// /jobs/paymentReminderJob.js

const cron = require('node-cron');
const Payment = require('../components/payments/paymentModel');
const User = require('../components/users/userModel');
const Course = require('../components/courses/courseModel');
const eventEmitter = require('../events/eventEmitter');
const EVENT_NAMES = require('../constants/eventNames');
const logger = require('../utils/logger');
const { getPayableAmount } = require('../utils/paymentAmount');
const { notifyAction } = require('../utils/actionNotify');
const { sendPaymentReminderSms } = require('../utils/senders/smsMessages');
const { resolveNotifyFlags } = require('../utils/notifyResolver');

const formatDueDate = (date) => {
  if (!date) return '';
  const parsed = new Date(date);
  if (Number.isNaN(parsed.getTime())) return '';
  return parsed.toLocaleDateString('fa-IR');
};

const notifyPaymentReminder = async (payment, user) => {
  const notify = await resolveNotifyFlags({}, 'paymentReminder');
  if (!notify.sms && !notify.email && !notify.bot) return;

  let courseName = '-';
  if (payment.course) {
    const course = await Course.findById(payment.course).select('title').lean();
    if (course?.title) courseName = course.title;
  }

  const amountDue = getPayableAmount(payment) - (payment.paidAmount || 0);

  await notifyAction({
    actionKey: 'paymentReminder',
    userId: user._id,
    phoneNumber: user.phoneNumber,
    email: user.email,
    subject: 'یادآوری سررسید پرداخت',
    body: `یادآوری: مبلغ ${amountDue} تومان تا ${formatDueDate(payment.dueDate)} سررسید دارد. کد صورتحساب: ${payment.uniqueCode || ''}`,
    smsHandler: () => sendPaymentReminderSms(user.phoneNumber, {
      fullName: user.name || '',
      amount: amountDue,
      dueDate: formatDueDate(payment.dueDate),
      invoiceCode: payment.uniqueCode || '',
      course: courseName
    }, user._id)
  });
};

const runPaymentReminderJob = async () => {
  try {
    const now = new Date();
    const threeDaysFromNow = new Date();
    threeDaysFromNow.setDate(now.getDate() + 3);

    const upcomingPayments = await Payment.find({
      status: { $in: ['pending', 'partial'] },
      dueDate: { $gte: now, $lte: threeDaysFromNow }
    }).populate({ path: 'user', select: 'name phoneNumber email' });

    for (const payment of upcomingPayments) {
      if (payment.user) {
        eventEmitter.emit(EVENT_NAMES.PAYMENT_REMINDER_DUE, {
          paymentId: payment._id,
          userId: payment.user._id,
          amountDue: getPayableAmount(payment) - (payment.paidAmount || 0),
          dueDate: payment.dueDate
        });
        try {
          await notifyPaymentReminder(payment, payment.user);
        } catch (err) {
          logger.error(`[PaymentReminderJob] Notification failed for payment ${payment._id}: ${err.message}`);
        }
      }
    }

    const overduePayments = await Payment.find({
      status: { $in: ['pending', 'partial'] },
      dueDate: { $lt: now }
    });

    for (const payment of overduePayments) {
      const previousStatus = payment.status;
      payment.status = 'overdue';
      await payment.save();
      if (payment.user) {
        eventEmitter.emit(EVENT_NAMES.PAYMENT_STATUS_CHANGED, {
          paymentId: payment._id,
          userId: payment.user,
          oldStatus: previousStatus,
          newStatus: 'overdue'
        });
      }
    }
  } catch (error) {
    logger.error(`[PaymentReminderJob ERROR]: ${error.message}`);
  }
};

const startPaymentReminderJob = () => {
  cron.schedule('0 0 * * *', async () => {
    await runPaymentReminderJob();
  });
  logger.info('[PaymentReminderJob] Scheduled to run daily at midnight.');
};

module.exports = {
  startPaymentReminderJob,
  runPaymentReminderJob
};