import 'dart:convert';
import 'package:cryptography/cryptography.dart';
import 'package:flutter/services.dart';
import '../core/build_info.dart';
import '../core/failure.dart';
import 'secure_store.dart';

class Legal {
  final SecureStore store;
  String license = '';
  final Map<String, String> guidance = {};
  String? _identity;
  Legal(this.store);
  Future<bool> load() async {
    try {
      license = await rootBundle.loadString('assets/legal/LICENSE.txt');
      if (!license.contains('Version 1.14') || license.length < 20000) {
        throw const Failure('licenseError');
      }
      for (final lang in ['cs', 'de', 'en']) {
        guidance[lang] = await rootBundle.loadString(
          'assets/legal/guidance_$lang.md',
        );
        if (guidance[lang]!.isEmpty) throw const Failure('licenseError');
      }
      _identity = base64Encode(
        (await Sha256().hash(
          utf8.encode(jsonEncode([appVersion, buildId, license, guidance])),
        )).bytes,
      );
      final record = await store.read('consent');
      if (record == null) return false;
      final data = jsonDecode(record);
      return data['identity'] == _identity &&
          data['accepted'] == true &&
          data['guidanceDisplayed'] == true;
    } catch (_) {
      throw const Failure('licenseError');
    }
  }

  Future<void> accept({required bool guidanceDisplayed}) async {
    if (_identity == null || !guidanceDisplayed) {
      throw const Failure('licenseError');
    }
    await store.write(
      'consent',
      jsonEncode({
        'identity': _identity,
        'accepted': true,
        'guidanceDisplayed': true,
        'version': appVersion,
        'buildId': buildId,
        'licenseVersion': '1.14',
        'acceptedAt': DateTime.now().toUtc().toIso8601String(),
      }),
    );
  }
}