export function canDomModuleBeInlined(domModule: parse5.ASTNode) {
  if (domModule.attrs.some((a) => a.name !== 'id')) {
    return false;  // attributes other than 'id' on dom-module
  }
  let templateTagsSeen = 0;
  for (const node of domModule.childNodes || []) {
    if (node.tagName === 'template') {
      if (node.attrs.length > 0) {
        return false;  // attributes on template
      }
      templateTagsSeen++;
    } else if (node.tagName === 'script') {
      // this is fine, scripts are handled elsewhere
    } else if (
        dom5.isTextNode(node) && dom5.getTextContent(node).trim() === '') {
      // empty text nodes are fine
    } else {
      return false;  // anything else, we can't convert it
    }
  }
  if (templateTagsSeen > 1) {
    return false;  // more than one template tag, can't convert
  }

  return true;
}

export function addIndentation(
    textNode: dom5.Node, additionalIndentation = '  ') {
  if (!dom5.isTextNode(textNode)) {
    return;
  }
  const text = dom5.getTextContent(textNode);
  const indentedText =
      text.split('\n')
          .map((line) => {
            return line.length > 0 ? additionalIndentation + line : line;
          })
          .join('\n');
  dom5.setTextContent(textNode, indentedText);
}

export function removeNode(
    parsedDocument: ParsedHtmlDocument, node: dom5.Node): Replacement[] {
  const parentChildren = node.parentNode!.childNodes!;
  const prevNode = parentChildren[parentChildren.indexOf(node)! - 1];
  const fix: Replacement[] = [];
  if (prevNode && dom5.isTextNode(prevNode)) {
    const trailingWhiteSpace =
        removeTrailingWhitespace(prevNode, parsedDocument);
    if (trailingWhiteSpace) {
      fix.push(trailingWhiteSpace);
    }
  }
  fix.push(
      {replacementText: '', range: parsedDocument.sourceRangeForNode(node)!});
  return fix;
}

export function getIndentationInside(parentNode: dom5.Node) {
  if (!parentNode.childNodes || parentNode.childNodes.length === 0) {
    return '';
  }
  const firstChild = parentNode.childNodes[0];
  if (!dom5.isTextNode(firstChild)) {
    return '';
  }
  const text = dom5.getTextContent(firstChild);
  const match = text.match(/(^|\n)([ \t]+)/);
  if (!match) {
    return '';
  }
  // If the it's an empty node with just one line of whitespace, like this:
  //     <div>
  //     </div>
  // Then the indentation of actual content inside is one level deeper than
  // the whitespace on that second line.
  if (parentNode.childNodes.length === 1 && text.match(/^\n[ \t]+$/)) {
    return match[2] + '  ';
  }
  return match[2];
}

export function isBlankTextNode(node: ASTNode): boolean {
  return node && dom5.isTextNode(node) &&
      dom5.getTextContent(node).trim() === '';
}