/**
 * file-upload-queue.js
 *
 * Powers two UI features:
 *
 *  1. TFE multi-file upload queue (#tfe-file-queue)
 *     - Renders each selected file as a sortable row with icon, name, size
 *       and an optional label input.
 *     - Drag-to-reorder via SortableJS.
 *     - Injects hidden `file_labels[]` and `file_orders[]` inputs so PHP
 *       receives per-file label and intended sort-order data.
 *     - Works for both the add/partage form (pure new uploads) and the edit
 *       form (new uploads only; existing-file sort is handled server-side).
 *
 *  2. Legacy single-file previews (data-preview="CONTAINER_ID")
 *     - Backward-compatible with cover-image and banner inputs.
 */
(() => {
  /* ── Helpers ──────────────────────────────────────────────────────────── */

  const ICONS = {
    pdf:   '📄',
    video: '🎬',
    audio: '🔊',
    zip:   '🗜️',
    vtt:   '💬',
    image: '🖼️',
    other: '📎',
  };

  function iconFor(file) {
    const t = file.type || '';
    const n = file.name.toLowerCase();
    if (t.startsWith('image/'))                                        return ICONS.image;
    if (t === 'application/pdf' || n.endsWith('.pdf'))                 return ICONS.pdf;
    if (t.startsWith('video/') || /\.(mp4|webm|mov|ogv)$/.test(n))    return ICONS.video;
    if (t.startsWith('audio/') || /\.(mp3|ogg|oga|wav|flac|aac|m4a)$/.test(n)) return ICONS.audio;
    if (t === 'application/zip' || /\.(zip|tar|gz|tgz)$/.test(n))     return ICONS.zip;
    if (n.endsWith('.vtt'))                                             return ICONS.vtt;
    return ICONS.other;
  }

  function humanSize(bytes) {
    if (bytes >= 1073741824) return `${(bytes / 1073741824).toFixed(2)} GB`;
    if (bytes >= 1048576)   return `${(bytes / 1048576).toFixed(2)} MB`;
    if (bytes >= 1024)      return `${(bytes / 1024).toFixed(1)} KB`;
    return `${bytes} B`;
  }

  function esc(str) {
    return str.replace(/&/g,'&amp;').replace(/</g,'&lt;').replace(/>/g,'&gt;').replace(/"/g,'&quot;');
  }

  /* ── DataTransfer-backed file list ────────────────────────────────────── */
  // We keep a parallel array so we can freely re-order and remove files
  // then reconstruct a proper FileList via DataTransfer when needed.

  function syncInputFiles(input, fileArray) {
    try {
      const dt = new DataTransfer();
      for (const f of fileArray) dt.items.add(f);
      input.files = dt.files;
    } catch {
      // DataTransfer not available in older browsers — graceful degradation.
    }
  }

  /* ── TFE file queue ───────────────────────────────────────────────────── */

  function initFileQueue() {
    const picker   = document.getElementById('tfe-files-input');
    const queue    = document.getElementById('tfe-file-queue');
    const empty    = document.getElementById('tfe-file-queue-empty');

    if (!picker || !queue) return;

    // Array parallel to the visual queue
    let fileArray = [];

    // Keep SortableJS instance reference
    let _sortable = null;
    if (typeof Sortable !== 'undefined') {
      _sortable = Sortable.create(queue, {
        animation: 150,
        handle:    '.fq-drag-handle',
        ghostClass: 'fq-ghost',
        onEnd: () => reorderFiles(),
      });
    }

    picker.addEventListener('change', () => {
      const newFiles = Array.from(picker.files);
      fileArray = fileArray.concat(newFiles);
      renderQueue();
      // Reset input so the same file can be selected again if needed
      picker.value = '';
    });

    function renderQueue() {
      queue.innerHTML = '';

      if (fileArray.length === 0) {
        empty.style.display = '';
        syncInputFiles(picker, []);
        return;
      }
      empty.style.display = 'none';

      fileArray.forEach((file, idx) => {
        const li = document.createElement('li');
        li.className = 'fq-item';
        li.setAttribute('data-idx', idx);

        li.innerHTML =
          '<span class="fq-drag-handle" title="Réordonner">⠿</span>' +
          '<span class="fq-icon">' + iconFor(file) + '</span>' +
          '<span class="fq-info">' +
            '<span class="fq-name">' + esc(file.name) + '</span>' +
            '<span class="fq-size">' + humanSize(file.size) + '</span>' +
            '<input type="text" class="fq-label admin-file-label-input" ' +
                   'placeholder="Légende / description (optionnel)">' +
          '</span>' +
          '<button type="button" class="admin-btn-remove fq-remove" aria-label="Retirer ' + esc(file.name) + '">✕</button>';

        // Remove button
        li.querySelector('.fq-remove').addEventListener('click', () => {
          fileArray.splice(idx, 1);
          renderQueue();
        });

        queue.appendChild(li);
      });

      syncInputFiles(picker, fileArray);
      injectHiddenFields();
    }

    function reorderFiles() {
      // Re-sync fileArray to match current DOM order
      const items   = Array.from(queue.querySelectorAll('.fq-item'));
      const newArr  = items.map(li => fileArray[parseInt(li.getAttribute('data-idx'), 10)]);
      fileArray = newArr;
      // Re-render to update data-idx attributes
      renderQueue();
    }

    function injectHiddenFields() {
      // Remove previous hidden fields
      const form = picker.closest('form');
      if (!form) return;
      for (const el of form.querySelectorAll('.fq-hidden-label, .fq-hidden-order')) el.remove();

      // Inject current labels and order indices
      // We use the queue DOM (post-sort) as the source of truth.
      const items = Array.from(queue.querySelectorAll('.fq-item'));
      items.forEach((li, sortedIdx) => {
        const labelVal = li.querySelector('.fq-label').value;

        const lInput = document.createElement('input');
        lInput.type  = 'hidden';
        lInput.name  = 'file_labels[]';
        lInput.value = labelVal;
        lInput.className = 'fq-hidden-label';
        form.appendChild(lInput);

        const oInput = document.createElement('input');
        oInput.type  = 'hidden';
        oInput.name  = 'file_orders[]';
        oInput.value = sortedIdx + 1;
        oInput.className = 'fq-hidden-order';
        form.appendChild(oInput);
      });
    }

    // Before form submit, inject hidden fields so labels are up-to-date
    const form = picker.closest('form');
    if (form) {
      form.addEventListener('submit', () => {
        syncInputFiles(picker, fileArray);
        injectHiddenFields();
      });
    }
  }

  /* ── Existing-files sortable (edit form only) ─────────────────────────── */

  function initExistingFilesSortable() {
    const list = document.getElementById('existing-files-sortable');
    if (!list || typeof Sortable === 'undefined') return;

    Sortable.create(list, {
      animation: 150,
      handle:    '.admin-file-drag-handle',
      ghostClass: 'fq-ghost',
      onEnd: () => {
        // Update the hidden file_sort_order[] inputs to reflect new order
        const items = list.querySelectorAll('.admin-file-list-item[data-file-id]');
        for (const el of list.querySelectorAll('input[name="file_sort_order[]"]')) el.remove();
        items.forEach((li) => {
          const inp = document.createElement('input');
          inp.type  = 'hidden';
          inp.name  = 'file_sort_order[]';
          inp.value = li.getAttribute('data-file-id');
          li.prepend(inp);
        });
      },
    });
  }

  /* ── Legacy single-file preview (data-preview="CONTAINER_ID") ─────────── */

  function initLegacyPreviews() {
    document.querySelectorAll('input[type="file"][data-preview]').forEach((input) => {
      // Skip the TFE multi-file picker (handled by queue above)
      if (input.id === 'tfe-files-input') return;

      const containerId = input.getAttribute('data-preview');
      const container   = document.getElementById(containerId);
      if (!container) return;

      input.addEventListener('change', () => {
        renderLegacyPreview(input, container);
      });
    });
  }

  function renderLegacyPreview(input, container) {
    container.innerHTML = '';
    const files = Array.from(input.files);
    if (!files.length) return;

    files.forEach((file) => {
      const item = document.createElement('div');
      item.className = 'fp-item';

      if (file.type.startsWith('image/')) {
        const img    = document.createElement('img');
        img.className = 'fp-thumb';
        img.alt = file.name;
        const reader = new FileReader();
        reader.onload = (e) => { img.src = e.target.result; };
        reader.readAsDataURL(file);
        item.appendChild(img);
      } else {
        const icon = document.createElement('span');
        icon.className   = 'fp-icon';
        icon.textContent = iconFor(file);
        item.appendChild(icon);
      }

      const meta = document.createElement('span');
      meta.className = 'fp-meta';
      meta.innerHTML =
        '<span class="fp-name">' + esc(file.name) + '</span>' +
        '<span class="fp-size">' + humanSize(file.size) + '</span>';
      item.appendChild(meta);
      container.appendChild(item);
    });
  }

  /* ── Bootstrap ────────────────────────────────────────────────────────── */

  function init() {
    initFileQueue();
    initExistingFilesSortable();
    initLegacyPreviews();
  }

  if (document.readyState === 'loading') {
    document.addEventListener('DOMContentLoaded', init);
  } else {
    init();
  }
})();