import 'dart:async';
import 'dart:io';

import 'package:flutter/services.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:komet_crypto/komet_crypto.dart';
import 'package:image/image.dart' as img;
import 'package:path_provider_platform_interface/path_provider_platform_interface.dart';
import 'package:ikar/backend/api.dart';
import 'package:ikar/backend/modules/messages.dart';
import 'package:ikar/backend/modules/outgoing_text.dart';
import 'package:ikar/backend/modules/outbox_queue.dart';
import 'package:ikar/core/crypto/e2ee_service.dart';
import 'package:ikar/core/crypto/encrypted_photo.dart';
import 'package:ikar/core/crypto/message_decryption_cache.dart';
import 'package:ikar/core/storage/app_database.dart';
import 'package:ikar/core/utils/media_cache.dart';
import 'package:shared_preferences/shared_preferences.dart';
import 'package:sqflite_common_ffi/sqflite_ffi.dart';

class _Paths extends PathProviderPlatform {
  _Paths(this.path);
  final String path;
  @override
  Future<String?> getApplicationSupportPath() async => path;
  @override
  Future<String?> getTemporaryPath() async => path;
  @override
  Future<String?> getApplicationDocumentsPath() async => path;
}

class _Messages extends MessagesModule {
  _Messages() : super(Api());
  final wire = <CachedMessage>[];
  @override
  Future<String> sendMessage(
    int accountId,
    int chatId,
    String text, {
    void Function()? beforeSend,
    int? clientId,
    bool notify = true,
    int? scheduledTime,
    int? replyToMessageId,
    int? replySourceChatId,
    List<Map<String, dynamic>> elements = const [],
  }) async {
    beforeSend?.call();
    final id = '${wire.length + 100}';
    wire.add(
      CachedMessage(
        id: id,
        accountId: accountId,
        chatId: chatId,
        senderId: accountId,
        text: text,
        time: wire.length + 100,
      ),
    );
    return id;
  }

  @override
  Future<bool> editMessage(
    int chatId,
    String messageId, {
    required String text,
    List<Map<String, dynamic>> elements = const [],
    bool sendAttachments = false,
  }) async => true;
}

void main() {
  TestWidgetsFlutterBinding.ensureInitialized();
  const channel = MethodChannel('plugins.it_nomads.com/flutter_secure_storage');
  final service = E2eeService.instance;
  late Directory dir;
  late _Messages transport;
  final secrets = <String, String>{};
  final previousPaths = PathProviderPlatform.instance;

  CachedMessage incoming(CachedMessage wire, int recipient) => CachedMessage(
    id: wire.id,
    accountId: recipient,
    chatId: wire.chatId,
    senderId: wire.senderId,
    text: wire.text,
    time: wire.time,
  );

  Future<void> handshake() async {
    expect(
      await service.startOffer(accountId: 42, chatId: 7, peerId: 84),
      isTrue,
    );
    final offer = incoming(transport.wire.last, 84);
    await service.inspectHistory(84, 7, [offer]);
    expect(service.phaseOf(84, 7), E2eePhase.pendingConsent);
    expect(await service.acceptOffer(accountId: 84, chatId: 7), isTrue);
    await service.inspect(incoming(transport.wire.last, 42));
    expect(service.phaseOf(42, 7), E2eePhase.established);
  }

  setUp(() async {
    KometCrypto.libraryPath =
        Platform.environment['QLYRA_E2EE_LIBRARY'] ??
        '${Directory.current.path}/build/native-tests/crypto-core/Debug/komet_crypto.dll';
    expect(
      KometCrypto.isAvailable,
      isTrue,
      reason: 'Build the C crypto library first',
    );
    SharedPreferences.setMockInitialValues({});
    secrets.clear();
    TestDefaultBinaryMessengerBinding.instance.defaultBinaryMessenger
        .setMockMethodCallHandler(channel, (call) async {
          final args = call.arguments as Map;
          switch (call.method) {
            case 'read':
              return secrets[args['key']];
            case 'write':
              secrets[args['key'] as String] = args['value'] as String;
              return null;
            case 'delete':
              secrets.remove(args['key']);
              return null;
            case 'readAll':
              return secrets;
          }
          return null;
        });
    dir = await Directory.systemTemp.createTemp('qlyra-e2ee-test-');
    PathProviderPlatform.instance = _Paths(dir.path);
    MediaCache.resetForTesting();
    await AppDatabase.init();
    for (final account in [42, 84]) {
      service.forgetAccount(account);
      await AppDatabase.saveProfile(ProfileData.stub(account));
      await AppDatabase.saveChats([
        {'id': 7, 'account_id': account, 'type': 'DIALOG', 'cached_at': 1},
      ]);
    }
    transport = _Messages();
    service.attach(transport);
  });
  tearDown(() async {
    service.forgetAccount(42);
    service.forgetAccount(84);
    await AppDatabase.close();
    MediaCache.resetForTesting();
    PathProviderPlatform.instance = previousPaths;
    TestDefaultBinaryMessengerBinding.instance.defaultBinaryMessenger
        .setMockMethodCallHandler(channel, null);
    await dir.delete(recursive: true);
  });

  test(
    'copy and edit resolve the same sealed text without exposing ciphertext',
    () async {
      await handshake();
      const plaintext = 'synthetic message for editing';
      final wire = await service.encryptText(42, 7, plaintext);
      final incoming = CachedMessage(
        id: '501',
        accountId: 84,
        chatId: 7,
        senderId: 42,
        text: wire,
        time: 501,
      );
      final decoded = await service.inspect(
        incoming,
        commit: (message) => AppDatabase.saveMessages([message.toDbRow()]),
      );
      final cache = MessageDecryptionCache.instance;
      cache.clear();
      expect(cache.readableText(decoded), isNull);
      final results = await Future.wait([
        cache.resolveText(decoded),
        cache.resolveText(decoded),
      ]);
      expect(results, [plaintext, plaintext]);
      expect(cache.readableText(decoded), plaintext);
      cache.clear();
      final pending = cache.resolveText(decoded);
      cache.clear();
      expect(await pending, isNull);
      expect(cache.readableText(decoded), isNull);
      expect((await AppDatabase.loadMessage(84, 7, '501'))!['text'], wire);
    },
  );

  test(
    'history establishes a session; fingerprints match; restart preserves decryption',
    () async {
      await handshake();
      expect(
        await service.fingerprint(42, 7),
        await service.fingerprint(84, 7),
      );
      final wire = await service.encryptText(42, 7, 'synthetic secret');
      final received = CachedMessage(
        id: '200',
        accountId: 84,
        chatId: 7,
        senderId: 42,
        text: wire,
        time: 200,
      );
      final decoded = await service.inspect(
        received,
        commit: (m) => AppDatabase.saveMessages([m.toDbRow()]),
      );
      expect(decoded.e2ee, CachedMessage.e2eeText);
      service.forgetAccount(84);
      await service.ensureLoaded(84);
      expect(
        await service.openText(84, 7, decoded.sealedText!),
        'synthetic secret',
      );
      final row = (await AppDatabase.loadMessage(84, 7, '200'))!;
      expect(row['text'], wire);
      expect(
        row.values.whereType<String>().join(),
        isNot(contains('synthetic secret')),
      );
      final history = await service.inspectHistory(84, 7, [received]);
      expect(history.single.sealedText, decoded.sealedText);
    },
  );

  test(
    'outbox retry keeps ciphertext, cid and the sealed local copy',
    () async {
      await handshake();
      final wire = (await service.encryptText(42, 7, 'queued secret'))!;
      final sealed = await service.sealText(42, 7, 'queued secret');
      CachedMessage saved = OutgoingText.prepare(
        accountId: 42,
        chatId: 7,
        wireText: wire,
        encrypted: true,
        sealedText: sealed,
        e2ee: CachedMessage.e2eeText,
      );
      var fail = true;
      var clock = DateTime(2026);
      final requests = <(String, int)>[];
      OutboxQueue queue() => OutboxQueue(
        activeAccount: () async => 42,
        isOnline: () => true,
        sessionEpoch: () => 1,
        now: () => clock,
        load: (_) async => saved.status == 'pending' ? [saved] : [],
        save: (m) async {
          saved = CachedMessage.fromDbRow(m.toDbRow());
        },
        updatePending: (m) async {
          saved = CachedMessage.fromDbRow(m.toDbRow());
          return true;
        },
        replace: (_, m) async {
          saved = CachedMessage.fromDbRow(m.toDbRow());
        },
        send: (m, cid) async {
          requests.add((m.text!, cid));
          if (fail) throw TimeoutException('lost ack');
          return '250';
        },
        onChanged: (_, _) {},
        onError: (_, _) {},
      );
      final first = queue();
      await first.flush();
      first.dispose();
      service.lock();
      clock = clock.add(const Duration(minutes: 1));
      fail = false;
      final second = queue();
      await second.flush();
      second.dispose();
      expect(requests[0], requests[1]);
      expect(saved.status, 'sent');
      expect(saved.e2ee, CachedMessage.e2eeText);
      expect(await service.openText(42, 7, saved.sealedText!), 'queued secret');
      final peer = await service.inspect(incoming(saved, 84));
      expect(await service.openText(84, 7, peer.sealedText!), 'queued secret');
    },
  );

  test(
    'own scheduled message can be recovered from history after restart',
    () async {
      await handshake();
      final wire = await service.encryptText(42, 7, 'scheduled secret');
      service.forgetAccount(42);
      final restored = (await service.inspectHistory(42, 7, [
        CachedMessage(
          id: '350',
          accountId: 42,
          chatId: 7,
          senderId: 42,
          text: wire,
          time: 350,
        ),
      ])).single;
      expect(
        await service.openText(42, 7, restored.sealedText!),
        'scheduled secret',
      );
    },
  );

  test(
    'schema 23 migration preserves existing messages and adds crypto storage',
    () async {
      await AppDatabase.saveMessages([
        CachedMessage(
          id: 'legacy',
          accountId: 42,
          chatId: 7,
          senderId: 42,
          text: 'legacy synthetic',
          time: 1,
        ).toDbRow(),
      ]);
      await AppDatabase.close();
      final db = await databaseFactoryFfi.openDatabase('${dir.path}/qlyra.db');
      await db.execute('DROP TABLE e2ee_outgoing');
      await db.execute('DROP TABLE e2ee_sessions');
      await db.execute('ALTER TABLE messages DROP COLUMN text_sealed');
      await db.execute('ALTER TABLE messages DROP COLUMN e2ee');
      await db.setVersion(23);
      await db.close();
      expect(
        (await AppDatabase.loadMessage(42, 7, 'legacy'))!['text'],
        'legacy synthetic',
      );
      await handshake();
      expect(await service.encryptText(42, 7, 'after migration'), isNotNull);
    },
  );

  test(
    'server plaintext cannot replace an authenticated cached message',
    () async {
      await handshake();
      final wire = await service.encryptText(42, 7, 'authentic');
      final source = CachedMessage(
        id: '360',
        accountId: 84,
        chatId: 7,
        senderId: 42,
        text: wire,
        time: 360,
      );
      await service.inspect(
        source,
        commit: (m) => AppDatabase.saveMessages([m.toDbRow()]),
      );
      final result = (await service.inspectHistory(84, 7, [
        CachedMessage(
          id: source.id,
          accountId: source.accountId,
          chatId: source.chatId,
          senderId: source.senderId,
          text: 'forged',
          time: source.time,
        ),
      ])).single;
      expect(result.text, wire);
      expect(await service.openText(84, 7, result.sealedText!), 'authentic');
    },
  );

  test(
    'failed export file write leaves the source session available',
    () async {
      await handshake();
      final result = await service.exportTransfer(
        42,
        'test password',
        persist: (_) async {
          throw const FileSystemException('synthetic write failure');
        },
      );
      expect(result, isNull);
      expect(service.isActive(42, 7), isTrue);
      expect(await service.encryptText(42, 7, 'still available'), isNotNull);
    },
  );

  test('photo uses a separate file key and an encrypted ticket', () async {
    await handshake();
    final png = Uint8List.fromList([137, 80, 78, 71]);
    final key = KometCrypto.randomBytes(KometCryptoSizes.fileKey);
    final nonce = KometCrypto.randomBytes(KometCryptoSizes.fileNonce);
    final seal = KometCrypto.fileSealer(key, nonce);
    final encrypted = File('${dir.path}/synthetic.kce');
    await encrypted.writeAsBytes(seal.chunk(png, last: true));
    seal.dispose();
    final ticket = Uint8List(key.length + nonce.length + 8)
      ..setAll(0, key)
      ..setAll(key.length, nonce);
    ticket[ticket.length - 1] = png.length;
    final wire = await service.encryptBytes(42, 7, ContentType.file, ticket);
    final received = await service.inspect(
      CachedMessage(
        id: '300',
        accountId: 84,
        chatId: 7,
        senderId: 42,
        text: wire,
        time: 300,
      ),
    );
    expect(received.e2ee, CachedMessage.e2eeFile);
    final opened = await openE2eePhoto(
      encrypted: encrypted,
      ticket: (await service.openBytes(84, 7, received.sealedText!))!,
    );
    expect(opened.isOk, isTrue);
    expect(await opened.file!.readAsBytes(), png);
  });

  test(
    'transfer rejects wrong password and restores a session after restart',
    () async {
      await handshake();
      final before = await service.encryptText(42, 7, 'before transfer');
      await service.inspect(
        CachedMessage(
          id: '390',
          accountId: 84,
          chatId: 7,
          senderId: 42,
          text: before,
          time: 390,
        ),
      );
      final originalPublic = await service.identityPublic(42);
      final transfer = await service.exportTransfer(
        42,
        'synthetic transfer password',
      );
      expect(transfer, isNotNull);
      expect(service.isActive(42, 7), isFalse);
      expect(await service.importTransfer(42, transfer!, 'wrong'), isNull);
      final peerIdentity = await service.identityPublic(84);
      expect(
        await service.importTransfer(
          84,
          transfer,
          'synthetic transfer password',
        ),
        isNull,
      );
      expect(await service.identityPublic(84), peerIdentity);
      expect(
        await service.importTransfer(
          42,
          transfer,
          'synthetic transfer password',
        ),
        1,
      );
      service.forgetAccount(42);
      await service.ensureLoaded(42);
      expect(await service.identityPublic(42), originalPublic);
      expect(service.isActive(42, 7), isTrue);
      final movedWire = await service.encryptText(
        42,
        7,
        'first after transfer',
      );
      final movedReceived = await service.inspect(
        CachedMessage(
          id: '400',
          accountId: 84,
          chatId: 7,
          senderId: 42,
          text: movedWire,
          time: 400,
        ),
      );
      expect(
        await service.openText(84, 7, movedReceived.sealedText!),
        'first after transfer',
      );
      final peerWire = await service.encryptText(84, 7, 'peer after transfer');
      final received = await service.inspect(
        CachedMessage(
          id: '401',
          accountId: 42,
          chatId: 7,
          senderId: 84,
          text: peerWire,
          time: 401,
        ),
      );
      expect(
        await service.openText(42, 7, received.sealedText!),
        'peer after transfer',
      );
      final reply = await service.encryptText(42, 7, 'reply after transfer');
      expect(reply, isNotNull);
    },
  );

  test(
    'a transferred unused initiator session cannot emit an unreadable ratchet step',
    () async {
      await handshake();
      final transfer = (await service.exportTransfer(42, 'transfer test'))!;
      expect(await service.importTransfer(42, transfer, 'transfer test'), 1);
      await expectLater(
        service.encryptText(42, 7, 'unsafe first send'),
        throwsA(isA<E2eeAwaitingPeer>()),
      );
      await service.resetSession(accountId: 42, chatId: 7);
      expect(
        await service.startOffer(accountId: 42, chatId: 7, peerId: 84),
        isTrue,
      );
      await service.inspect(incoming(transport.wire.last, 84));
      expect(await service.acceptOffer(accountId: 84, chatId: 7), isTrue);
      await service.inspect(incoming(transport.wire.last, 42));
      expect(await service.encryptText(42, 7, 'new session'), isNotNull);
    },
  );

  test(
    'photo preparation uses fresh keys and rejects corrupt content before caching',
    () async {
      final source = File('${dir.path}/photo.png');
      await source.writeAsBytes(img.encodePng(img.Image(width: 4, height: 4)));
      final a = (await prepareE2eePhoto(source: source, stamp: 'one'))!;
      final b = (await prepareE2eePhoto(source: source, stamp: 'two'))!;
      expect(a.ticket, isNot(b.ticket));
      final ciphertext = await a.file.readAsBytes();
      final corrupt = Uint8List.fromList(ciphertext)..[0] ^= 1;
      await a.file.writeAsBytes(corrupt);
      expect(
        (await openE2eePhoto(encrypted: a.file, ticket: a.ticket)).isOk,
        isFalse,
      );
      expect(
        await (await MediaCache.fileFor(
          e2eeDecryptedCacheName(a.ticket),
        )).exists(),
        isFalse,
      );
      await a.file.writeAsBytes(ciphertext);
      final opened = await openE2eePhoto(encrypted: a.file, ticket: a.ticket);
      expect(opened.isOk, isTrue);
      expect(img.decodePng(await opened.file!.readAsBytes())!.width, 4);
    },
  );

  test(
    'changed identity clears verification and repeated history does not reset a session',
    () async {
      await handshake();
      await service.setVerified(accountId: 42, chatId: 7, verified: true);
      final oldOffer = incoming(transport.wire.first, 84);
      await AppDatabase.saveMessages([oldOffer.toDbRow()]);
      await service.inspectHistory(84, 7, [oldOffer]);
      expect(service.phaseOf(84, 7), E2eePhase.established);
      await service.rotateIdentity(84);
      expect(
        await service.startOffer(accountId: 84, chatId: 7, peerId: 42),
        isTrue,
      );
      await service.inspect(incoming(transport.wire.last, 42));
      expect(service.phaseOf(42, 7), E2eePhase.keyChanged);
      expect(service.info(42, 7)!.verified, isFalse);
      expect(service.offerChangesPeer(42, 7), isTrue);
    },
  );
}