(function () {
  const boot = window.APP_BOOT || { steps: [], csrf: '' };
  const state = {
    email: '',
    currentStep: 1,
    totalSteps: boot.steps.length,
    autosaveId: null,
  };

  const startForm = document.getElementById('startForm');
  const wizardSection = document.getElementById('wizardSection');
  const blockedSection = document.getElementById('blockedSection');
  const statusSection = document.getElementById('statusSection');
  const statusMessage = document.getElementById('statusMessage');
  const applicationForm = document.getElementById('applicationForm');
  const applicationEmail = document.getElementById('applicationEmail');
  const progress = document.getElementById('progress');
  const prevBtn = document.getElementById('prevBtn');
  const nextBtn = document.getElementById('nextBtn');
  const submitBtn = document.getElementById('submitBtn');
  const uploadNowBtn = document.getElementById('uploadNowBtn');

  const stepElements = Array.from(document.querySelectorAll('.step'));

  function showMessage(text) {
    statusSection.classList.remove('hidden');
    statusMessage.textContent = text;
  }

  function clearErrors() {
    document.querySelectorAll('[data-error-for]').forEach((el) => {
      el.textContent = '';
    });
  }

  function showErrors(errors) {
    clearErrors();
    Object.keys(errors || {}).forEach((key) => {
      const el = document.querySelector('[data-error-for="' + key + '"]');
      if (el) {
        el.textContent = errors[key];
      }
    });
  }

  function updateProgress() {
    progress.textContent = 'Schritt ' + state.currentStep + ' von ' + state.totalSteps;
    stepElements.forEach((el) => {
      const step = Number(el.getAttribute('data-step'));
      el.classList.toggle('hidden', step !== state.currentStep);
    });

    prevBtn.disabled = state.currentStep === 1;
    nextBtn.classList.toggle('hidden', state.currentStep === state.totalSteps);
    submitBtn.classList.toggle('hidden', state.currentStep !== state.totalSteps);
  }

  function fillFormData(data) {
    Object.keys(data || {}).forEach((key) => {
      const field = applicationForm.querySelector('[name="form_data[' + key + ']"]');
      if (!field) return;

      if (field.type === 'checkbox') {
        field.checked = ['1', 'on', 'true', true].includes(data[key]);
      } else {
        field.value = data[key] || '';
      }
    });
  }

  function renderUploadInfo(uploads) {
    document.querySelectorAll('[data-upload-list]').forEach((el) => {
      el.innerHTML = '';
    });

    Object.keys(uploads || {}).forEach((field) => {
      const target = document.querySelector('[data-upload-list="' + field + '"]');
      if (!target || !Array.isArray(uploads[field])) return;

      uploads[field].forEach((item) => {
        const div = document.createElement('div');
        div.className = 'upload-item';
        div.textContent = item.original_filename + ' (' + item.uploaded_at + ')';
        target.appendChild(div);
      });
    });
  }

  async function postForm(url, formData) {
    const response = await fetch(url, {
      method: 'POST',
      body: formData,
      credentials: 'same-origin',
      headers: { 'X-Requested-With': 'XMLHttpRequest' },
    });

    const payload = await response.json();
    if (!response.ok || payload.ok === false) {
      const err = new Error(payload.message || 'Anfrage fehlgeschlagen');
      err.payload = payload;
      throw err;
    }

    return payload;
  }

  function collectPayload(includeFiles) {
    const fd = new FormData();
    fd.append('csrf', boot.csrf);
    fd.append('email', state.email);
    fd.append('step', String(state.currentStep));
    fd.append('website', '');

    Array.from(applicationForm.elements).forEach((el) => {
      if (!el.name) return;
      if (!el.name.startsWith('form_data[')) return;

      if (el.type === 'checkbox') {
        fd.append(el.name, el.checked ? '1' : '0');
      } else {
        fd.append(el.name, el.value || '');
      }
    });

    if (includeFiles) {
      Array.from(applicationForm.querySelectorAll('input[type="file"]')).forEach((input) => {
        if (input.files && input.files[0]) {
          fd.append(input.name, input.files[0]);
        }
      });
    }

    return fd;
  }

  async function loadDraft(email) {
    const fd = new FormData();
    fd.append('csrf', boot.csrf);
    fd.append('email', email);
    fd.append('website', '');

    return postForm('/api/load-draft.php', fd);
  }

  async function saveDraft(includeFiles, showSavedText) {
    const payload = collectPayload(includeFiles);
    const response = await postForm('/api/save-draft.php', payload);

    if (response.upload_errors && Object.keys(response.upload_errors).length > 0) {
      showErrors(response.upload_errors);
      showMessage('Einige Dateien konnten nicht gespeichert werden.');
    } else if (showSavedText) {
      showMessage('Entwurf gespeichert: ' + (response.updated_at || '')); 
    }

    if (response.uploads) {
      renderUploadInfo(response.uploads);
    }

    if (includeFiles) {
      Array.from(applicationForm.querySelectorAll('input[type="file"]')).forEach((input) => {
        input.value = '';
      });
    }

    return response;
  }

  async function submitApplication() {
    const payload = collectPayload(true);
    const response = await postForm('/api/submit.php', payload);
    clearErrors();
    showMessage('Antrag erfolgreich abgeschlossen. Vielen Dank.');
    submitBtn.disabled = true;
    nextBtn.disabled = true;
    prevBtn.disabled = true;
    return response;
  }

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

    const emailInput = document.getElementById('startEmail');
    const email = (emailInput.value || '').trim().toLowerCase();
    if (!email) {
      showMessage('Bitte E-Mail eingeben.');
      return;
    }

    try {
      const result = await loadDraft(email);
      state.email = email;
      applicationEmail.value = email;

      if (result.already_submitted) {
        wizardSection.classList.add('hidden');
        blockedSection.classList.remove('hidden');
        showMessage(result.message || 'Antrag bereits abgeschlossen.');
        return;
      }

      blockedSection.classList.add('hidden');
      wizardSection.classList.remove('hidden');

      fillFormData(result.data || {});
      renderUploadInfo(result.uploads || {});

      state.currentStep = Math.min(Math.max(Number(result.step || 1), 1), state.totalSteps);
      updateProgress();

      showMessage('Formular geladen. Entwurf wird automatisch gespeichert.');

      if (state.autosaveId) {
        clearInterval(state.autosaveId);
      }
      state.autosaveId = setInterval(async () => {
        if (!state.email || wizardSection.classList.contains('hidden')) {
          return;
        }
        try {
          await saveDraft(false, false);
        } catch (_err) {
          // Autsave errors are visible on next manual action.
        }
      }, 15000);
    } catch (err) {
      const msg = (err.payload && err.payload.message) || err.message || 'Laden fehlgeschlagen.';
      showMessage(msg);
    }
  });

  prevBtn.addEventListener('click', async () => {
    if (state.currentStep <= 1) return;

    try {
      await saveDraft(false, true);
      state.currentStep -= 1;
      updateProgress();
    } catch (err) {
      const msg = (err.payload && err.payload.message) || err.message;
      showMessage(msg);
    }
  });

  nextBtn.addEventListener('click', async () => {
    if (state.currentStep >= state.totalSteps) return;

    try {
      await saveDraft(false, true);
      state.currentStep += 1;
      updateProgress();
    } catch (err) {
      const msg = (err.payload && err.payload.message) || err.message;
      showMessage(msg);
    }
  });

  if (uploadNowBtn) {
    uploadNowBtn.addEventListener('click', async () => {
      try {
        await saveDraft(true, true);
      } catch (err) {
        const msg = (err.payload && err.payload.message) || err.message;
        showMessage(msg);
      }
    });
  }

  submitBtn.addEventListener('click', async () => {
    try {
      await submitApplication();
    } catch (err) {
      const payload = err.payload || {};
      if (payload.errors) {
        showErrors(payload.errors);
      }
      const msg = payload.message || err.message || 'Absenden fehlgeschlagen.';
      showMessage(msg);
      if (payload.already_submitted) {
        blockedSection.classList.remove('hidden');
        wizardSection.classList.add('hidden');
      }
    }
  });

  updateProgress();
})();