(() => {
  const form = document.getElementById('paddleAccountForm');
  if (!form) return;

  const button = form.querySelector('[data-paddle-prepare]');
  const errorBox = document.getElementById('paddleCheckoutError');
  const stage = document.getElementById('paddlePaymentStage');
  const stageStatus = document.getElementById('paddleStageStatus');
  let initialized = false;
  let currentOrderId = null;
  let successUrl = form.dataset.successUrl || '/';

  function message(text) {
    if (!errorBox) return;
    errorBox.textContent = text || '';
    errorBox.hidden = !text;
  }

  function setBusy(busy) {
    if (!button) return;
    button.disabled = busy;
    button.classList.toggle('is-loading', busy);
    const defaultText = button.dataset.defaultText || button.textContent;
    button.dataset.defaultText = defaultText;
    button.textContent = busy
      ? (form.dataset.loadingText || 'Paddle wird vorbereitet …')
      : defaultText;
  }

  function onPaddleEvent(event) {
    const name = String(event?.name || '');
    if (name === 'checkout.completed') {
      if (stageStatus) {
        stageStatus.textContent = form.dataset.completedText || 'Zahlung abgeschlossen – GoVipe verarbeitet den Webhook …';
      }
      const suffix = currentOrderId ? ('?order=' + encodeURIComponent(currentOrderId)) : '';
      window.setTimeout(() => {
        window.location.assign(successUrl + suffix);
      }, 700);
    }
  }

  form.addEventListener('submit', async (event) => {
    event.preventDefault();
    message('');

    if (!window.Paddle) {
      message(form.dataset.loadError || 'Paddle.js konnte nicht geladen werden.');
      return;
    }

    setBusy(true);
    try {
      const response = await fetch('/actions/prepare-paddle-purchase.php', {
        method: 'POST',
        credentials: 'same-origin',
        headers: { 'Accept': 'application/json' },
        body: new FormData(form)
      });
      const data = await response.json().catch(() => ({}));
      if (!response.ok || !data.ok) {
        throw new Error(data.error || 'Die Zahlung konnte nicht vorbereitet werden.');
      }

      currentOrderId = data.order_id || null;
      successUrl = data.success_url || successUrl;

      if (!initialized) {
        if (data.environment === 'sandbox') {
          Paddle.Environment.set('sandbox');
        }
        Paddle.Initialize({
          token: data.client_token,
          eventCallback: onPaddleEvent,
          checkout: {
            settings: {
              displayMode: 'inline',
              frameTarget: 'paddle-checkout-frame',
              frameInitialHeight: 620,
              frameStyle: 'width:100%;min-width:312px;background-color:transparent;border:none;',
              theme: 'dark',
              locale: form.dataset.locale || 'en',
              variant: 'one-page',
              allowLogout: false
            }
          }
        });
        initialized = true;
      }

      form.classList.add('is-prepared');
      if (stage) {
        stage.hidden = false;
        stage.scrollIntoView({ behavior: 'smooth', block: 'center' });
      }
      if (stageStatus) {
        stageStatus.textContent = form.dataset.readyText || 'Paddle ist bereit.';
      }

      Paddle.Checkout.open({
        transactionId: data.transaction_id,
        customer: {
          email: data.email || String(form.elements.email?.value || '')
        }
      });
    } catch (error) {
      message(error instanceof Error ? error.message : String(error));
      setBusy(false);
    }
  });
})();