dateformat

-module(dateformat@internal@day).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch]).

-export([to_day_of_week/2, to_iso_week_of_year/1, to_weekday_string/1, to_weekday_short_string/1, to_weekday_shorter_string/1, to_day_of_year/1]).

-spec to_day_of_week(birl:time(), boolean()) -> integer().
to_day_of_week(Time, Iso) ->
    case {birl:weekday(Time), Iso} of
        {mon, _} ->
            1;

        {tue, _} ->
            2;

        {wed, _} ->
            3;

        {thu, _} ->
            4;

        {fri, _} ->
            5;

        {sat, _} ->
            6;

        {sun, false} ->
            0;

        {sun, true} ->
            7
    end.

-spec to_iso_week_of_year(birl:time()) -> integer().
to_iso_week_of_year(T) ->
    Day_num = (to_day_of_week(T, false) + 6) rem 7,
    Day = birl:get_day(T),
    T@1 = birl:set_day(
        T,
        erlang:setelement(4, Day, (erlang:element(4, Day) - Day_num) + 3)
    ),
    First_thursday = birl:to_unix_micro(T@1),
    T@2 = birl:set_day(
        T@1,
        erlang:setelement(4, erlang:setelement(3, birl:get_day(T@1), 1), 1)
    ),
    T@3 = case to_day_of_week(T@2, false) of
        4 ->
            T@2;

        D ->
            birl:set_day(
                T@2,
                erlang:setelement(
                    4,
                    erlang:setelement(3, birl:get_day(T@2), 1),
                    1 + (((4 - D) + 7) rem 7)
                )
            )
    end,
    1 + gleam@float:truncate(
        gleam@float:ceiling(
            gleam@int:to_float(First_thursday - birl:to_unix_micro(T@3)) / 604800000000.0
        )
    ).

-spec to_weekday_string(birl:time()) -> binary().
to_weekday_string(Time) ->
    case birl:weekday(Time) of
        mon ->
            <<"Monday"/utf8>>;

        tue ->
            <<"Tuesday"/utf8>>;

        wed ->
            <<"Wednesday"/utf8>>;

        thu ->
            <<"Thursday"/utf8>>;

        fri ->
            <<"Friday"/utf8>>;

        sat ->
            <<"Saturday"/utf8>>;

        sun ->
            <<"Sunday"/utf8>>
    end.

-spec to_weekday_short_string(birl:time()) -> binary().
to_weekday_short_string(Time) ->
    case birl:weekday(Time) of
        mon ->
            <<"Mon"/utf8>>;

        tue ->
            <<"Tue"/utf8>>;

        wed ->
            <<"Wed"/utf8>>;

        thu ->
            <<"Thu"/utf8>>;

        fri ->
            <<"Fri"/utf8>>;

        sat ->
            <<"Sat"/utf8>>;

        sun ->
            <<"Sun"/utf8>>
    end.

-spec to_weekday_shorter_string(birl:time()) -> binary().
to_weekday_shorter_string(Time) ->
    case birl:weekday(Time) of
        mon ->
            <<"Mo"/utf8>>;

        tue ->
            <<"Tu"/utf8>>;

        wed ->
            <<"We"/utf8>>;

        thu ->
            <<"Th"/utf8>>;

        fri ->
            <<"Fr"/utf8>>;

        sat ->
            <<"Sa"/utf8>>;

        sun ->
            <<"Su"/utf8>>
    end.

-spec to_day_of_year(birl:time()) -> integer().
to_day_of_year(T2) ->
    Time = {time_of_day, 0, 0, 0, 0},
    T2@1 = begin
        _pipe = T2,
        birl:set_time_of_day(_pipe, Time)
    end,
    Day = begin
        _pipe@1 = T2@1,
        birl:get_day(_pipe@1)
    end,
    T1 = begin
        _pipe@2 = T2@1,
        _pipe@3 = birl:set_day(_pipe@2, {day, erlang:element(2, Day), 1, 1}),
        birl:set_time_of_day(_pipe@3, Time)
    end,
    Duration_micro = begin
        _pipe@4 = T2@1,
        birl:to_unix_micro(_pipe@4)
    end
    - begin
        _pipe@5 = T1,
        birl:to_unix_micro(_pipe@5)
    end,
    1 + (case 86400000000 of
        0 -> 0;
        Gleam@denominator -> Duration_micro div Gleam@denominator
    end).