import {
  Alignment,
  BlockQuote,
  Bold,
  ClassicEditor,
  Essentials,
  FontBackgroundColor,
  FontColor,
  FontFamily,
  FontSize,
  Heading,
  HorizontalLine,
  Indent,
  IndentBlock,
  Italic,
  InputTextView,
  Plugin,
  Paragraph,
  Strikethrough,
  Subscript,
  Superscript,
  Underline
} from '/assets/js/ckeditor5/ckeditor5.js';

(function () {
  var dataElement = document.getElementById('slide-editor-data');
  if (!dataElement) {
    return;
  }

  var slideEditorData = {};
  try {
    slideEditorData = JSON.parse(dataElement.getAttribute('data-json') || dataElement.textContent || '{}') || {};
  } catch (_error) {
    slideEditorData = {};
  }

  var templates = Array.isArray(slideEditorData.templates) ? slideEditorData.templates : [];
  var existingTemplateId = slideEditorData.existingTemplateId !== undefined ? slideEditorData.existingTemplateId : null;
  var existingContent = slideEditorData.existingContent || {};
  var templateSelect = document.getElementById('template-select');
  var templateFields = document.getElementById('template-fields');
  var slideForm = document.getElementById('slide-form');
  var slidePreviewMeta = document.getElementById('slide-preview-meta');
  var slidePreviewStage = document.getElementById('slide-preview-stage');
  var slidePreviewBackground = document.getElementById('slide-preview-background');
  var slidePreviewEmpty = document.getElementById('slide-preview-empty');
  var slidePreviewOverlay = document.getElementById('slide-preview-overlay');
  var editorInstances = new Map();
  var submitting = false;

  class FontSizeInputUI extends Plugin {
    static get pluginName() {
      return 'FontSizeInputUI';
    }

    init() {
      var editor = this.editor;
      var fontSizeCommand = editor.commands.get('fontSize');
      var plugin = this;

      if (!fontSizeCommand) {
        return;
      }

      editor.ui.componentFactory.add('fontSizeInput', function (locale) {
        var view = new InputTextView(locale);

        view.extendTemplate({
          attributes: {
            class: ['ck-font-size-input']
          }
        });

        view.set({
          placeholder: 'Font size',
          ariaLabel: 'Font size'
        });

        function getCurrentFontSizeValue() {
          var value = fontSizeCommand.value;
          if (value === null || value === undefined || value === '') {
            return '';
          }

          var parsed = Math.round(Number(String(value).replace(/[^0-9.]/g, '')));
          return Number.isFinite(parsed) && parsed > 0 ? String(parsed) : '';
        }

        function syncValue() {
          if (view.element && document.activeElement === view.element) {
            return;
          }

          view.value = getCurrentFontSizeValue();
        }

        view.on('render', function () {
          if (!view.element) {
            return;
          }

          view.element.type = 'text';
          view.element.inputMode = 'numeric';
          view.element.autocomplete = 'off';
          view.element.spellcheck = false;
          syncValue();
        });

        function applyValue() {
          if (!view.element) {
            return;
          }

          var size = Math.max(1, Math.round(Number(view.element.value || 0)));
          if (!size) {
            return;
          }

          editor.execute('fontSize', { value: size + 'px' });
        }

        view.on('input', applyValue);
        view.on('blur', applyValue);

        view.on('keydown', function (_eventInfo, domEvent) {
          if (domEvent.key === 'Enter') {
            domEvent.preventDefault();
            if (view.element) {
              view.element.blur();
            }
          }
        });

        plugin.listenTo(editor.model.document.selection, 'change:range', syncValue);
        plugin.listenTo(fontSizeCommand, 'change:value', syncValue);

        syncValue();

        return view;
      });
    }
  }

  function escapeHtml(value) {
    return String(value ?? '')
      .replace(/&/g, '&')
      .replace(/</g, '&lt;')
      .replace(/>/g, '&gt;')
      .replace(/"/g, '&quot;')
      .replace(/'/g, '&#39;');
  }

  function getTemplateById(id) {
    return templates.find(function (item) { return Number(item.id) === Number(id); }) || null;
  }

  function getCurrentRegionValue(region) {
    var current = existingContent[region.region_key];
    return current && current.value !== undefined ? current.value : '';
  }

  function normalizeEditorData(value) {
    return String(value || '');
  }

  function sanitizePreviewHtml(html) {
    var output = String(html || '');
    output = output.replace(/<script[\s\S]*?<\/script>/gi, '');
    output = output.replace(/<style[\s\S]*?<\/style>/gi, '');
    return output.replace(/<[^>]+>/g, function (tag) {
      var match = tag.match(/^<\s*(\/?)\s*([a-z0-9]+)([\s\S]*?)(\/?)>$/i);
      if (!match) {
        return '';
      }
      var closing = Boolean(match[1]);
      var name = String(match[2] || '').toLowerCase();
      var attrText = String(match[3] || '');
      var selfClosing = Boolean(match[4]) || name === 'br' || name === 'hr';
      var allowed = ['a', 'b', 'blockquote', 'br', 'code', 'div', 'em', 'figure', 'figcaption', 'h1', 'h2', 'h3', 'h4', 'h5', 'h6', 'hr', 'i', 'li', 'ol', 'p', 'pre', 'span', 'strong', 'sub', 'sup', 'table', 'tbody', 'td', 'th', 'thead', 'tr', 'u', 'ul'];
      if (allowed.indexOf(name) === -1) {
        return '';
      }
      if (closing) {
        return '</' + name + '>';
      }
      if (selfClosing) {
        return '<' + name + sanitizeTagAttributes(name, attrText) + '>';
      }
      return '<' + name + sanitizeTagAttributes(name, attrText) + '>';
    });
  }

  function sanitizeTagAttributes(tagName, attrText) {
    var allowedAttributes = {
      a: ['href', 'title', 'target', 'rel', 'class', 'style'],
      blockquote: ['class', 'style'],
      div: ['class', 'style'],
      figure: ['class', 'style'],
      figcaption: ['class', 'style'],
      h1: ['class', 'style'],
      h2: ['class', 'style'],
      h3: ['class', 'style'],
      h4: ['class', 'style'],
      h5: ['class', 'style'],
      h6: ['class', 'style'],
      li: ['class', 'style'],
      ol: ['class', 'style', 'start'],
      p: ['class', 'style'],
      pre: ['class', 'style'],
      span: ['class', 'style'],
      table: ['class', 'style'],
      td: ['class', 'style', 'colspan', 'rowspan'],
      th: ['class', 'style', 'colspan', 'rowspan', 'scope'],
      tr: ['class', 'style'],
      ul: ['class', 'style']
    };
    var allowed = allowedAttributes[tagName] || [];
    if (!allowed.length) {
      return '';
    }

    var attrs = [];
    attrText.replace(/([a-zA-Z0-9:-]+)(?:\s*=\s*("([^"]*)"|'([^']*)'|([^\s"'>/=`]+)))?/g, function (_full, key, _valuePart, doubleQuoted, singleQuoted, bareValue) {
      var lowerKey = String(key || '').toLowerCase();
      if (allowed.indexOf(lowerKey) === -1) {
        return '';
      }
      var value = doubleQuoted !== undefined ? doubleQuoted : singleQuoted !== undefined ? singleQuoted : bareValue !== undefined ? bareValue : '';
      if (lowerKey === 'href' && /^(?:\s*javascript:|\s*data:)/i.test(String(value || ''))) {
        return '';
      }
      if (lowerKey === 'style' && /(?:expression\s*\(|javascript:|url\s*\()/i.test(String(value || ''))) {
        return '';
      }
      if (lowerKey === 'target') {
        var targetValue = String(value || '').trim();
        if (targetValue === '_blank') {
          attrs.push(' target="_blank"');
          if (attrs.indexOf(' rel="noreferrer noopener"') === -1) {
            attrs.push(' rel="noreferrer noopener"');
          }
          return '';
        }
      }
      attrs.push(' ' + lowerKey + '="' + escapeHtml(value) + '"');
      return '';
    });

    return attrs.join('');
  }

  function renderPreviewListItem(item, tag) {
    if (item && typeof item === 'object') {
      var content = item.content !== undefined ? item.content : (item.text !== undefined ? item.text : item.value !== undefined ? item.value : '');
      var children = Array.isArray(item.items) ? item.items : Array.isArray(item.subItems) ? item.subItems : Array.isArray(item.children) ? item.children : [];
      var nested = children.length ? '<' + tag + ' style="list-style-type:' + (tag === 'ol' ? 'decimal' : 'disc') + ';padding-left:1.4em;">' + children.map(function (child) { return renderPreviewListItem(child, tag); }).join('') + '</' + tag + '>' : '';
      return '<li>' + sanitizePreviewHtml(content || '') + nested + '</li>';
    }
    return '<li>' + sanitizePreviewHtml(item || '') + '</li>';
  }

  function renderPreviewTable(data) {
    var rows = Array.isArray(data.content) ? data.content : Array.isArray(data.rows) ? data.rows : [];
    if (!rows.length) {
      return '';
    }
    var hasHeadings = Boolean(data.withHeadings);
    var body = rows.map(function (row, rowIndex) {
      var cells = Array.isArray(row) ? row : [];
      var cellTag = hasHeadings && rowIndex === 0 ? 'th' : 'td';
      var cellAttrs = cellTag === 'th' ? ' scope="col"' : '';
      return '<tr>' + cells.map(function (cell) {
        return '<' + cellTag + cellAttrs + '>' + sanitizePreviewHtml(cell || '') + '</' + cellTag + '>';
      }).join('') + '</tr>';
    }).join('');
    return '<table class="slide-preview-table">' + body + '</table>';
  }

  function renderPreviewBlock(block) {
    if (!block || !block.type || !block.data) {
      return '';
    }
    if (block.type === 'header') {
      var level = Math.max(1, Math.min(6, Number(block.data.level || 2)));
      return '<h' + level + '>' + sanitizePreviewHtml(block.data.text || '') + '</h' + level + '>';
    }
    if (block.type === 'list') {
      var tag = block.data.style === 'ordered' ? 'ol' : 'ul';
      var items = Array.isArray(block.data.items) ? block.data.items : [];
      return '<' + tag + ' style="list-style-type:' + (tag === 'ol' ? 'decimal' : 'disc') + ';padding-left:1.4em;">' + items.map(function (item) { return renderPreviewListItem(item, tag); }).join('') + '</' + tag + '>';
    }
    if (block.type === 'delimiter') {
      return '<hr />';
    }
    if (block.type === 'code') {
      return '<pre><code>' + sanitizePreviewHtml(block.data.code || '') + '</code></pre>';
    }
    if (block.type === 'table') {
      return renderPreviewTable(block.data);
    }
    if (block.type === 'paragraph') {
      return '<p>' + sanitizePreviewHtml(block.data.text || '') + '</p>';
    }
    return '';
  }

  function renderPreviewText(value) {
    var raw = String(value || '');
    if (!raw) {
      return '<div class="slide-preview-placeholder">Empty text</div>';
    }
    return sanitizePreviewHtml(raw);
  }

  function renderPreviewTextRegion(region, value, style, scale) {
    var fontFamily = style.font_family ? 'font-family:' + escapeHtml(style.font_family) + ';' : '';
    var color = style.font_color ? 'color:' + escapeHtml(style.font_color) + ';' : '';
    var fontSize = style.font_size ? 'font-size:' + Math.max(1, Math.round(Number(style.font_size))) + 'px;' : '';
    var width = Math.max(1, Math.round(Number(region && region.width ? region.width : 0) || 1));
    var height = Math.max(1, Math.round(Number(region && region.height ? region.height : 0) || 1));
    var wrapperStyle = 'width:' + width + 'px;height:' + height + 'px;overflow:hidden;' + fontFamily + fontSize + color;
    return '<div class="slide-preview-text-content" style="' + wrapperStyle + '">' + renderPreviewText(value) + '</div>';
  }

  function renderPreviewWebpageRegion(value) {
    var src = String(value || '').trim();
    if (!src) {
      return '<div class="slide-preview-placeholder">Webpage</div>';
    }
    return '<iframe class="slide-preview-webpage-frame" src="' + escapeHtml(src) + '" title="Webpage preview" loading="eager" referrerpolicy="no-referrer" scrolling="no"></iframe>';
  }

  function renderPreviewHtmlRegion(value) {
    var html = String(value || '').trim();
    if (!html) {
      return '<div class="slide-preview-placeholder">HTML</div>';
    }
    return '<iframe class="slide-preview-html-frame" sandbox="" scrolling="no" srcdoc="<!doctype html><html><head><style>html,body{margin:0;width:100%;height:100%;overflow:hidden;background:transparent;}</style></head><body>' + escapeHtml(html) + '</body></html>" title="HTML preview" loading="eager"></iframe>';
  }

  function destroyEditors() {
    editorInstances.forEach(function (editor) {
      if (editor && typeof editor.destroy === 'function') {
        editor.destroy();
      }
    });
    editorInstances.clear();
  }

  function getEditorHiddenInput(regionId) {
    var card = templateFields.querySelector('[data-region-id="' + regionId + '"]');
    return card ? card.querySelector('input[type="hidden"][name="region_text_' + regionId + '"]') : null;
  }

  function getEditorFontSizeHiddenInput(regionId) {
    var card = templateFields.querySelector('[data-region-id="' + regionId + '"]');
    return card ? card.querySelector('input[name="region_font_size_' + regionId + '"]') : null;
  }

  function normalizeFontSizeValue(value) {
    var size = Math.max(1, Math.round(Number(String(value || '').replace(/[^0-9.]/g, ''))));
    return size ? String(size) : '';
  }

  function getCurrentTextStyle(region) {
    var current = existingContent[region.region_key] || {};
    return {
      font_family: String(current.font_family || region.font_family || 'Arial').trim() || 'Arial',
      font_size: Math.max(8, Number(current.font_size || 24)),
      font_color: String(current.font_color || region.font_color || '#000000').trim() || '#000000'
    };
  }

  function getTextStyleFromCard(_card, region) {
    return getCurrentTextStyle(region);
  }

  function getSelectedTemplate() {
    return templates.find(function (item) { return Number(item.id) === Number(templateSelect.value); }) || null;
  }

  function clearImagePreviewUrls() {
    templateFields.querySelectorAll('input[type="file"][name^="region_image_"]').forEach(function (input) {
      if (input.dataset.previewUrl) {
        URL.revokeObjectURL(input.dataset.previewUrl);
        delete input.dataset.previewUrl;
      }
    });
  }

  function getRegionBox(region, canvasWidth, canvasHeight) {
    return {
      left: Math.max(0, Math.round(Number(region.x || 0))),
      top: Math.max(0, Math.round(Number(region.y || 0))),
      width: Math.max(1, Math.round(Number(region.width || 0) || 1)),
      height: Math.max(1, Math.round(Number(region.height || 0) || 1))
    };
  }

  function renderPreview() {
    var template = getSelectedTemplate();
    if (!template) {
      slidePreviewMeta.textContent = 'Select a template to preview the slide.';
      slidePreviewBackground.style.display = 'none';
      slidePreviewEmpty.style.display = 'flex';
      slidePreviewEmpty.textContent = 'Select a template to preview the slide.';
      slidePreviewOverlay.innerHTML = '';
      slidePreviewOverlay.style.width = '';
      slidePreviewOverlay.style.height = '';
      slidePreviewOverlay.style.transform = '';
      slidePreviewStage.style.aspectRatio = '16 / 9';
      return;
    }

    var canvasWidth = Math.max(1, Number(template.canvas_size_width || 1920));
    var canvasHeight = Math.max(1, Number(template.canvas_size_height || 1080));
    slidePreviewStage.style.aspectRatio = canvasWidth + ' / ' + canvasHeight;
    slidePreviewMeta.textContent = template.name + ' • ' + canvasWidth + 'x' + canvasHeight;
    if (!(template.regions || []).length) {
      slidePreviewEmpty.style.display = 'flex';
      slidePreviewEmpty.textContent = 'This template has no regions.';
      slidePreviewBackground.style.display = template.background_image_path ? 'block' : 'none';
      slidePreviewBackground.src = template.background_image_path || '';
      slidePreviewOverlay.innerHTML = '';
      slidePreviewOverlay.style.width = '';
      slidePreviewOverlay.style.height = '';
      slidePreviewOverlay.style.transform = '';
      return;
    }

    slidePreviewEmpty.style.display = 'none';
    slidePreviewBackground.style.display = template.background_image_path ? 'block' : 'none';
    slidePreviewBackground.src = template.background_image_path || '';

    var stageRect = slidePreviewStage.getBoundingClientRect();
    var scale = Math.min(stageRect.width / canvasWidth, stageRect.height / canvasHeight) || 1;
    slidePreviewOverlay.style.width = canvasWidth + 'px';
    slidePreviewOverlay.style.height = canvasHeight + 'px';
    slidePreviewOverlay.style.transform = 'scale(' + scale + ')';
    slidePreviewOverlay.style.transformOrigin = 'top left';
    var regions = template.regions || [];
    slidePreviewOverlay.innerHTML = regions.map(function (region) {
      var box = getRegionBox(region, canvasWidth, canvasHeight);
      var card = templateFields.querySelector('[data-region-id="' + region.id + '"]');
      var hiddenInput = card && card.querySelector('input[type="hidden"][name="region_text_' + region.id + '"]');
      var htmlInput = card && card.querySelector('textarea[name="region_html_' + region.id + '"]');
      var imageHidden = card && card.querySelector('input[type="hidden"][name="existing_region_image_' + region.id + '"]');
      var imageFileInput = card && card.querySelector('input[type="file"][name="region_image_' + region.id + '"]');
      var webpageInput = card && card.querySelector('input[type="url"][name="region_webpage_' + region.id + '"]');
      var value = region.region_type === 'image'
        ? ((imageFileInput && imageFileInput.dataset.previewUrl) ? imageFileInput.dataset.previewUrl : (imageHidden ? imageHidden.value : ''))
        : region.region_type === 'webpage'
          ? (webpageInput ? webpageInput.value : '')
          : region.region_type === 'html'
            ? (htmlInput ? htmlInput.value : '')
          : (hiddenInput ? hiddenInput.value : '');
      var style = region.region_type === 'image'
        ? null
        : region.region_type === 'webpage'
          ? null
          : region.region_type === 'html'
            ? null
          : getTextStyleFromCard(card, region);
      var content = region.region_type === 'image'
        ? (value ? '<img class="slide-preview-image" src="' + escapeHtml(value) + '" alt="" />' : '<div class="slide-preview-placeholder">Image</div>')
        : region.region_type === 'webpage'
          ? renderPreviewWebpageRegion(value)
          : region.region_type === 'html'
            ? renderPreviewHtmlRegion(value)
          : renderPreviewTextRegion(region, value, style, scale);
      var selected = region.region_type === 'image'
        ? ' slide-preview-image-region'
        : region.region_type === 'webpage'
          ? ' slide-preview-webpage-region'
          : region.region_type === 'html'
            ? ' slide-preview-html-region'
          : ' slide-preview-text-region';
      return '<div class="slide-preview-region' + selected + '" style="left:' + box.left + 'px;top:' + box.top + 'px;width:' + box.width + 'px;height:' + box.height + 'px;">' + content + '</div>';
    }).join('');
  }

  function renderTextRegion(region) {
    var current = getCurrentRegionValue(region);
    return '' +
      '<div class="card template-field-card" data-region-id="' + region.id + '">' +
        '<div class="template-field-head">' +
          '<strong>' + escapeHtml(region.label) + '</strong>' +
          '<span class="chip">Text</span>' +
        '</div>' +
        '<div class="ckeditor-holder" data-region-id="' + region.id + '">' +
          '<textarea class="ckeditor-source" rows="10">' + escapeHtml(current) + '</textarea>' +
        '</div>' +
        '<input type="hidden" name="region_font_size_' + region.id + '" value="' + escapeHtml(getCurrentTextStyle(region).font_size) + '" />' +
        '<input type="hidden" name="region_text_' + region.id + '" value="' + escapeHtml(current) + '" />' +
      '</div>';
  }

  function renderWebpageRegion(region) {
    var current = getCurrentRegionValue(region);
    return '' +
        '<div class="card template-field-card" data-region-id="' + region.id + '">' +
          '<div class="template-field-head">' +
            '<strong>' + escapeHtml(region.label) + '</strong>' +
            '<span class="chip">Webpage</span>' +
          '</div>' +
          '<label style="display:block; margin-top:12px;">Webpage URL' +
            '<input type="url" name="region_webpage_' + region.id + '" value="' + escapeHtml(current) + '" placeholder="https://example.com" />' +
          '</label>' +
          '<div class="muted slide-image-file">The webpage will be loaded in an iframe.</div>' +
        '</div>';
  }

  function renderHtmlRegion(region) {
    var current = getCurrentRegionValue(region);
    return '' +
        '<div class="card template-field-card" data-region-id="' + region.id + '">' +
          '<div class="template-field-head">' +
            '<strong>' + escapeHtml(region.label) + '</strong>' +
            '<span class="chip">HTML</span>' +
          '</div>' +
          '<label style="display:block; margin-top:12px;">HTML content' +
            '<textarea name="region_html_' + region.id + '" rows="10" placeholder="<div>Hello</div>">' + escapeHtml(current) + '</textarea>' +
          '</label>' +
          '<div class="muted slide-image-file">HTML is rendered in a sandboxed iframe preview.</div>' +
        '</div>';
  }

  function renderImageRegion(region) {
    var current = getCurrentRegionValue(region);
    return '' +
      '<div class="card template-field-card" data-region-id="' + region.id + '">' +
        '<div class="template-field-head">' +
          '<strong>' + escapeHtml(region.label) + '</strong>' +
          '<span class="chip">Image</span>' +
        '</div>' +
        '<label style="display:block; margin-top:12px;">Image file' +
          '<input type="file" name="region_image_' + region.id + '" accept="image/*" />' +
        '</label>' +
        '<input type="hidden" name="existing_region_image_' + region.id + '" value="' + escapeHtml(current) + '" />' +
        (current
          ? '<div class="muted slide-image-file">Current: <a href="' + escapeHtml(current) + '" target="_blank" rel="noreferrer">' + escapeHtml(current) + '</a></div>'
          : '<div class="muted slide-image-file">No image selected.</div>') +
      '</div>';
  }

  function renderTemplate() {
    clearImagePreviewUrls();
    destroyEditors();
    var template = getTemplateById(templateSelect.value);
    if (!template) {
      templateFields.innerHTML = '';
      renderPreview();
      return;
    }

    templateFields.innerHTML = template.regions.length ? template.regions.map(function (region) {
      if (region.region_type === 'image') {
        return renderImageRegion(region);
      }
      if (region.region_type === 'webpage') {
        return renderWebpageRegion(region);
      }
      if (region.region_type === 'html') {
        return renderHtmlRegion(region);
      }
      return renderTextRegion(region);
    }).join('') : '<div class="muted">This template has no regions.</div>';

    templateFields.querySelectorAll('.ckeditor-holder').forEach(function (holder) {
      var regionId = holder.getAttribute('data-region-id');
      var source = holder.querySelector('.ckeditor-source');
      var hidden = getEditorHiddenInput(regionId);
      var editorConfig = {
        licenseKey: 'GPL',
        placeholder: 'Write content...',
        toolbar: {
          items: [
            'undo',
            'redo',
            '|',
            'heading',
            '|',
            'fontSizeInput',
            'fontFamily',
            'fontColor',
            'fontBackgroundColor',
            '|',
            'bold',
            'italic',
            'underline',
            'strikethrough',
            'subscript',
            'superscript',
            '|',
            'horizontalLine',
            'blockQuote',
            '|',
            'alignment',
            '|',
            'outdent',
            'indent'
          ],
          shouldNotGroupWhenFull: false
        },
        plugins: [
          Alignment,
          BlockQuote,
          Bold,
          Essentials,
          FontBackgroundColor,
          FontColor,
          FontFamily,
          FontSize,
          FontSizeInputUI,
          Heading,
          HorizontalLine,
          Indent,
          IndentBlock,
          Italic,
          Paragraph,
          Strikethrough,
          Subscript,
          Superscript,
          Underline
        ],
        fontFamily: {
          supportAllValues: true
        },
        fontSize: {
          options: [20, 24, 28, 32, 36, 40, 44],
          supportAllValues: true
        },
        heading: {
          options: [
            { model: 'paragraph', title: 'Paragraph', class: 'ck-heading_paragraph' },
            { model: 'heading1', view: 'h1', title: 'Heading 1', class: 'ck-heading_heading1' },
            { model: 'heading2', view: 'h2', title: 'Heading 2', class: 'ck-heading_heading2' },
            { model: 'heading3', view: 'h3', title: 'Heading 3', class: 'ck-heading_heading3' },
            { model: 'heading4', view: 'h4', title: 'Heading 4', class: 'ck-heading_heading4' }
          ]
        },
        initialData: normalizeEditorData((source && source.value) || (hidden ? hidden.value : ''))
      };

      ClassicEditor.create(source || holder, editorConfig).then(function (editor) {
        editorInstances.set(regionId, editor);
        var fontSizeHidden = getEditorFontSizeHiddenInput(regionId);
        var fontSizeCommand = editor.commands.get('fontSize');
        if (hidden) {
          hidden.value = editor.getData();
        }
        if (fontSizeHidden && fontSizeCommand) {
          fontSizeHidden.value = normalizeFontSizeValue(fontSizeCommand.value) || fontSizeHidden.value;
          fontSizeCommand.on('change:value', function () {
            fontSizeHidden.value = normalizeFontSizeValue(fontSizeCommand.value) || fontSizeHidden.value;
          });
        }
        editor.model.document.on('change:data', function () {
          var instance = editorInstances.get(regionId);
          if (instance !== editor) {
            return;
          }
          if (hidden) {
            hidden.value = editor.getData();
          }
          renderPreview();
        });
        renderPreview();
      }).catch(function (error) {
        console.error('Failed to initialize CKEditor.', error);
      });
    });

    templateFields.querySelectorAll('input[type="file"][name^="region_image_"]').forEach(function (input) {
      input.addEventListener('change', function () {
        if (input.dataset.previewUrl) {
          URL.revokeObjectURL(input.dataset.previewUrl);
          delete input.dataset.previewUrl;
        }
        if (input.files && input.files.length) {
          input.dataset.previewUrl = URL.createObjectURL(input.files[0]);
        }
        renderPreview();
      });
    });
    renderPreview();
  }

  slideForm.addEventListener('submit', async function (event) {
    if (submitting) {
      return;
    }
    event.preventDefault();
    var saves = Array.prototype.map.call(templateFields.querySelectorAll('.ckeditor-holder'), function (holder) {
      var regionId = holder.getAttribute('data-region-id');
      var editor = editorInstances.get(regionId);
      var hidden = getEditorHiddenInput(regionId);
      if (!editor || !hidden) {
        return Promise.resolve();
      }
      hidden.value = editor.getData();
      return Promise.resolve();
    });
    submitting = true;
    try {
      await Promise.all(saves);
      var response = await fetch(slideForm.action, {
        method: (slideForm.method || 'POST').toUpperCase(),
        headers: {
          'X-Requested-With': 'XMLHttpRequest',
          'Accept': 'text/html, application/json, text/plain, */*'
        },
        body: new FormData(slideForm),
        credentials: 'same-origin'
      });

      if (!response.ok) {
        throw new Error(await response.text() || 'Unable to save slide.');
      }

      var responseText = await response.text();
      var savedMessage = '';
      try {
        var doc = new DOMParser().parseFromString(responseText || '', 'text/html');
        var toastBody = doc.querySelector('.toast-body');
        if (toastBody && toastBody.textContent) {
          savedMessage = toastBody.textContent.trim();
        }
      } catch (_error) {
        savedMessage = '';
      }

      showToast(savedMessage || 'Saved slide.');
      window.location.href = response.url || slideForm.action;
    } finally {
      submitting = false;
    }
  });

  templateSelect.addEventListener('change', renderTemplate);
  templateFields.addEventListener('change', renderPreview);
  templateFields.addEventListener('input', renderPreview);
  if (existingTemplateId) {
    templateSelect.value = String(existingTemplateId);
  }
  renderTemplate();
  window.addEventListener('resize', renderPreview);
})();