-module(tempo@offset).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch]).

-export([new/1, to_string/1, from_string/1, literal/1, to_duration/1, local_minutes/0, local/0, local_nano/0]).

-spec validate(tempo:offset()) -> {ok, tempo:offset()} | {error, tempo:error()}.
validate(Offset) ->
    case (erlang:element(2, Offset) >= -720) andalso (erlang:element(2, Offset)
    =< 840) of
        true ->
            {ok, Offset};

        false ->
            {error, offset_out_of_bounds}
    end.

-spec new(integer()) -> {ok, tempo:offset()} | {error, tempo:error()}.
new(Minutes) ->
    _pipe = {offset, Minutes},
    validate(_pipe).

-spec to_string(tempo:offset()) -> binary().
to_string(Offset) ->
    {Is_negative, Hours} = case erlang:element(2, Offset) div 60 of
        H when H =< 0 ->
            {true, - H};

        H@1 ->
            {false, H@1}
    end,
    Mins = case erlang:element(2, Offset) rem 60 of
        M when M < 0 ->
            - M;

        M@1 ->
            M@1
    end,
    case {Is_negative, Hours, Mins} of
        {_, 0, 0} ->
            <<"-00:00"/utf8>>;

        {_, 0, M@2} ->
            <<"-00:"/utf8,
                (begin
                    _pipe = gleam@int:to_string(M@2),
                    gleam@string:pad_left(_pipe, 2, <<"0"/utf8>>)
                end)/binary>>;

        {true, H@2, M@3} ->
            <<<<<<"-"/utf8,
                        (begin
                            _pipe@1 = gleam@int:to_string(H@2),
                            gleam@string:pad_left(_pipe@1, 2, <<"0"/utf8>>)
                        end)/binary>>/binary,
                    ":"/utf8>>/binary,
                (begin
                    _pipe@2 = gleam@int:to_string(M@3),
                    gleam@string:pad_left(_pipe@2, 2, <<"0"/utf8>>)
                end)/binary>>;

        {false, H@3, M@4} ->
            <<<<<<"+"/utf8,
                        (begin
                            _pipe@3 = gleam@int:to_string(H@3),
                            gleam@string:pad_left(_pipe@3, 2, <<"0"/utf8>>)
                        end)/binary>>/binary,
                    ":"/utf8>>/binary,
                (begin
                    _pipe@4 = gleam@int:to_string(M@4),
                    gleam@string:pad_left(_pipe@4, 2, <<"0"/utf8>>)
                end)/binary>>
    end.

-spec from_string(binary()) -> {ok, tempo:offset()} | {error, tempo:error()}.
from_string(Offset) ->
    _pipe = case Offset of
        <<"Z"/utf8>> ->
            {ok, {offset, 0}};

        <<"z"/utf8>> ->
            {ok, {offset, 0}};

        _ ->
            gleam@result:'try'(case gleam@string:split(Offset, <<":"/utf8>>) of
                    [Hour, Minute] ->
                        case {gleam@string:length(Hour),
                            gleam@string:length(Minute)} of
                            {3, 2} ->
                                {ok,
                                    {gleam@string:slice(Hour, 0, 1),
                                        gleam@string:slice(Hour, 1, 2),
                                        Minute}};

                            {_, _} ->
                                {error, offset_invalid_format}
                        end;

                    _ ->
                        case gleam@string:length(Offset) of
                            5 ->
                                {ok,
                                    {gleam@string:slice(Offset, 0, 1),
                                        gleam@string:slice(Offset, 1, 2),
                                        gleam@string:slice(Offset, 3, 2)}};

                            3 ->
                                {ok,
                                    {gleam@string:slice(Offset, 0, 1),
                                        gleam@string:slice(Offset, 1, 2),
                                        <<"0"/utf8>>}};

                            2 ->
                                {ok,
                                    {gleam@string:slice(Offset, 0, 1),
                                        gleam@string:slice(Offset, 1, 1),
                                        <<"0"/utf8>>}};

                            _ ->
                                {error, offset_invalid_format}
                        end
                end, fun(_use0) ->
                    {Sign, Hour@1, Minute@1} = _use0,
                    case {Sign,
                        gleam@int:parse(Hour@1),
                        gleam@int:parse(Minute@1)} of
                        {_, {ok, 0}, {ok, 0}} ->
                            {ok, {offset, 0}};

                        {<<"-"/utf8>>, {ok, Hour@2}, {ok, Minute@2}} when (Hour@2 =< 24) andalso (Minute@2 =< 60) ->
                            {ok, {offset, - ((Hour@2 * 60) + Minute@2)}};

                        {<<"+"/utf8>>, {ok, Hour@3}, {ok, Minute@3}} when (Hour@3 =< 24) andalso (Minute@3 =< 60) ->
                            {ok, {offset, (Hour@3 * 60) + Minute@3}};

                        {_, _, _} ->
                            {error, offset_invalid_format}
                    end
                end)
    end,
    gleam@result:'try'(_pipe, fun validate/1).

-spec literal(binary()) -> tempo:offset().
literal(Offset) ->
    case from_string(Offset) of
        {ok, Offset@1} ->
            Offset@1;

        {error, offset_invalid_format} ->
            erlang:error(#{gleam_error => panic,
                    message => <<"Invalid offset literal format"/utf8>>,
                    module => <<"tempo/offset"/utf8>>,
                    function => <<"literal"/utf8>>,
                    line => 44});

        {error, offset_out_of_bounds} ->
            erlang:error(#{gleam_error => panic,
                    message => <<"Invalid offset literal value"/utf8>>,
                    module => <<"tempo/offset"/utf8>>,
                    function => <<"literal"/utf8>>,
                    line => 45});

        {error, _} ->
            erlang:error(#{gleam_error => panic,
                    message => <<"Invalid offset literal"/utf8>>,
                    module => <<"tempo/offset"/utf8>>,
                    function => <<"literal"/utf8>>,
                    line => 46})
    end.

-spec to_duration(tempo:offset()) -> tempo:duration().
to_duration(Offset) ->
    _pipe = - erlang:element(2, Offset) * 60000000000,
    {duration, _pipe}.

-spec local_minutes() -> integer().
local_minutes() ->
    tempo_ffi:local_offset().

-spec local() -> tempo:offset().
local() ->
    _pipe = tempo_ffi:local_offset(),
    {offset, _pipe}.

-spec local_nano() -> integer().
local_nano() ->
    tempo_ffi:local_offset() * 60000000000.