sidereal

-module(calendar@date_range).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch, inline]).
-define(FILEPATH, "src/calendar/date_range.gleam").
-export([new_with_step/3, new/2, size/1, member/2, to_list/1]).
-export_type([date_range/0, date_range_error/0]).

-if(?OTP_RELEASE >= 27).
-define(MODULEDOC(Str), -moduledoc(Str)).
-define(DOC(Str), -doc(Str)).
-else.
-define(MODULEDOC(Str), -compile([])).
-define(DOC(Str), -compile([])).
-endif.

-type date_range() :: {date_range,
        calendar@date:date(),
        calendar@date:date(),
        integer()}.

-type date_range_error() :: invalid_range.

-file("src/calendar/date_range.gleam", 19).
?DOC(" Creates a date range with a custom step.\n").
-spec new_with_step(calendar@date:date(), calendar@date:date(), integer()) -> {ok,
        date_range()} |
    {error, date_range_error()}.
new_with_step(First, Last, Step) ->
    case Step =:= 0 of
        true ->
            {error, invalid_range};

        false ->
            case erlang:element(5, First) =:= erlang:element(5, Last) of
                false ->
                    {error, invalid_range};

                true ->
                    {ok, {date_range, First, Last, Step}}
            end
    end.

-file("src/calendar/date_range.gleam", 14).
?DOC(" Creates a date range with step 1.\n").
-spec new(calendar@date:date(), calendar@date:date()) -> {ok, date_range()} |
    {error, date_range_error()}.
new(First, Last) ->
    new_with_step(First, Last, 1).

-file("src/calendar/date_range.gleam", 44).
?DOC(" Returns the number of dates in the range.\n").
-spec size(date_range()) -> integer().
size(Range) ->
    First_days = calendar@date:to_gregorian_days(erlang:element(2, Range)),
    Last_days = calendar@date:to_gregorian_days(erlang:element(3, Range)),
    Diff = Last_days - First_days,
    case (erlang:element(4, Range) > 0) andalso (Diff >= 0) of
        true ->
            (case erlang:element(4, Range) of
                0 -> 0;
                Gleam@denominator -> Diff div Gleam@denominator
            end) + 1;

        false ->
            case (erlang:element(4, Range) < 0) andalso (Diff =< 0) of
                true ->
                    (case (- erlang:element(4, Range)) of
                        0 -> 0;
                        Gleam@denominator@1 -> (- Diff) div Gleam@denominator@1
                    end) + 1;

                false ->
                    0
            end
    end.

-file("src/calendar/date_range.gleam", 59).
?DOC(" Checks if a date is in the range.\n").
-spec member(date_range(), calendar@date:date()) -> boolean().
member(Range, D) ->
    D_days = calendar@date:to_gregorian_days(D),
    First_days = calendar@date:to_gregorian_days(erlang:element(2, Range)),
    Last_days = calendar@date:to_gregorian_days(erlang:element(3, Range)),
    Diff = D_days - First_days,
    case erlang:element(4, Range) > 0 of
        true ->
            ((D_days >= First_days) andalso (D_days =< Last_days)) andalso ((case erlang:element(
                4,
                Range
            ) of
                0 -> 0;
                Gleam@denominator -> Diff rem Gleam@denominator
            end)
            =:= 0);

        false ->
            ((D_days =< First_days) andalso (D_days >= Last_days)) andalso ((case erlang:element(
                4,
                Range
            ) of
                0 -> 0;
                Gleam@denominator@1 -> Diff rem Gleam@denominator@1
            end)
            =:= 0)
    end.

-file("src/calendar/date_range.gleam", 72).
-spec date_range_to_list(
    calendar@date:date(),
    integer(),
    integer(),
    integer(),
    list(calendar@date:date())
) -> list(calendar@date:date()).
date_range_to_list(Current, Current_days, Target_days, Step, Acc) ->
    case ((Step > 0) andalso (Current_days > Target_days)) orelse ((Step < 0)
    andalso (Current_days < Target_days)) of
        true ->
            Acc;

        false ->
            Next = calendar@date:add(Current, Step),
            date_range_to_list(
                Next,
                Current_days + Step,
                Target_days,
                Step,
                [Current | Acc]
            )
    end.

-file("src/calendar/date_range.gleam", 36).
?DOC(" Converts a date range to a list of dates.\n").
-spec to_list(date_range()) -> list(calendar@date:date()).
to_list(Range) ->
    First_days = calendar@date:to_gregorian_days(erlang:element(2, Range)),
    Last_days = calendar@date:to_gregorian_days(erlang:element(3, Range)),
    _pipe = date_range_to_list(
        erlang:element(2, Range),
        First_days,
        Last_days,
        erlang:element(4, Range),
        []
    ),
    lists:reverse(_pipe).