/* Local interaction preview: no requests, uploads, or storage. */
(() => {
  'use strict';
  const form = document.querySelector('.inquiry-form');
  if (!form) return;

  const message = form.elements.message;
  const counter = form.querySelector('[data-message-count]');
  const input = form.elements.attachments;
  const dropzone = form.querySelector('.inquiry-upload');
  const list = form.querySelector('.inquiry-files');
  const uploadStatus = form.querySelector('.inquiry-upload-status');
  const dialog = document.querySelector('#inquiry-success-dialog');
  const submitButton = form.querySelector('.inquiry-submit');
  submitButton.disabled = false;
  const maxFiles = 5;
  const maxBytes = 20 * 1024 * 1024;
  let files = [];
  let dragDepth = 0;

  function formatSize(size) {
    return size >= 1024 * 1024 ? `${(size / 1024 / 1024).toFixed(1)} MB` : `${Math.max(1, Math.ceil(size / 1024))} KB`;
  }

  function showFiles() {
    list.replaceChildren();
    files.forEach((file, index) => {
      const item = document.createElement('li');
      const name = document.createElement('span');
      name.className = 'inquiry-file-name';
      name.textContent = file.name;
      const size = document.createElement('span');
      size.className = 'inquiry-file-size';
      size.textContent = formatSize(file.size);
      const remove = document.createElement('button');
      remove.type = 'button';
      remove.className = 'inquiry-file-remove';
      remove.textContent = '×';
      remove.setAttribute('aria-label', `${file.name} 삭제`);
      remove.addEventListener('click', () => {
        files.splice(index, 1);
        showFiles();
        const next = list.querySelectorAll('button')[Math.min(index, files.length - 1)];
        (next || input).focus();
      });
      item.append(name, size, remove);
      list.append(item);
    });
    uploadStatus.classList.remove('is-error');
    uploadStatus.textContent = files.length ? `${files.length}개 선택 · 총 ${formatSize(files.reduce((sum, file) => sum + file.size, 0))}` : '';
  }

  function addFiles(selection) {
    const next = [...files];
    for (const file of selection) {
      if (!next.some(existing => existing.name === file.name && existing.size === file.size && existing.lastModified === file.lastModified)) next.push(file);
    }
    let error = '';
    if (next.length > maxFiles) error = '파일은 최대 5개까지 첨부할 수 있습니다.';
    else if (next.reduce((sum, file) => sum + file.size, 0) > maxBytes) error = '첨부파일의 총 용량은 20MB 이하여야 합니다.';
    input.value = '';
    if (error) {
      uploadStatus.textContent = error;
      uploadStatus.classList.add('is-error');
      return;
    }
    files = next;
    showFiles();
  }

  input.addEventListener('change', () => addFiles([...input.files]));
  dropzone.addEventListener('dragenter', event => {
    event.preventDefault();
    dragDepth++;
    dropzone.classList.add('is-dragging');
  });
  dropzone.addEventListener('dragover', event => {
    event.preventDefault();
    event.dataTransfer.dropEffect = 'copy';
  });
  dropzone.addEventListener('dragleave', () => {
    if (--dragDepth <= 0) dropzone.classList.remove('is-dragging');
  });
  dropzone.addEventListener('drop', event => {
    event.preventDefault();
    dragDepth = 0;
    dropzone.classList.remove('is-dragging');
    addFiles([...event.dataTransfer.files]);
  });
  // Avoid navigating away if a file is dropped just outside the attachment area.
  for (const type of ['dragover', 'drop']) {
    form.addEventListener(type, event => {
      if ([...event.dataTransfer.types].includes('Files')) event.preventDefault();
    });
  }

  form.addEventListener('input', event => {
    if (event.target.matches('input, textarea')) event.target.setCustomValidity('');
    counter.textContent = message.value.length.toLocaleString('ko-KR');
  });
  dialog.querySelectorAll('[data-close-inquiry]').forEach(button => {
    button.addEventListener('click', () => dialog.close());
  });
  let backdropPressed = false;
  function isBackdrop(event) {
    const bounds = dialog.getBoundingClientRect();
    return event.target === dialog && (event.clientX < bounds.left || event.clientX > bounds.right || event.clientY < bounds.top || event.clientY > bounds.bottom);
  }
  dialog.addEventListener('pointerdown', event => { backdropPressed = isBackdrop(event); });
  dialog.addEventListener('click', event => {
    if (backdropPressed && isBackdrop(event)) dialog.close();
    backdropPressed = false;
  });
  dialog.addEventListener('close', () => {
    document.documentElement.classList.remove('inquiry-success-open');
    submitButton.focus({ preventScroll: true });
  });
  form.addEventListener('submit', event => {
    event.preventDefault();
    for (const field of [form.elements.name, message]) {
      field.setCustomValidity(field.value.trim() ? '' : '공백을 제외한 내용을 입력해 주세요.');
    }
    if (!form.reportValidity()) return;
    if (!dialog.open) {
      dialog.showModal();
      document.documentElement.classList.add('inquiry-success-open');
    }
  });
})();