// /components/notifications/notificationService.js

const Notification = require('./notificationModel');
const User = require('../users/userModel');
const AppError = require('../../utils/AppError');
const { sendEmail } = require('../../utils/senders/emailSender');
const { sendSMS } = require('../../utils/senders/smsSender');
const { sendBaleMessage } = require('../../utils/senders/baleBotSender');
const { parsePaginationAndSort, buildFilterQuery, calculateMeta } = require('../../utils/pagination');

const createNotification = async (data) => {
  const user = await User.findById(data.user);
  if (!user) throw new AppError('USER_NOT_FOUND');

  const notification = await Notification.create(data);

  // Attempt sending immediately
  try {
    if (data.channel === 'email' && user.email) {
      await sendEmail({ to: user.email, subject: data.subject, body: data.body });
    } else if (data.channel === 'baleBot') {
      await sendBaleMessage({ chatId: user.phoneNumber, body: data.body });
    } else {
      await sendSMS({ phoneNumber: user.phoneNumber, body: data.body });
    }
    notification.status = 'sent';
    notification.sentAt = new Date();
    await notification.save();
  } catch (err) {
    notification.status = 'failed';
    notification.lastError = err.message;
    notification.retryCount = 1;
    await notification.save();
  }

  return notification;
};

const getNotificationById = async (id) => {
  const notification = await Notification.findById(id).populate('user', 'name surname username email phoneNumber');
  if (!notification) {
    throw new AppError('NOTIFICATION_NOT_FOUND');
  }
  return notification;
};

const getAllNotifications = async (queryParams) => {
  const { page, limit, skip, sort } = parsePaginationAndSort(queryParams);
  const filter = buildFilterQuery(queryParams, ['subject', 'body']);

  const [notifications, totalCount] = await Promise.all([
    Notification.find(filter).populate('user', 'name surname username').sort(sort).skip(skip).limit(limit),
    Notification.countDocuments(filter)
  ]);

  const meta = calculateMeta(totalCount, page, limit);
  return { data: notifications, meta };
};

const updateNotification = async (id, updateData) => {
  const notification = await Notification.findById(id);
  if (!notification) {
    throw new AppError('NOTIFICATION_NOT_FOUND');
  }
  Object.assign(notification, updateData);
  await notification.save();
  return notification;
};

const deleteNotification = async (id) => {
  const notification = await Notification.findById(id);
  if (!notification) {
    throw new AppError('NOTIFICATION_NOT_FOUND');
  }
  await Notification.findByIdAndDelete(id);
  return null;
};

const searchNotifications = async (queryParams) => {
  return getAllNotifications(queryParams);
};

const retryNotification = async (id) => {
  const notification = await Notification.findById(id).populate('user');
  if (!notification) {
    throw new AppError('NOTIFICATION_NOT_FOUND');
  }

  const user = notification.user;
  if (!user) throw new AppError('USER_NOT_FOUND');

  notification.status = 'retrying';
  notification.retryCount += 1;
  await notification.save();

  try {
    if (notification.channel === 'email' && user.email) {
      await sendEmail({ to: user.email, subject: notification.subject, body: notification.body });
    } else if (notification.channel === 'baleBot') {
      await sendBaleMessage({ chatId: user.phoneNumber, body: notification.body });
    } else {
      await sendSMS({ phoneNumber: user.phoneNumber, body: notification.body });
    }
    notification.status = 'sent';
    notification.sentAt = new Date();
    await notification.save();
    return { success: true, notification };
  } catch (err) {
    notification.status = 'failed';
    notification.lastError = err.message;
    await notification.save();
    throw new Error(`Retry attempt ${notification.retryCount} failed: ${err.message}`);
  }
};

const getMyNotifications = async (userId, queryParams) => {
  const filter = { user: userId, ...buildFilterQuery(queryParams) };
  const { page, limit, skip, sort } = parsePaginationAndSort(queryParams);

  const [notifications, totalCount] = await Promise.all([
    Notification.find(filter).sort(sort).skip(skip).limit(limit),
    Notification.countDocuments(filter)
  ]);

  const meta = calculateMeta(totalCount, page, limit);
  return { data: notifications, meta };
};

module.exports = {
  createNotification,
  getNotificationById,
  getAllNotifications,
  updateNotification,
  deleteNotification,
  searchNotifications,
  retryNotification,
  getMyNotifications
};