/**
 * Failure notification via email.
 *
 * Reads SMTP config from config/notify.json (gitignored, written by deploy-to-ad2.py).
 * Silently swallows send errors so a notification failure never masks the real error.
 */

const fs   = require('fs');
const path = require('path');

const CONFIG_PATH = path.join(__dirname, '..', 'config', 'notify.json');

function loadConfig() {
    try {
        return JSON.parse(fs.readFileSync(CONFIG_PATH, 'utf8'));
    } catch (err) {
        console.error(`[NOTIFY] Could not read ${CONFIG_PATH}: ${err.message}`);
        return null;
    }
}

/**
 * Send a failure notification email.
 * @param {string} subject
 * @param {string} body  - plain text
 */
async function sendFailureEmail(subject, body) {
    const cfg = loadConfig();
    if (!cfg) return;

    let nodemailer;
    try {
        nodemailer = require('nodemailer');
    } catch (err) {
        console.error('[NOTIFY] nodemailer not installed — skipping email');
        return;
    }

    const transporter = nodemailer.createTransport({
        host: cfg.smtp.host,
        port: cfg.smtp.port,
        secure: false,
        requireTLS: true,
        auth: {
            user: cfg.smtp.user,
            pass: cfg.smtp.pass,
        },
    });

    try {
        await transporter.sendMail({
            from: cfg.from,
            to:   cfg.to,
            subject,
            text: body,
        });
        console.log(`[NOTIFY] Failure email sent: ${subject}`);
    } catch (err) {
        console.error(`[NOTIFY] Failed to send email: ${err.message}`);
    }
}

module.exports = { sendFailureEmail };