import 'dart:io';

import 'package:drift/native.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:http/http.dart' as http;
import 'package:life_helper/data/ai/llm_service.dart';
import 'package:life_helper/data/ai/model_lifecycle.dart';
import 'package:life_helper/data/db/app_database.dart';
import 'package:life_helper/data/db/daos/meta_dao.dart';
import 'package:life_helper/state/chat_warmup_provider.dart';

class _NoopStorage implements StorageAdapter {
  _NoopStorage(this.dir);
  final Directory dir;

  @override
  Future<Directory> supportDir() async => dir;

  @override
  Future<http.StreamedResponse> rangeGet(Uri url, int from) =>
      throw UnimplementedError();
}

/// quickCheck 만 사용하는 controller 테스트에서는 download 경로가 필요 없다.
/// `meta_kv` 를 직접 세팅해 quickCheck 가 ready/missing 등으로 분기되게 만든다.
Future<ModelLifecycle> _setupLifecycle({
  required MetaDao meta,
  required Directory tmp,
  required bool readyOnDisk,
}) async {
  final lc = ModelLifecycle(
    meta: meta,
    config: ModelConfig(
      url: Uri.parse('https://example/model.bin'),
      expectedSha256: 'x',
      filename: 'warmup_test.bin',
    ),
    storage: _NoopStorage(tmp),
  );
  await meta.put(AiMetaKeys.optIn, 'true');
  if (readyOnDisk) {
    final path = '${tmp.path}/warmup_test.bin';
    File(path).writeAsStringSync('payload');
    await meta.put(AiMetaKeys.modelPath, path);
    await meta.put(AiMetaKeys.modelSha, 'any');
  }
  return lc;
}

void main() {
  late AppDatabase db;
  late MetaDao meta;
  late Directory tmp;

  setUp(() async {
    db = AppDatabase(NativeDatabase.memory());
    meta = MetaDao(db);
    tmp = await Directory.systemTemp.createTemp('warmup_test_');
  });

  tearDown(() async {
    await db.close();
    if (tmp.existsSync()) await tmp.delete(recursive: true);
  });

  test('AC1/AC3/AC4: happy path emits Idle → Loading → Ready', () async {
    final lc = await _setupLifecycle(meta: meta, tmp: tmp, readyOnDisk: true);
    final mock = MockLlmService()..loadDelay = const Duration(milliseconds: 30);
    final controller =
        ChatWarmupController(llm: mock, lifecycle: lc);
    final seen = <ChatWarmupState>[];
    controller.addListener(seen.add, fireImmediately: false);

    await controller.start();

    expect(seen.first, isA<ChatWarmupLoading>());
    expect(seen.last, isA<ChatWarmupReady>());
    expect(mock.isLoaded, true);
    expect(mock.loadCount, 1);
  });

  test('AC11 / UX R4: fast path skips Loading when already loaded', () async {
    final lc = await _setupLifecycle(meta: meta, tmp: tmp, readyOnDisk: true);
    final mock = MockLlmService();
    await mock.load(); // pre-loaded
    final controller = ChatWarmupController(llm: mock, lifecycle: lc);
    final seen = <ChatWarmupState>[];
    controller.addListener(seen.add, fireImmediately: false);

    await controller.start();

    expect(seen, hasLength(1));
    expect(seen.single, isA<ChatWarmupReady>());
    // 추가 native init 호출 없음 (사전 mock.load() 1 회만 — fast path 가
    // _doLoad 를 다시 호출하지 않음을 검증).
    expect(mock.loadCount, 1);
  });

  test('AC2: quickCheck != ready → Unavailable, load not called', () async {
    // readyOnDisk: false → meta_kv 의 modelPath 가 없음 → missing.
    final lc = await _setupLifecycle(meta: meta, tmp: tmp, readyOnDisk: false);
    final mock = MockLlmService();
    final controller = ChatWarmupController(llm: mock, lifecycle: lc);

    await controller.start();

    expect(controller.state, isA<ChatWarmupUnavailable>());
    expect(mock.loadCount, 0);
    expect(mock.isLoaded, false);
  });

  test('AC5: FileSystemException → Failed(fileMissing)', () async {
    final lc = await _setupLifecycle(meta: meta, tmp: tmp, readyOnDisk: true);
    final mock = MockLlmService()
      ..loadThrows = const FileSystemException('model file missing', '/x');
    final controller = ChatWarmupController(llm: mock, lifecycle: lc);

    await controller.start();

    expect(controller.state, isA<ChatWarmupFailed>());
    final failed = controller.state as ChatWarmupFailed;
    expect(failed.kind, ChatWarmupFailureKind.fileMissing);
    expect(failed.message, 'AI 모델 파일을 찾을 수 없어요.');
    // AC12: message 에 명령형 문구 금지.
    expect(failed.message, isNot(contains('다시 시도')));
  });

  test('AC5: generic error → Failed(runtime)', () async {
    final lc = await _setupLifecycle(meta: meta, tmp: tmp, readyOnDisk: true);
    final mock = MockLlmService()..loadThrows = StateError('boom');
    final controller = ChatWarmupController(llm: mock, lifecycle: lc);

    await controller.start();

    final failed = controller.state as ChatWarmupFailed;
    expect(failed.kind, ChatWarmupFailureKind.runtime);
    expect(failed.message, 'AI 를 시작하지 못했어요.');
    expect(failed.message, isNot(contains('다시 시도')));
  });

  test('retry: Failed → retry() → Loading → Ready', () async {
    final lc = await _setupLifecycle(meta: meta, tmp: tmp, readyOnDisk: true);
    final mock = MockLlmService()..loadThrows = StateError('first fails');
    final controller = ChatWarmupController(llm: mock, lifecycle: lc);

    await controller.start();
    expect(controller.state, isA<ChatWarmupFailed>());

    // 두 번째 시도는 성공시킴.
    mock.loadThrows = null;
    final seen = <ChatWarmupState>[];
    controller.addListener(seen.add, fireImmediately: false);
    await controller.retry();

    expect(seen.map((s) => s.runtimeType).toList(), [
      ChatWarmupIdle,
      ChatWarmupLoading,
      ChatWarmupReady,
    ]);
    expect(mock.loadCount, 2);
  });

  test('AC6: dispose 도중 state 변경 시도 무시 (race 안전)', () async {
    final lc = await _setupLifecycle(meta: meta, tmp: tmp, readyOnDisk: true);
    final mock = MockLlmService()..loadDelay = const Duration(milliseconds: 50);
    final controller = ChatWarmupController(llm: mock, lifecycle: lc);

    // listener 로 마지막 상태 추적 (StateNotifier.state 는 dispose 후 throw).
    final seen = <ChatWarmupState>[];
    controller.addListener(seen.add, fireImmediately: false);

    final f = controller.start();
    // quickCheck 완료 + Loading 진입까지 진행한 다음 dispose.
    await Future<void>.delayed(const Duration(milliseconds: 10));
    controller.dispose();
    await f; // throw 하지 않아야 함.
    // dispose 후 load() 완료가 _safeSet(Ready) 를 시도해도 막혀야 한다.
    expect(seen.last, isA<ChatWarmupLoading>());
    expect(
      seen.whereType<ChatWarmupReady>(),
      isEmpty,
      reason: 'dispose 이후 Ready 로 전이되면 안 됨',
    );
  });

  test('AC7: concurrent load shares future (loadCount = 1)', () async {
    final lc = await _setupLifecycle(meta: meta, tmp: tmp, readyOnDisk: true);
    final mock = MockLlmService()..loadDelay = const Duration(milliseconds: 30);

    // 두 caller (warmup controller + 가상 userTurn) 가 동시에 load.
    final future1 = mock.load();
    final future2 = mock.load();

    await Future.wait([future1, future2]);

    expect(mock.loadCount, 1);
    expect(mock.isLoaded, true);
    // lc 는 본 케이스에서는 사용 안 함 (gemma 서비스 가드 검증).
    expect(lc, isNotNull);
  });

  test('재진입 가드: Loading 상태에서 start 재호출은 no-op', () async {
    final lc = await _setupLifecycle(meta: meta, tmp: tmp, readyOnDisk: true);
    final mock = MockLlmService()..loadDelay = const Duration(milliseconds: 50);
    final controller = ChatWarmupController(llm: mock, lifecycle: lc);

    final first = controller.start();
    // 첫 호출이 Loading 으로 들어간 직후 두 번째 start 호출.
    await Future<void>.delayed(const Duration(milliseconds: 5));
    final second = controller.start(); // no-op

    await Future.wait([first, second]);
    expect(mock.loadCount, 1);
    expect(controller.state, isA<ChatWarmupReady>());
  });
}