-module(caffeine_lang@source_snippet).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch, inline]).
-define(FILEPATH, "src/caffeine_lang/source_snippet.gleam").
-export([extract_snippet/4]).
-export_type([source_snippet/0]).

-if(?OTP_RELEASE >= 27).
-define(MODULEDOC(Str), -moduledoc(Str)).
-define(DOC(Str), -doc(Str)).
-else.
-define(MODULEDOC(Str), -compile([])).
-define(DOC(Str), -compile([])).
-endif.

-type source_snippet() :: {source_snippet, binary()}.

-file("src/caffeine_lang/source_snippet.gleam", 125).
-spec insert_marker_loop(
    list(binary()),
    integer(),
    binary(),
    integer(),
    list(binary())
) -> list(binary()).
insert_marker_loop(Lines, Error_index, Marker, Current, Acc) ->
    case Lines of
        [] ->
            Acc;

        [Line | Rest] ->
            New_acc = case Current =:= Error_index of
                true ->
                    [Marker, Line | Acc];

                false ->
                    [Line | Acc]
            end,
            insert_marker_loop(Rest, Error_index, Marker, Current + 1, New_acc)
    end.

-file("src/caffeine_lang/source_snippet.gleam", 115).
?DOC(" Inserts the marker line after the error line in the context.\n").
-spec insert_marker(list(binary()), integer(), integer(), binary()) -> list(binary()).
insert_marker(Context_lines, Error_line, Start_line, Marker_line) ->
    _pipe = insert_marker_loop(
        Context_lines,
        Error_line - Start_line,
        Marker_line,
        0,
        []
    ),
    lists:reverse(_pipe).

-file("src/caffeine_lang/source_snippet.gleam", 107).
?DOC(" Formats the marker line with carets under the error position.\n").
-spec format_marker(integer(), integer(), integer()) -> binary().
format_marker(Column, Span_width, Gutter_width) ->
    Gutter_space = gleam@string:repeat(<<" "/utf8>>, Gutter_width),
    Col_space = gleam@string:repeat(<<" "/utf8>>, gleam@int:max(0, Column - 1)),
    Carets = gleam@string:repeat(<<"^"/utf8>>, Span_width),
    <<<<<<Gutter_space/binary, " | "/utf8>>/binary, Col_space/binary>>/binary,
        Carets/binary>>.

-file("src/caffeine_lang/source_snippet.gleam", 100).
?DOC(" Formats a single line with its line number gutter.\n").
-spec format_line(integer(), binary(), integer()) -> binary().
format_line(Line_num, Content, Gutter_width) ->
    Num_str = erlang:integer_to_binary(Line_num),
    Padding = gleam@string:repeat(
        <<" "/utf8>>,
        Gutter_width - string:length(Num_str)
    ),
    <<<<<<Padding/binary, Num_str/binary>>/binary, " | "/utf8>>/binary,
        Content/binary>>.

-file("src/caffeine_lang/source_snippet.gleam", 78).
?DOC(" Collects lines from current_line to end_line (inclusive).\n").
-spec collect_lines(binary(), integer(), integer(), list({integer(), binary()})) -> list({integer(),
    binary()}).
collect_lines(Source, Current_line, End_line, Acc) ->
    gleam@bool:guard(
        Current_line > End_line,
        Acc,
        fun() -> case gleam@string:split_once(Source, <<"\n"/utf8>>) of
                {ok, {Line, Rest}} ->
                    collect_lines(
                        Rest,
                        Current_line + 1,
                        End_line,
                        [{Current_line, Line} | Acc]
                    );

                {error, _} ->
                    gleam@bool:guard(
                        gleam@string:is_empty(Source),
                        Acc,
                        fun() -> [{Current_line, Source} | Acc] end
                    )
            end end
    ).

-file("src/caffeine_lang/source_snippet.gleam", 69).
?DOC(" Skips past the first `count` lines by splitting on newlines.\n").
-spec skip_lines(binary(), integer()) -> binary().
skip_lines(Source, Count) ->
    gleam@bool:guard(
        Count =< 0,
        Source,
        fun() -> case gleam@string:split_once(Source, <<"\n"/utf8>>) of
                {ok, {_, Rest}} ->
                    skip_lines(Rest, Count - 1);

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

-file("src/caffeine_lang/source_snippet.gleam", 58).
?DOC(
    " Extracts only the lines in [start_line, end_line] without splitting the entire source.\n"
    " Uses split_once to skip lines before the range and stop after it.\n"
).
-spec extract_context_lines(binary(), integer(), integer()) -> list({integer(),
    binary()}).
extract_context_lines(Source, Start_line, End_line) ->
    Remaining = skip_lines(Source, Start_line - 1),
    _pipe = collect_lines(Remaining, Start_line, End_line, []),
    lists:reverse(_pipe).

-file("src/caffeine_lang/source_snippet.gleam", 18).
?DOC(
    " Extracts a source snippet around the given line/column position.\n"
    " Shows 1 line of context above and below the error line.\n"
    " Adds a caret (^) marker under the error position.\n"
    " Line and column are 1-indexed.\n"
).
-spec extract_snippet(
    binary(),
    integer(),
    integer(),
    gleam@option:option(integer())
) -> source_snippet().
extract_snippet(Source_content, Line, Column, End_column) ->
    Start_line = gleam@int:max(1, Line - 1),
    End_line = Line + 1,
    Context = extract_context_lines(Source_content, Start_line, End_line),
    Max_line_num = case gleam@list:last(Context) of
        {ok, {N, _}} ->
            N;

        {error, _} ->
            End_line
    end,
    Gutter_width = string:length(erlang:integer_to_binary(Max_line_num)),
    Context_lines = begin
        _pipe = Context,
        gleam@list:map(
            _pipe,
            fun(Pair) ->
                format_line(
                    erlang:element(1, Pair),
                    erlang:element(2, Pair),
                    Gutter_width
                )
            end
        )
    end,
    Span_width = case End_column of
        {some, End_col} ->
            gleam@int:max(1, End_col - Column);

        none ->
            1
    end,
    Marker_line = format_marker(Column, Span_width, Gutter_width),
    Rendered = begin
        _pipe@1 = insert_marker(Context_lines, Line, Start_line, Marker_line),
        gleam@string:join(_pipe@1, <<"\n"/utf8>>)
    end,
    {source_snippet, Rendered}.