%%%-------------------------------------------------------------------
%%% EUnit: прокси транскрибации голоса (logic_ai_transcribe, Front#76).
%%% Без реальных HTTP: апстрим подменяется хуком stt_http_post.
%%%-------------------------------------------------------------------
-module(logic_ai_transcribe_tests).
-include_lib("eunit/include/eunit.hrl").

-define(RL_TABLE, eventhub_stt_rl).
-define(UP, eventhub_stt_upstream).
-define(XAI_URL, <<"https://stt.test/xai">>).

setup() ->
  logic_ai_transcribe:ensure(),
  ets:delete_all_objects(?RL_TABLE),
  ets:delete_all_objects(?UP),
  os:putenv("STT_API_KEY", "test-key"),
  os:putenv("STT_PROVIDER", "xai"),
  os:putenv("STT_URL", binary_to_list(?XAI_URL)),
  application:set_env(eventhub, stt_http_post, fun stub_post/4),
  ok.

cleanup(_) ->
  os:unsetenv("STT_API_KEY"),
  os:unsetenv("STT_PROVIDER"),
  os:unsetenv("STT_URL"),
  os:unsetenv("STT_MODEL"),
  application:unset_env(eventhub, stt_http_post),
  ok.

logic_ai_transcribe_test_() ->
  {foreach, fun setup/0, fun cleanup/1, [
    {"no key means unavailable", fun test_unavailable/0},
    {"xai adapter posts to configured url", fun test_xai_success/0},
    {"openai adapter uses model field", fun test_openai_adapter/0},
    {"upstream errors mapped", fun test_upstream_errors/0},
    {"per-user rate limit", fun test_user_rate_limit/0},
    {"global upstream throttle", fun test_global_throttle/0},
    {"invalid audio rejected", fun test_invalid_audio/0},
    {"multipart layout", fun test_multipart/0}
  ]}.

%% Стаб апстрима: фиксирует запрос и отвечает успешным JSON.
stub_post(Url, Headers, ContentType, Body) ->
  put(stt_call, {Url, Headers, ContentType, Body}),
  {ok, <<"{\"text\":\"привет\",\"language\":\"ru\"}">>}.

test_unavailable() ->
  os:unsetenv("STT_API_KEY"),
  ?assertEqual({error, unavailable},
    logic_ai_transcribe:transcribe(<<"u1">>, <<"audio">>, <<"audio/webm">>)).

test_xai_success() ->
  ?assertEqual({ok, <<"привет">>, <<"ru">>},
    logic_ai_transcribe:transcribe(<<"u1">>, <<"audio-bytes">>, <<"audio/webm">>)),
  {Url, Headers, ContentType, Body} = get(stt_call),
  ?assertEqual(?XAI_URL, Url),
  ?assertEqual([{"authorization", "Bearer test-key"}], Headers),
  ?assertMatch("multipart/form-data; boundary=" ++ _, ContentType),
  ?assertMatch({_, _}, binary:match(Body, <<"name=\"format\"">>)),
  ?assertMatch({_, _}, binary:match(Body, <<"name=\"file\"">>)),
  ?assertMatch({_, _}, binary:match(Body, <<"audio-bytes">>)),
  %% Поле file — последнее (требование xAI).
  {PosFormat, _} = binary:match(Body, <<"name=\"format\"">>),
  {PosFile, _} = binary:match(Body, <<"name=\"file\"">>),
  ?assert(PosFormat < PosFile).

test_openai_adapter() ->
  os:putenv("STT_PROVIDER", "openai"),
  os:putenv("STT_URL", "https://stt.test/openai"),
  os:putenv("STT_MODEL", "whisper-large-v3"),
  ?assertEqual({ok, <<"привет">>, <<"ru">>},
    logic_ai_transcribe:transcribe(<<"u1">>, <<"audio">>, <<"audio/webm">>)),
  {Url, _Headers, _CType, Body} = get(stt_call),
  ?assertEqual(<<"https://stt.test/openai">>, Url),
  ?assertMatch({_, _}, binary:match(Body, <<"name=\"model\"">>)),
  ?assertMatch({_, _}, binary:match(Body, <<"whisper-large-v3">>)).

test_upstream_errors() ->
  %% Ошибка транспорта.
  application:set_env(eventhub, stt_http_post,
    fun(_Url, _H, _C, _B) -> {error, nxdomain} end),
  ?assertEqual({error, upstream_error},
    logic_ai_transcribe:transcribe(<<"u1">>, <<"audio">>, <<"audio/webm">>)),
  %% Некорректный JSON от апстрима.
  ets:delete_all_objects(?UP),
  application:set_env(eventhub, stt_http_post,
    fun(_Url, _H, _C, _B) -> {ok, <<"not-json">>} end),
  ?assertEqual({error, upstream_error},
    logic_ai_transcribe:transcribe(<<"u2">>, <<"audio">>, <<"audio/webm">>)),
  %% JSON без поля text.
  ets:delete_all_objects(?UP),
  application:set_env(eventhub, stt_http_post,
    fun(_Url, _H, _C, _B) -> {ok, <<"{\"language\":\"ru\"}">>} end),
  ?assertEqual({error, upstream_error},
    logic_ai_transcribe:transcribe(<<"u3">>, <<"audio">>, <<"audio/webm">>)).

test_user_rate_limit() ->
  Now = erlang:system_time(millisecond),
  ets:insert(?RL_TABLE, {{rl, <<"u-rl">>}, Now, 10}),
  ?assertEqual({error, rate_limited},
    logic_ai_transcribe:transcribe(<<"u-rl">>, <<"audio">>, <<"audio/webm">>)),
  %% Другой пользователь не затронут.
  ?assertEqual({ok, <<"привет">>, <<"ru">>},
    logic_ai_transcribe:transcribe(<<"u-ok">>, <<"audio">>, <<"audio/webm">>)).

test_global_throttle() ->
  ets:insert(?UP, {last, erlang:monotonic_time(millisecond)}),
  ?assertEqual({error, rate_limited},
    logic_ai_transcribe:transcribe(<<"u1">>, <<"audio">>, <<"audio/webm">>)).

test_invalid_audio() ->
  ?assertEqual({error, invalid_audio},
    logic_ai_transcribe:transcribe(<<"u1">>, <<>>, <<"audio/webm">>)),
  ?assertEqual({error, invalid_audio},
    logic_ai_transcribe:transcribe(<<"u1">>,
      binary:copy(<<"x">>, logic_ai_transcribe:max_bytes() + 1),
      <<"audio/webm">>)).

test_multipart() ->
  Body = logic_ai_transcribe:build_multipart(
    [{<<"a">>, <<"1">>}], <<"DATA">>, <<"voice.dat">>, <<"audio/webm">>),
  ?assertMatch({_, _}, binary:match(Body, <<"name=\"a\"\r\n\r\n1\r\n">>)),
  ?assertMatch({_, _}, binary:match(
    Body, <<"name=\"file\"; filename=\"voice.dat\"">>)),
  ?assertMatch({_, _}, binary:match(Body, <<"Content-Type: audio/webm">>)),
  ?assertMatch({_, _}, binary:match(Body, <<"DATA">>)),
  ?assert(binary:match(Body, <<"--\r\n">>) =/= nomatch),
  %% Завершающий boundary в конце тела: --<B>--\r\n.
  ?assertEqual(<<"--\r\n">>, binary:part(Body, byte_size(Body), -4)).