// General sanitization and sizing helpers.
// Strip unsupported characters from a font family string.
function sanitizeFontFamily(value) {
  return String(value || '').replace(/[^a-zA-Z0-9 ,\"-]/g, '').trim();
}

// Clamp font size to the supported range.
function sanitizeFontSize(value) {
  return Math.max(8, Number(value || 0) || 24);
}

// Validate a text color and fall back when needed.
function sanitizeTextColor(value, fallback) {
  var raw = String(value || '').trim();
  if (/^#[0-9a-fA-F]{6}$/.test(raw) || /^#[0-9a-fA-F]{3}$/.test(raw)) {
    return raw;
  }
  return fallback || '#000000';
}

// Read the template's canvas dimensions with safe defaults.
function getTemplateCanvasSize(template) {
  return {
    width: Math.max(1, Number(template.canvas_size_width || 1920)),
    height: Math.max(1, Number(template.canvas_size_height || 1080))
  };
}

// Read the server-supplied playlist revision, or fall back to the ETag.
function getPlaylistRevision(data) {
  if (data && data.revision) {
    return String(data.revision);
  }
  if (data && data.playlist && data.playlist.revision) {
    return String(data.playlist.revision);
  }
  if (currentPlaylistEtag) {
    return String(currentPlaylistEtag).replace(/^"|"$/g, '');
  }
  return String(Date.now());
}

// Scale a canvas to fit within the viewport.
function fitCanvasSize(canvasWidth, canvasHeight, maxWidth, maxHeight) {
  var width = Math.max(1, Number(canvasWidth || 0) || 1920);
  var height = Math.max(1, Number(canvasHeight || 0) || 1080);
  var viewportWidth = Math.max(1, Number(maxWidth || 0) || width);
  var viewportHeight = Math.max(1, Number(maxHeight || 0) || height);
  var scale = Math.min(viewportWidth / width, viewportHeight / height);
  return {
    width: Math.round(width * scale),
    height: Math.round(height * scale)
  };
}

const ALLOWED_RICH_TEXT_TAGS = ['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'];

function sanitizeRichTextAttributes(tagName, attrText) {
  const 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']
  };
  const allowed = allowedAttributes[tagName] || [];
  if (!allowed.length) {
    return '';
  }

  const attrs = [];
  String(attrText || '').replace(/([a-zA-Z0-9:-]+)(?:\s*=\s*("([^"]*)"|'([^']*)'|([^\s"'>/=`]+)))?/g, (_full, key, _valuePart, doubleQuoted, singleQuoted, bareValue) => {
    const lowerKey = String(key || '').toLowerCase();
    if (!allowed.includes(lowerKey)) {
      return '';
    }
    const 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') {
      const targetValue = String(value || '').trim();
      if (targetValue === '_blank') {
        attrs.push(' target="_blank"');
        if (!attrs.includes(' rel="noreferrer noopener"')) {
          attrs.push(' rel="noreferrer noopener"');
        }
        return '';
      }
    }
    attrs.push(' ' + lowerKey + '="' + escapeHtml(value) + '"');
    return '';
  });

  return attrs.join('');
}

// Remove unsafe markup while preserving richer CKEditor formatting.
function sanitizeRichText(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] || '');
    if (ALLOWED_RICH_TEXT_TAGS.indexOf(name) === -1) {
      return '';
    }
    if (closing) {
      return '</' + name + '>';
    }
    return '<' + name + sanitizeRichTextAttributes(name, attrText) + '>';
  });
}

// Render a single Editor.js block to HTML.
function renderEditorJsBlock(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 + '>' + sanitizeRichText(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 renderEditorJsListItem(item, tag); }).join('') + '</' + tag + '>';
  }

  if (block.type === 'delimiter') {
    return '<hr />';
  }

  if (block.type === 'code') {
    return '<pre><code>' + escapeHtml(block.data.code || '') + '</code></pre>';
  }

  if (block.type === 'table') {
    return renderEditorJsTable(block.data);
  }

  if (block.type === 'paragraph') {
    return '<p>' + sanitizeRichText(block.data.text || '') + '</p>';
  }

  return '';
}

// Render a list item and any nested sub-items.
function renderEditorJsListItem(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 renderEditorJsListItem(child, tag); }).join('') + '</' + tag + '>' : '';
    return '<li>' + sanitizeRichText(content || '') + nested + '</li>';
  }
  return '<li>' + sanitizeRichText(item || '') + '</li>';
}

// Render an Editor.js table block.
function renderEditorJsTable(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 tableRows = 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 + '>' + sanitizeRichText(cell || '') + '</' + cellTag + '>';
    }).join('') + '</tr>';
  }).join('');
  return '<table class="ck-content-table">' + tableRows + '</table>';
}

// Render Editor.js JSON or plain content safely.
function renderEditorJsContent(value) {
  if (value && typeof value === 'object') {
    if (Array.isArray(value.blocks)) {
      return value.blocks.map(renderEditorJsBlock).join('');
    }
    if (value.value !== undefined) {
      return renderEditorJsContent(value.value);
    }
  }
  var raw = String(value || '');
  try {
    var parsed = JSON.parse(raw);
    if (parsed && Array.isArray(parsed.blocks)) {
      return parsed.blocks.map(renderEditorJsBlock).join('');
    }
  } catch (_error) {
    // fall through to legacy HTML rendering
  }
  return sanitizeRichText(raw);
}

// Parse string values that look like JSON.
function parseMaybeJson(value) {
  if (typeof value !== 'string') {
    return value;
  }
  var raw = value.trim();
  if (!raw) {
    return value;
  }
  if (raw.charAt(0) !== '{' && raw.charAt(0) !== '[') {
    return value;
  }
  try {
    return JSON.parse(raw);
  } catch (_error) {
    return value;
  }
}

// Normalize a slide region's stored content value.
function normalizeContentValue(value) {
  var normalized;
  if (!value || typeof value !== 'object') {
    return {
      type: 'text',
      value: parseMaybeJson(value)
    };
  }
  normalized = {};
  Object.keys(value).forEach(function (key) {
    normalized[key] = value[key];
  });
  if (normalized.value !== undefined) {
    normalized.value = parseMaybeJson(normalized.value);
  }
  if (normalized.font_family !== undefined && normalized.font_family !== null) {
    normalized.font_family = sanitizeFontFamily(normalized.font_family);
  }
  if (normalized.font_size !== undefined && normalized.font_size !== null) {
    normalized.font_size = sanitizeFontSize(normalized.font_size);
  }
  if (normalized.font_color !== undefined && normalized.font_color !== null) {
    normalized.font_color = sanitizeTextColor(normalized.font_color);
  }
  if (!normalized.type) {
    normalized.type = 'text';
  }
  return normalized;
}

// Normalize a slide and its nested region content.
function normalizeSlide(slide) {
  var normalized = {};
  var content;
  Object.keys(slide || {}).forEach(function (key) {
    normalized[key] = slide[key];
  });
  normalized.content = {};
  content = slide && slide.content && typeof slide.content === 'object' ? slide.content : {};
  Object.keys(content).forEach(function (regionKey) {
    normalized.content[regionKey] = normalizeContentValue(content[regionKey]);
  });
  return normalized;
}

// Parse the stored schedule-day list into numbers.
function parseScheduleDays(value) {
  if (!value) {
    return [];
  }
  if (Array.isArray(value)) {
    return value.map(function (item) { return Number(item); }).filter(function (item) { return !Number.isNaN(item); });
  }
  try {
    const parsed = JSON.parse(value);
    return Array.isArray(parsed) ? parsed.map(function (item) { return Number(item); }).filter(function (item) { return !Number.isNaN(item); }) : [];
  } catch (_error) {
    return [];
  }
}

// Convert a HH:MM time string to minutes since midnight.
function parseTimeToMinutes(value) {
  const raw = String(value || '').trim();
  if (!raw) {
    return null;
  }
  const match = raw.match(/^(\d{2}):(\d{2})/);
  if (!match) {
    return null;
  }
  return Number(match[1]) * 60 + Number(match[2]);
}

// Determine whether a slide should be shown at the current time.
function isSlideActive(slide, now) {
  const mode = String(slide.schedule_mode || 'always');
  if (mode === 'always') {
    return true;
  }
  if (mode === 'dates') {
    const start = slide.schedule_start_datetime ? new Date(slide.schedule_start_datetime) : null;
    const end = slide.schedule_end_datetime ? new Date(slide.schedule_end_datetime) : null;
    if (!start || !end || Number.isNaN(start.getTime()) || Number.isNaN(end.getTime())) {
      return false;
    }
    return now >= start && now <= end;
  }
  if (mode === 'times') {
    const days = parseScheduleDays(slide.schedule_days_json);
    if (!days.length) {
      return false;
    }
    const day = now.getDay();
    if (days.indexOf(day) === -1) {
      return false;
    }
    const startMinutes = parseTimeToMinutes(slide.schedule_start_time);
    const endMinutes = parseTimeToMinutes(slide.schedule_end_time);
    if (startMinutes === null || endMinutes === null) {
      return false;
    }
    const nowMinutes = now.getHours() * 60 + now.getMinutes();
    if (startMinutes <= endMinutes) {
      return nowMinutes >= startMinutes && nowMinutes <= endMinutes;
    }
    return nowMinutes >= startMinutes || nowMinutes <= endMinutes;
  }
  return true;
}
// Build the cache key for a template layout.
function getTemplateLayoutCacheKey(template) {
  var viewportKey = window.innerWidth + 'x' + window.innerHeight;
  return [currentPlaylistSignature || '', template && template.id ? template.id : '', viewportKey].join('|');
}

// Build or reuse layout metadata for a template.
function getTemplateLayout(template) {
  if (!template || !template.id) {
    return null;
  }

  syncRenderCacheViewport();

  var cacheKey = getTemplateLayoutCacheKey(template);
  if (Object.prototype.hasOwnProperty.call(templateLayoutCache, cacheKey)) {
    return templateLayoutCache[cacheKey];
  }

  var templateCanvas = getTemplateCanvasSize(template);
  var canvasSize = fitCanvasSize(templateCanvas.width, templateCanvas.height, window.innerWidth, window.innerHeight);
  var canvasScale = canvasSize.width / templateCanvas.width;
  var regions = (template.regions || []).map(function (region) {
    var left = (Number(region.x) / templateCanvas.width) * 100;
    var top = (Number(region.y) / templateCanvas.height) * 100;
    var width = (Number(region.width) / templateCanvas.width) * 100;
    var height = (Number(region.height) / templateCanvas.height) * 100;
    var baseStyle = 'left:' + left + '%;top:' + top + '%;width:' + width + '%;height:' + height + '%;z-index:' + Number(region.z_index || 0) + ';';
    var pixelWidth = Math.max(1, Math.round(Number(region.width || 0) || 1));
    var pixelHeight = Math.max(1, Math.round(Number(region.height || 0) || 1));

    return {
      regionKey: region.region_key,
      regionType: region.region_type,
      label: region.label,
      baseStyle: baseStyle,
      pixelWidth: pixelWidth,
      pixelHeight: pixelHeight,
      fontFamily: region.font_family || null,
      fontSize: region.font_size || null,
      fontColor: region.font_color || null,
      canvasScale: canvasScale
    };
  });

  var layout = {
    canvasWidth: canvasSize.width,
    canvasHeight: canvasSize.height,
    background: template.background_image_path ? '<img class="template-background" src="' + escapeHtml(template.background_image_path) + '" alt="" />' : '',
    backgroundColor: template.background_color || '#111111',
    regions: regions
  };

  templateLayoutCache[cacheKey] = layout;
  return layout;
}

// Build a dark backdrop style for template and media canvases.
function buildBackdropStyle(backgroundColor, backgroundImagePath) {
  var color = String(backgroundColor || '#111111').trim() || '#111111';
  var style = 'background-color:' + escapeHtml(color) + ';';
  var gradient = 'linear-gradient(rgba(0, 0, 0, 0.42), rgba(0, 0, 0, 0.42))';

  if (backgroundImagePath) {
    style += 'background-image:' + gradient + ',url("' + escapeHtml(backgroundImagePath) + '");';
    style += 'background-position:center,center;background-size:100% 100%,cover;background-repeat:no-repeat,no-repeat;';
    return style;
  }

  style += 'background-image:' + gradient + ';background-position:center;background-size:100% 100%;background-repeat:no-repeat;';
  return style;
}

// Build the cache key for a template render plan.
function getTemplateRenderPlanCacheKey(template) {
  return getTemplateLayoutCacheKey(template);
}

// Build or reuse the render plan for a template.
function getTemplateRenderPlan(template) {
  if (!template || !template.id) {
    return null;
  }

  syncRenderCacheViewport();

  var cacheKey = getTemplateRenderPlanCacheKey(template);
  if (Object.prototype.hasOwnProperty.call(templateRenderPlanCache, cacheKey)) {
    return templateRenderPlanCache[cacheKey];
  }

  var layout = getTemplateLayout(template);
  var plan = {
    layout: layout,
    renderRegion: function (region, regionContent) {
      if (region.regionType === 'image') {
        return renderImageRegion(region, regionContent);
      }
      if (region.regionType === 'webpage') {
        return renderWebpageRegion(region, regionContent);
      }
      if (region.regionType === 'rtmp') {
        return renderRtmpRegion(region, regionContent);
      }
      if (region.regionType === 'rss') {
        return renderRssRegion(region, regionContent);
      }
      if (region.regionType === 'api') {
        return renderApiRegion(region, regionContent);
      }
      if (region.regionType === 'html') {
        return renderHtmlRegion(region, regionContent);
      }
      return renderTextRegion(region, regionContent);
    }
  };

  templateRenderPlanCache[cacheKey] = plan;
  return plan;
}

// Render a template-based slide using the cached layout.
function renderTemplateSlideMarkup(slide) {
  const template = slide.template;
  const content = slide.content || {};
  const plan = getTemplateRenderPlan(template);
  const layout = plan ? plan.layout : null;
  const regions = layout ? layout.regions.map(function (region) {
    const regionContent = content[region.regionKey] || {};
    return plan.renderRegion(region, regionContent);
  }).join('') : '';
  const stageStyle = layout ? buildBackdropStyle(layout.backgroundColor || '#111111', template.background_image_path) : '';
  return renderSlideShell(slide, '', (layout ? layout.canvasWidth : 0) + 'px', (layout ? layout.canvasHeight : 0) + 'px', '<div class="template-stage" style="' + stageStyle + '">' + (layout ? layout.background : '') + regions + '</div>');
}

// Media rendering helpers.
// Build the direct media element for a slide.
function renderMediaSlideContent(slide) {
  if (slide.kind === 'image') {
    return '<img src="' + escapeHtml(slide.media_url) + '" alt="slide" />';
  }
  return '';
}

// Render a slide that contains direct media content.
function renderMediaSlideMarkup(slide) {
  const canvasSize = fitCanvasSize(16, 9, window.innerWidth, window.innerHeight);
  const media = renderMediaSlideContent(slide);
  const canvasStyle = slide.kind === 'image' ? buildBackdropStyle('#111111', slide.media_url) : '';
  return renderSlideShell(slide, 'slide-media', canvasSize.width + 'px', canvasSize.height + 'px', media, canvasStyle);
}

// Render the shared slide shell around slide-specific inner content.
function renderSlideShell(slide, canvasClass, canvasWidth, canvasHeight, innerHtml, canvasStyle) {
  const body = slide.body ? '<div class="body">' + escapeHtml(slide.body) + '</div>' : '';
  const className = canvasClass ? 'slide-canvas ' + canvasClass : 'slide-canvas';
  const style = 'width:' + canvasWidth + ';height:' + canvasHeight + ';' + (canvasStyle || '');
  return '<div class="slide"><div class="' + className + '" style="' + style + '">' + innerHtml + body + '</div></div>';
}

// Build the cache key for rendered slide markup.
function getSlideMarkupCacheKey(slide) {
  var viewportKey = window.innerWidth + 'x' + window.innerHeight;
  return [currentPlaylistSignature || '', slide && slide.id ? slide.id : '', slide && slide.template_id ? slide.template_id : '', viewportKey].join('|');
}

// Look up a previously rendered slide in the cache.
function getCachedSlideMarkup(slide) {
  var cacheKey = getSlideMarkupCacheKey(slide);
  return Object.prototype.hasOwnProperty.call(slideMarkupCache, cacheKey) ? slideMarkupCache[cacheKey] : null;
}

// Store rendered slide markup in the cache.
function setCachedSlideMarkup(slide, markup) {
  syncRenderCacheViewport();
  slideMarkupCache[getSlideMarkupCacheKey(slide)] = markup;
}

// Slide rendering and markup cache helpers.
// Choose the right slide renderer and cache the result.
function buildSlideMarkup(slide) {
  lastRenderedSlide = slide || null;
  syncBlackoutState();
  var cachedMarkup = getCachedSlideMarkup(slide);
  if (cachedMarkup) {
    return cachedMarkup;
  }

  var markup = '';
  if (slide.template_id && slide.template) {
    markup = renderTemplateSlideMarkup(slide);
    setCachedSlideMarkup(slide, markup);
    return markup;
  }

  markup = renderMediaSlideMarkup(slide);
  setCachedSlideMarkup(slide, markup);
  return markup;
}