-module(birl@time).
-compile([no_auto_import, nowarn_unused_vars]).

-export([compare/2, difference/2, add/2, subtract/2, now/0, utc_now/0, now_with_offset/1, to_parts/1, to_iso8601/1, from_parts/3, from_iso8601/1, weekday/1]).
-export_type([time/0, week_day/0]).

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

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

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

        _ ->
            {Wta + Oa, Wtb + Ob}
    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, Oa, Mta} = A,
    {time, Wtb, Ob, Mtb} = B,
    {Ta@1, Tb@1} = case {Mta, Mtb} of
        {{some, Ta}, {some, Tb}} ->
            {Ta, Tb};

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

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

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

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

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

-spec parse_offset(binary()) -> {ok, integer()} | {error, nil}.
parse_offset(Offset) ->
    _assert_subject = gleam@regex:from_string(<<"([+-])"/utf8>>),
    {ok, Re} = case _assert_subject of
        {ok, _} -> _assert_subject;
        _assert_fail ->
            erlang:error(#{gleam_error => assert,
                        message => <<"Assertion pattern match failed"/utf8>>,
                        value => _assert_fail,
                        module => <<"birl/time"/utf8>>,
                        function => <<"parse_offset"/utf8>>,
                        line => 253})
    end,
    gleam@result:then(case gleam@regex:split(Re, Offset) of
            [<<""/utf8>>, <<"+"/utf8>>, Offset@1] ->
                {ok, {1, Offset@1}};

            [<<""/utf8>>, <<"-"/utf8>>, Offset@2] ->
                {ok, {-1, Offset@2}};

            [_] ->
                {ok, {1, Offset}};

            _ ->
                {error, nil}
        end, fun(_use0) ->
            {Sign, Offset@3} = _use0,
            case gleam@string:split(Offset@3, <<":"/utf8>>) of
                [Hour_str, Minute_str] ->
                    gleam@result:then(
                        gleam@int:parse(Hour_str),
                        fun(Hour) ->
                            gleam@result:then(
                                gleam@int:parse(Minute_str),
                                fun(Minute) ->
                                    {ok,
                                        ((Sign
                                        * ((Hour
                                        * 60)
                                        + Minute))
                                        * 60)
                                        * 1000000}
                                end
                            )
                        end
                    );

                [Offset@4] ->
                    case gleam@string:length(Offset@4) of
                        1 ->
                            gleam@result:then(
                                gleam@int:parse(Offset@4),
                                fun(Hour@1) ->
                                    {ok, ((Sign * Hour@1) * 3600) * 1000000}
                                end
                            );

                        2 ->
                            gleam@result:then(
                                gleam@int:parse(Offset@4),
                                fun(Hour@1) ->
                                    {ok, ((Sign * Hour@1) * 3600) * 1000000}
                                end
                            );

                        3 ->
                            _assert_subject@1 = gleam@string:first(Offset@4),
                            {ok, Hour_str@1} = case _assert_subject@1 of
                                {ok, _} -> _assert_subject@1;
                                _assert_fail@1 ->
                                    erlang:error(#{gleam_error => assert,
                                                message => <<"Assertion pattern match failed"/utf8>>,
                                                value => _assert_fail@1,
                                                module => <<"birl/time"/utf8>>,
                                                function => <<"parse_offset"/utf8>>,
                                                line => 274})
                            end,
                            Minute_str@1 = gleam@string:slice(Offset@4, 1, 2),
                            gleam@result:then(
                                gleam@int:parse(Hour_str@1),
                                fun(Hour@2) ->
                                    gleam@result:then(
                                        gleam@int:parse(Minute_str@1),
                                        fun(Minute@1) ->
                                            {ok,
                                                ((Sign
                                                * ((Hour@2
                                                * 60)
                                                + Minute@1))
                                                * 60)
                                                * 1000000}
                                        end
                                    )
                                end
                            );

                        4 ->
                            Hour_str@2 = gleam@string:slice(Offset@4, 0, 2),
                            Minute_str@2 = gleam@string:slice(Offset@4, 2, 2),
                            gleam@result:then(
                                gleam@int:parse(Hour_str@2),
                                fun(Hour@3) ->
                                    gleam@result:then(
                                        gleam@int:parse(Minute_str@2),
                                        fun(Minute@2) ->
                                            {ok,
                                                ((Sign
                                                * ((Hour@3
                                                * 60)
                                                + Minute@2))
                                                * 60)
                                                * 1000000}
                                        end
                                    )
                                end
                            );

                        _ ->
                            {error, nil}
                    end;

                _ ->
                    {error, nil}
            end
        end).

-spec generate_offset(integer()) -> {ok, binary()} | {error, nil}.
generate_offset(Offset) ->
    case Offset of
        0 ->
            {ok, <<"Z"/utf8>>};

        _ ->
            case begin
                _pipe = [{Offset, micro_second}],
                _pipe@1 = birl@duration:new(_pipe),
                birl@duration:decompose(_pipe@1)
            end of
                [{Hour, hour}, {Minute, minute}] ->
                    _pipe@10 = [case Hour > 0 of
                            true ->
                                gleam@string:concat(
                                    [<<"+"/utf8>>,
                                        begin
                                            _pipe@2 = Hour,
                                            _pipe@3 = gleam@int:to_string(
                                                _pipe@2
                                            ),
                                            gleam@string:pad_left(
                                                _pipe@3,
                                                2,
                                                <<"0"/utf8>>
                                            )
                                        end]
                                );

                            false ->
                                gleam@string:concat(
                                    [<<"-"/utf8>>,
                                        begin
                                            _pipe@4 = Hour,
                                            _pipe@5 = gleam@int:absolute_value(
                                                _pipe@4
                                            ),
                                            _pipe@6 = gleam@int:to_string(
                                                _pipe@5
                                            ),
                                            gleam@string:pad_left(
                                                _pipe@6,
                                                2,
                                                <<"0"/utf8>>
                                            )
                                        end]
                                )
                        end, begin
                            _pipe@7 = Minute,
                            _pipe@8 = gleam@int:absolute_value(_pipe@7),
                            _pipe@9 = gleam@int:to_string(_pipe@8),
                            gleam@string:pad_left(_pipe@9, 2, <<"0"/utf8>>)
                        end],
                    _pipe@11 = gleam@string:join(_pipe@10, <<":"/utf8>>),
                    {ok, _pipe@11};

                _ ->
                    {error, nil}
            end
    end.

-spec parse_iso_section(binary(), binary(), integer()) -> {ok, list(integer())} |
    {error, nil}.
parse_iso_section(Section, Pattern_string, Default) ->
    _assert_subject = gleam@regex:from_string(Pattern_string),
    {ok, Pattern} = case _assert_subject of
        {ok, _} -> _assert_subject;
        _assert_fail ->
            erlang:error(#{gleam_error => assert,
                        message => <<"Assertion pattern match failed"/utf8>>,
                        value => _assert_fail,
                        module => <<"birl/time"/utf8>>,
                        function => <<"parse_iso_section"/utf8>>,
                        line => 338})
    end,
    _pipe = case gleam@regex:scan(Pattern, Section) of
        [{match, _, [{some, Major}]}] ->
            [gleam@int:parse(Major), {ok, Default}, {ok, Default}];

        [{match, _, [{some, Major}, none]}] ->
            [gleam@int:parse(Major), {ok, Default}, {ok, Default}];

        [{match, _, [{some, Major@1}, {some, Middle}]}] ->
            [gleam@int:parse(Major@1), gleam@int:parse(Middle), {ok, Default}];

        [{match, _, [{some, Major@1}, {some, Middle}, none]}] ->
            [gleam@int:parse(Major@1), gleam@int:parse(Middle), {ok, Default}];

        [{match, _, [{some, Major@2}, {some, Middle@1}, {some, Minor}]}] ->
            [gleam@int:parse(Major@2),
                gleam@int:parse(Middle@1),
                gleam@int:parse(Minor)];

        _ ->
            [{error, nil}]
    end,
    gleam@list:try_map(_pipe, fun(Part) -> case Part of
                {ok, Inner} ->
                    {ok, Inner};

                {error, nil} ->
                    {error, nil}
            end end).

-spec now() -> time().
now() ->
    Now = birl_ffi:now(),
    Offset_in_minutes = birl_ffi:local_offset(),
    Monotonic_now = birl_ffi:monotonic_now(),
    {time, Now, Offset_in_minutes * 60000000, {some, Monotonic_now}}.

-spec utc_now() -> time().
utc_now() ->
    Now = birl_ffi:now(),
    Monotonic_now = birl_ffi:monotonic_now(),
    {time, Now, 0, {some, Monotonic_now}}.

-spec now_with_offset(binary()) -> {ok, time()} | {error, nil}.
now_with_offset(Offset) ->
    gleam@result:then(
        parse_offset(Offset),
        fun(Offset@1) ->
            Now = birl_ffi:now(),
            Monotonic_now = birl_ffi:monotonic_now(),
            _pipe = {time, Now, Offset@1, {some, Monotonic_now}},
            {ok, _pipe}
        end
    ).

-spec to_parts(time()) -> {{integer(), integer(), integer()},
    {integer(), integer(), integer(), integer()},
    binary()}.
to_parts(Value) ->
    case Value of
        {time, T, O, _} ->
            {Date, Time} = birl_ffi:to_parts(T + O),
            _assert_subject = generate_offset(O),
            {ok, Offset} = case _assert_subject of
                {ok, _} -> _assert_subject;
                _assert_fail ->
                    erlang:error(#{gleam_error => assert,
                                message => <<"Assertion pattern match failed"/utf8>>,
                                value => _assert_fail,
                                module => <<"birl/time"/utf8>>,
                                function => <<"to_parts"/utf8>>,
                                line => 58})
            end,
            {Date, Time, Offset}
    end.

-spec to_iso8601(time()) -> binary().
to_iso8601(Value) ->
    {{Year, Month, Day}, {Hour, Minute, Second, Milli_second}, Offset} = to_parts(
        Value
    ),
    <<<<<<<<<<<<<<<<<<<<<<<<<<(gleam@int:to_string(Year))/binary, "-"/utf8>>/binary,
                                                    (begin
                                                        _pipe = Month,
                                                        _pipe@1 = gleam@int:to_string(
                                                            _pipe
                                                        ),
                                                        gleam@string:pad_left(
                                                            _pipe@1,
                                                            2,
                                                            <<"0"/utf8>>
                                                        )
                                                    end)/binary>>/binary,
                                                "-"/utf8>>/binary,
                                            (begin
                                                _pipe@2 = Day,
                                                _pipe@3 = gleam@int:to_string(
                                                    _pipe@2
                                                ),
                                                gleam@string:pad_left(
                                                    _pipe@3,
                                                    2,
                                                    <<"0"/utf8>>
                                                )
                                            end)/binary>>/binary,
                                        "T"/utf8>>/binary,
                                    (begin
                                        _pipe@4 = Hour,
                                        _pipe@5 = gleam@int:to_string(_pipe@4),
                                        gleam@string:pad_left(
                                            _pipe@5,
                                            2,
                                            <<"0"/utf8>>
                                        )
                                    end)/binary>>/binary,
                                ":"/utf8>>/binary,
                            (begin
                                _pipe@6 = Minute,
                                _pipe@7 = gleam@int:to_string(_pipe@6),
                                gleam@string:pad_left(_pipe@7, 2, <<"0"/utf8>>)
                            end)/binary>>/binary,
                        ":"/utf8>>/binary,
                    (begin
                        _pipe@8 = Second,
                        _pipe@9 = gleam@int:to_string(_pipe@8),
                        gleam@string:pad_left(_pipe@9, 2, <<"0"/utf8>>)
                    end)/binary>>/binary,
                "."/utf8>>/binary,
            (begin
                _pipe@10 = Milli_second,
                _pipe@11 = gleam@int:to_string(_pipe@10),
                gleam@string:pad_left(_pipe@11, 3, <<"0"/utf8>>)
            end)/binary>>/binary,
        Offset/binary>>.

-spec from_parts(
    {integer(), integer(), integer()},
    {integer(), integer(), integer(), integer()},
    binary()
) -> {ok, time()} | {error, nil}.
from_parts(Date, Time, Offset) ->
    gleam@result:then(
        parse_offset(Offset),
        fun(Offset_number) ->
            _pipe = birl_ffi:from_parts({Date, Time}, Offset_number),
            _pipe@1 = {time, _pipe, Offset_number, none},
            {ok, _pipe@1}
        end
    ).

-spec from_iso8601(binary()) -> {ok, time()} | {error, nil}.
from_iso8601(Value) ->
    _assert_subject = gleam@regex:from_string(<<"(.*)([+|\\-].*)"/utf8>>),
    {ok, Offset_pattern} = case _assert_subject of
        {ok, _} -> _assert_subject;
        _assert_fail ->
            erlang:error(#{gleam_error => assert,
                        message => <<"Assertion pattern match failed"/utf8>>,
                        value => _assert_fail,
                        module => <<"birl/time"/utf8>>,
                        function => <<"from_iso8601"/utf8>>,
                        line => 106})
    end,
    Value@1 = gleam@string:trim(Value),
    {Date_string@2, Offsetted_time_string@1} = case gleam@string:split(
        Value@1,
        <<"T"/utf8>>
    ) of
        [Date_string] ->
            {Date_string, <<"00"/utf8>>};

        [Date_string@1, Offsetted_time_string] ->
            {Date_string@1, Offsetted_time_string}
    end,
    {Time_string@1, Offset_string@1} = case gleam@string:ends_with(
        Offsetted_time_string@1,
        <<"Z"/utf8>>
    ) of
        true ->
            {gleam@string:drop_right(Offsetted_time_string@1, 1),
                <<"+00:00"/utf8>>};

        false ->
            case gleam@regex:scan(Offset_pattern, Offsetted_time_string@1) of
                [{match, _, [{some, Time_string}, {some, Offset_string}]}] ->
                    {Time_string, Offset_string};

                [] ->
                    Local_offset_in_minutes = birl_ffi:local_offset(),
                    _assert_subject@1 = generate_offset(
                        Local_offset_in_minutes
                        * 60000000
                    ),
                    {ok, Local_offset_string} = case _assert_subject@1 of
                        {ok, _} -> _assert_subject@1;
                        _assert_fail@1 ->
                            erlang:error(#{gleam_error => assert,
                                        message => <<"Assertion pattern match failed"/utf8>>,
                                        value => _assert_fail@1,
                                        module => <<"birl/time"/utf8>>,
                                        function => <<"from_iso8601"/utf8>>,
                                        line => 129})
                    end,
                    {Offsetted_time_string@1, Local_offset_string}
            end
    end,
    Date_string@3 = gleam@string:replace(
        Date_string@2,
        <<"-"/utf8>>,
        <<""/utf8>>
    ),
    Time_string@2 = gleam@string:replace(
        Time_string@1,
        <<":"/utf8>>,
        <<""/utf8>>
    ),
    {Time_string@5, Milli_seconds_result} = case gleam@string:split(
        Time_string@2,
        <<"."/utf8>>
    ) of
        [Time_string@3] ->
            {Time_string@3, {ok, 0}};

        [Time_string@4, Milli_seconds_string] ->
            {Time_string@4, gleam@int:parse(Milli_seconds_string)}
    end,
    case Milli_seconds_result of
        {ok, Milli_seconds} ->
            gleam@result:then(
                parse_iso_section(
                    Date_string@3,
                    <<"(\\d{4})(\\d{2})?(\\d{2})?"/utf8>>,
                    1
                ),
                fun(_use0) ->
                    [Year, Month, Day] = _use0,
                    gleam@result:then(
                        parse_iso_section(
                            Time_string@5,
                            <<"(\\d{2})(\\d{2})?(\\d{2})?"/utf8>>,
                            0
                        ),
                        fun(_use0@1) ->
                            [Hour, Minute, Second] = _use0@1,
                            case from_parts(
                                {Year, Month, Day},
                                {Hour, Minute, Second, Milli_seconds},
                                Offset_string@1
                            ) of
                                {ok, {time, Timestamp, Offset, none}} ->
                                    {ok, {time, Timestamp, Offset, none}};

                                {error, nil} ->
                                    {error, nil}
                            end
                        end
                    )
                end
            );

        {error, nil} ->
            {error, nil}
    end.

-spec weekday(time()) -> week_day().
weekday(Value) ->
    case Value of
        {time, T, O, _} ->
            _assert_subject = gleam@list:at(
                [monday, tuesday, wednesday, thursday, friday, saturday, sunday],
                birl_ffi:weekday(T + O)
            ),
            {ok, Weekday} = case _assert_subject of
                {ok, _} -> _assert_subject;
                _assert_fail ->
                    erlang:error(#{gleam_error => assert,
                                message => <<"Assertion pattern match failed"/utf8>>,
                                value => _assert_fail,
                                module => <<"birl/time"/utf8>>,
                                function => <<"weekday"/utf8>>,
                                line => 246})
            end,
            Weekday
    end.