/
naive_datetime.ex
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naive_datetime.ex
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defmodule NaiveDateTime do
@moduledoc """
A NaiveDateTime struct (without a time zone) and functions.
The NaiveDateTime struct contains the fields year, month, day, hour,
minute, second, microsecond and calendar. New naive datetimes can be
built with the `new/2` and `new/8` functions or using the
`~N` (see `Kernel.sigil_N/2`) sigil:
iex> ~N[2000-01-01 23:00:07]
~N[2000-01-01 23:00:07]
The date and time fields in the struct can be accessed directly:
iex> naive = ~N[2000-01-01 23:00:07]
iex> naive.year
2000
iex> naive.second
7
We call them "naive" because this datetime representation does not
have a time zone. This means the datetime may not actually exist in
certain areas in the world even though it is valid.
For example, when daylight saving changes are applied by a region,
the clock typically moves forward or backward by one hour. This means
certain datetimes never occur or may occur more than once. Since
`NaiveDateTime` is not validated against a time zone, such errors
would go unnoticed.
Developers should avoid creating the NaiveDateTime structs directly
and instead, rely on the functions provided by this module as well
as the ones in third-party calendar libraries.
## Comparing naive date times
Comparisons in Elixir using `==/2`, `>/2`, `</2` and similar are structural
and based on the `NaiveDateTime` struct fields. For proper comparison
between naive datetimes, use the `compare/2` function.
## Using epochs
The `add/3` and `diff/3` functions can be used for computing with
date times or retrieving the number of seconds between instants.
For example, if there is an interest in computing the number of
seconds from the Unix epoch (1970-01-01 00:00:00):
iex> NaiveDateTime.diff(~N[2010-04-17 14:00:00], ~N[1970-01-01 00:00:00])
1271512800
iex> NaiveDateTime.add(~N[1970-01-01 00:00:00], 1_271_512_800)
~N[2010-04-17 14:00:00]
Those functions are optimized to deal with common epochs, such
as the Unix Epoch above or the Gregorian Epoch (0000-01-01 00:00:00).
"""
@enforce_keys [:year, :month, :day, :hour, :minute, :second]
defstruct [
:year,
:month,
:day,
:hour,
:minute,
:second,
microsecond: {0, 0},
calendar: Calendar.ISO
]
@type t :: %__MODULE__{
year: Calendar.year(),
month: Calendar.month(),
day: Calendar.day(),
calendar: Calendar.calendar(),
hour: Calendar.hour(),
minute: Calendar.minute(),
second: Calendar.second(),
microsecond: Calendar.microsecond()
}
@seconds_per_day 24 * 60 * 60
@doc """
Returns the current naive datetime in UTC.
Prefer using `DateTime.utc_now/0` when possible as, opposite
to `NaiveDateTime`, it will keep the time zone information.
## Examples
iex> naive_datetime = NaiveDateTime.utc_now()
iex> naive_datetime.year >= 2016
true
"""
@doc since: "1.4.0"
@spec utc_now(Calendar.calendar()) :: t
def utc_now(calendar \\ Calendar.ISO)
def utc_now(Calendar.ISO) do
{:ok, {year, month, day}, {hour, minute, second}, microsecond} =
Calendar.ISO.from_unix(:os.system_time(), :native)
%NaiveDateTime{
year: year,
month: month,
day: day,
hour: hour,
minute: minute,
second: second,
microsecond: microsecond,
calendar: Calendar.ISO
}
end
def utc_now(calendar) do
calendar
|> DateTime.utc_now()
|> DateTime.to_naive()
end
@doc """
Returns the "local time" for the machine the Elixir program is running on.
WARNING: This function can cause insidious bugs. It depends on the time zone
configuration at run time. This can changed and be set to a time zone that has
daylight saving jumps (spring forward or fall back).
This function can be used to display what the time is right now for the time
zone configuration that the machine happens to have. An example would be a
desktop program displaying a clock to the user. For any other uses it is
probably a bad idea to use this function.
For most cases, use `DateTime.now/2` or `DateTime.utc_now/1` instead.
Does not include fractional seconds.
## Examples
iex> naive_datetime = NaiveDateTime.local_now()
iex> naive_datetime.year >= 2019
true
"""
@doc since: "1.10.0"
@spec local_now(Calendar.calendar()) :: t
def local_now(calendar \\ Calendar.ISO)
def local_now(Calendar.ISO) do
{{year, month, day}, {hour, minute, second}} = :erlang.localtime()
{:ok, ndt} = NaiveDateTime.new(year, month, day, hour, minute, second)
ndt
end
def local_now(calendar) do
naive_datetime = local_now()
case convert(naive_datetime, calendar) do
{:ok, value} ->
value
{:error, :incompatible_calendars} ->
raise ArgumentError,
~s(cannot get "local now" in target calendar #{inspect(calendar)}, ) <>
"reason: cannot convert from Calendar.ISO to #{inspect(calendar)}."
end
end
@doc """
Builds a new ISO naive datetime.
Expects all values to be integers. Returns `{:ok, naive_datetime}`
if each entry fits its appropriate range, returns `{:error, reason}`
otherwise.
## Examples
iex> NaiveDateTime.new(2000, 1, 1, 0, 0, 0)
{:ok, ~N[2000-01-01 00:00:00]}
iex> NaiveDateTime.new(2000, 13, 1, 0, 0, 0)
{:error, :invalid_date}
iex> NaiveDateTime.new(2000, 2, 29, 0, 0, 0)
{:ok, ~N[2000-02-29 00:00:00]}
iex> NaiveDateTime.new(2000, 2, 30, 0, 0, 0)
{:error, :invalid_date}
iex> NaiveDateTime.new(2001, 2, 29, 0, 0, 0)
{:error, :invalid_date}
iex> NaiveDateTime.new(2000, 1, 1, 23, 59, 59, {0, 1})
{:ok, ~N[2000-01-01 23:59:59.0]}
iex> NaiveDateTime.new(2000, 1, 1, 23, 59, 59, 999_999)
{:ok, ~N[2000-01-01 23:59:59.999999]}
iex> NaiveDateTime.new(2000, 1, 1, 24, 59, 59, 999_999)
{:error, :invalid_time}
iex> NaiveDateTime.new(2000, 1, 1, 23, 60, 59, 999_999)
{:error, :invalid_time}
iex> NaiveDateTime.new(2000, 1, 1, 23, 59, 60, 999_999)
{:error, :invalid_time}
iex> NaiveDateTime.new(2000, 1, 1, 23, 59, 59, 1_000_000)
{:error, :invalid_time}
iex> NaiveDateTime.new(2000, 1, 1, 23, 59, 59, {0, 1}, Calendar.ISO)
{:ok, ~N[2000-01-01 23:59:59.0]}
"""
@spec new(
Calendar.year(),
Calendar.month(),
Calendar.day(),
Calendar.hour(),
Calendar.minute(),
Calendar.second(),
Calendar.microsecond() | non_neg_integer,
Calendar.calendar()
) :: {:ok, t} | {:error, atom}
def new(year, month, day, hour, minute, second, microsecond \\ {0, 0}, calendar \\ Calendar.ISO)
def new(year, month, day, hour, minute, second, microsecond, calendar)
when is_integer(microsecond) do
new(year, month, day, hour, minute, second, {microsecond, 6}, calendar)
end
def new(year, month, day, hour, minute, second, microsecond, calendar) do
cond do
not calendar.valid_date?(year, month, day) ->
{:error, :invalid_date}
not calendar.valid_time?(hour, minute, second, microsecond) ->
{:error, :invalid_time}
true ->
naive_datetime = %NaiveDateTime{
calendar: calendar,
year: year,
month: month,
day: day,
hour: hour,
minute: minute,
second: second,
microsecond: microsecond
}
{:ok, naive_datetime}
end
end
@doc """
Builds a new ISO naive datetime.
Expects all values to be integers. Returns `naive_datetime`
if each entry fits its appropriate range, raises if
time or date is invalid.
## Examples
iex> NaiveDateTime.new!(2000, 1, 1, 0, 0, 0)
~N[2000-01-01 00:00:00]
iex> NaiveDateTime.new!(2000, 2, 29, 0, 0, 0)
~N[2000-02-29 00:00:00]
iex> NaiveDateTime.new!(2000, 1, 1, 23, 59, 59, {0, 1})
~N[2000-01-01 23:59:59.0]
iex> NaiveDateTime.new!(2000, 1, 1, 23, 59, 59, 999_999)
~N[2000-01-01 23:59:59.999999]
iex> NaiveDateTime.new!(2000, 1, 1, 23, 59, 59, {0, 1}, Calendar.ISO)
~N[2000-01-01 23:59:59.0]
iex> NaiveDateTime.new!(2000, 1, 1, 24, 59, 59, 999_999)
** (ArgumentError) cannot build naive datetime, reason: :invalid_time
"""
@doc since: "1.11.0"
@spec new!(
Calendar.year(),
Calendar.month(),
Calendar.day(),
Calendar.hour(),
Calendar.minute(),
Calendar.second(),
Calendar.microsecond() | non_neg_integer,
Calendar.calendar()
) :: t
def new!(
year,
month,
day,
hour,
minute,
second,
microsecond \\ {0, 0},
calendar \\ Calendar.ISO
)
def new!(year, month, day, hour, minute, second, microsecond, calendar) do
case new(year, month, day, hour, minute, second, microsecond, calendar) do
{:ok, naive_datetime} ->
naive_datetime
{:error, reason} ->
raise ArgumentError, "cannot build naive datetime, reason: #{inspect(reason)}"
end
end
@doc """
Builds a naive datetime from date and time structs.
## Examples
iex> NaiveDateTime.new(~D[2010-01-13], ~T[23:00:07.005])
{:ok, ~N[2010-01-13 23:00:07.005]}
"""
@spec new(Date.t(), Time.t()) :: {:ok, t}
def new(date, time)
def new(%Date{calendar: calendar} = date, %Time{calendar: calendar} = time) do
%{year: year, month: month, day: day} = date
%{hour: hour, minute: minute, second: second, microsecond: microsecond} = time
naive_datetime = %NaiveDateTime{
calendar: calendar,
year: year,
month: month,
day: day,
hour: hour,
minute: minute,
second: second,
microsecond: microsecond
}
{:ok, naive_datetime}
end
@doc """
Builds a naive datetime from date and time structs.
## Examples
iex> NaiveDateTime.new!(~D[2010-01-13], ~T[23:00:07.005])
~N[2010-01-13 23:00:07.005]
"""
@doc since: "1.11.0"
@spec new!(Date.t(), Time.t()) :: t
def new!(date, time)
def new!(%Date{calendar: calendar} = date, %Time{calendar: calendar} = time) do
{:ok, naive_datetime} = new(date, time)
naive_datetime
end
@doc """
Adds a specified amount of time to a `NaiveDateTime`.
Accepts an `amount_to_add` in any `unit` available from `t:System.time_unit/0`.
Negative values will move backwards in time.
## Examples
# adds seconds by default
iex> NaiveDateTime.add(~N[2014-10-02 00:29:10], 2)
~N[2014-10-02 00:29:12]
# accepts negative offsets
iex> NaiveDateTime.add(~N[2014-10-02 00:29:10], -2)
~N[2014-10-02 00:29:08]
# can work with other units
iex> NaiveDateTime.add(~N[2014-10-02 00:29:10], 2_000, :millisecond)
~N[2014-10-02 00:29:12]
# keeps the same precision
iex> NaiveDateTime.add(~N[2014-10-02 00:29:10.021], 21, :second)
~N[2014-10-02 00:29:31.021]
# changes below the precision will not be visible
iex> hidden = NaiveDateTime.add(~N[2014-10-02 00:29:10], 21, :millisecond)
iex> hidden.microsecond # ~N[2014-10-02 00:29:10]
{21000, 0}
# from Gregorian seconds
iex> NaiveDateTime.add(~N[0000-01-01 00:00:00], 63_579_428_950)
~N[2014-10-02 00:29:10]
Passing a `DateTime` automatically converts it to `NaiveDateTime`,
discarding the time zone information:
iex> dt = %DateTime{year: 2000, month: 2, day: 29, zone_abbr: "CET",
...> hour: 23, minute: 0, second: 7, microsecond: {0, 0},
...> utc_offset: 3600, std_offset: 0, time_zone: "Europe/Warsaw"}
iex> NaiveDateTime.add(dt, 21, :second)
~N[2000-02-29 23:00:28]
"""
@doc since: "1.4.0"
@spec add(Calendar.naive_datetime(), integer, System.time_unit()) :: t
def add(
%{microsecond: {_, precision}, calendar: calendar} = naive_datetime,
amount_to_add,
unit \\ :second
)
when is_integer(amount_to_add) do
ppd = System.convert_time_unit(86400, :second, unit)
naive_datetime
|> to_iso_days()
|> Calendar.ISO.add_day_fraction_to_iso_days(amount_to_add, ppd)
|> from_iso_days(calendar, precision)
end
@doc """
Subtracts `naive_datetime2` from `naive_datetime1`.
The answer can be returned in any `unit` available from `t:System.time_unit/0`.
This function returns the difference in seconds where seconds are measured
according to `Calendar.ISO`.
## Examples
iex> NaiveDateTime.diff(~N[2014-10-02 00:29:12], ~N[2014-10-02 00:29:10])
2
iex> NaiveDateTime.diff(~N[2014-10-02 00:29:12], ~N[2014-10-02 00:29:10], :microsecond)
2_000_000
iex> NaiveDateTime.diff(~N[2014-10-02 00:29:10.042], ~N[2014-10-02 00:29:10.021], :millisecond)
21
iex> NaiveDateTime.diff(~N[2014-10-02 00:29:10], ~N[2014-10-02 00:29:12])
-2
iex> NaiveDateTime.diff(~N[-0001-10-02 00:29:10], ~N[-0001-10-02 00:29:12])
-2
# to Gregorian seconds
iex> NaiveDateTime.diff(~N[2014-10-02 00:29:10], ~N[0000-01-01 00:00:00])
63579428950
"""
@doc since: "1.4.0"
@spec diff(Calendar.naive_datetime(), Calendar.naive_datetime(), System.time_unit()) :: integer
def diff(
%{calendar: calendar1} = naive_datetime1,
%{calendar: calendar2} = naive_datetime2,
unit \\ :second
) do
if not Calendar.compatible_calendars?(calendar1, calendar2) do
raise ArgumentError,
"cannot calculate the difference between #{inspect(naive_datetime1)} and " <>
"#{inspect(naive_datetime2)} because their calendars are not compatible " <>
"and thus the result would be ambiguous"
end
units1 = naive_datetime1 |> to_iso_days() |> Calendar.ISO.iso_days_to_unit(unit)
units2 = naive_datetime2 |> to_iso_days() |> Calendar.ISO.iso_days_to_unit(unit)
units1 - units2
end
@doc """
Returns the given naive datetime with the microsecond field truncated to the
given precision (`:microsecond`, `:millisecond` or `:second`).
The given naive datetime is returned unchanged if it already has lower precision
than the given precision.
## Examples
iex> NaiveDateTime.truncate(~N[2017-11-06 00:23:51.123456], :microsecond)
~N[2017-11-06 00:23:51.123456]
iex> NaiveDateTime.truncate(~N[2017-11-06 00:23:51.123456], :millisecond)
~N[2017-11-06 00:23:51.123]
iex> NaiveDateTime.truncate(~N[2017-11-06 00:23:51.123456], :second)
~N[2017-11-06 00:23:51]
"""
@doc since: "1.6.0"
@spec truncate(t(), :microsecond | :millisecond | :second) :: t()
def truncate(%NaiveDateTime{microsecond: microsecond} = naive_datetime, precision) do
%{naive_datetime | microsecond: Calendar.truncate(microsecond, precision)}
end
def truncate(
%{
calendar: calendar,
year: year,
month: month,
day: day,
hour: hour,
minute: minute,
second: second,
microsecond: microsecond
},
precision
) do
%NaiveDateTime{
calendar: calendar,
year: year,
month: month,
day: day,
hour: hour,
minute: minute,
second: second,
microsecond: Calendar.truncate(microsecond, precision)
}
end
@doc """
Converts a `NaiveDateTime` into a `Date`.
Because `Date` does not hold time information,
data will be lost during the conversion.
## Examples
iex> NaiveDateTime.to_date(~N[2002-01-13 23:00:07])
~D[2002-01-13]
"""
@spec to_date(Calendar.naive_datetime()) :: Date.t()
def to_date(%{
year: year,
month: month,
day: day,
calendar: calendar,
hour: _,
minute: _,
second: _,
microsecond: _
}) do
%Date{year: year, month: month, day: day, calendar: calendar}
end
@doc """
Converts a `NaiveDateTime` into `Time`.
Because `Time` does not hold date information,
data will be lost during the conversion.
## Examples
iex> NaiveDateTime.to_time(~N[2002-01-13 23:00:07])
~T[23:00:07]
"""
@spec to_time(Calendar.naive_datetime()) :: Time.t()
def to_time(%{
year: _,
month: _,
day: _,
calendar: calendar,
hour: hour,
minute: minute,
second: second,
microsecond: microsecond
}) do
%Time{
hour: hour,
minute: minute,
second: second,
microsecond: microsecond,
calendar: calendar
}
end
@doc """
Converts the given naive datetime to a string according to its calendar.
### Examples
iex> NaiveDateTime.to_string(~N[2000-02-28 23:00:13])
"2000-02-28 23:00:13"
iex> NaiveDateTime.to_string(~N[2000-02-28 23:00:13.001])
"2000-02-28 23:00:13.001"
iex> NaiveDateTime.to_string(~N[-0100-12-15 03:20:31])
"-0100-12-15 03:20:31"
This function can also be used to convert a DateTime to a string without
the time zone information:
iex> dt = %DateTime{year: 2000, month: 2, day: 29, zone_abbr: "CET",
...> hour: 23, minute: 0, second: 7, microsecond: {0, 0},
...> utc_offset: 3600, std_offset: 0, time_zone: "Europe/Warsaw"}
iex> NaiveDateTime.to_string(dt)
"2000-02-29 23:00:07"
"""
@spec to_string(Calendar.naive_datetime()) :: String.t()
def to_string(%{calendar: calendar} = naive_datetime) do
%{
year: year,
month: month,
day: day,
hour: hour,
minute: minute,
second: second,
microsecond: microsecond
} = naive_datetime
calendar.naive_datetime_to_string(year, month, day, hour, minute, second, microsecond)
end
@doc """
Parses the extended "Date and time of day" format described by
[ISO 8601:2019](https://en.wikipedia.org/wiki/ISO_8601).
Time zone offset may be included in the string but they will be
simply discarded as such information is not included in naive date
times.
As specified in the standard, the separator "T" may be omitted if
desired as there is no ambiguity within this function.
Note leap seconds are not supported by the built-in Calendar.ISO.
## Examples
iex> NaiveDateTime.from_iso8601("2015-01-23 23:50:07")
{:ok, ~N[2015-01-23 23:50:07]}
iex> NaiveDateTime.from_iso8601("2015-01-23T23:50:07")
{:ok, ~N[2015-01-23 23:50:07]}
iex> NaiveDateTime.from_iso8601("2015-01-23T23:50:07Z")
{:ok, ~N[2015-01-23 23:50:07]}
iex> NaiveDateTime.from_iso8601("2015-01-23 23:50:07.0")
{:ok, ~N[2015-01-23 23:50:07.0]}
iex> NaiveDateTime.from_iso8601("2015-01-23 23:50:07,0123456")
{:ok, ~N[2015-01-23 23:50:07.012345]}
iex> NaiveDateTime.from_iso8601("2015-01-23 23:50:07.0123456")
{:ok, ~N[2015-01-23 23:50:07.012345]}
iex> NaiveDateTime.from_iso8601("2015-01-23T23:50:07.123Z")
{:ok, ~N[2015-01-23 23:50:07.123]}
iex> NaiveDateTime.from_iso8601("2015-01-23P23:50:07")
{:error, :invalid_format}
iex> NaiveDateTime.from_iso8601("2015:01:23 23-50-07")
{:error, :invalid_format}
iex> NaiveDateTime.from_iso8601("2015-01-23 23:50:07A")
{:error, :invalid_format}
iex> NaiveDateTime.from_iso8601("2015-01-23 23:50:61")
{:error, :invalid_time}
iex> NaiveDateTime.from_iso8601("2015-01-32 23:50:07")
{:error, :invalid_date}
iex> NaiveDateTime.from_iso8601("2015-01-23T23:50:07.123+02:30")
{:ok, ~N[2015-01-23 23:50:07.123]}
iex> NaiveDateTime.from_iso8601("2015-01-23T23:50:07.123+00:00")
{:ok, ~N[2015-01-23 23:50:07.123]}
iex> NaiveDateTime.from_iso8601("2015-01-23T23:50:07.123-02:30")
{:ok, ~N[2015-01-23 23:50:07.123]}
iex> NaiveDateTime.from_iso8601("2015-01-23T23:50:07.123-00:00")
{:error, :invalid_format}
iex> NaiveDateTime.from_iso8601("2015-01-23T23:50:07.123-00:60")
{:error, :invalid_format}
iex> NaiveDateTime.from_iso8601("2015-01-23T23:50:07.123-24:00")
{:error, :invalid_format}
"""
@spec from_iso8601(String.t(), Calendar.calendar()) :: {:ok, t} | {:error, atom}
def from_iso8601(string, calendar \\ Calendar.ISO) do
with {:ok, {year, month, day, hour, minute, second, microsecond}} <-
Calendar.ISO.parse_naive_datetime(string) do
convert(
%NaiveDateTime{
year: year,
month: month,
day: day,
hour: hour,
minute: minute,
second: second,
microsecond: microsecond
},
calendar
)
end
end
@doc """
Parses the extended "Date and time of day" format described by
[ISO 8601:2019](https://en.wikipedia.org/wiki/ISO_8601).
Raises if the format is invalid.
## Examples
iex> NaiveDateTime.from_iso8601!("2015-01-23T23:50:07.123Z")
~N[2015-01-23 23:50:07.123]
iex> NaiveDateTime.from_iso8601!("2015-01-23T23:50:07,123Z")
~N[2015-01-23 23:50:07.123]
iex> NaiveDateTime.from_iso8601!("2015-01-23P23:50:07")
** (ArgumentError) cannot parse "2015-01-23P23:50:07" as naive datetime, reason: :invalid_format
"""
@spec from_iso8601!(String.t(), Calendar.calendar()) :: t
def from_iso8601!(string, calendar \\ Calendar.ISO) do
case from_iso8601(string, calendar) do
{:ok, value} ->
value
{:error, reason} ->
raise ArgumentError,
"cannot parse #{inspect(string)} as naive datetime, reason: #{inspect(reason)}"
end
end
@doc """
Converts the given naive datetime to
[ISO 8601:2019](https://en.wikipedia.org/wiki/ISO_8601).
By default, `NaiveDateTime.to_iso8601/2` returns naive datetimes formatted in the "extended"
format, for human readability. It also supports the "basic" format through passing the `:basic` option.
Only supports converting naive datetimes which are in the ISO calendar,
attempting to convert naive datetimes from other calendars will raise.
### Examples
iex> NaiveDateTime.to_iso8601(~N[2000-02-28 23:00:13])
"2000-02-28T23:00:13"
iex> NaiveDateTime.to_iso8601(~N[2000-02-28 23:00:13.001])
"2000-02-28T23:00:13.001"
iex> NaiveDateTime.to_iso8601(~N[2000-02-28 23:00:13.001], :basic)
"20000228T230013.001"
This function can also be used to convert a DateTime to ISO 8601 without
the time zone information:
iex> dt = %DateTime{year: 2000, month: 2, day: 29, zone_abbr: "CET",
...> hour: 23, minute: 0, second: 7, microsecond: {0, 0},
...> utc_offset: 3600, std_offset: 0, time_zone: "Europe/Warsaw"}
iex> NaiveDateTime.to_iso8601(dt)
"2000-02-29T23:00:07"
"""
@spec to_iso8601(Calendar.naive_datetime(), :basic | :extended) :: String.t()
def to_iso8601(naive_datetime, format \\ :extended)
def to_iso8601(%{calendar: Calendar.ISO} = naive_datetime, format)
when format in [:basic, :extended] do
%{
year: year,
month: month,
day: day,
hour: hour,
minute: minute,
second: second,
microsecond: microsecond
} = naive_datetime
Calendar.ISO.date_to_string(year, month, day, format) <>
"T" <> Calendar.ISO.time_to_string(hour, minute, second, microsecond, format)
end
def to_iso8601(%{calendar: _} = naive_datetime, format) when format in [:basic, :extended] do
naive_datetime
|> convert!(Calendar.ISO)
|> to_iso8601(format)
end
@doc """
Converts a `NaiveDateTime` struct to an Erlang datetime tuple.
Only supports converting naive datetimes which are in the ISO calendar,
attempting to convert naive datetimes from other calendars will raise.
WARNING: Loss of precision may occur, as Erlang time tuples only store
hour/minute/second.
## Examples
iex> NaiveDateTime.to_erl(~N[2000-01-01 13:30:15])
{{2000, 1, 1}, {13, 30, 15}}
This function can also be used to convert a DateTime to an Erlang
datetime tuple without the time zone information:
iex> dt = %DateTime{year: 2000, month: 2, day: 29, zone_abbr: "CET",
...> hour: 23, minute: 0, second: 7, microsecond: {0, 0},
...> utc_offset: 3600, std_offset: 0, time_zone: "Europe/Warsaw"}
iex> NaiveDateTime.to_erl(dt)
{{2000, 2, 29}, {23, 00, 07}}
"""
@spec to_erl(Calendar.naive_datetime()) :: :calendar.datetime()
def to_erl(%{calendar: _} = naive_datetime) do
%{year: year, month: month, day: day, hour: hour, minute: minute, second: second} =
convert!(naive_datetime, Calendar.ISO)
{{year, month, day}, {hour, minute, second}}
end
@doc """
Converts an Erlang datetime tuple to a `NaiveDateTime` struct.
Attempting to convert an invalid ISO calendar date will produce an error tuple.
## Examples
iex> NaiveDateTime.from_erl({{2000, 1, 1}, {13, 30, 15}})
{:ok, ~N[2000-01-01 13:30:15]}
iex> NaiveDateTime.from_erl({{2000, 1, 1}, {13, 30, 15}}, {5000, 3})
{:ok, ~N[2000-01-01 13:30:15.005]}
iex> NaiveDateTime.from_erl({{2000, 13, 1}, {13, 30, 15}})
{:error, :invalid_date}
iex> NaiveDateTime.from_erl({{2000, 13, 1}, {13, 30, 15}})
{:error, :invalid_date}
"""
@spec from_erl(:calendar.datetime(), Calendar.microsecond(), Calendar.calendar()) ::
{:ok, t} | {:error, atom}
def from_erl(tuple, microsecond \\ {0, 0}, calendar \\ Calendar.ISO)
def from_erl({{year, month, day}, {hour, minute, second}}, microsecond, calendar) do
with {:ok, iso_naive_dt} <- new(year, month, day, hour, minute, second, microsecond),
do: convert(iso_naive_dt, calendar)
end
@doc """
Converts an Erlang datetime tuple to a `NaiveDateTime` struct.
Raises if the datetime is invalid.
Attempting to convert an invalid ISO calendar date will produce an error tuple.
## Examples
iex> NaiveDateTime.from_erl!({{2000, 1, 1}, {13, 30, 15}})
~N[2000-01-01 13:30:15]
iex> NaiveDateTime.from_erl!({{2000, 1, 1}, {13, 30, 15}}, {5000, 3})
~N[2000-01-01 13:30:15.005]
iex> NaiveDateTime.from_erl!({{2000, 13, 1}, {13, 30, 15}})
** (ArgumentError) cannot convert {{2000, 13, 1}, {13, 30, 15}} to naive datetime, reason: :invalid_date
"""
@spec from_erl!(:calendar.datetime(), Calendar.microsecond(), Calendar.calendar()) :: t
def from_erl!(tuple, microsecond \\ {0, 0}, calendar \\ Calendar.ISO) do
case from_erl(tuple, microsecond, calendar) do
{:ok, value} ->
value
{:error, reason} ->
raise ArgumentError,
"cannot convert #{inspect(tuple)} to naive datetime, reason: #{inspect(reason)}"
end
end
@doc """
Converts a number of gregorian seconds to a `NaiveDateTime` struct.
## Examples
iex> NaiveDateTime.from_gregorian_seconds(1)
~N[0000-01-01 00:00:01]
iex> NaiveDateTime.from_gregorian_seconds(63_755_511_991, {5000, 3})
~N[2020-05-01 00:26:31.005]
iex> NaiveDateTime.from_gregorian_seconds(-1)
~N[-0001-12-31 23:59:59]
"""
@doc since: "1.11.0"
@spec from_gregorian_seconds(integer(), Calendar.microsecond(), Calendar.calendar()) :: t
def from_gregorian_seconds(
seconds,
{microsecond, precision} \\ {0, 0},
calendar \\ Calendar.ISO
)
when is_integer(seconds) do
iso_days = Calendar.ISO.gregorian_seconds_to_iso_days(seconds, microsecond)
{year, month, day, hour, minute, second, {microsecond, _}} =
calendar.naive_datetime_from_iso_days(iso_days)
%NaiveDateTime{
calendar: calendar,
year: year,
month: month,
day: day,
hour: hour,
minute: minute,
second: second,
microsecond: {microsecond, precision}
}
end
@doc """
Converts a `NaiveDateTime` struct to a number of gregorian seconds and microseconds.
## Examples
iex> NaiveDateTime.to_gregorian_seconds(~N[0000-01-01 00:00:01])
{1, 0}
iex> NaiveDateTime.to_gregorian_seconds(~N[2020-05-01 00:26:31.005])
{63_755_511_991, 5000}
"""
@doc since: "1.11.0"
@spec to_gregorian_seconds(Calendar.naive_datetime()) :: {integer(), non_neg_integer()}
def to_gregorian_seconds(%{
calendar: calendar,
year: year,
month: month,
day: day,
hour: hour,
minute: minute,
second: second,
microsecond: {microsecond, precision}
}) do
{days, day_fraction} =
calendar.naive_datetime_to_iso_days(
year,
month,
day,
hour,
minute,
second,
{microsecond, precision}
)
seconds_in_day = seconds_from_day_fraction(day_fraction)
{days * @seconds_per_day + seconds_in_day, microsecond}
end
@doc """
Compares two `NaiveDateTime` structs.
Returns `:gt` if first is later than the second
and `:lt` for vice versa. If the two NaiveDateTime
are equal `:eq` is returned.
## Examples
iex> NaiveDateTime.compare(~N[2016-04-16 13:30:15], ~N[2016-04-28 16:19:25])
:lt
iex> NaiveDateTime.compare(~N[2016-04-16 13:30:15.1], ~N[2016-04-16 13:30:15.01])
:gt
This function can also be used to compare a DateTime without
the time zone information:
iex> dt = %DateTime{year: 2000, month: 2, day: 29, zone_abbr: "CET",
...> hour: 23, minute: 0, second: 7, microsecond: {0, 0},
...> utc_offset: 3600, std_offset: 0, time_zone: "Europe/Warsaw"}
iex> NaiveDateTime.compare(dt, ~N[2000-02-29 23:00:07])
:eq
iex> NaiveDateTime.compare(dt, ~N[2000-01-29 23:00:07])
:gt
iex> NaiveDateTime.compare(dt, ~N[2000-03-29 23:00:07])
:lt
"""
@doc since: "1.4.0"
@spec compare(Calendar.naive_datetime(), Calendar.naive_datetime()) :: :lt | :eq | :gt
def compare(%{calendar: calendar1} = naive_datetime1, %{calendar: calendar2} = naive_datetime2) do
if Calendar.compatible_calendars?(calendar1, calendar2) do
case {to_iso_days(naive_datetime1), to_iso_days(naive_datetime2)} do
{first, second} when first > second -> :gt
{first, second} when first < second -> :lt
_ -> :eq
end
else
raise ArgumentError, """
cannot compare #{inspect(naive_datetime1)} with #{inspect(naive_datetime2)}.
This comparison would be ambiguous as their calendars have incompatible day rollover moments.
Specify an exact time of day (using `DateTime`s) to resolve this ambiguity
"""
end
end
@doc """
Converts the given `naive_datetime` from one calendar to another.
If it is not possible to convert unambiguously between the calendars
(see `Calendar.compatible_calendars?/2`), an `{:error, :incompatible_calendars}` tuple
is returned.
## Examples
Imagine someone implements `Calendar.Holocene`, a calendar based on the
Gregorian calendar that adds exactly 10,000 years to the current Gregorian
year:
iex> NaiveDateTime.convert(~N[2000-01-01 13:30:15], Calendar.Holocene)
{:ok, %NaiveDateTime{calendar: Calendar.Holocene, year: 12000, month: 1, day: 1,
hour: 13, minute: 30, second: 15, microsecond: {0, 0}}}
"""
@doc since: "1.5.0"
@spec convert(Calendar.naive_datetime(), Calendar.calendar()) ::
{:ok, t} | {:error, :incompatible_calendars}
# Keep it multiline for proper function clause errors.
def convert(
%{
calendar: calendar,
year: year,
month: month,
day: day,
hour: hour,
minute: minute,
second: second,
microsecond: microsecond
},