class Asciidoctor::Converter::Html5Converter

def append_boolean_attribute name, xml
  xml ? %( #{name}="#{name}") : %( #{name})
end

def append_link_constraint_attrs node, attrs = []
  rel = 'nofollow' if node.option? 'nofollow'
  if (window = node.attributes['window'])
    attrs << %( target="#{window}")
    attrs << (rel ? %( rel="#{rel} noopener") : ' rel="noopener"') if window == '_blank' || (node.option? 'noopener')
  elsif rel
    attrs << %( rel="#{rel}")
  end
  attrs
end

def convert node, transform = node.node_name, opts = nil
  if transform == 'inline_quoted'; return convert_inline_quoted node
  elsif transform == 'paragraph'; return convert_paragraph node
  elsif transform == 'inline_anchor'; return convert_inline_anchor node
  elsif transform == 'section'; return convert_section node
  elsif transform == 'listing'; return convert_listing node
  elsif transform == 'literal'; return convert_literal node
  elsif transform == 'ulist'; return convert_ulist node
  elsif transform == 'olist'; return convert_olist node
  elsif transform == 'dlist'; return convert_dlist node
  elsif transform == 'admonition'; return convert_admonition node
  elsif transform == 'colist'; return convert_colist node
  elsif transform == 'embedded'; return convert_embedded node
  elsif transform == 'example'; return convert_example node
  elsif transform == 'floating_title'; return convert_floating_title node
  elsif transform == 'image'; return convert_image node
  elsif transform == 'inline_break'; return convert_inline_break node
  elsif transform == 'inline_button'; return convert_inline_button node
  elsif transform == 'inline_callout'; return convert_inline_callout node
  elsif transform == 'inline_footnote'; return convert_inline_footnote node
  elsif transform == 'inline_image'; return convert_inline_image node
  elsif transform == 'inline_indexterm'; return convert_inline_indexterm node
  elsif transform == 'inline_kbd'; return convert_inline_kbd node
  elsif transform == 'inline_menu'; return convert_inline_menu node
  elsif transform == 'open'; return convert_open node
  elsif transform == 'page_break'; return convert_page_break node
  elsif transform == 'preamble'; return convert_preamble node
  elsif transform == 'quote'; return convert_quote node
  elsif transform == 'sidebar'; return convert_sidebar node
  elsif transform == 'stem'; return convert_stem node
  elsif transform == 'table'; return convert_table node
  elsif transform == 'thematic_break'; return convert_thematic_break node
  elsif transform == 'verse'; return convert_verse node
  elsif transform == 'video'; return convert_video node
  elsif transform == 'document'; return convert_document node
  elsif transform == 'toc'; return convert_toc node
  elsif transform == 'pass'; return convert_pass node
  elsif transform == 'audio'; return convert_audio node
  else; return super
  end
end

def convert_admonition node
  id_attr = node.id ? %( id="#{node.id}") : ''
  name = node.attr 'name'
  title_element = node.title? ? %(<div class="title">#{node.title}</div>\n) : ''
  if node.document.attr? 'icons'
    if (node.document.attr? 'icons', 'font') && !(node.attr? 'icon')
      label = %(<i class="fa icon-#{name}" title="#{node.attr 'textlabel'}"></i>)
    else
      label = %(<img src="#{node.icon_uri name}" alt="#{node.attr 'textlabel'}"#{@void_element_slash}>)
    end
  else
    label = %(<div class="title">#{node.attr 'textlabel'}</div>)
  end
  %(<div#{id_attr} class="admonitionblock #{name}#{(role = node.role) ? " #{role}" : ''}">
able>
r>
d class="icon">
label}
td>
d class="content">
title_element}#{node.content}
td>
tr>
table>
div>)
end

def convert_audio node
  xml = @xml_mode
  id_attribute = node.id ? %( id="#{node.id}") : ''
  classes = ['audioblock', node.role].compact
  class_attribute = %( class="#{classes.join ' '}")
  title_element = node.title? ? %(<div class="title">#{node.title}</div>\n) : ''
  start_t = node.attr 'start'
  end_t = node.attr 'end'
  time_anchor = (start_t || end_t) ? %(#t=#{start_t || ''}#{end_t ? ",#{end_t}" : ''}) : ''
  %(<div#{id_attribute}#{class_attribute}>
title_element}<div class="content">
udio src="#{node.media_uri(node.attr 'target')}#{time_anchor}"#{(node.option? 'autoplay') ? (append_boolean_attribute 'autoplay', xml) : ''}#{(node.option? 'nocontrols') ? '' : (append_boolean_attribute 'controls', xml)}#{(node.option? 'loop') ? (append_boolean_attribute 'loop', xml) : ''}>
ur browser does not support the audio tag.
audio>
div>
div>)
end

def convert_colist node
  result = []
  id_attribute = node.id ? %( id="#{node.id}") : ''
  classes = ['colist', node.style, node.role].compact
  class_attribute = %( class="#{classes.join ' '}")
  result << %(<div#{id_attribute}#{class_attribute}>)
  result << %(<div class="title">#{node.title}</div>) if node.title?
  if node.document.attr? 'icons'
    result << '<table>'
    font_icons, num = (node.document.attr? 'icons', 'font'), 0
    node.items.each do |item|
      num += 1
      if font_icons
        num_label = %(<i class="conum" data-value="#{num}"></i><b>#{num}</b>)
      else
        num_label = %(<img src="#{node.icon_uri "callouts/#{num}"}" alt="#{num}"#{@void_element_slash}>)
      end
      result << %(<tr>
d>#{num_label}</td>
d>#{item.text}#{item.blocks? ? LF + item.content : ''}</td>
tr>)
    end
    result << '</table>'
  else
    result << '<ol>'
    node.items.each do |item|
      result << %(<li>
>#{item.text}</p>#{item.blocks? ? LF + item.content : ''}
li>)
    end
    result << '</ol>'
  end
  result << '</div>'
  result.join LF
end

def convert_dlist node
  result = []
  id_attribute = node.id ? %( id="#{node.id}") : ''
  classes = case node.style
  when 'qanda'
    ['qlist', 'qanda', node.role]
  when 'horizontal'
    ['hdlist', node.role]
  else
    ['dlist', node.style, node.role]
  end.compact
  class_attribute = %( class="#{classes.join ' '}")
  result << %(<div#{id_attribute}#{class_attribute}>)
  result << %(<div class="title">#{node.title}</div>) if node.title?
  case node.style
  when 'qanda'
    result << '<ol>'
    node.items.each do |terms, dd|
      result << '<li>'
      terms.each do |dt|
        result << %(<p><em>#{dt.text}</em></p>)
      end
      if dd
        result << %(<p>#{dd.text}</p>) if dd.text?
        result << dd.content if dd.blocks?
      end
      result << '</li>'
    end
    result << '</ol>'
  when 'horizontal'
    slash = @void_element_slash
    result << '<table>'
    if (node.attr? 'labelwidth') || (node.attr? 'itemwidth')
      result << '<colgroup>'
      col_style_attribute = (node.attr? 'labelwidth') ? %( style="width: #{(node.attr 'labelwidth').chomp '%'}%;") : ''
      result << %(<col#{col_style_attribute}#{slash}>)
      col_style_attribute = (node.attr? 'itemwidth') ? %( style="width: #{(node.attr 'itemwidth').chomp '%'}%;") : ''
      result << %(<col#{col_style_attribute}#{slash}>)
      result << '</colgroup>'
    end
    node.items.each do |terms, dd|
      result << '<tr>'
      result << %(<td class="hdlist1#{(node.option? 'strong') ? ' strong' : ''}">)
      first_term = true
      terms.each do |dt|
        result << %(<br#{slash}>) unless first_term
        result << dt.text
        first_term = nil
      end
      result << '</td>'
      result << '<td class="hdlist2">'
      if dd
        result << %(<p>#{dd.text}</p>) if dd.text?
        result << dd.content if dd.blocks?
      end
      result << '</td>'
      result << '</tr>'
    end
    result << '</table>'
  else
    result << '<dl>'
    dt_style_attribute = node.style ? '' : ' class="hdlist1"'
    node.items.each do |terms, dd|
      terms.each do |dt|
        result << %(<dt#{dt_style_attribute}>#{dt.text}</dt>)
      end
      if dd
        result << '<dd>'
        result << %(<p>#{dd.text}</p>) if dd.text?
        result << dd.content if dd.blocks?
        result << '</dd>'
      end
    end
    result << '</dl>'
  end
  result << '</div>'
  result.join LF
end

def convert_document node
  br = %(<br#{slash = @void_element_slash}>)
  unless (asset_uri_scheme = (node.attr 'asset-uri-scheme', 'https')).empty?
    asset_uri_scheme = %(#{asset_uri_scheme}:)
  end
  cdn_base_url = %(#{asset_uri_scheme}//cdnjs.cloudflare.com/ajax/libs)
  linkcss = node.attr? 'linkcss'
  result = ['<!DOCTYPE html>']
  lang_attribute = (node.attr? 'nolang') ? '' : %( lang="#{node.attr 'lang', 'en'}")
  result << %(<html#{@xml_mode ? ' xmlns="http://www.w3.org/1999/xhtml"' : ''}#{lang_attribute}>)
  result << %(<head>
eta charset="#{node.attr 'encoding', 'UTF-8'}"#{slash}>
eta http-equiv="X-UA-Compatible" content="IE=edge"#{slash}>
eta name="viewport" content="width=device-width, initial-scale=1.0"#{slash}>
eta name="generator" content="Asciidoctor #{node.attr 'asciidoctor-version'}"#{slash}>)
  result << %(<meta name="application-name" content="#{node.attr 'app-name'}"#{slash}>) if node.attr? 'app-name'
  result << %(<meta name="description" content="#{node.attr 'description'}"#{slash}>) if node.attr? 'description'
  result << %(<meta name="keywords" content="#{node.attr 'keywords'}"#{slash}>) if node.attr? 'keywords'
  result << %(<meta name="author" content="#{((authors = node.sub_replacements node.attr 'authors').include? '<') ? (authors.gsub XmlSanitizeRx, '') : authors}"#{slash}>) if node.attr? 'authors'
  result << %(<meta name="copyright" content="#{node.attr 'copyright'}"#{slash}>) if node.attr? 'copyright'
  if node.attr? 'favicon'
    if (icon_href = node.attr 'favicon').empty?
      icon_href, icon_type = 'favicon.ico', 'image/x-icon'
    else
      icon_type = (icon_ext = ::File.extname icon_href) == '.ico' ? 'image/x-icon' : %(image/#{icon_ext.slice 1, icon_ext.length})
    end
    result << %(<link rel="icon" type="#{icon_type}" href="#{icon_href}"#{slash}>)
  end
  result << %(<title>#{node.doctitle sanitize: true, use_fallback: true}</title>)
  if DEFAULT_STYLESHEET_KEYS.include?(node.attr 'stylesheet')
    if (webfonts = node.attr 'webfonts')
      result << %(<link rel="stylesheet" href="#{asset_uri_scheme}//fonts.googleapis.com/css?family=#{webfonts.empty? ? 'Open+Sans:300,300italic,400,400italic,600,600italic%7CNoto+Serif:400,400italic,700,700italic%7CDroid+Sans+Mono:400,700' : webfonts}"#{slash}>)
    end
    if linkcss
      result << %(<link rel="stylesheet" href="#{node.normalize_web_path DEFAULT_STYLESHEET_NAME, (node.attr 'stylesdir', ''), false}"#{slash}>)
    else
      result << %(<style>
Stylesheets.instance.primary_stylesheet_data}
style>)
    end
  elsif node.attr? 'stylesheet'
    if linkcss
      result << %(<link rel="stylesheet" href="#{node.normalize_web_path((node.attr 'stylesheet'), (node.attr 'stylesdir', ''))}"#{slash}>)
    else
      result << %(<style>
node.read_asset node.normalize_system_path((node.attr 'stylesheet'), (node.attr 'stylesdir', '')), warn_on_failure: true, label: 'stylesheet'}
style>)
    end
  end
  if node.attr? 'icons', 'font'
    if node.attr? 'iconfont-remote'
      result << %(<link rel="stylesheet" href="#{node.attr 'iconfont-cdn', %[#{cdn_base_url}/font-awesome/#{FONT_AWESOME_VERSION}/css/font-awesome.min.css]}"#{slash}>)
    else
      iconfont_stylesheet = %(#{node.attr 'iconfont-name', 'font-awesome'}.css)
      result << %(<link rel="stylesheet" href="#{node.normalize_web_path iconfont_stylesheet, (node.attr 'stylesdir', ''), false}"#{slash}>)
    end
  end
  if (syntax_hl = node.syntax_highlighter) && (syntax_hl.docinfo? :head)
    result << (syntax_hl.docinfo :head, node, linkcss: linkcss)
  end
  unless (docinfo_content = node.docinfo).empty?
    result << docinfo_content
  end
  result << '</head>'
  body_attrs = node.id ? [%(id="#{node.id}")] : []
  if (sectioned = node.sections?) && (node.attr? 'toc-class') && (node.attr? 'toc') && (node.attr? 'toc-placement', 'auto')
    classes = [node.doctype, (node.attr 'toc-class'), %(toc-#{node.attr 'toc-position', 'header'})]
  else
    classes = [node.doctype]
  end
  classes << node.role if node.role?
  body_attrs << %(class="#{classes.join ' '}")
  body_attrs << %(style="max-width: #{node.attr 'max-width'};") if node.attr? 'max-width'
  result << %(<body #{body_attrs.join ' '}>)
  unless (docinfo_content = node.docinfo :header).empty?
    result << docinfo_content
  end
  unless node.noheader
    result << '<div id="header">'
    if node.doctype == 'manpage'
      result << %(<h1>#{node.doctitle} Manual Page</h1>)
      if sectioned && (node.attr? 'toc') && (node.attr? 'toc-placement', 'auto')
        result << %(<div id="toc" class="#{node.attr 'toc-class', 'toc'}">
iv id="toctitle">#{node.attr 'toc-title'}</div>
convert_outline node}
div>)
      end
      result << (generate_manname_section node) if node.attr? 'manpurpose'
    else
      if node.header?
        result << %(<h1>#{node.header.title}</h1>) unless node.notitle
        details = []
        idx = 1
        node.authors.each do |author|
          details << %(<span id="author#{idx > 1 ? idx : ''}" class="author">#{node.sub_replacements author.name}</span>#{br})
          details << %(<span id="email#{idx > 1 ? idx : ''}" class="email">#{node.sub_macros author.email}</span>#{br}) if author.email
          idx += 1
        end
        if node.attr? 'revnumber'
          details << %(<span id="revnumber">#{((node.attr 'version-label') || '').downcase} #{node.attr 'revnumber'}#{(node.attr? 'revdate') ? ',' : ''}</span>)
        end
        if node.attr? 'revdate'
          details << %(<span id="revdate">#{node.attr 'revdate'}</span>)
        end
        if node.attr? 'revremark'
          details << %(#{br}<span id="revremark">#{node.attr 'revremark'}</span>)
        end
        unless details.empty?
          result << '<div class="details">'
          result.concat details
          result << '</div>'
        end
      end
      if sectioned && (node.attr? 'toc') && (node.attr? 'toc-placement', 'auto')
        result << %(<div id="toc" class="#{node.attr 'toc-class', 'toc'}">
iv id="toctitle">#{node.attr 'toc-title'}</div>
convert_outline node}
div>)
      end
    end
    result << '</div>'
  end
  result << %(<div id="content">
node.content}
div>)
  if node.footnotes? && !(node.attr? 'nofootnotes')
    result << %(<div id="footnotes">
r#{slash}>)
    node.footnotes.each do |footnote|
      result << %(<div class="footnote" id="_footnotedef_#{footnote.index}">
 href="#_footnoteref_#{footnote.index}">#{footnote.index}</a>. #{footnote.text}
div>)
    end
    result << '</div>'
  end
  unless node.nofooter
    result << '<div id="footer">'
    result << '<div id="footer-text">'
    result << %(#{node.attr 'version-label'} #{node.attr 'revnumber'}#{br}) if node.attr? 'revnumber'
    result << %(#{node.attr 'last-update-label'} #{node.attr 'docdatetime'}) if (node.attr? 'last-update-label') && !(node.attr? 'reproducible')
    result << '</div>'
    result << '</div>'
  end
  # JavaScript (and auxiliary stylesheets) loaded at the end of body for performance reasons
  # See http://www.html5rocks.com/en/tutorials/speed/script-loading/
  if syntax_hl && (syntax_hl.docinfo? :footer)
    result << (syntax_hl.docinfo :footer, node, cdn_base_url: cdn_base_url, linkcss: linkcss, self_closing_tag_slash: slash)
  end
  if node.attr? 'stem'
    eqnums_val = node.attr 'eqnums', 'none'
    eqnums_val = 'AMS' if eqnums_val.empty?
    eqnums_opt = %( equationNumbers: { autoNumber: "#{eqnums_val}" } )
    # IMPORTANT inspect calls on delimiter arrays are intentional for JavaScript compat (emulates JSON.stringify)
    result << %(<script type="text/x-mathjax-config">
thJax.Hub.Config({
messageStyle: "none",
tex2jax: {
  inlineMath: [#{INLINE_MATH_DELIMITERS[:latexmath].inspect}],
  displayMath: [#{BLOCK_MATH_DELIMITERS[:latexmath].inspect}],
  ignoreClass: "nostem|nolatexmath"
},
asciimath2jax: {
  delimiters: [#{BLOCK_MATH_DELIMITERS[:asciimath].inspect}],
  ignoreClass: "nostem|noasciimath"
},
TeX: {#{eqnums_opt}}

thJax.Hub.Register.StartupHook("AsciiMath Jax Ready", function () {
MathJax.InputJax.AsciiMath.postfilterHooks.Add(function (data, node) {
  if ((node = data.script.parentNode) && (node = node.parentNode) && node.classList.contains('stemblock')) {
    data.math.root.display = "block"
  }
  return data
})

script>
cript src="#{cdn_base_url}/mathjax/#{MATHJAX_VERSION}/MathJax.js?config=TeX-MML-AM_HTMLorMML"></script>)
  end
  unless (docinfo_content = node.docinfo :footer).empty?
    result << docinfo_content
  end
  result << '</body>'
  result << '</html>'
  result.join LF
end

def convert_embedded node
  result = []
  if node.doctype == 'manpage'
    # QUESTION should notitle control the manual page title?
    unless node.notitle
      id_attr = node.id ? %( id="#{node.id}") : ''
      result << %(<h1#{id_attr}>#{node.doctitle} Manual Page</h1>)
    end
    result << (generate_manname_section node) if node.attr? 'manpurpose'
  elsif node.header? && !node.notitle
    id_attr = node.id ? %( id="#{node.id}") : ''
    result << %(<h1#{id_attr}>#{node.header.title}</h1>)
  end
  if node.sections? && (node.attr? 'toc') && (toc_p = node.attr 'toc-placement') != 'macro' && toc_p != 'preamble'
    result << %(<div id="toc" class="toc">
iv id="toctitle">#{node.attr 'toc-title'}</div>
convert_outline node}
div>)
  end
  result << node.content
  if node.footnotes? && !(node.attr? 'nofootnotes')
    result << %(<div id="footnotes">
r#{@void_element_slash}>)
    node.footnotes.each do |footnote|
      result << %(<div class="footnote" id="_footnotedef_#{footnote.index}">
 href="#_footnoteref_#{footnote.index}">#{footnote.index}</a>. #{footnote.text}
div>)
    end
    result << '</div>'
  end
  result.join LF
end

def convert_example node
  id_attribute = node.id ? %( id="#{node.id}") : ''
  if node.option? 'collapsible'
    class_attribute = node.role ? %( class="#{node.role}") : ''
    summary_element = node.title? ? %(<summary class="title">#{node.title}</summary>) : '<summary class="title">Details</summary>'
    %(<details#{id_attribute}#{class_attribute}#{(node.option? 'open') ? ' open' : ''}>
summary_element}
iv class="content">
node.content}
div>
details>)
  else
    title_element = node.title? ? %(<div class="title">#{node.captioned_title}</div>\n) : ''
    %(<div#{id_attribute} class="exampleblock#{(role = node.role) ? " #{role}" : ''}">
title_element}<div class="content">
node.content}
div>
div>)
  end
end

def convert_floating_title node
  tag_name = %(h#{node.level + 1})
  id_attribute = node.id ? %( id="#{node.id}") : ''
  classes = [node.style, node.role].compact
  %(<#{tag_name}#{id_attribute} class="#{classes.join ' '}">#{node.title}</#{tag_name}>)
end

def convert_image node
  target = node.attr 'target'
  width_attr = (node.attr? 'width') ? %( width="#{node.attr 'width'}") : ''
  height_attr = (node.attr? 'height') ? %( height="#{node.attr 'height'}") : ''
  if ((node.attr? 'format', 'svg') || (target.include? '.svg')) && node.document.safe < SafeMode::SECURE &&
      ((svg = (node.option? 'inline')) || (obj = (node.option? 'interactive')))
    if svg
      img = (read_svg_contents node, target) || %(<span class="alt">#{node.alt}</span>)
    elsif obj
      fallback = (node.attr? 'fallback') ? %(<img src="#{node.image_uri(node.attr 'fallback')}" alt="#{encode_attribute_value node.alt}"#{width_attr}#{height_attr}#{@void_element_slash}>) : %(<span class="alt">#{node.alt}</span>)
      img = %(<object type="image/svg+xml" data="#{node.image_uri target}"#{width_attr}#{height_attr}>#{fallback}</object>)
    end
  end
  img ||= %(<img src="#{node.image_uri target}" alt="#{encode_attribute_value node.alt}"#{width_attr}#{height_attr}#{@void_element_slash}>)
  if node.attr? 'link'
    img = %(<a class="image" href="#{node.attr 'link'}"#{(append_link_constraint_attrs node).join}>#{img}</a>)
  end
  id_attr = node.id ? %( id="#{node.id}") : ''
  classes = ['imageblock']
  classes << (node.attr 'float') if node.attr? 'float'
  classes << %(text-#{node.attr 'align'}) if node.attr? 'align'
  classes << node.role if node.role
  class_attr = %( class="#{classes.join ' '}")
  title_el = node.title? ? %(\n<div class="title">#{node.captioned_title}</div>) : ''
  %(<div#{id_attr}#{class_attr}>
iv class="content">
img}
div>#{title_el}
div>)
end

def convert_inline_anchor node
  case node.type
  when :xref
    if (path = node.attributes['path'])
      attrs = (append_link_constraint_attrs node, node.role ? [%( class="#{node.role}")] : []).join
      text = node.text || path
    else
      attrs = node.role ? %( class="#{node.role}") : ''
      unless (text = node.text)
        refid = node.attributes['refid']
        if AbstractNode === (ref = (@refs ||= node.document.catalog[:refs])[refid])
          text = (ref.xreftext node.attr('xrefstyle', nil, true)) || %([#{refid}])
        else
          text = %([#{refid}])
        end
      end
    end
    %(<a href="#{node.target}"#{attrs}>#{text}</a>)
  when :ref
    %(<a id="#{node.id}"></a>)
  when :link
    attrs = node.id ? [%( id="#{node.id}")] : []
    attrs << %( class="#{node.role}") if node.role
    attrs << %( title="#{node.attr 'title'}") if node.attr? 'title'
    %(<a href="#{node.target}"#{(append_link_constraint_attrs node, attrs).join}>#{node.text}</a>)
  when :bibref
    %(<a id="#{node.id}"></a>[#{node.reftext || node.id}])
  else
    logger.warn %(unknown anchor type: #{node.type.inspect})
    nil
  end
end

def convert_inline_break node
  %(#{node.text}<br#{@void_element_slash}>)
end

def convert_inline_button node
  %(<b class="button">#{node.text}</b>)
end

def convert_inline_callout node
  if node.document.attr? 'icons', 'font'
    %(<i class="conum" data-value="#{node.text}"></i><b>(#{node.text})</b>)
  elsif node.document.attr? 'icons'
    src = node.icon_uri("callouts/#{node.text}")
    %(<img src="#{src}" alt="#{node.text}"#{@void_element_slash}>)
  else
    %(#{node.attributes['guard']}<b class="conum">(#{node.text})</b>)
  end
end

def convert_inline_footnote node
  if (index = node.attr 'index')
    if node.type == :xref
      %(<sup class="footnoteref">[<a class="footnote" href="#_footnotedef_#{index}" title="View footnote.">#{index}</a>]</sup>)
    else
      id_attr = node.id ? %( id="_footnote_#{node.id}") : ''
      %(<sup class="footnote"#{id_attr}>[<a id="_footnoteref_#{index}" class="footnote" href="#_footnotedef_#{index}" title="View footnote.">#{index}</a>]</sup>)
    end
  elsif node.type == :xref
    %(<sup class="footnoteref red" title="Unresolved footnote reference.">[#{node.text}]</sup>)
  end
end

def convert_inline_image node
  if (type = node.type) == 'icon' && (node.document.attr? 'icons', 'font')
    class_attr_val = %(fa fa-#{node.target})
    { 'size' => 'fa-', 'rotate' => 'fa-rotate-', 'flip' => 'fa-flip-' }.each do |key, prefix|
      class_attr_val = %(#{class_attr_val} #{prefix}#{node.attr key}) if node.attr? key
    end
    title_attr = (node.attr? 'title') ? %( title="#{node.attr 'title'}") : ''
    img = %(<i class="#{class_attr_val}"#{title_attr}></i>)
  elsif type == 'icon' && !(node.document.attr? 'icons')
    img = %([#{node.alt}])
  else
    target = node.target
    attrs = ['width', 'height', 'title'].map {|name| (node.attr? name) ? %( #{name}="#{node.attr name}") : '' }.join
    if type != 'icon' && ((node.attr? 'format', 'svg') || (target.include? '.svg')) &&
        node.document.safe < SafeMode::SECURE && ((svg = (node.option? 'inline')) || (obj = (node.option? 'interactive')))
      if svg
        img = (read_svg_contents node, target) || %(<span class="alt">#{node.alt}</span>)
      elsif obj
        fallback = (node.attr? 'fallback') ? %(<img src="#{node.image_uri(node.attr 'fallback')}" alt="#{encode_attribute_value node.alt}"#{attrs}#{@void_element_slash}>) : %(<span class="alt">#{node.alt}</span>)
        img = %(<object type="image/svg+xml" data="#{node.image_uri target}"#{attrs}>#{fallback}</object>)
      end
    end
    img ||= %(<img src="#{type == 'icon' ? (node.icon_uri target) : (node.image_uri target)}" alt="#{encode_attribute_value node.alt}"#{attrs}#{@void_element_slash}>)
  end
  if node.attr? 'link'
    img = %(<a class="image" href="#{node.attr 'link'}"#{(append_link_constraint_attrs node).join}>#{img}</a>)
  end
  if (role = node.role)
    if node.attr? 'float'
      class_attr_val = %(#{type} #{node.attr 'float'} #{role})
    else
      class_attr_val = %(#{type} #{role})
    end
  elsif node.attr? 'float'
    class_attr_val = %(#{type} #{node.attr 'float'})
  else
    class_attr_val = type
  end
  %(<span class="#{class_attr_val}">#{img}</span>)
end

def convert_inline_indexterm node
  node.type == :visible ? node.text : ''
end

def convert_inline_kbd node
  if (keys = node.attr 'keys').size == 1
    %(<kbd>#{keys[0]}</kbd>)
  else
    %(<span class="keyseq"><kbd>#{keys.join '</kbd>+<kbd>'}</kbd></span>)
  end
end

def convert_inline_menu node
  caret = (node.document.attr? 'icons', 'font') ? '&#160;<i class="fa fa-angle-right caret"></i> ' : '&#160;<b class="caret">&#8250;</b> '
  submenu_joiner = %(</b>#{caret}<b class="submenu">)
  menu = node.attr 'menu'
  if (submenus = node.attr 'submenus').empty?
    if (menuitem = node.attr 'menuitem')
      %(<span class="menuseq"><b class="menu">#{menu}</b>#{caret}<b class="menuitem">#{menuitem}</b></span>)
    else
      %(<b class="menuref">#{menu}</b>)
    end
  else
    %(<span class="menuseq"><b class="menu">#{menu}</b>#{caret}<b class="submenu">#{submenus.join submenu_joiner}</b>#{caret}<b class="menuitem">#{node.attr 'menuitem'}</b></span>)
  end
end

def convert_inline_quoted node
  open, close, tag = QUOTE_TAGS[node.type]
  if node.id
    class_attr = node.role ? %( class="#{node.role}") : ''
    if tag
      %(#{open.chop} id="#{node.id}"#{class_attr}>#{node.text}#{close})
    else
      %(<span id="#{node.id}"#{class_attr}>#{open}#{node.text}#{close}</span>)
    end
  elsif node.role
    if tag
      %(#{open.chop} class="#{node.role}">#{node.text}#{close})
    else
      %(<span class="#{node.role}">#{open}#{node.text}#{close}</span>)
    end
  else
    %(#{open}#{node.text}#{close})
  end
end

def convert_listing node
  nowrap = (node.option? 'nowrap') || !(node.document.attr? 'prewrap')
  if node.style == 'source'
    lang = node.attr 'language'
    if (syntax_hl = node.document.syntax_highlighter)
      opts = syntax_hl.highlight? ? {
        css_mode: ((doc_attrs = node.document.attributes)[%(#{syntax_hl.name}-css)] || :class).to_sym,
        style: doc_attrs[%(#{syntax_hl.name}-style)],
      } : {}
      opts[:nowrap] = nowrap
    else
      pre_open = %(<pre class="highlight#{nowrap ? ' nowrap' : ''}"><code#{lang ? %[ class="language-#{lang}" data-lang="#{lang}"] : ''}>)
      pre_close = '</code></pre>'
    end
  else
    pre_open = %(<pre#{nowrap ? ' class="nowrap"' : ''}>)
    pre_close = '</pre>'
  end
  id_attribute = node.id ? %( id="#{node.id}") : ''
  title_element = node.title? ? %(<div class="title">#{node.captioned_title}</div>\n) : ''
  %(<div#{id_attribute} class="listingblock#{(role = node.role) ? " #{role}" : ''}">
title_element}<div class="content">
syntax_hl ? (syntax_hl.format node, lang, opts) : pre_open + (node.content || '') + pre_close}
div>
div>)
end

def convert_literal node
  id_attribute = node.id ? %( id="#{node.id}") : ''
  title_element = node.title? ? %(<div class="title">#{node.title}</div>\n) : ''
  nowrap = !(node.document.attr? 'prewrap') || (node.option? 'nowrap')
  %(<div#{id_attribute} class="literalblock#{(role = node.role) ? " #{role}" : ''}">
title_element}<div class="content">
re#{nowrap ? ' class="nowrap"' : ''}>#{node.content}</pre>
div>
div>)
end

def convert_olist node
  result = []
  id_attribute = node.id ? %( id="#{node.id}") : ''
  classes = ['olist', node.style, node.role].compact
  class_attribute = %( class="#{classes.join ' '}")
  result << %(<div#{id_attribute}#{class_attribute}>)
  result << %(<div class="title">#{node.title}</div>) if node.title?
  type_attribute = (keyword = node.list_marker_keyword) ? %( type="#{keyword}") : ''
  start_attribute = (node.attr? 'start') ? %( start="#{node.attr 'start'}") : ''
  reversed_attribute = (node.option? 'reversed') ? (append_boolean_attribute 'reversed', @xml_mode) : ''
  result << %(<ol class="#{node.style}"#{type_attribute}#{start_attribute}#{reversed_attribute}>)
  node.items.each do |item|
    if item.id
      result << %(<li id="#{item.id}"#{item.role ? %[ class="#{item.role}"] : ''}>)
    elsif item.role
      result << %(<li class="#{item.role}">)
    else
      result << '<li>'
    end
    result << %(<p>#{item.text}</p>)
    result << item.content if item.blocks?
    result << '</li>'
  end
  result << '</ol>'
  result << '</div>'
  result.join LF
end

def convert_open node
  if (style = node.style) == 'abstract'
    if node.parent == node.document && node.document.doctype == 'book'
      logger.warn 'abstract block cannot be used in a document without a title when doctype is book. Excluding block content.'
      ''
    else
      id_attr = node.id ? %( id="#{node.id}") : ''
      title_el = node.title? ? %(<div class="title">#{node.title}</div>\n) : ''
      %(<div#{id_attr} class="quoteblock abstract#{(role = node.role) ? " #{role}" : ''}">
title_el}<blockquote>
node.content}
blockquote>
div>)
    end
  elsif style == 'partintro' && (node.level > 0 || node.parent.context != :section || node.document.doctype != 'book')
    logger.error 'partintro block can only be used when doctype is book and must be a child of a book part. Excluding block content.'
    ''
  else
      id_attr = node.id ? %( id="#{node.id}") : ''
      title_el = node.title? ? %(<div class="title">#{node.title}</div>\n) : ''
    %(<div#{id_attr} class="openblock#{style && style != 'open' ? " #{style}" : ''}#{(role = node.role) ? " #{role}" : ''}">
title_el}<div class="content">
node.content}
div>
div>)
  end
end

def convert_outline node, opts = {}
  return unless node.sections?
  sectnumlevels = opts[:sectnumlevels] || (node.document.attributes['sectnumlevels'] || 3).to_i
  toclevels = opts[:toclevels] || (node.document.attributes['toclevels'] || 2).to_i
  sections = node.sections
  # FIXME top level is incorrect if a multipart book starts with a special section defined at level 0
  result = [%(<ul class="sectlevel#{sections[0].level}">)]
  sections.each do |section|
    slevel = section.level
    if section.caption
      stitle = section.captioned_title
    elsif section.numbered && slevel <= sectnumlevels
      if slevel < 2 && node.document.doctype == 'book'
        if section.sectname == 'chapter'
          stitle =  %(#{(signifier = node.document.attributes['chapter-signifier']) ? "#{signifier} " : ''}#{section.sectnum} #{section.title})
        elsif section.sectname == 'part'
          stitle =  %(#{(signifier = node.document.attributes['part-signifier']) ? "#{signifier} " : ''}#{section.sectnum nil, ':'} #{section.title})
        else
          stitle = %(#{section.sectnum} #{section.title})
        end
      else
        stitle = %(#{section.sectnum} #{section.title})
      end
    else
      stitle = section.title
    end
    stitle = stitle.gsub DropAnchorRx, '' if stitle.include? '<a'
    if slevel < toclevels && (child_toc_level = convert_outline section, toclevels: toclevels, sectnumlevels: sectnumlevels)
      result << %(<li><a href="##{section.id}">#{stitle}</a>)
      result << child_toc_level
      result << '</li>'
    else
      result << %(<li><a href="##{section.id}">#{stitle}</a></li>)
    end
  end
  result << '</ul>'
  result.join LF
end

def convert_page_break node
  '<div style="page-break-after: always;"></div>'
end

def convert_paragraph node
  if node.role
    attributes = %(#{node.id ? %[ id="#{node.id}"] : ''} class="paragraph #{node.role}")
  elsif node.id
    attributes = %( id="#{node.id}" class="paragraph")
  else
    attributes = ' class="paragraph"'
  end
  if node.title?
    %(<div#{attributes}>
iv class="title">#{node.title}</div>
>#{node.content}</p>
div>)
  else
    %(<div#{attributes}>
>#{node.content}</p>
div>)
  end
end

def convert_preamble node
  if (doc = node.document).attr?('toc-placement', 'preamble') && doc.sections? && (doc.attr? 'toc')
    toc = %(
iv id="toc" class="#{doc.attr 'toc-class', 'toc'}">
iv id="toctitle">#{doc.attr 'toc-title'}</div>
convert_outline doc}
div>)
  else
    toc = ''
  end
  %(<div id="preamble">
iv class="sectionbody">
node.content}
div>#{toc}
div>)
end

def convert_quote node
  id_attribute = node.id ? %( id="#{node.id}") : ''
  classes = ['quoteblock', node.role].compact
  class_attribute = %( class="#{classes.join ' '}")
  title_element = node.title? ? %(\n<div class="title">#{node.title}</div>) : ''
  attribution = (node.attr? 'attribution') ? (node.attr 'attribution') : nil
  citetitle = (node.attr? 'citetitle') ? (node.attr 'citetitle') : nil
  if attribution || citetitle
    cite_element = citetitle ? %(<cite>#{citetitle}</cite>) : ''
    attribution_text = attribution ? %(&#8212; #{attribution}#{citetitle ? "<br#{@void_element_slash}>\n" : ''}) : ''
    attribution_element = %(\n<div class="attribution">\n#{attribution_text}#{cite_element}\n</div>)
  else
    attribution_element = ''
  end
  %(<div#{id_attribute}#{class_attribute}>#{title_element}
lockquote>
node.content}
blockquote>#{attribution_element}
div>)
end

def convert_section node
  doc_attrs = node.document.attributes
  level = node.level
  if node.caption
    title = node.captioned_title
  elsif node.numbered && level <= (doc_attrs['sectnumlevels'] || 3).to_i
    if level < 2 && node.document.doctype == 'book'
      if node.sectname == 'chapter'
        title = %(#{(signifier = doc_attrs['chapter-signifier']) ? "#{signifier} " : ''}#{node.sectnum} #{node.title})
      elsif node.sectname == 'part'
        title = %(#{(signifier = doc_attrs['part-signifier']) ? "#{signifier} " : ''}#{node.sectnum nil, ':'} #{node.title})
      else
        title = %(#{node.sectnum} #{node.title})
      end
    else
      title = %(#{node.sectnum} #{node.title})
    end
  else
    title = node.title
  end
  if node.id
    id_attr = %( id="#{id = node.id}")
    if doc_attrs['sectlinks']
      title = %(<a class="link" href="##{id}">#{title}</a>)
    end
    if doc_attrs['sectanchors']
      # QUESTION should we add a font-based icon in anchor if icons=font?
      if doc_attrs['sectanchors'] == 'after'
        title = %(#{title}<a class="anchor" href="##{id}"></a>)
      else
        title = %(<a class="anchor" href="##{id}"></a>#{title})
      end
    end
  else
    id_attr = ''
  end
  if level == 0
    %(<h1#{id_attr} class="sect0#{(role = node.role) ? " #{role}" : ''}">#{title}</h1>
node.content})
  else
    %(<div class="sect#{level}#{(role = node.role) ? " #{role}" : ''}">
#{level + 1}#{id_attr}>#{title}</h#{level + 1}>
level == 1 ? %[<div class="sectionbody">
node.content}
div>] : node.content}
div>)
  end
end

def convert_sidebar node
  id_attribute = node.id ? %( id="#{node.id}") : ''
  title_element = node.title? ? %(<div class="title">#{node.title}</div>\n) : ''
  %(<div#{id_attribute} class="sidebarblock#{(role = node.role) ? " #{role}" : ''}">
iv class="content">
title_element}#{node.content}
div>
div>)
end

def convert_stem node
  id_attribute = node.id ? %( id="#{node.id}") : ''
  title_element = node.title? ? %(<div class="title">#{node.title}</div>\n) : ''
  open, close = BLOCK_MATH_DELIMITERS[style = node.style.to_sym]
  if (equation = node.content)
    if style == :asciimath && (equation.include? LF)
      br = %(<br#{@void_element_slash}>#{LF})
      equation = equation.gsub(StemBreakRx) { %(#{close}#{br * ($&.count LF)}#{open}) }
    end
    unless (equation.start_with? open) && (equation.end_with? close)
      equation = %(#{open}#{equation}#{close})
    end
  else
    equation = ''
  end
  %(<div#{id_attribute} class="stemblock#{(role = node.role) ? " #{role}" : ''}">
title_element}<div class="content">
equation}
div>
div>)
end

def convert_table node
  result = []
  id_attribute = node.id ? %( id="#{node.id}") : ''
  classes = ['tableblock', %(frame-#{node.attr 'frame', 'all', 'table-frame'}), %(grid-#{node.attr 'grid', 'all', 'table-grid'})]
  if (stripes = node.attr 'stripes', nil, 'table-stripes')
    classes << %(stripes-#{stripes})
  end
  styles = []
  if (autowidth = node.option? 'autowidth') && !(node.attr? 'width')
    classes << 'fit-content'
  elsif (tablewidth = node.attr 'tablepcwidth') == 100
    classes << 'stretch'
  else
    styles << %(width: #{tablewidth}%;)
  end
  classes << (node.attr 'float') if node.attr? 'float'
  if (role = node.role)
    classes << role
  end
  class_attribute = %( class="#{classes.join ' '}")
  style_attribute = styles.empty? ? '' : %( style="#{styles.join ' '}")
  result << %(<table#{id_attribute}#{class_attribute}#{style_attribute}>)
  result << %(<caption class="title">#{node.captioned_title}</caption>) if node.title?
  if (node.attr 'rowcount') > 0
    slash = @void_element_slash
    result << '<colgroup>'
    if autowidth
      result += (Array.new node.columns.size, %(<col#{slash}>))
    else
      node.columns.each do |col|
        result << ((col.option? 'autowidth') ? %(<col#{slash}>) : %(<col style="width: #{col.attr 'colpcwidth'}%;"#{slash}>))
      end
    end
    result << '</colgroup>'
    node.rows.to_h.each do |tsec, rows|
      next if rows.empty?
      result << %(<t#{tsec}>)
      rows.each do |row|
        result << '<tr>'
        row.each do |cell|
          if tsec == :head
            cell_content = cell.text
          else
            case cell.style
            when :asciidoc
              cell_content = %(<div class="content">#{cell.content}</div>)
            when :literal
              cell_content = %(<div class="literal"><pre>#{cell.text}</pre></div>)
            else
              cell_content = (cell_content = cell.content).empty? ? '' : %(<p class="tableblock">#{cell_content.join '</p>
 class="tableblock">'}</p>)
            end
          end
          cell_tag_name = (tsec == :head || cell.style == :header ? 'th' : 'td')
          cell_class_attribute = %( class="tableblock halign-#{cell.attr 'halign'} valign-#{cell.attr 'valign'}")
          cell_colspan_attribute = cell.colspan ? %( colspan="#{cell.colspan}") : ''
          cell_rowspan_attribute = cell.rowspan ? %( rowspan="#{cell.rowspan}") : ''
          cell_style_attribute = (node.document.attr? 'cellbgcolor') ? %( style="background-color: #{node.document.attr 'cellbgcolor'};") : ''
          result << %(<#{cell_tag_name}#{cell_class_attribute}#{cell_colspan_attribute}#{cell_rowspan_attribute}#{cell_style_attribute}>#{cell_content}</#{cell_tag_name}>)
        end
        result << '</tr>'
      end
      result << %(</t#{tsec}>)
    end
  end
  result << '</table>'
  result.join LF
end

def convert_thematic_break node
  %(<hr#{@void_element_slash}>)
end

def convert_toc node
  unless (doc = node.document).attr?('toc-placement', 'macro') && doc.sections? && (doc.attr? 'toc')
    return '<!-- toc disabled -->'
  end
  if node.id
    id_attr = %( id="#{node.id}")
    title_id_attr = %( id="#{node.id}title")
  else
    id_attr = ' id="toc"'
    title_id_attr = ' id="toctitle"'
  end
  title = node.title? ? node.title : (doc.attr 'toc-title')
  levels = (node.attr? 'levels') ? (node.attr 'levels').to_i : nil
  role = node.role? ? node.role : (doc.attr 'toc-class', 'toc')
  %(<div#{id_attr} class="#{role}">
iv#{title_id_attr} class="title">#{title}</div>
convert_outline doc, toclevels: levels}
div>)
end

def convert_ulist node
  result = []
  id_attribute = node.id ? %( id="#{node.id}") : ''
  div_classes = ['ulist', node.style, node.role].compact
  marker_checked = marker_unchecked = ''
  if (checklist = node.option? 'checklist')
    div_classes.unshift div_classes.shift, 'checklist'
    ul_class_attribute = ' class="checklist"'
    if node.option? 'interactive'
      if @xml_mode
        marker_checked = '<input type="checkbox" data-item-complete="1" checked="checked"/> '
        marker_unchecked = '<input type="checkbox" data-item-complete="0"/> '
      else
        marker_checked = '<input type="checkbox" data-item-complete="1" checked> '
        marker_unchecked = '<input type="checkbox" data-item-complete="0"> '
      end
    elsif node.document.attr? 'icons', 'font'
      marker_checked = '<i class="fa fa-check-square-o"></i> '
      marker_unchecked = '<i class="fa fa-square-o"></i> '
    else
      marker_checked = '&#10003; '
      marker_unchecked = '&#10063; '
    end
  else
    ul_class_attribute = node.style ? %( class="#{node.style}") : ''
  end
  result << %(<div#{id_attribute} class="#{div_classes.join ' '}">)
  result << %(<div class="title">#{node.title}</div>) if node.title?
  result << %(<ul#{ul_class_attribute}>)
  node.items.each do |item|
    if item.id
      result << %(<li id="#{item.id}"#{item.role ? %[ class="#{item.role}"] : ''}>)
    elsif item.role
      result << %(<li class="#{item.role}">)
    else
      result << '<li>'
    end
    if checklist && (item.attr? 'checkbox')
      result << %(<p>#{(item.attr? 'checked') ? marker_checked : marker_unchecked}#{item.text}</p>)
    else
      result << %(<p>#{item.text}</p>)
    end
    result << item.content if item.blocks?
    result << '</li>'
  end
  result << '</ul>'
  result << '</div>'
  result.join LF
end

def convert_verse node
  id_attribute = node.id ? %( id="#{node.id}") : ''
  classes = ['verseblock', node.role].compact
  class_attribute = %( class="#{classes.join ' '}")
  title_element = node.title? ? %(\n<div class="title">#{node.title}</div>) : ''
  attribution = (node.attr? 'attribution') ? (node.attr 'attribution') : nil
  citetitle = (node.attr? 'citetitle') ? (node.attr 'citetitle') : nil
  if attribution || citetitle
    cite_element = citetitle ? %(<cite>#{citetitle}</cite>) : ''
    attribution_text = attribution ? %(&#8212; #{attribution}#{citetitle ? "<br#{@void_element_slash}>\n" : ''}) : ''
    attribution_element = %(\n<div class="attribution">\n#{attribution_text}#{cite_element}\n</div>)
  else
    attribution_element = ''
  end
  %(<div#{id_attribute}#{class_attribute}>#{title_element}
re class="content">#{node.content}</pre>#{attribution_element}
div>)
end

def convert_video node
  xml = @xml_mode
  id_attribute = node.id ? %( id="#{node.id}") : ''
  classes = ['videoblock']
  classes << (node.attr 'float') if node.attr? 'float'
  classes << %(text-#{node.attr 'align'}) if node.attr? 'align'
  classes << node.role if node.role
  class_attribute = %( class="#{classes.join ' '}")
  title_element = node.title? ? %(\n<div class="title">#{node.title}</div>) : ''
  width_attribute = (node.attr? 'width') ? %( width="#{node.attr 'width'}") : ''
  height_attribute = (node.attr? 'height') ? %( height="#{node.attr 'height'}") : ''
  case node.attr 'poster'
  when 'vimeo'
    unless (asset_uri_scheme = (node.document.attr 'asset-uri-scheme', 'https')).empty?
      asset_uri_scheme = %(#{asset_uri_scheme}:)
    end
    start_anchor = (node.attr? 'start') ? %(#at=#{node.attr 'start'}) : ''
    delimiter = ['?']
    autoplay_param = (node.option? 'autoplay') ? %(#{delimiter.pop || '&amp;'}autoplay=1) : ''
    loop_param = (node.option? 'loop') ? %(#{delimiter.pop || '&amp;'}loop=1) : ''
    muted_param = (node.option? 'muted') ? %(#{delimiter.pop || '&amp;'}muted=1) : ''
    %(<div#{id_attribute}#{class_attribute}>#{title_element}
iv class="content">
frame#{width_attribute}#{height_attribute} src="#{asset_uri_scheme}//player.vimeo.com/video/#{node.attr 'target'}#{autoplay_param}#{loop_param}#{muted_param}#{start_anchor}" frameborder="0"#{(node.option? 'nofullscreen') ? '' : (append_boolean_attribute 'allowfullscreen', xml)}></iframe>
div>
div>)
  when 'youtube'
    unless (asset_uri_scheme = (node.document.attr 'asset-uri-scheme', 'https')).empty?
      asset_uri_scheme = %(#{asset_uri_scheme}:)
    end
    rel_param_val = (node.option? 'related') ? 1 : 0
    # NOTE start and end must be seconds (t parameter allows XmYs where X is minutes and Y is seconds)
    start_param = (node.attr? 'start') ? %(&amp;start=#{node.attr 'start'}) : ''
    end_param = (node.attr? 'end') ? %(&amp;end=#{node.attr 'end'}) : ''
    autoplay_param = (node.option? 'autoplay') ? '&amp;autoplay=1' : ''
    loop_param = (has_loop_param = node.option? 'loop') ? '&amp;loop=1' : ''
    mute_param = (node.option? 'muted') ? '&amp;mute=1' : ''
    controls_param = (node.option? 'nocontrols') ? '&amp;controls=0' : ''
    # cover both ways of controlling fullscreen option
    if node.option? 'nofullscreen'
      fs_param = '&amp;fs=0'
      fs_attribute = ''
    else
      fs_param = ''
      fs_attribute = append_boolean_attribute 'allowfullscreen', xml
    end
    modest_param = (node.option? 'modest') ? '&amp;modestbranding=1' : ''
    theme_param = (node.attr? 'theme') ? %(&amp;theme=#{node.attr 'theme'}) : ''
    hl_param = (node.attr? 'lang') ? %(&amp;hl=#{node.attr 'lang'}) : ''
    # parse video_id/list_id syntax where list_id (i.e., playlist) is optional
    target, list = (node.attr 'target').split '/', 2
    if (list ||= (node.attr 'list'))
      list_param = %(&amp;list=#{list})
    else
      # parse dynamic playlist syntax: video_id1,video_id2,...
      target, playlist = target.split ',', 2
      if (playlist ||= (node.attr 'playlist'))
        # INFO playlist bar doesn't appear in Firefox unless showinfo=1 and modestbranding=1
        list_param = %(&amp;playlist=#{playlist})
      else
        # NOTE for loop to work, playlist must be specified; use VIDEO_ID if there's no explicit playlist
        list_param = has_loop_param ? %(&amp;playlist=#{target}) : ''
      end
    end
    %(<div#{id_attribute}#{class_attribute}>#{title_element}
iv class="content">
frame#{width_attribute}#{height_attribute} src="#{asset_uri_scheme}//www.youtube.com/embed/#{target}?rel=#{rel_param_val}#{start_param}#{end_param}#{autoplay_param}#{loop_param}#{mute_param}#{controls_param}#{list_param}#{fs_param}#{modest_param}#{theme_param}#{hl_param}" frameborder="0"#{fs_attribute}></iframe>
div>
div>)
  else
    poster_attribute = (val = node.attr 'poster').nil_or_empty? ? '' : %( poster="#{node.media_uri val}")
    preload_attribute = (val = node.attr 'preload').nil_or_empty? ? '' : %( preload="#{val}")
    start_t = node.attr 'start'
    end_t = node.attr 'end'
    time_anchor = (start_t || end_t) ? %(#t=#{start_t || ''}#{end_t ? ",#{end_t}" : ''}) : ''
    %(<div#{id_attribute}#{class_attribute}>#{title_element}
iv class="content">
ideo src="#{node.media_uri(node.attr 'target')}#{time_anchor}"#{width_attribute}#{height_attribute}#{poster_attribute}#{(node.option? 'autoplay') ? (append_boolean_attribute 'autoplay', xml) : ''}#{(node.option? 'nocontrols') ? '' : (append_boolean_attribute 'controls', xml)}#{(node.option? 'loop') ? (append_boolean_attribute 'loop', xml) : ''}#{preload_attribute}>
ur browser does not support the video tag.
video>
div>
div>)
  end
end