import type { APIRoute } from 'astro';
import {
  absoluteUrl,
  createToken,
  getEmailBinding,
  getNewsletterDb,
  getRuntimeEnv,
  isValidEmail,
  normalizeEmail,
  readEnv,
  required,
  sanitizeRedirect,
  sendCloudflareEmail,
  siteOrigin,
  verifyTurnstile,
  type NewsletterSubscriber,
} from '../../../lib/newsletter';

export const prerender = false;

function confirmEmailCopy(
  locale: string,
  confirmUrl: string,
  unsubscribeUrl: string,
): { subject: string; text: string } {
  if (locale === 'en') {
    return {
      subject: 'Confirm your NexStudio newsletter subscription',
      text: [
        'Thanks for subscribing to the NexStudio newsletter.',
        '',
        'Confirm your email by opening this link:',
        confirmUrl,
        '',
        'If you did not request this, you can ignore this message.',
        '',
        'Unsubscribe:',
        unsubscribeUrl,
      ].join('\n'),
    };
  }
  if (locale === 'th') {
    return {
      subject: 'ยืนยันการสมัครรับจดหมายข่าว NexStudio',
      text: [
        'ขอบคุณที่สมัครรับจดหมายข่าว NexStudio',
        '',
        'ยืนยันอีเมลของคุณโดยเปิดลิงก์นี้:',
        confirmUrl,
        '',
        'หากคุณไม่ได้ขอสมัคร สามารถเพิกเฉยต่อข้อความนี้ได้',
        '',
        'ยกเลิกการสมัคร:',
        unsubscribeUrl,
      ].join('\n'),
    };
  }
  return {
    subject: 'Conferma iscrizione newsletter NexStudio',
    text: [
      'Grazie per esserti iscritto alla newsletter di NexStudio.',
      '',
      'Conferma l’indirizzo email aprendo questo link:',
      confirmUrl,
      '',
      'Se non hai richiesto l’iscrizione, puoi ignorare questo messaggio.',
      '',
      'Per disiscriverti:',
      unsubscribeUrl,
    ].join('\n'),
  };
}

export const POST: APIRoute = async ({ request, locals, url }) => {
  const runtimeEnv = getRuntimeEnv(locals);
  const mode = (readEnv('NEWSLETTER_MODE', runtimeEnv) || readEnv('CONTACT_FORM_MODE', runtimeEnv) || 'dev').toLowerCase();
  const db = getNewsletterDb(runtimeEnv);
  const form = await request.formData();

  const redirectOk =
    sanitizeRedirect(required(form.get('_next')), url) ||
    '/newsletter/grazie';
  const redirectErr = sanitizeRedirect(required(form.get('_error')), url) || redirectOk;

  // Honeypot
  if (required(form.get('_gotcha'))) {
    return Response.redirect(new URL(redirectOk, url).toString(), 303);
  }

  const emailRaw = required(form.get('email'));
  const locale = required(form.get('locale')) || 'it';
  const source = required(form.get('source')) || 'footer';

  if (!emailRaw || !isValidEmail(emailRaw)) {
    return new Response('Invalid email.', { status: 400 });
  }
  const email = normalizeEmail(emailRaw);

  // Turnstile solo se configurato esplicitamente per la newsletter.
  // Non riusare CONTACT_TURNSTILE_SECRET_KEY: il form footer non ha il widget.
  const turnstileSecret = readEnv('NEWSLETTER_TURNSTILE_SECRET_KEY', runtimeEnv);
  if (turnstileSecret) {
    const turnstileToken = required(form.get('cf-turnstile-response'));
    const isHuman = await verifyTurnstile(
      turnstileToken,
      turnstileSecret,
      request.headers.get('CF-Connecting-IP'),
    );
    if (!isHuman) {
      return new Response('Turnstile verification failed.', { status: 400 });
    }
  }

  const confirmToken = createToken();
  const unsubscribeToken = createToken();
  const origin = siteOrigin(url, runtimeEnv);
  const confirmUrl = absoluteUrl(origin, `/api/newsletter/confirm?token=${confirmToken}`);
  const unsubscribeUrl = absoluteUrl(
    origin,
    `/api/newsletter/unsubscribe?token=${unsubscribeToken}`,
  );

  if (mode !== 'live') {
    console.info('[newsletter:dev] Subscription request', {
      email,
      locale,
      source,
      confirmUrl,
    });
    return Response.redirect(new URL(redirectOk, url).toString(), 303);
  }

  if (!db) {
    return new Response('Newsletter database binding NEWSLETTER_DB is not configured.', {
      status: 500,
    });
  }

  const emailBinding = getEmailBinding(runtimeEnv);
  const fromEmail =
    readEnv('NEWSLETTER_FROM_EMAIL', runtimeEnv) ||
    readEnv('CONTACT_FORM_FROM_EMAIL', runtimeEnv);
  const notifyTo =
    readEnv('NEWSLETTER_NOTIFY_TO_EMAIL', runtimeEnv) ||
    readEnv('CONTACT_FORM_TO_EMAIL', runtimeEnv);

  if (!emailBinding || !fromEmail) {
    return new Response(
      'Live mode requires EMAIL binding (Cloudflare Email Service) and NEWSLETTER_FROM_EMAIL (or CONTACT_FORM_FROM_EMAIL).',
      { status: 500 },
    );
  }

  const existing = await db
    .prepare('SELECT * FROM newsletter_subscribers WHERE email = ? LIMIT 1')
    .bind(email)
    .first<NewsletterSubscriber>();

  if (existing?.status === 'active') {
    // Already subscribed: redirect without revealing status too loudly.
    return Response.redirect(new URL(redirectOk, url).toString(), 303);
  }

  if (existing?.status === 'unsubscribed' || existing?.status === 'pending') {
    await db
      .prepare(
        `UPDATE newsletter_subscribers
         SET status = 'pending',
             locale = ?,
             source = ?,
             confirm_token = ?,
             unsubscribe_token = ?,
             confirmed_at = NULL,
             unsubscribed_at = NULL
         WHERE id = ?`,
      )
      .bind(locale, source, confirmToken, unsubscribeToken, existing.id)
      .run();
  } else {
    await db
      .prepare(
        `INSERT INTO newsletter_subscribers
          (email, status, locale, confirm_token, unsubscribe_token, source)
         VALUES (?, 'pending', ?, ?, ?, ?)`,
      )
      .bind(email, locale, confirmToken, unsubscribeToken, source)
      .run();
  }

  const copy = confirmEmailCopy(locale, confirmUrl, unsubscribeUrl);
  try {
    await sendCloudflareEmail(emailBinding, {
      fromEmail,
      toEmail: email,
      subject: copy.subject,
      text: copy.text,
    });
  } catch (error) {
    console.error('[newsletter] confirm email failed', error);
    return Response.redirect(new URL(redirectErr, url).toString(), 303);
  }

  if (notifyTo) {
    try {
      await sendCloudflareEmail(emailBinding, {
        fromEmail,
        toEmail: notifyTo,
        subject: required(form.get('_subject')) || 'Nuova richiesta newsletter — NexStudio',
        text: [
          `Nuova richiesta di iscrizione (pending conferma).`,
          `Email: ${email}`,
          `Locale: ${locale}`,
          `Source: ${source}`,
        ].join('\n'),
      });
    } catch (error) {
      console.warn('[newsletter] admin notify failed', error);
    }
  }

  return Response.redirect(new URL(redirectOk, url).toString(), 303);
};