-module(handles@format).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch]).

-export([format_tokenizer_error/2, format_runtime_error/2]).
-export_type([position/0]).

-type position() :: {position, integer(), integer(), integer()} | out_of_bounds.

-spec resolve_position(binary(), integer(), position()) -> position().
resolve_position(Input, Target_index, Current) ->
    case Current of
        {position, Index, Row, Col} when Index =:= Target_index ->
            {position, Target_index, Row, Col};

        {position, Index@1, Row@1, Col@1} ->
            case gleam@string:first(Input) of
                {ok, Char} ->
                    case Char of
                        <<"\n"/utf8>> ->
                            resolve_position(
                                gleam@string:drop_left(Input, 1),
                                Target_index,
                                {position, Index@1 + 1, Row@1 + 1, 0}
                            );

                        _ ->
                            resolve_position(
                                gleam@string:drop_left(Input, 1),
                                Target_index,
                                {position, Index@1 + 1, Row@1, Col@1 + 1}
                            )
                    end;

                {error, _} ->
                    out_of_bounds
            end;

        out_of_bounds ->
            out_of_bounds
    end.

-spec transform_error(binary(), integer(), binary()) -> {ok, binary()} |
    {error, nil}.
transform_error(Template, Offset, Message) ->
    case resolve_position(Template, Offset, {position, 0, 0, 0}) of
        {position, _, Row, Col} ->
            {ok,
                <<<<<<<<<<Message/binary, " (row="/utf8>>/binary,
                                (gleam@int:to_string(Row))/binary>>/binary,
                            ", col="/utf8>>/binary,
                        (gleam@int:to_string(Col))/binary>>/binary,
                    ")"/utf8>>};

        out_of_bounds ->
            {error, nil}
    end.

-spec format_tokenizer_error(handles@error:tokenizer_error(), binary()) -> {ok,
        binary()} |
    {error, nil}.
format_tokenizer_error(Error, Template) ->
    case Error of
        {unbalanced_tag, Index} ->
            transform_error(
                Template,
                Index,
                <<"Tag is missing closing braces }}"/utf8>>
            );

        {unexpected_block_argument, Index@1} ->
            transform_error(
                Template,
                Index@1,
                <<"Tag is a closing block, which does not take any arguments"/utf8>>
            );

        {missing_block_argument, Index@2} ->
            transform_error(
                Template,
                Index@2,
                <<"Tag is missing block argument"/utf8>>
            );

        {missing_property_path, Index@3} ->
            transform_error(
                Template,
                Index@3,
                <<"Tag is missing property path"/utf8>>
            );

        {unexpected_block_kind, Index@4} ->
            transform_error(
                Template,
                Index@4,
                <<"Tag is of unknown block kind"/utf8>>
            )
    end.

-spec format_runtime_error(handles@error:runtime_error(), binary()) -> {ok,
        binary()} |
    {error, nil}.
format_runtime_error(Error, Template) ->
    case Error of
        {unexpected_type_error, Index, Path, Got, Expected} ->
            transform_error(
                Template,
                Index,
                <<<<<<<<<<"Unexpected type of property "/utf8,
                                    (gleam@string:join(Path, <<"."/utf8>>))/binary>>/binary,
                                ", extepced "/utf8>>/binary,
                            (gleam@string:join(Expected, <<" or "/utf8>>))/binary>>/binary,
                        " but found found "/utf8>>/binary,
                    Got/binary>>
            );

        {unknown_property_error, Index@1, Path@1} ->
            transform_error(
                Template,
                Index@1,
                <<"Unable to resolve property "/utf8,
                    (gleam@string:join(Path@1, <<"."/utf8>>))/binary>>
            )
    end.