const express = require('express');
const nodemailer = require('nodemailer');
const cors = require('cors');

const app = express();
app.use(cors());
app.use(express.json());

// SMTP Configuration from environment variables
const transporter = nodemailer.createTransport({
  host: process.env.SMTP_ADDRESS || 'smtp.gmail.com',
  port: parseInt(process.env.SMTP_PORT || '587'),
  secure: false, // true for 465, false for other ports
  auth: {
    user: process.env.SMTP_USER_NAME,
    pass: process.env.SMTP_PASSWORD,
  },
});

// Verify SMTP connection on startup
transporter.verify((error) => {
  if (error) {
    console.error('SMTP connection error:', error);
  } else {
    console.log('SMTP server is ready to send emails');
  }
});

// Health check endpoint
app.get('/health', (req, res) => {
  res.json({ status: 'ok' });
});

// Send email endpoint
app.post('/send', async (req, res) => {
  const { to, subject, html, text } = req.body;

  if (!to || !subject || (!html && !text)) {
    return res.status(400).json({ error: 'Missing required fields: to, subject, and html or text' });
  }

  try {
    const info = await transporter.sendMail({
      from: `"Traceability Dashboard" <${process.env.SMTP_USER_NAME}>`,
      to,
      subject,
      text,
      html,
    });

    console.log('Email sent:', info.messageId);
    res.json({ success: true, messageId: info.messageId });
  } catch (error) {
    console.error('Failed to send email:', error);
    res.status(500).json({ error: 'Failed to send email', details: error.message });
  }
});

// Predefined email templates
app.post('/send/welcome', async (req, res) => {
  const { to, username } = req.body;

  if (!to || !username) {
    return res.status(400).json({ error: 'Missing required fields: to, username' });
  }

  try {
    const info = await transporter.sendMail({
      from: `"Traceability Dashboard" <${process.env.SMTP_USER_NAME}>`,
      to,
      subject: 'Welcome to Traceability Dashboard - Registration Pending',
      html: `
        <div style="font-family: Arial, sans-serif; max-width: 600px; margin: 0 auto;">
          <h1 style="color: #333;">Welcome, ${username}!</h1>
          <p>Thank you for registering at the Traceability Dashboard.</p>
          <p>Your registration is pending admin approval. You will receive another email once your account has been approved.</p>
          <hr style="border: none; border-top: 1px solid #eee; margin: 20px 0;" />
          <p style="color: #666; font-size: 12px;">This is an automated message from NABD Solutions.</p>
        </div>
      `,
    });

    console.log('Welcome email sent:', info.messageId);
    res.json({ success: true, messageId: info.messageId });
  } catch (error) {
    console.error('Failed to send welcome email:', error);
    res.status(500).json({ error: 'Failed to send email', details: error.message });
  }
});

app.post('/send/admin-notification', async (req, res) => {
  const { username, email } = req.body;

  if (!username || !email) {
    return res.status(400).json({ error: 'Missing required fields: username, email' });
  }

  const adminEmail = process.env.ADMIN_EMAIL || 'support@nabd-co.com';

  try {
    const info = await transporter.sendMail({
      from: `"Traceability Dashboard" <${process.env.SMTP_USER_NAME}>`,
      to: adminEmail,
      subject: 'New User Registration - Pending Approval',
      html: `
        <div style="font-family: Arial, sans-serif; max-width: 600px; margin: 0 auto;">
          <h1 style="color: #333;">New User Registration</h1>
          <p>A new user has registered and is awaiting approval:</p>
          <ul>
            <li><strong>Username:</strong> ${username}</li>
            <li><strong>Email:</strong> ${email}</li>
          </ul>
          <p>Please log in to the admin dashboard to approve or reject this registration.</p>
          <hr style="border: none; border-top: 1px solid #eee; margin: 20px 0;" />
          <p style="color: #666; font-size: 12px;">This is an automated message from NABD Solutions.</p>
        </div>
      `,
    });

    console.log('Admin notification sent:', info.messageId);
    res.json({ success: true, messageId: info.messageId });
  } catch (error) {
    console.error('Failed to send admin notification:', error);
    res.status(500).json({ error: 'Failed to send email', details: error.message });
  }
});

app.post('/send/approval', async (req, res) => {
  const { to, username } = req.body;

  if (!to || !username) {
    return res.status(400).json({ error: 'Missing required fields: to, username' });
  }

  try {
    const info = await transporter.sendMail({
      from: `"Traceability Dashboard" <${process.env.SMTP_USER_NAME}>`,
      to,
      subject: 'Account Approved - Traceability Dashboard',
      html: `
        <div style="font-family: Arial, sans-serif; max-width: 600px; margin: 0 auto;">
          <h1 style="color: #333;">Account Approved!</h1>
          <p>Congratulations, ${username}!</p>
          <p>Your account has been approved. You can now log in to the Traceability Dashboard.</p>
          <hr style="border: none; border-top: 1px solid #eee; margin: 20px 0;" />
          <p style="color: #666; font-size: 12px;">This is an automated message from NABD Solutions.</p>
        </div>
      `,
    });

    console.log('Approval email sent:', info.messageId);
    res.json({ success: true, messageId: info.messageId });
  } catch (error) {
    console.error('Failed to send approval email:', error);
    res.status(500).json({ error: 'Failed to send email', details: error.message });
  }
});

app.post('/send/rejection', async (req, res) => {
  const { to, username, reason } = req.body;

  if (!to || !username) {
    return res.status(400).json({ error: 'Missing required fields: to, username' });
  }

  try {
    const info = await transporter.sendMail({
      from: `"Traceability Dashboard" <${process.env.SMTP_USER_NAME}>`,
      to,
      subject: 'Registration Update - Traceability Dashboard',
      html: `
        <div style="font-family: Arial, sans-serif; max-width: 600px; margin: 0 auto;">
          <h1 style="color: #333;">Registration Update</h1>
          <p>Hello ${username},</p>
          <p>Unfortunately, your registration request was not approved.</p>
          ${reason ? `<p><strong>Reason:</strong> ${reason}</p>` : ''}
          <p>If you believe this was a mistake, please contact the administrator.</p>
          <hr style="border: none; border-top: 1px solid #eee; margin: 20px 0;" />
          <p style="color: #666; font-size: 12px;">This is an automated message from NABD Solutions.</p>
        </div>
      `,
    });

    console.log('Rejection email sent:', info.messageId);
    res.json({ success: true, messageId: info.messageId });
  } catch (error) {
    console.error('Failed to send rejection email:', error);
    res.status(500).json({ error: 'Failed to send email', details: error.message });
  }
});

app.post('/send/member-added', async (req, res) => {
  const { to, username, addedBy } = req.body;

  if (!to || !username) {
    return res.status(400).json({ error: 'Missing required fields: to, username' });
  }

  try {
    const info = await transporter.sendMail({
      from: `"Traceability Dashboard" <${process.env.SMTP_USER_NAME}>`,
      to,
      subject: 'You have been added to Traceability Dashboard',
      html: `
        <div style="font-family: Arial, sans-serif; max-width: 600px; margin: 0 auto;">
          <h1 style="color: #333;">Welcome to Traceability Dashboard!</h1>
          <p>Hello ${username},</p>
          <p>You have been added to the Traceability Dashboard${addedBy ? ` by ${addedBy}` : ''}.</p>
          <p>You can now log in using your credentials.</p>
          <hr style="border: none; border-top: 1px solid #eee; margin: 20px 0;" />
          <p style="color: #666; font-size: 12px;">This is an automated message from NABD Solutions.</p>
        </div>
      `,
    });

    console.log('Member added email sent:', info.messageId);
    res.json({ success: true, messageId: info.messageId });
  } catch (error) {
    console.error('Failed to send member added email:', error);
    res.status(500).json({ error: 'Failed to send email', details: error.message });
  }
});

app.post('/send/member-removed', async (req, res) => {
  const { to, username } = req.body;

  if (!to || !username) {
    return res.status(400).json({ error: 'Missing required fields: to, username' });
  }

  try {
    const info = await transporter.sendMail({
      from: `"Traceability Dashboard" <${process.env.SMTP_USER_NAME}>`,
      to,
      subject: 'Account Update - Traceability Dashboard',
      html: `
        <div style="font-family: Arial, sans-serif; max-width: 600px; margin: 0 auto;">
          <h1 style="color: #333;">Account Update</h1>
          <p>Hello ${username},</p>
          <p>Your access to the Traceability Dashboard has been removed.</p>
          <p>If you believe this was a mistake, please contact the administrator.</p>
          <hr style="border: none; border-top: 1px solid #eee; margin: 20px 0;" />
          <p style="color: #666; font-size: 12px;">This is an automated message from NABD Solutions.</p>
        </div>
      `,
    });

    console.log('Member removed email sent:', info.messageId);
    res.json({ success: true, messageId: info.messageId });
  } catch (error) {
    console.error('Failed to send member removed email:', error);
    res.status(500).json({ error: 'Failed to send email', details: error.message });
  }
});

const PORT = process.env.PORT || 3001;
app.listen(PORT, () => {
  console.log(`Email service running on port ${PORT}`);
});