function getRssFeedById(feedId) {
  var feeds = Array.isArray(initialData && initialData.rssFeeds) ? initialData.rssFeeds : [];
  var normalizedId = Number(feedId || 0);
  return feeds.find(function (feed) {
    return Number(feed.id) === normalizedId;
  }) || null;
}

function getRssFeedItem(feedId, itemNumber) {
  var feed = getRssFeedById(feedId);
  var items = feed && Array.isArray(feed.items) ? feed.items : [];
  var parsedItemNumber = Math.max(1, Number(itemNumber || 1));
  var index = Number.isFinite(parsedItemNumber) && parsedItemNumber > 0 ? parsedItemNumber - 1 : 0;
  return items[index] || null;
}

function resolveRssPath(value, path) {
  var current = value;
  if (!path) {
    return current;
  }

  String(path).split('.').forEach(function (segment) {
    if (current === undefined || current === null) {
      current = '';
      return;
    }
    current = current[segment];
  });

  return current === undefined || current === null ? '' : current;
}

function substituteRssVariables(html, item) {
  var source = String(html || '');
  return source.replace(/\{\{\s*([a-zA-Z0-9_]+)(?:\.([a-zA-Z0-9_.]+))?\s*\}\}/g, function (_match, tokenName, tokenPath) {
    if (!item || typeof item !== 'object') {
      return '';
    }
    var key = tokenName === 'item' && tokenPath ? tokenPath : tokenName;
    return escapeHtml(resolveRssPath(item, key || ''));
  });
}

function renderRssRegion(region, regionContent) {
  var content = regionContent && regionContent.value !== undefined ? regionContent.value : '';
  var feedId = regionContent && regionContent.feed_id !== undefined ? regionContent.feed_id : null;
  var itemNumber = regionContent && regionContent.item_number !== undefined ? regionContent.item_number : 1;
  var fontFamily = sanitizeFontFamily(regionContent.font_family || region.fontFamily);
  var fontSize = sanitizeFontSize(regionContent.font_size || region.fontSize);
  var fontColor = sanitizeTextColor(regionContent.font_color || region.fontColor);
  var item = getRssFeedItem(feedId, itemNumber);
  var body = item ? substituteRssVariables(content, item) : '';
  if (!body && item) {
    var summaryParts = [];
    if (item.title) {
      summaryParts.push('<h3>' + escapeHtml(item.title) + '</h3>');
    }
    if (item.description) {
      summaryParts.push('<div>' + sanitizeRichText(item.description) + '</div>');
    }
    body = summaryParts.join('');
  }
  var contentStyle = 'width:' + region.pixelWidth + 'px;height:' + region.pixelHeight + 'px;transform:scale(' + region.canvasScale + ');transform-origin:top left;' + (fontFamily ? 'font-family:' + escapeHtml(fontFamily) + ';' : '') + 'font-size:' + fontSize + 'px;color:' + escapeHtml(fontColor) + ';';
  var renderedBody = body ? renderEditorJsContent(body) : '<div class="template-region-placeholder">RSS item</div>';
  return '<div class="template-region rss" style="' + region.baseStyle + '"><div class="template-region-text-scale" style="' + contentStyle + '">' + renderedBody + '</div></div>';
}