import 'package:flutter/services.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:halkyon_app/halkyon_app.dart';

/// The device's speech recognition through `speech_to_text`, its platform
/// channel answering as Android does: a phone without a recogniser
/// installed (GrapheneOS has none) fails with a PlatformException, which
/// left the microphone doing nothing and stuck listening (4 Nov 2026).
void main() {
  TestWidgetsFlutterBinding.ensureInitialized();
  const channel = MethodChannel('plugin.csdcorp.com/speech_to_text');
  late List<MethodCall> calls;

  void answer(Object? Function(MethodCall call) answers) {
    calls = [];
    TestDefaultBinaryMessengerBinding.instance.defaultBinaryMessenger
        .setMockMethodCallHandler(channel, (call) async {
          calls.add(call);
          return answers(call);
        });
  }

  tearDown(
    () => TestDefaultBinaryMessengerBinding.instance.defaultBinaryMessenger
        .setMockMethodCallHandler(channel, null),
  );

  Future<SpeechStart> listen() => DeviceSpeechInput().listen(
    language: 'en',
    onWords: (_) {},
    onDone: () => fail('nothing was heard'),
  );

  test('without a recogniser installed, it says so, asking for no '
      'Bluetooth permission', () async {
    answer(
      (call) => throw PlatformException(
        code: 'recognizerNotAvailable',
        message: 'Speech recognition not available on this device',
      ),
    );
    expect(await listen(), SpeechStart.noRecognizer);
    final initialize = calls.single;
    expect(initialize.method, 'initialize');
    expect(
      (initialize.arguments as Map<Object?, Object?>)['noBluetooth'],
      isTrue,
    );
  });

  test('any other failure, it says it cannot listen now', () async {
    answer((call) => throw PlatformException(code: 'missingContext'));
    expect(await listen(), SpeechStart.unavailable);
  });

  test('the microphone refused, it says it cannot listen now', () async {
    answer((call) => call.method == 'initialize' ? false : null);
    expect(await listen(), SpeechStart.unavailable);
  });

  group('with a voice input app installed (ADR 0038, D18)', () {
    late _VoiceInputApp app;
    late List<String> heard;
    late SpeechInput speech;

    setUp(() {
      // speech_to_text answering as with the microphone refused, which
      // leaves its one instance uninitialised for the tests after these.
      answer((call) => call.method == 'initialize' ? false : null);
      app = _VoiceInputApp();
      heard = [];
      speech = DeviceSpeechInput(voiceInputApp: app);
    });

    Future<SpeechStart> listen() => speech.listen(
      language: 'de-DE',
      prompt: 'Was hast du geträumt?',
      onWords: heard.add,
      onDone: () => fail('the app has listened, once'),
    );

    test('hands listening to it, in the language and with the prompt '
        'given, and the words it returns on, once', () async {
      app.words = 'Ich war am Meer';
      expect(await listen(), SpeechStart.finished);
      expect(app.asked, [('de-DE', 'Was hast du geträumt?')]);
      expect(heard, ['Ich war am Meer']);
    });

    test('asks speech_to_text nothing, so our app never asks for the '
        'microphone: the voice input app records', () async {
      app.words = 'Ich war am Meer';
      await listen();
      expect(calls, isEmpty);
    });

    test('cancelled in it, hands nothing on and listens no more', () async {
      app.words = '';
      expect(await listen(), SpeechStart.finished);
      expect(heard, isEmpty);
      expect(calls, isEmpty);
    });

    test('where it could not be opened, listens in line instead', () async {
      app.words = null;
      expect(await listen(), SpeechStart.unavailable);
      expect(app.asked, hasLength(1));
      expect(calls.first.method, 'initialize');
    });

    test('none installed, listens in line', () async {
      app.installs = false;
      expect(await listen(), SpeechStart.unavailable);
      expect(app.asked, isEmpty);
      expect(calls.first.method, 'initialize');
    });
  });

  // Last: `speech_to_text` keeps one instance, initialised from here on.
  test('a listen that fails to start says it cannot listen now', () async {
    answer(
      (call) => switch (call.method) {
        'initialize' => true,
        'locales' => <Object?>[],
        'listen' => throw PlatformException(code: 'listenFailed'),
        _ => null,
      },
    );
    expect(await listen(), SpeechStart.unavailable);
  });
}

/// A voice input app the test sets up: installed or not, returning [words]
/// ('' as cancelled, null as failing to open).
class _VoiceInputApp() implements VoiceInputApp {
  bool installs = true;
  String? words = '';

  /// The language and prompt of each listen, in order.
  final asked = <(String?, String?)>[];

  @override
  Future<bool> installed() async => installs;

  @override
  Future<String?> listen({required String? language, String? prompt}) async {
    asked.add((language, prompt));
    return words;
  }
}