-module(datadog_query@lint).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch, inline]).
-define(FILEPATH, "src/datadog_query/lint.gleam").
-export([at_prefixed_attrs/1, unbalanced_braces/1, unbalanced_parens/1, dangling_joiner/1, reserved_word_as_tag_name/1, wildcard_in_quoted_value/1, empty_scope_with_grouping/1]).
-export_type([balance_error/0, balance_state/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 balance_error() :: {unmatched, binary()} | {unclosed, binary()}.

-type balance_state() :: balance_ok | balance_unmatched | balance_unclosed.

-file("src/datadog_query/lint.gleam", 35).
-spec token_to_at_attr(binary()) -> {ok, binary()} | {error, nil}.
token_to_at_attr(Token) ->
    Stripped = case gleam_stdlib:string_starts_with(Token, <<"!"/utf8>>) of
        true ->
            gleam@string:drop_start(Token, 1);

        false ->
            Token
    end,
    case gleam_stdlib:string_starts_with(Stripped, <<"@"/utf8>>) of
        false ->
            {error, nil};

        true ->
            Attr = case gleam@string:split_once(Stripped, <<":"/utf8>>) of
                {ok, {Before_colon, _}} ->
                    Before_colon;

                {error, _} ->
                    Stripped
            end,
            case Attr of
                <<"@"/utf8>> ->
                    {error, nil};

                _ ->
                    {ok, Attr}
            end
    end.

-file("src/datadog_query/lint.gleam", 23).
?DOC(
    " Scans a Datadog query string for `@`-prefixed attribute names used in\n"
    " filter position (e.g. `@type:foo` or `@type IN (...)`).\n"
    "\n"
    " Datadog metric filters strip the leading `@` from log facets when log-based\n"
    " metrics are generated — the metric tag for log facet `@type` is just `type`.\n"
    " A query that filters on `@type` against a log-based metric is rejected by\n"
    " the SLO API with `400: numerator query is invalid`.\n"
    "\n"
    " Returns a deduplicated list of `@`-prefixed attribute names found.\n"
).
-spec at_prefixed_attrs(binary()) -> list(binary()).
at_prefixed_attrs(Query) ->
    _pipe = Query,
    _pipe@1 = gleam@string:replace(_pipe, <<"{"/utf8>>, <<" "/utf8>>),
    _pipe@2 = gleam@string:replace(_pipe@1, <<"}"/utf8>>, <<" "/utf8>>),
    _pipe@3 = gleam@string:replace(_pipe@2, <<"("/utf8>>, <<" "/utf8>>),
    _pipe@4 = gleam@string:replace(_pipe@3, <<")"/utf8>>, <<" "/utf8>>),
    _pipe@5 = gleam@string:replace(_pipe@4, <<","/utf8>>, <<" "/utf8>>),
    _pipe@6 = gleam@string:split(_pipe@5, <<" "/utf8>>),
    _pipe@7 = gleam@list:filter_map(_pipe@6, fun token_to_at_attr/1),
    gleam@list:unique(_pipe@7).

-file("src/datadog_query/lint.gleam", 85).
-spec scan_balance(list(binary()), binary(), binary(), integer(), boolean()) -> balance_state().
scan_balance(Graphemes, Open, Close, Depth, In_string) ->
    case Graphemes of
        [] ->
            case Depth of
                0 ->
                    balance_ok;

                _ ->
                    balance_unclosed
            end;

        [G | Rest] ->
            case {In_string, G} of
                {true, <<"\""/utf8>>} ->
                    scan_balance(Rest, Open, Close, Depth, false);

                {true, _} ->
                    scan_balance(Rest, Open, Close, Depth, true);

                {false, <<"\""/utf8>>} ->
                    scan_balance(Rest, Open, Close, Depth, true);

                {false, _} ->
                    case {G =:= Open, G =:= Close} of
                        {true, _} ->
                            scan_balance(Rest, Open, Close, Depth + 1, false);

                        {_, true} ->
                            case Depth of
                                0 ->
                                    balance_unmatched;

                                _ ->
                                    scan_balance(
                                        Rest,
                                        Open,
                                        Close,
                                        Depth - 1,
                                        false
                                    )
                            end;

                        {_, _} ->
                            scan_balance(Rest, Open, Close, Depth, false)
                    end
            end
    end.

-file("src/datadog_query/lint.gleam", 66).
-spec check_balance(binary(), binary(), binary()) -> {ok, nil} |
    {error, balance_error()}.
check_balance(Query, Open, Close) ->
    Result = scan_balance(
        gleam@string:to_graphemes(Query),
        Open,
        Close,
        0,
        false
    ),
    case Result of
        balance_ok ->
            {ok, nil};

        balance_unmatched ->
            {error, {unmatched, Close}};

        balance_unclosed ->
            {error, {unclosed, Open}}
    end.

-file("src/datadog_query/lint.gleam", 57).
?DOC(
    " Verifies `{` / `}` are balanced. Ignores braces inside double-quoted\n"
    " strings so `tag:\"a{b}c\"` doesn't trigger a false positive.\n"
).
-spec unbalanced_braces(binary()) -> {ok, nil} | {error, balance_error()}.
unbalanced_braces(Query) ->
    check_balance(Query, <<"{"/utf8>>, <<"}"/utf8>>).

-file("src/datadog_query/lint.gleam", 62).
?DOC(" Verifies `(` / `)` are balanced (string-aware).\n").
-spec unbalanced_parens(binary()) -> {ok, nil} | {error, balance_error()}.
unbalanced_parens(Query) ->
    check_balance(Query, <<"("/utf8>>, <<")"/utf8>>).

-file("src/datadog_query/lint.gleam", 149).
-spec check_scope_joiners(binary()) -> list(binary()).
check_scope_joiners(Scope) ->
    Trimmed = gleam@string:trim(Scope),
    case Trimmed of
        <<""/utf8>> ->
            [];

        _ ->
            Leading = case gleam_stdlib:string_starts_with(
                Trimmed,
                <<"AND "/utf8>>
            )
            orelse gleam_stdlib:string_starts_with(Trimmed, <<"OR "/utf8>>) of
                true ->
                    [<<"leading joiner: "/utf8, Trimmed/binary>>];

                false ->
                    []
            end,
            Trailing = case gleam_stdlib:string_ends_with(
                Trimmed,
                <<" AND"/utf8>>
            )
            orelse gleam_stdlib:string_ends_with(Trimmed, <<" OR"/utf8>>) of
                true ->
                    [<<"trailing joiner: "/utf8, Trimmed/binary>>];

                false ->
                    []
            end,
            Doubled = case ((gleam_stdlib:contains_string(
                Trimmed,
                <<" AND  AND "/utf8>>
            )
            orelse gleam_stdlib:contains_string(Trimmed, <<" OR  OR "/utf8>>))
            orelse gleam_stdlib:contains_string(Trimmed, <<" AND  OR "/utf8>>))
            orelse gleam_stdlib:contains_string(Trimmed, <<" OR  AND "/utf8>>) of
                true ->
                    [<<"doubled joiner: "/utf8, Trimmed/binary>>];

                false ->
                    []
            end,
            lists:append([Leading, Trailing, Doubled])
    end.

-file("src/datadog_query/lint.gleam", 133).
-spec extract_scopes(binary()) -> list(binary()).
extract_scopes(Query) ->
    case gleam@string:split(Query, <<"{"/utf8>>) of
        [_ | Rest] ->
            gleam@list:filter_map(
                Rest,
                fun(Chunk) ->
                    case gleam@string:split_once(Chunk, <<"}"/utf8>>) of
                        {ok, {Inside, _}} ->
                            {ok, Inside};

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

        _ ->
            []
    end.

-file("src/datadog_query/lint.gleam", 127).
?DOC(
    " Detects scope-internal artifacts produced by composing `tag_in([])` /\n"
    " `tag_not_in([])` returning `\"\"`. Returns the offending fragment(s) when\n"
    " the scope contains a leading/trailing/doubled boolean joiner.\n"
    "\n"
    " Examples flagged:\n"
    "   `metric{ AND env:prod}`     → [\"leading AND\"]\n"
    "   `metric{env:prod AND }`     → [\"trailing AND\"]\n"
    "   `metric{env:prod AND  AND service:api}` → [\"doubled joiner\"]\n"
).
-spec dangling_joiner(binary()) -> list(binary()).
dangling_joiner(Query) ->
    _pipe = Query,
    _pipe@1 = extract_scopes(_pipe),
    gleam@list:flat_map(_pipe@1, fun check_scope_joiners/1).

-file("src/datadog_query/lint.gleam", 185).
?DOC(
    " Detects tag *names* that collide with grammar keywords. Datadog accepts\n"
    " these tokens as separators, so a tag literally named `IN` produces\n"
    " confusing parse errors.\n"
).
-spec reserved_word_as_tag_name(binary()) -> list(binary()).
reserved_word_as_tag_name(Query) ->
    Reserved = [<<"IN"/utf8>>,
        <<"NOT"/utf8>>,
        <<"AND"/utf8>>,
        <<"OR"/utf8>>,
        <<"true"/utf8>>,
        <<"false"/utf8>>],
    _pipe = Query,
    _pipe@1 = extract_scopes(_pipe),
    _pipe@7 = gleam@list:flat_map(_pipe@1, fun(Scope) -> _pipe@2 = Scope,
            _pipe@3 = gleam@string:replace(_pipe@2, <<"("/utf8>>, <<" "/utf8>>),
            _pipe@4 = gleam@string:replace(_pipe@3, <<")"/utf8>>, <<" "/utf8>>),
            _pipe@5 = gleam@string:replace(_pipe@4, <<","/utf8>>, <<" "/utf8>>),
            _pipe@6 = gleam@string:split(_pipe@5, <<" "/utf8>>),
            gleam@list:filter_map(
                _pipe@6,
                fun(Token) ->
                    case gleam@string:split_once(Token, <<":"/utf8>>) of
                        {ok, {Name, _}} ->
                            case gleam@list:contains(Reserved, Name) of
                                true ->
                                    {ok, Name};

                                false ->
                                    {error, nil}
                            end;

                        {error, _} ->
                            {error, nil}
                    end
                end
            ) end),
    gleam@list:unique(_pipe@7).

-file("src/datadog_query/lint.gleam", 218).
-spec scan_wildcard_quoted(list(binary()), boolean()) -> boolean().
scan_wildcard_quoted(Graphemes, In_string) ->
    case Graphemes of
        [] ->
            false;

        [G | Rest] ->
            case {In_string, G} of
                {true, <<"*"/utf8>>} ->
                    true;

                {true, <<"\\"/utf8>>} ->
                    case Rest of
                        [_ | Tail] ->
                            scan_wildcard_quoted(Tail, true);

                        [] ->
                            false
                    end;

                {true, <<"\""/utf8>>} ->
                    scan_wildcard_quoted(Rest, false);

                {true, _} ->
                    scan_wildcard_quoted(Rest, true);

                {false, <<"\""/utf8>>} ->
                    scan_wildcard_quoted(Rest, true);

                {false, _} ->
                    scan_wildcard_quoted(Rest, false)
            end
    end.

-file("src/datadog_query/lint.gleam", 214).
?DOC(
    " Detects values where wildcards have been collapsed to literals by\n"
    " quoting. Datadog matches `*` as a wildcard in bare values but as a\n"
    " literal asterisk inside `\"...\"`.\n"
    "\n"
    " Example: `metric{service:\"foo*\"}` — the `*` is now literal.\n"
).
-spec wildcard_in_quoted_value(binary()) -> boolean().
wildcard_in_quoted_value(Query) ->
    scan_wildcard_quoted(gleam@string:to_graphemes(Query), false).

-file("src/datadog_query/lint.gleam", 240).
?DOC(
    " Detects `metric{} by {tag}` — a legal but suspicious query (a copy-paste\n"
    " bug that would group a \"match-everything\" set; usually `metric{*}` was\n"
    " intended).\n"
).
-spec empty_scope_with_grouping(binary()) -> boolean().
empty_scope_with_grouping(Query) ->
    case gleam@string:split_once(Query, <<"{}"/utf8>>) of
        {ok, {_, After}} ->
            gleam_stdlib:contains_string(After, <<"by {"/utf8>>);

        {error, _} ->
            false
    end.