-module(birl@time).
-compile(no_auto_import).

-export([now/0, to_parts/1, from_parts/2, to_iso/1, from_iso/1, compare/2, difference/2, add/2, subtract/2, get_weekday/1]).
-export_type([time/0, week_day/0]).

-opaque time() :: {time, integer(), gleam@option:option(integer())}.

-type week_day() :: monday |
    tuesday |
    wednesday |
    thursday |
    friday |
    saturday |
    sunday.

-spec now() -> time().
now() ->
    Now = birl_ffi:now(),
    Monotonic_now = birl_ffi:monotonic_now(),
    {time, Now, {some, Monotonic_now}}.

-spec to_parts(time()) -> {{integer(), integer(), integer()},
    {integer(), integer(), integer()}}.
to_parts(Value) ->
    case Value of
        {time, T, _@1} ->
            birl_ffi:to_parts(T)
    end.

-spec from_parts(
    {integer(), integer(), integer()},
    {integer(), integer(), integer()}
) -> time().
from_parts(Date, Time) ->
    String_date = case Date of
        {Year, Month, Day} ->
            _pipe = [gleam@int:to_string(Year),
                gleam@int:to_string(Month),
                gleam@int:to_string(Day)],
            _pipe@1 = gleam@list:map(
                _pipe,
                fun gleam@string_builder:from_string/1
            ),
            gleam@string_builder:join(_pipe@1, <<"-"/utf8>>)
    end,
    String_time = case Time of
        {Hour, Minute, Second} ->
            _pipe@2 = [gleam@int:to_string(Hour),
                gleam@int:to_string(Minute),
                gleam@int:to_string(Second)],
            _pipe@3 = gleam@list:map(
                _pipe@2,
                fun gleam@string_builder:from_string/1
            ),
            _pipe@4 = gleam@string_builder:join(_pipe@3, <<":"/utf8>>),
            gleam@string_builder:append(_pipe@4, <<".000Z"/utf8>>)
    end,
    {ok, Value@1} = case begin
        _pipe@5 = gleam@string_builder:join(
            [String_date, String_time],
            <<"T"/utf8>>
        ),
        _pipe@6 = gleam@string_builder:to_string(_pipe@5),
        from_iso(_pipe@6)
    end of
        {ok, Value} -> {ok, Value};
        _try ->
            erlang:error(#{gleam_error => assert,
                        message => <<"Assertion pattern match failed"/utf8>>,
                        value => _try,
                        module => <<"birl/time"/utf8>>,
                        function => <<"from_parts"/utf8>>,
                        line => 51})
    end,
    Value@1.

-spec to_iso(time()) -> binary().
to_iso(Value) ->
    case Value of
        {time, T, _@1} ->
            birl_ffi:to_iso(T)
    end.

-spec from_iso(binary()) -> {ok, time()} | {error, nil}.
from_iso(Value) ->
    {ok, Pattern@1} = case gleam@regex:from_string(
        <<"\\d{4}-\\d{1,2}-\\d{1,2}T\\d{1,2}:\\d{1,2}:\\d{1,2}.\\d{3}Z"/utf8>>
    ) of
        {ok, Pattern} -> {ok, Pattern};
        _try ->
            erlang:error(#{gleam_error => assert,
                        message => <<"Assertion pattern match failed"/utf8>>,
                        value => _try,
                        module => <<"birl/time"/utf8>>,
                        function => <<"from_iso"/utf8>>,
                        line => 68})
    end,
    case gleam@regex:check(Pattern@1, Value) of
        true ->
            _pipe = Value,
            _pipe@1 = birl_ffi:from_iso(_pipe),
            _pipe@2 = {time, _pipe@1, none},
            {ok, _pipe@2};

        false ->
            {error, nil}
    end.

-spec compare(time(), time()) -> gleam@order:order().
compare(A, B) ->
    {time, Wta, Mta} = A,
    {time, Wtb, Mtb} = B,
    {Ta@1, Tb@1} = case {Mta, Mtb} of
        {{some, Ta}, {some, Tb}} ->
            {Ta, Tb};

        _@1 ->
            {Wta, Wtb}
    end,
    case Ta@1 =:= Tb@1 of
        true ->
            eq;

        false ->
            case Ta@1 < Tb@1 of
                true ->
                    lt;

                false ->
                    gt
            end
    end.

-spec difference(time(), time()) -> birl@duration:duration().
difference(A, B) ->
    {time, Wta, Mta} = A,
    {time, Wtb, Mtb} = B,
    {Ta@1, Tb@1} = case {Mta, Mtb} of
        {{some, Ta}, {some, Tb}} ->
            {Ta, Tb};

        _@1 ->
            {Wta, Wtb}
    end,
    {duration, Ta@1 - Tb@1}.

-spec add(time(), birl@duration:duration()) -> time().
add(Value, Duration) ->
    {time, Wt, Mt} = Value,
    {duration, Duration@1} = Duration,
    case Mt of
        {some, Mt@1} ->
            {time, Wt + Duration@1, {some, Mt@1 + Duration@1}};

        none ->
            {time, Wt + Duration@1, none}
    end.

-spec subtract(time(), birl@duration:duration()) -> time().
subtract(Value, Duration) ->
    {time, Wt, Mt} = Value,
    {duration, Duration@1} = Duration,
    case Mt of
        {some, Mt@1} ->
            {time, Wt - Duration@1, {some, Mt@1 - Duration@1}};

        none ->
            {time, Wt - Duration@1, none}
    end.

-spec get_weekday(time()) -> week_day().
get_weekday(Value) ->
    case Value of
        {time, T, _@1} ->
            {ok, Weekday@1} = case gleam@list:at(
                [monday, tuesday, wednesday, thursday, friday, saturday, sunday],
                birl_ffi:get_weekday(T)
            ) of
                {ok, Weekday} -> {ok, Weekday};
                _try ->
                    erlang:error(#{gleam_error => assert,
                                message => <<"Assertion pattern match failed"/utf8>>,
                                value => _try,
                                module => <<"birl/time"/utf8>>,
                                function => <<"get_weekday"/utf8>>,
                                line => 133})
            end,
            Weekday@1
    end.