-module(caffeine_lang@codegen@relay).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch, inline]).
-define(FILEPATH, "src/caffeine_lang/codegen/relay.gleam").
-export([generate/1]).
-export_type([signal_entry/0, signal_kind/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 signal_entry() :: {signal_entry,
        binary(),
        signal_kind(),
        binary(),
        gleam@dict:dict(binary(), caffeine_lang@value:value()),
        gleam@dict:dict(binary(), binary()),
        gleam@option:option(binary())}.

-type signal_kind() :: count | distribution.

-file("src/caffeine_lang/codegen/relay.gleam", 125).
?DOC(
    " Serialize the `tags` dict — already `Dict(String, String)` because every\n"
    " codegen-emitted tag is a string. Sorted by key for deterministic output.\n"
).
-spec tags_dict_json(gleam@dict:dict(binary(), binary())) -> gleam@json:json().
tags_dict_json(Tags) ->
    _pipe = Tags,
    _pipe@1 = maps:to_list(_pipe),
    _pipe@2 = gleam@list:sort(
        _pipe@1,
        fun(A, B) ->
            gleam@string:compare(erlang:element(1, A), erlang:element(1, B))
        end
    ),
    _pipe@3 = gleam@list:map(
        _pipe@2,
        fun(Pair) ->
            {erlang:element(1, Pair),
                gleam@json:string(erlang:element(2, Pair))}
        end
    ),
    gleam@json:object(_pipe@3).

-file("src/caffeine_lang/codegen/relay.gleam", 154).
-spec match_value_json(caffeine_lang@value:value()) -> gleam@json:json().
match_value_json(V) ->
    case V of
        {string_value, S} ->
            gleam@json:string(S);

        {int_value, I} ->
            gleam@json:int(I);

        {float_value, F} ->
            gleam@json:float(F);

        {bool_value, B} ->
            gleam@json:bool(B);

        _ ->
            gleam@json:null()
    end.

-file("src/caffeine_lang/codegen/relay.gleam", 146).
?DOC(
    " Serialize a `match` dict. Match values are runtime-untyped at the relay,\n"
    " so we emit each as its nearest JSON shape. Strings stay strings; numeric\n"
    " and boolean values keep their JSON-native form. Other shapes fall back\n"
    " to `null` (shouldn't appear post-validate). Entries are sorted by key for\n"
    " deterministic output across compile targets — `dict.to_list` doesn't\n"
    " guarantee insertion order on JavaScript.\n"
).
-spec match_dict_json(gleam@dict:dict(binary(), caffeine_lang@value:value())) -> gleam@json:json().
match_dict_json(Match) ->
    _pipe = Match,
    _pipe@1 = maps:to_list(_pipe),
    _pipe@2 = gleam@list:sort(
        _pipe@1,
        fun(A, B) ->
            gleam@string:compare(erlang:element(1, A), erlang:element(1, B))
        end
    ),
    _pipe@3 = gleam@list:map(
        _pipe@2,
        fun(Pair) ->
            {erlang:element(1, Pair), match_value_json(erlang:element(2, Pair))}
        end
    ),
    gleam@json:object(_pipe@3).

-file("src/caffeine_lang/codegen/relay.gleam", 133).
-spec signal_kind_to_string(signal_kind()) -> binary().
signal_kind_to_string(Kind) ->
    case Kind of
        count ->
            <<"count"/utf8>>;

        distribution ->
            <<"distribution"/utf8>>
    end.

-file("src/caffeine_lang/codegen/relay.gleam", 109).
-spec signal_entry_json(signal_entry()) -> gleam@json:json().
signal_entry_json(Entry) ->
    gleam@json:object(
        [{<<"metric"/utf8>>, gleam@json:string(erlang:element(2, Entry))},
            {<<"kind"/utf8>>,
                gleam@json:string(
                    signal_kind_to_string(erlang:element(3, Entry))
                )},
            {<<"source"/utf8>>, gleam@json:string(erlang:element(4, Entry))},
            {<<"match"/utf8>>, match_dict_json(erlang:element(5, Entry))},
            {<<"tags"/utf8>>, tags_dict_json(erlang:element(6, Entry))},
            {<<"value_path"/utf8>>, case erlang:element(7, Entry) of
                    none ->
                        gleam@json:null();

                    {some, P} ->
                        gleam@json:string(P)
                end}]
    ).

-file("src/caffeine_lang/codegen/relay.gleam", 102).
?DOC(
    " Wrap a list of entries in the top-level `signals.json` object: a version\n"
    " tag plus the routing array. Schema version 2 adds the per-entry `tags`\n"
    " field; relay builds before 2026-05-23 read v1 and don't know about tags.\n"
).
-spec signals_json(list(signal_entry())) -> gleam@json:json().
signals_json(Entries) ->
    gleam@json:object(
        [{<<"version"/utf8>>, gleam@json:int(2)},
            {<<"signals"/utf8>>,
                gleam@json:array(Entries, fun signal_entry_json/1)}]
    ).

-file("src/caffeine_lang/codegen/relay.gleam", 66).
?DOC(
    " Build the list of signal entries from a single resolved IR by walking\n"
    " `slo.indicators` for `ExternalSignal` variants. Literal-query indicators\n"
    " are skipped — they don't need relay routing. Entries are sorted by\n"
    " indicator name for deterministic output across compile targets.\n"
).
-spec ir_to_signal_entries(
    caffeine_lang@linker@ir:intermediate_representation(caffeine_lang@linker@ir:resolved())
) -> list(signal_entry()).
ir_to_signal_entries(Ir) ->
    _pipe = erlang:element(3, erlang:element(5, Ir)),
    _pipe@1 = maps:to_list(_pipe),
    _pipe@2 = gleam@list:sort(
        _pipe@1,
        fun(A, B) ->
            gleam@string:compare(erlang:element(1, A), erlang:element(1, B))
        end
    ),
    gleam@list:filter_map(
        _pipe@2,
        fun(Pair) ->
            {Name, Src} = Pair,
            case Src of
                {external_signal, Source, Match, Value_extraction} ->
                    {ok,
                        {signal_entry,
                            <<"caffeine."/utf8,
                                (caffeine_lang@codegen@generator_utils:dd_metric_safe(
                                    erlang:element(3, Ir)
                                ))/binary>>,
                            case Value_extraction of
                                none ->
                                    count;

                                {some, _} ->
                                    distribution
                            end,
                            Source,
                            Match,
                            maps:from_list(
                                [{<<"indicator"/utf8>>,
                                        caffeine_lang@codegen@generator_utils:dd_metric_safe(
                                            Name
                                        )}]
                            ),
                            gleam@option:map(
                                Value_extraction,
                                fun(Ve) -> erlang:element(2, Ve) end
                            )}};

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

-file("src/caffeine_lang/codegen/relay.gleam", 52).
?DOC(false).
-spec generate(
    list(caffeine_lang@linker@ir:intermediate_representation(caffeine_lang@linker@ir:resolved()))
) -> gleam@option:option(binary()).
generate(Irs) ->
    Entries = gleam@list:flat_map(Irs, fun ir_to_signal_entries/1),
    case Entries of
        [] ->
            none;

        _ ->
            {some, gleam@json:to_string(signals_json(Entries))}
    end.