import 'package:flutter_test/flutter_test.dart';
import 'package:ikar/backend/modules/chats.dart';
import 'package:ikar/backend/modules/messages.dart';
import 'package:ikar/frontend/screens/chats/chat/unread_message_count.dart';

CachedChat snapshot({int unread = 10, int read = 100, int last = 110}) =>
    CachedChat(
      id: 2,
      accountId: 1,
      type: 'CHANNEL',
      unreadCount: unread,
      lastEventTime: last,
      lastMsgTime: last,
      cachedAt: 0,
      dontDisturbUntil: ChatsModule.muteOff,
      isOnline: false,
      seenTime: 0,
      participants: {1: read},
    );

CachedMessage message(
  int time, {
  int sender = 2,
  bool control = false,
  bool deleted = false,
}) => CachedMessage(
  id: '$time',
  accountId: 1,
  chatId: 2,
  senderId: sender,
  time: time,
  isControl: control,
  deleted: deleted,
);

void main() {
  test(
    'opening a chat counts existing unread messages before history loads',
    () {
      expect(
        countUnreadMessages(
          chat: snapshot(unread: 200),
          messages: [],
          accountId: 1,
          readTime: 100,
          newestLoaded: false,
        ),
        200,
      );
    },
  );

  test('old read history does not acquire an unread badge', () {
    expect(
      countUnreadMessages(
        chat: snapshot(unread: 0, read: 110),
        messages: [message(90), message(110)],
        accountId: 1,
        readTime: 110,
        newestLoaded: true,
      ),
      0,
    );
  });

  test('reading part of the loaded tail reduces the badge immediately', () {
    expect(
      countUnreadMessages(
        chat: snapshot(),
        messages: [for (var t = 101; t <= 110; t++) message(t)],
        accountId: 1,
        readTime: 106,
        newestLoaded: true,
      ),
      4,
    );
  });

  test('unloaded newer messages remain counted when reading a middle page', () {
    expect(
      countUnreadMessages(
        chat: snapshot(unread: 100, last: 200),
        messages: [for (var t = 101; t <= 110; t++) message(t)],
        accountId: 1,
        readTime: 106,
        newestLoaded: false,
      ),
      94,
    );
  });

  test(
    'reaching the last message clears the badge despite a stale snapshot',
    () {
      expect(
        countUnreadMessages(
          chat: snapshot(),
          messages: [for (var t = 101; t <= 110; t++) message(t)],
          accountId: 1,
          readTime: 110,
          newestLoaded: true,
        ),
        0,
      );
    },
  );

  test('live arrivals count once while chat metadata is being saved', () {
    final incoming = message(111);
    final messages = [message(110), incoming, incoming];
    expect(
      countUnreadMessages(
        chat: snapshot(),
        messages: messages,
        accountId: 1,
        readTime: 100,
        newestLoaded: true,
      ),
      11,
    );
    expect(
      countUnreadMessages(
        chat: snapshot(unread: 11, last: 111),
        messages: messages,
        accountId: 1,
        readTime: 100,
        newestLoaded: true,
      ),
      11,
    );
  });

  test('own, control and deleted arrivals do not add unread posts', () {
    expect(
      countUnreadMessages(
        chat: snapshot(),
        messages: [
          message(111, sender: 1),
          message(112, control: true),
          message(113, deleted: true),
        ],
        accountId: 1,
        readTime: 100,
        newestLoaded: true,
      ),
      10,
    );
  });

  test('a read marker from another device updates the count', () {
    expect(
      countUnreadMessages(
        chat: snapshot(unread: 2, read: 108),
        messages: [for (var t = 101; t <= 110; t++) message(t)],
        accountId: 1,
        readTime: 100,
        newestLoaded: true,
      ),
      2,
    );
  });
}