const nodemailer = require('nodemailer');
const { getPool, query, getRow, getConfig } = require('./db');

async function getSmtpConfig() {
  try {
    const rows = await query("SELECT k, v FROM settings WHERE k LIKE 'smtp_%'");
    const cfg = {};
    for (const r of rows) cfg[r.k] = r.v;
    return {
      host: cfg.smtp_host || '',
      port: parseInt(cfg.smtp_port) || 587,
      secure: cfg.smtp_secure === '1',
      user: cfg.smtp_user || '',
      pass: cfg.smtp_pass || '',
      from: cfg.smtp_from || 'noreply@example.com',
    };
  } catch { return { host: '', port: 587, secure: false, user: '', pass: '', from: '' }; }
}

async function getSiteName() {
  const row = await getRow("SELECT v FROM settings WHERE k = 'site_name'");
  return row ? row.v : 'MC举报系统';
}

async function getSiteUrl() {
  const row = await getRow("SELECT v FROM settings WHERE k = 'site_url'");
  return row ? row.v : 'http://localhost:3100';
}

async function getTemplate(code) {
  return getRow('SELECT * FROM email_templates WHERE code = ?', [code]);
}

function renderTemplate(template, vars) {
  let { subject, body } = template;
  for (const [k, v] of Object.entries(vars)) {
    const re = new RegExp(`\\{\\{${k}\\}\\}`, 'g');
    subject = subject.replace(re, v || '');
    body = body.replace(re, v || '');
  }
  return { subject, body };
}

async function sendEmail(to, templateCode, vars) {
  try {
    const cfg = await getSmtpConfig();
    if (!cfg.host || !cfg.user) { console.log('[Mailer] SMTP未配置'); return false; }
    const template = await getTemplate(templateCode);
    if (!template) { console.log('[Mailer] 模板不存在:', templateCode); return false; }
    const allVars = { ...vars, site_name: await getSiteName(), site_url: await getSiteUrl() };
    const { subject, body } = renderTemplate(template, allVars);

    const transporter = nodemailer.createTransport({ host: cfg.host, port: cfg.port, secure: cfg.secure, auth: { user: cfg.user, pass: cfg.pass } });
    await transporter.sendMail({ from: `"${await getSiteName()}" <${cfg.from}>`, to, subject, html: body });
    return true;
  } catch (err) { console.error('[Mailer]', err.message); return false; }
}

module.exports = { sendEmail, renderTemplate, getTemplate, getSmtpConfig, getSiteName, getSiteUrl };