Calculates the year and era from the given `year`,
`month` and `day`.
"""
@spec year_of_era(year, month, day) :: {year :: Calendar.year(), era :: 0..1}
@impl Calendar
def year_of_era(year, _month, _day) do
year_of_era(year)
end
@doc """
Returns the calendar year as displayed
on rendered calendars.
"""
@spec calendar_year(year, month, day) :: Calendar.year()
@impl Cldr.Calendar
def calendar_year(year, _month, _day) do
year
end
@doc """
Returns the related gregorian year as displayed
on rendered calendars.
"""
@spec related_gregorian_year(year, month, day) :: Calendar.year()
@impl Cldr.Calendar
def related_gregorian_year(year, month, day) do
iso_days = date_to_iso_days(year, month, day)
{year, _month, _day} = Cldr.Calendar.Gregorian.date_from_iso_days(iso_days)
year
end
@doc """
Returns the extended year as displayed
on rendered calendars.
"""
@spec extended_year(year, month, day) :: Calendar.year()
@impl Cldr.Calendar
def extended_year(year, _month, _day) do
year
end
@doc """
Returns the cyclic year as displayed
on rendered calendars.
"""
@spec cyclic_year(year, month, day) :: Calendar.year()
@impl Cldr.Calendar
def cyclic_year(year, _month, _day) do
year
end
@doc """
Calculates the quarter of the year from the given `year`, `month`, and `day`.
It is an integer from 1 to 4.
"""
@spec quarter_of_year(year, month, day) :: 1..4
@impl Calendar
def quarter_of_year(_year, month, _day) do
Float.ceil(month / @months_in_quarter)
|> trunc
end
@doc """
Calculates the month of the year from the given `year`, `month`, and `day`.
It is an integer from 1 to 12.
"""
@spec month_of_year(year, month, day) :: month
@impl Cldr.Calendar
def month_of_year(_year, month, _day) do
month
end
@doc """
Calculates the week of the year from the given `year`, `month`, and `day`.
It is an integer from 1 to 53.
"""
@spec week_of_year(year, month, day) :: {:error, :not_defined}
@impl Cldr.Calendar
def week_of_year(_year, _month, _day) do
{:error, :not_defined}
end
@doc """
Calculates the ISO week of the year from the given `year`, `month`, and `day`.
It is an integer from 1 to 53.
"""
@spec iso_week_of_year(year, month, day) :: {:error, :not_defined}
@impl Cldr.Calendar
def iso_week_of_year(_year, _month, _day) do
{:error, :not_defined}
end
@doc """
Calculates the week of the year from the given `year`, `month`, and `day`.
It is an integer from 1 to 53.
"""
@spec week_of_month(year, month, day) :: {pos_integer(), pos_integer()} | {:error, :not_defined}
@impl Cldr.Calendar
def week_of_month(_year, _month, _day) do
{:error, :not_defined}
end
@doc """
Calculates the day and era from the given `year`, `month`, and `day`.
"""
@spec day_of_era(year, month, day) :: {day :: pos_integer(), era :: 0..1}
@impl Calendar
def day_of_era(year, month, day) do
{_, era} = year_of_era(year)
days = date_to_iso_days(year, month, day)
{days + epoch(), era}
end
@doc """
Calculates the day of the year from the given `year`, `month`, and `day`.
"""
@spec day_of_year(year, month, day) :: 1..366
@impl Calendar
def day_of_year(year, month, day) do
first_day = date_to_iso_days(year, 1, 1)
this_day = date_to_iso_days(year, month, day)
this_day - first_day + 1
end
@doc """
Calculates the day of the week from the given `year`, `month`, and `day`.
It is an integer from 1 to 7, where 1 is Monday and 7 is Sunday.
"""
if Code.ensure_loaded?(Date) && function_exported?(Date, :day_of_week, 2) do
@spec day_of_week(year, month, day, 1..7 | :default) ::
{Calendar.day_of_week(), first_day_of_week :: non_neg_integer(),
last_day_of_week :: non_neg_integer()}
@impl Calendar
@epoch_day_of_week 6
def day_of_week(year, month, day, :default) do
days = date_to_iso_days(year, month, day)
days_after_saturday = rem(days, 7)
day_of_week = Cldr.Math.amod(days_after_saturday + @epoch_day_of_week, @days_in_week)
{day_of_week, 1, 7}
end
else
@spec day_of_week(year, month, day) :: 1..7
@impl Calendar
@epoch_day_of_week 6
def day_of_week(year, month, day) do
days = date_to_iso_days(year, month, day)
days_after_saturday = rem(days, 7)
Cldr.Math.amod(days_after_saturday + @epoch_day_of_week, @days_in_week)
end
end
@doc """
Calculates the number of period in a given `year`. A period
corresponds to a month in month-based calendars and
a week in week-based calendars..
"""
@impl Cldr.Calendar
def periods_in_year(_year) do
@months_in_year
end
@impl Cldr.Calendar
def weeks_in_year(_year) do
{:error, :not_defined}
end
@doc """
Returns the number days in a given year.
"""
@impl Cldr.Calendar
def days_in_year(year) do
if leap_year?(year), do: 366, else: 365
end
@doc """
Returns how many days there are in the given year-month.
"""
@spec days_in_month(year, month) :: 28..31
@impl Calendar
def days_in_month(year, 2) do
if leap_year?(year), do: 29, else: 28
end
def days_in_month(_year, month) when month in @months_with_30_days do
30
end
def days_in_month(_year, month) when month in @months_with_31_days do
31
end
@doc """
Returns the number days in a a week.
"""
def days_in_week do
@days_in_week
end
@doc """
Returns a `Date.Range.t` representing
a given year.
"""
@impl Cldr.Calendar
def year(year) do
last_month = months_in_year(year)
days_in_last_month = days_in_month(year, last_month)
with {:ok, start_date} <- Date.new(year, 1, 1, __MODULE__),
{:ok, end_date} <- Date.new(year, last_month, days_in_last_month, __MODULE__) do
Date.range(start_date, end_date)
end
end
@doc """
Returns a `Date.Range.t` representing
a given quarter of a year.
"""
@impl Cldr.Calendar
def quarter(year, quarter) do
months_in_quarter = div(months_in_year(year), @quarters_in_year)
starting_month = months_in_quarter * (quarter - 1) + 1
starting_day = 1
ending_month = starting_month + months_in_quarter - 1
ending_day = days_in_month(year, ending_month)
with {:ok, start_date} <- Date.new(year, starting_month, starting_day, __MODULE__),
{:ok, end_date} <- Date.new(year, ending_month, ending_day, __MODULE__) do
Date.range(start_date, end_date)
end
end
@doc """
Returns a `Date.Range.t` representing
a given month of a year.
"""
@impl Cldr.Calendar
def month(year, month) do
starting_day = 1
ending_day = days_in_month(year, month)
with {:ok, start_date} <- Date.new(year, month, starting_day, __MODULE__),
{:ok, end_date} <- Date.new(year, month, ending_day, __MODULE__) do
Date.range(start_date, end_date)
end
end
@doc """
Returns a `Date.Range.t` representing
a given week of a year.
"""
@impl Cldr.Calendar
def week(_year, _week) do
{:error, :not_defined}
end
@doc """
Adds an `increment` number of `date_part`s
to a `year-month-day`.
`date_part` can be `:quarters`
or`:months`.
"""
@impl Cldr.Calendar
def plus(year, month, day, date_part, increment, options \\ [])
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
@doc """
Returns if the given year is a leap year.
"""
@spec leap_year?(year) :: boolean()
@impl Calendar
def leap_year?(year) do
Cldr.Math.mod(year, 4) == if year > 0, do: 0, else: 3
end
@doc """
Returns the number of days since the calendar
epoch for a given `year-month-day`
"""
def date_to_iso_days(year, month, day) do
adjustment = adjustment(year, month, day)
year = if year < 0, do: year + 1, else: year
epoch() - 1 +
365 * (year - 1) +
Integer.floor_div(year - 1, 4) +
Integer.floor_div(367 * month - 362, @months_in_year) +
adjustment +
day
end
defp adjustment(year, month, _day) do
cond do
month <= 2 -> 0
leap_year?(year) -> -1
true -> -2
end
end
@doc """
Returns a `{year, month, day}` calculated from
the number of `iso_days`.
"""
def date_from_iso_days(iso_days) do
approx = Integer.floor_div(4 * (iso_days - epoch()) + 1464, 1461)
year = if approx <= 0, do: approx - 1, else: approx
prior_days = iso_days - date_to_iso_days(year, 1, 1)
correction = correction(iso_days, year)
month = Integer.floor_div(@months_in_year * (prior_days + correction) + 373, 367)
day = 1 + (iso_days - date_to_iso_days(year, month, 1))
{year, month, day}
end
defp correction(iso_days, year) do
cond do
iso_days < date_to_iso_days(year, 3, 1) -> 0
leap_year?(year) -> 1
true -> 2
end
end
@doc """
Returns the `t:Calendar.iso_days/0` format of the specified date.
"""
@impl Calendar
@spec naive_datetime_to_iso_days(
Calendar.year(),
Calendar.month(),
Calendar.day(),
Calendar.hour(),
Calendar.minute(),
Calendar.second(),
Calendar.microsecond()
) :: Calendar.iso_days()
def naive_datetime_to_iso_days(year, month, day, hour, minute, second, microsecond) do
{date_to_iso_days(year, month, day), time_to_day_fraction(hour, minute, second, microsecond)}
end
@doc """
Converts the `t:Calendar.iso_days/0` format to the datetime format specified by this calendar.
"""
@spec naive_datetime_from_iso_days(Calendar.iso_days()) :: {
Calendar.year(),
Calendar.month(),
Calendar.day(),
Calendar.hour(),
Calendar.minute(),
Calendar.second(),
Calendar.microsecond()
}
@impl Calendar
def naive_datetime_from_iso_days({days, day_fraction}) do
{year, month, day} = date_from_iso_days(days)
{hour, minute, second, microsecond} = time_from_day_fraction(day_fraction)
{year, month, day, hour, minute, second, microsecond}
end
@doc false
@impl Calendar
defdelegate day_rollover_relative_to_midnight_utc, to: Calendar.ISO
@doc false
@impl Calendar
defdelegate months_in_year(year), to: Calendar.ISO
@doc false
@impl Calendar
defdelegate time_from_day_fraction(day_fraction), to: Calendar.ISO
@doc false
@impl Calendar
defdelegate time_to_day_fraction(hour, minute, second, microsecond), to: Calendar.ISO
@doc false
@impl Calendar
defdelegate parse_date(date_string), to: Calendar.ISO
@doc false
@impl Calendar
defdelegate parse_time(time_string), to: Calendar.ISO
@doc false
@impl Calendar
defdelegate parse_utc_datetime(dt_string), to: Calendar.ISO
@doc false
@impl Calendar
defdelegate parse_naive_datetime(dt_string), to: Calendar.ISO
@doc false
@impl Calendar
defdelegate date_to_string(year, month, day), to: Calendar.ISO
@doc false
@impl Calendar
defdelegate datetime_to_string(
year,
month,
day,
hour,
minute,
second,
microsecond,
time_zone,
zone_abbr,
utc_offset,
std_offset
),
to: Calendar.ISO
@doc false
@impl Calendar
defdelegate naive_datetime_to_string(
year,
month,
day,
hour,
minute,
second,
microsecond
),
to: Calendar.ISO
@doc false
@impl Calendar
defdelegate time_to_string(hour, minute, second, microsecond), to: Calendar.ISO
@doc false
@impl Calendar
defdelegate valid_time?(hour, minute, second, microsecond), to: Calendar.ISO
end
