mobilizon/lib/service/date_time/date_time.ex

231 lines
8.2 KiB
Elixir

defmodule Mobilizon.Service.DateTime do
@moduledoc """
Module to represent a datetime in a given locale
"""
alias Cldr.DateTime.Relative
@typep to_string_format :: :short | :medium | :long | :full
@utc_timezone "Etc/UTC"
@spec datetime_to_string(DateTime.t(), String.t(), to_string_format()) :: String.t()
def datetime_to_string(%DateTime{} = datetime, locale \\ "en", format \\ :medium) do
Mobilizon.Cldr.DateTime.to_string!(datetime,
format: format,
locale: Mobilizon.Cldr.locale_or_default(locale)
)
end
@spec datetime_to_time_string(DateTime.t(), String.t(), to_string_format()) :: String.t()
def datetime_to_time_string(%DateTime{} = datetime, locale \\ "en", format \\ :short) do
Mobilizon.Cldr.Time.to_string!(datetime,
format: format,
locale: Mobilizon.Cldr.locale_or_default(locale)
)
end
@spec datetime_to_date_string(DateTime.t(), String.t(), to_string_format()) :: String.t()
def datetime_to_date_string(%DateTime{} = datetime, locale \\ "en", format \\ :short) do
Mobilizon.Cldr.Date.to_string!(datetime,
format: format,
locale: Mobilizon.Cldr.locale_or_default(locale)
)
end
@spec datetime_tz_convert(DateTime.t(), String.t() | nil) :: DateTime.t()
def datetime_tz_convert(%DateTime{} = datetime, timezone) when is_binary(timezone) do
case DateTime.shift_zone(datetime, timezone) do
{:ok, datetime_with_tz} ->
datetime_with_tz
_ ->
datetime
end
end
def datetime_tz_convert(%DateTime{} = datetime, nil), do: datetime
@spec datetime_relative(DateTime.t(), String.t()) :: String.t()
def datetime_relative(%DateTime{} = datetime, locale \\ "en") do
Relative.to_string!(datetime, Mobilizon.Cldr,
relative_to: DateTime.utc_now(),
locale: Mobilizon.Cldr.locale_or_default(locale)
)
end
@spec is_first_day_of_week(Date.t(), String.t()) :: boolean()
defp is_first_day_of_week(%Date{} = date, locale) do
Date.day_of_week(date) == Cldr.Calendar.first_day_for_locale(locale)
end
@spec calculate_first_day_of_week(Date.t(), String.t()) :: Date.t()
def calculate_first_day_of_week(%Date{} = date, locale \\ "en") do
if is_first_day_of_week(date, locale),
do: date,
else: calculate_first_day_of_week(Date.add(date, -1), locale)
end
@doc """
Calculate the time when a notification should be sent, based on a daily schedule
## Parameters
* `compare_to` When to compare to. Defaults to the current datetime
* `notification_time` The time when the notification is being sent. Defaults to `~T[08:00:00]`
* `timezone` The user's timezone. Needed to convert the time in the user's local timezone. Defaults to `"Etc/UTC"`
"""
@spec calculate_next_day_notification(Date.t(), Keyword.t()) :: DateTime.t()
def calculate_next_day_notification(%Date{} = day, options \\ []) do
compare_to = Keyword.get(options, :compare_to, DateTime.utc_now())
notification_time = Keyword.get(options, :notification_time, ~T[18:00:00])
timezone = options |> Keyword.get(:timezone, @utc_timezone) |> fallback_tz()
send_at = DateTime.new!(day, notification_time, timezone)
if DateTime.compare(send_at, compare_to) == :lt do
day
|> Date.add(1)
|> DateTime.new!(notification_time, timezone)
else
send_at
end
end
@doc """
Calculate the time when a notification should be sent, based on a weekly schedule
## Parameters
* `compare_to` When to compare to. Defaults to the current datetime
* `notification_time` The time when the notification is being sent. Defaults to `~T[08:00:00]`
* `timezone` The user's timezone. Needed to convert the time in the user's local timezone. Defaults to `"Etc/UTC"`
* `locale` The user's locale. Allows to get the first day of the week to send the notification on the beginning of the week. Defaults to `"en"`.
"""
@spec calculate_next_week_notification(DateTime.t(), Keyword.t()) :: DateTime.t() | nil
def calculate_next_week_notification(begins_on, options \\ []) do
# That's now, but we allow to override it for tests
compare_to = Keyword.get(options, :compare_to, DateTime.utc_now())
# If the event is in the future
if DateTime.compare(begins_on, compare_to) == :gt do
# We get the day of the scheduled notification next week
notification_date = appropriate_first_day_of_week(begins_on, options)
if is_nil(notification_date) do
nil
else
# This is the datetime when the notification should be sent
if DateTime.compare(notification_date, compare_to) == :gt do
notification_date
else
nil
end
end
else
# In the past, don't send anything
nil
end
end
@spec next_first_day_of_week(DateTime.t(), Keyword.t()) :: Date.t() | nil
def next_first_day_of_week(%DateTime{} = datetime, options) do
locale = Keyword.get(options, :locale, "en")
compare_to = Keyword.get(options, :compare_to, DateTime.utc_now())
next_first_day_of_week =
compare_to
|> DateTime.to_date()
|> calculate_first_day_of_week(locale)
|> Date.add(7)
|> build_notification_datetime(options)
if next_first_day_of_week != nil && DateTime.compare(datetime, next_first_day_of_week) == :gt do
next_first_day_of_week
else
nil
end
end
@spec appropriate_first_day_of_week(DateTime.t(), keyword) :: DateTime.t() | nil
defp appropriate_first_day_of_week(%DateTime{} = datetime, options) do
locale = Keyword.get(options, :locale, "en")
timezone = options |> Keyword.get(:timezone, @utc_timezone) |> fallback_tz()
local_datetime = datetime_tz_convert(datetime, timezone)
first_day = local_datetime |> DateTime.to_date() |> calculate_first_day_of_week(locale)
first_datetime = build_notification_datetime(first_day, options)
if DateTime.compare(local_datetime, first_datetime) == :gt do
first_datetime
else
local_datetime
|> next_first_day_of_week(options)
|> build_notification_datetime(options)
end
end
@spec build_notification_datetime(Date.t(), Keyword.t()) :: DateTime.t()
@spec build_notification_datetime(nil, Keyword.t()) :: nil
defp build_notification_datetime(nil, _options), do: nil
defp build_notification_datetime(
%Date{} = date,
options
) do
notification_time = Keyword.get(options, :notification_time, ~T[08:00:00])
timezone = options |> Keyword.get(:timezone, @utc_timezone) |> fallback_tz()
DateTime.new!(date, notification_time, timezone)
end
@start_time ~T[08:00:00]
@end_time ~T[09:00:00]
@spec is_between_hours?(Keyword.t()) :: boolean()
def is_between_hours?(options \\ []) when is_list(options) do
compare_to_day = Keyword.get(options, :compare_to_day, Date.utc_today())
compare_to = Keyword.get(options, :compare_to_datetime, DateTime.utc_now())
start_time = Keyword.get(options, :start_time, @start_time)
timezone = options |> Keyword.get(:timezone, @utc_timezone) |> fallback_tz()
end_time = Keyword.get(options, :end_time, @end_time)
DateTime.compare(compare_to, DateTime.new!(compare_to_day, start_time, timezone)) in [
:gt,
:eq
] &&
DateTime.compare(
compare_to,
DateTime.new!(compare_to_day, end_time, timezone)
) == :lt
end
@spec is_between_hours_on_first_day?(Keyword.t()) :: boolean()
def is_between_hours_on_first_day?(options) when is_list(options) do
compare_to_day = Keyword.get(options, :compare_to_day, Date.utc_today())
locale = Keyword.get(options, :locale, "en")
is_first_day_of_week(compare_to_day, locale) && is_between_hours?(options)
end
@spec is_delay_ok_since_last_notification_sent?(DateTime.t(), pos_integer()) :: boolean()
def is_delay_ok_since_last_notification_sent?(
%DateTime{} = last_notification_sent,
delay \\ 3_600
) do
DateTime.compare(DateTime.add(last_notification_sent, delay), DateTime.utc_now()) ==
:lt
end
@spec is_same_day?(DateTime.t(), DateTime.t()) :: boolean()
def is_same_day?(%DateTime{} = one, %DateTime{} = two) do
DateTime.to_date(one) == DateTime.to_date(two)
end
@spec fallback_tz(String.t()) :: String.t()
defp fallback_tz(timezone) do
if Tzdata.zone_exists?(timezone) do
timezone
else
@utc_timezone
end
end
end