import 'dart:convert';
import 'dart:io';

import 'package:injectable/injectable.dart';
import 'package:isar/isar.dart';
import 'package:mnemo_cards_common_backend/mnemo_cards_common_backend.dart';
import 'package:mnemo_cards_backend/packs/pack_manager.dart';
import 'package:mnemo_cards_backend/tests/generators/models/creation_test_data.dart';
import 'package:mnemo_cards_backend/tests/test_extension.dart';
import 'package:mnemo_cards_common/mnemo_cards_common.dart';

import '../main.dart';
import '../packs/pack_dto_converter.dart';
import 'generators/question_generators/input_buttons_question_generator.dart';
import 'generators/pack_test_generator.dart';
import 'generators/question_generators/simple_question_generator.dart';

@lazySingleton
class TestManager {
  final PackDtoConverter _packDtoConverter;
  List<CreationTestData> _customCreationTestData = [];

  TestManager(this._packDtoConverter);

  Future<TestStatisticsDto?> _testStatisticsDto(
      UserModel user, int testId) async {
    return (await user.userData.value?.testsStatistics
            .filter()
            .test((q) => q.idEqualTo(testId))
            .findFirst())
        ?.toDto();
  }

  Future<TestDto?> fetchTest(String id, UserModel user) async {
    return (await isar.testModels.get(int.parse(id)))?.toDto(
      statistics: await _testStatisticsDto(user, int.parse(id)),
    );
  }

  Future<List<TestDto>> availableTests(UserModel userModel) async {
    final tests = (await isar.testModels.where().findAll());
    final dtos = await Future.wait(tests.map(
      (test) async => test.toDto(
        questions: [],
        statistics: await _testStatisticsDto(userModel, test.id!),
      ),
    ));
    return dtos.toList();
  }

  Future<List<TestDto>> fetchPackTests(
    UserModel user,
    CardPackModel model,
  ) async {
    final pack = (await isar.cardPackModels.get(model.id!))!;
    final Iterable<TestModel> testModels;
    if (await _updateGeneratedTestsIfRequired(pack)) {
      testModels = (await isar.cardPackModels.get(model.id!))!.tests;
    } else {
      testModels = pack.tests;
    }
    return (await Future.wait(
      testModels.map(
        (e) async => e.toDto(
          statistics: await _testStatisticsDto(user, e.id!),
        ),
      ),
    ))
        .toList();
  }

  Future<bool> _updateGeneratedTestsIfRequired(CardPackModel model) async {
    final generated = model.tests.where((t) => t.version == 'generated');
    if (generated.isEmpty) {
      await updateGeneratedTests(model);
      return true;
    }
    return false;
  }

  Future<void> refreshCustomCreationTestsData() async {
    final dir = Directory('${PackManager.assetsDirectory.path}/tests/');
    List<CreationTestData> data = [];
    if (await dir.exists()) {
      final files = dir.listSync().whereType<File>().toList();
      await Future.wait(
        files.map(
          (file) => file
              .readAsString()
              .then((s) => data.add(
                    s.decode(CreationTestData.fromJson),
                  ))
              .catchError(
            (err) {
              print('Error when loading custom test data: ${file.path}');
              print(err);
            },
          ),
        ),
      );
    }
    _customCreationTestData = data;
  }

  Future<void> updateGeneratedTests(CardPackModel model) async {
    final oldGenerated =
        model.tests.where((t) => t.version == 'generated').toList();
    final cardPackDto = _packDtoConverter.toDto(model);
    final packCreationTestData = CreationTestData.fromCardPackDto(cardPackDto);
    final customCreationTestData = _customCreationTestData.where(
      (data) => data.packId == cardPackDto.id,
    );
    final generator = PackTestGenerator(packCreationTestData);
    final testDtos = [
      await generator.generate(
        name: 'Мини тест',
        multiply: 1.0,
        ratios: {
          TestQuestionType.simple: 1.0,
          TestQuestionType.input_buttons: 0.1,
        },
      ),
      for (final customData in customCreationTestData)
        await PackTestGenerator(
          customData,
          color: customData.color ?? cardPackDto.color,
          generators: {
            TestQuestionType.simple: SimpleQuestionGenerator(
              customData,
              possibleTypes: {
                SimpleQuestionType.original_translation,
                SimpleQuestionType.translation_original,
                SimpleQuestionType.audio_translation,
              },
            ),
          },
        ).generate(
          name: customData.title,
          multiply: 1.0,
          ratios: {
            TestQuestionType.simple: 1.0,
          },
        ),
      await PackTestGenerator(
        packCreationTestData,
        generators: {
          TestQuestionType.simple: SimpleQuestionGenerator.images(
            packCreationTestData,
          ),
          TestQuestionType.input_buttons: InputButtonsQuestionGenerator.images(
            packCreationTestData,
          ),
        },
      ).generate(
        name: 'Тест с картинками',
        multiply: 2.0,
        ratios: {
          TestQuestionType.simple: 1.0,
          TestQuestionType.input_buttons: 0.25,
        },
      ),
      await generator.generate(
        name: 'Тест на написание',
        multiply: 2.0,
        ratios: {
          TestQuestionType.input_buttons: 1.0,
        },
      ),
      await generator.generate(
        name: 'Большой тест',
        multiply: 1.5,
        ratios: {
          TestQuestionType.simple: 1.0,
          TestQuestionType.input_buttons: 1.0,
        },
      ),
    ];

    isar.writeTxn(() async {
      for (final test in testDtos) {
        final testModel = test.toEmptyModel();
        final questionModels = test.questions
            .map(
              (e) => TestQuestionModel(
                questionType: e.questionType,
                body: jsonEncode(e.toJson()),
              ),
            )
            .toList();
        await isar.testQuestionModels.putAll(questionModels);
        testModel.questions.addAll(questionModels);
        testModel.packs.add(model);
        await isar.testModels.put(testModel);
        await testModel.packs.save();
        await testModel.questions.save();
      }
      if (oldGenerated.isNotEmpty) {
        for (final test in oldGenerated) {
          await test.questions.load();
          final questions =
              test.questions.map((e) => e.id).whereNotNull().toList();
          if (questions.isNotEmpty) {
            await isar.testQuestionModels.deleteAll(questions);
          }
          await isar.testModels.delete(test.id!);
        }
      }
    });
  }

  Future<void> addTest(TestDto testDto) async {
    await isar.writeTxn(() async {
      final questions = <TestQuestionModel>[];
      for (final q in testDto.questions.where((q) => q.body != null)) {
        final model = TestQuestionModel(
          id: q.id,
          questionType: q.questionType,
          body: q.body!,
        );
        await isar.testQuestionModels.put(model);
        questions.add(model);
      }
      final testModel = testDto.toEmptyModel();
      await isar.testModels.put(testModel);
      await testModel.questions
        ..addAll(questions)
        ..save();
    });
  }
}