class Asciidoctor::Converter::DocBook5Converter

def asciimath_available?
  (@asciimath_status ||= load_asciimath) == :loaded
end

def author_tag doc, author
  result = []
  result << '<author>'
  result << '<personname>'
  result << %(<firstname>#{doc.sub_replacements author.firstname}</firstname>) if author.firstname
  result << %(<othername>#{doc.sub_replacements author.middlename}</othername>) if author.middlename
  result << %(<surname>#{doc.sub_replacements author.lastname}</surname>) if author.lastname
  result << '</personname>'
  result << %(<email>#{author.email}</email>) if author.email
  result << '</author>'
  result.join LF
end

def blockquote_tag node, tag_name = nil
  if tag_name
    start_tag, end_tag = %(<#{tag_name}), %(</#{tag_name}>)
  else
    start_tag, end_tag = '<blockquote', '</blockquote>'
  end
  result = [%(#{start_tag}#{common_attributes node.id, node.role, node.reftext}>)]
  result << %(<title>#{node.title}</title>) if node.title?
  if (node.attr? 'attribution') || (node.attr? 'citetitle')
    result << '<attribution>'
    result << (node.attr 'attribution') if node.attr? 'attribution'
    result << %(<citetitle>#{node.attr 'citetitle'}</citetitle>) if node.attr? 'citetitle'
    result << '</attribution>'
  end
  result << yield
  result << end_tag
  result.join LF
end

def common_attributes id, role = nil, reftext = nil
  if id
    attrs = %( xml:id="#{id}"#{role ? %[ role="#{role}"] : ''})
  elsif role
    attrs = %( role="#{role}")
  else
    attrs = ''
  end
  if reftext
    if (reftext.include? '<') && ((reftext = reftext.gsub XmlSanitizeRx, '').include? ' ')
      reftext = (reftext.squeeze ' ').strip
    end
    reftext = (reftext.gsub '"', '&quot;') if reftext.include? '"'
    %(#{attrs} xreflabel="#{reftext}")
  else
    attrs
  end
end

def convert_admonition node
  %(<#{tag_name = node.attr 'name'}#{common_attributes node.id, node.role, node.reftext}>
title_tag node}#{enclose_content node}
#{tag_name}>)
end

def convert_colist node
  result = []
  result << %(<calloutlist#{common_attributes node.id, node.role, node.reftext}>)
  result << %(<title>#{node.title}</title>) if node.title?
  node.items.each do |item|
    result << %(<callout arearefs="#{item.attr 'coids'}">)
    result << %(<para>#{item.text}</para>)
    result << item.content if item.blocks?
    result << '</callout>'
  end
  result << %(</calloutlist>)
  result.join LF
end

def convert_dlist node
  result = []
  if node.style == 'horizontal'
    result << %(<#{tag_name = node.title? ? 'table' : 'informaltable'}#{common_attributes node.id, node.role, node.reftext} tabstyle="horizontal" frame="none" colsep="0" rowsep="0">
title_tag node}<tgroup cols="2">
olspec colwidth="#{node.attr 'labelwidth', 15}*"/>
olspec colwidth="#{node.attr 'itemwidth', 85}*"/>
body valign="top">)
    node.items.each do |terms, dd|
      result << %(<row>
ntry>)
      terms.each {|dt| result << %(<simpara>#{dt.text}</simpara>) }
      result << %(</entry>
ntry>)
      if dd
        result << %(<simpara>#{dd.text}</simpara>) if dd.text?
        result << dd.content if dd.blocks?
      end
      result << %(</entry>
row>)
    end
    result << %(</tbody>
tgroup>
#{tag_name}>)
  else
    tags = DLIST_TAGS[node.style]
    list_tag = tags[:list]
    entry_tag = tags[:entry]
    label_tag = tags[:label]
    term_tag = tags[:term]
    item_tag = tags[:item]
    if list_tag
      result << %(<#{list_tag}#{common_attributes node.id, node.role, node.reftext}>)
      result << %(<title>#{node.title}</title>) if node.title?
    end
    node.items.each do |terms, dd|
      result << %(<#{entry_tag}>)
      result << %(<#{label_tag}>) if label_tag
      terms.each {|dt| result << %(<#{term_tag}>#{dt.text}</#{term_tag}>) }
      result << %(</#{label_tag}>) if label_tag
      result << %(<#{item_tag}>)
      if dd
        result << %(<simpara>#{dd.text}</simpara>) if dd.text?
        result << dd.content if dd.blocks?
      end
      result << %(</#{item_tag}>)
      result << %(</#{entry_tag}>)
    end
    result << %(</#{list_tag}>) if list_tag
  end
  result.join LF
end

def convert_document node
  result = ['<?xml version="1.0" encoding="UTF-8"?>']
  if node.attr? 'toc'
    if node.attr? 'toclevels'
      result << %(<?asciidoc-toc maxdepth="#{node.attr 'toclevels'}"?>)
    else
      result << '<?asciidoc-toc?>'
    end
  end
  if node.attr? 'sectnums'
    if node.attr? 'sectnumlevels'
      result << %(<?asciidoc-numbered maxdepth="#{node.attr 'sectnumlevels'}"?>)
    else
      result << '<?asciidoc-numbered?>'
    end
  end
  lang_attribute = (node.attr? 'nolang') ? '' : %( xml:lang="#{node.attr 'lang', 'en'}")
  if (root_tag_name = node.doctype) == 'manpage'
    root_tag_name = 'refentry'
  end
  result << %(<#{root_tag_name} xmlns="http://docbook.org/ns/docbook" xmlns:xl="http://www.w3.org/1999/xlink" version="5.0"#{lang_attribute}#{common_attributes node.id}>)
  result << (document_info_tag node) unless node.noheader
  unless (docinfo_content = node.docinfo :header).empty?
    result << docinfo_content
  end
  result << node.content if node.blocks?
  unless (docinfo_content = node.docinfo :footer).empty?
    result << docinfo_content
  end
  result << %(</#{root_tag_name}>)
  result.join LF
end

def convert_example node
  if node.title?
    %(<example#{common_attributes node.id, node.role, node.reftext}>
itle>#{node.title}</title>
enclose_content node}
example>)
  else
    %(<informalexample#{common_attributes node.id, node.role, node.reftext}>
enclose_content node}
informalexample>)
  end
end

def convert_floating_title node
  %(<bridgehead#{common_attributes node.id, node.role, node.reftext} renderas="sect#{node.level}">#{node.title}</bridgehead>)
end

def convert_image node
  # NOTE according to the DocBook spec, content area, scaling, and scaling to fit are mutually exclusive
  # See http://tdg.docbook.org/tdg/4.5/imagedata-x.html#d0e79635
  if node.attr? 'scaledwidth'
    width_attribute = %( width="#{node.attr 'scaledwidth'}")
    depth_attribute = ''
    scale_attribute = ''
  elsif node.attr? 'scale'
    # QUESTION should we set the viewport using width and depth? (the scaled image would be contained within this box)
    #width_attribute = (node.attr? 'width') ? %( width="#{node.attr 'width'}") : ''
    #depth_attribute = (node.attr? 'height') ? %( depth="#{node.attr 'height'}") : ''
    scale_attribute = %( scale="#{node.attr 'scale'}")
  else
    width_attribute = (node.attr? 'width') ? %( contentwidth="#{node.attr 'width'}") : ''
    depth_attribute = (node.attr? 'height') ? %( contentdepth="#{node.attr 'height'}") : ''
    scale_attribute = ''
  end
  align_attribute = (node.attr? 'align') ? %( align="#{node.attr 'align'}") : ''
  mediaobject = %(<mediaobject>
mageobject>
magedata fileref="#{node.image_uri(node.attr 'target')}"#{width_attribute}#{depth_attribute}#{scale_attribute}#{align_attribute}/>
imageobject>
extobject><phrase>#{node.alt}</phrase></textobject>
mediaobject>)
  if node.title?
    %(<figure#{common_attributes node.id, node.role, node.reftext}>
itle>#{node.title}</title>
mediaobject}
figure>)
  else
    %(<informalfigure#{common_attributes node.id, node.role, node.reftext}>
mediaobject}
informalfigure>)
  end
end

def convert_inline_anchor node
  case node.type
  when :ref
    %(<anchor#{common_attributes((id = node.id), nil, node.reftext || %([#{id}]))}/>)
  when :xref
    if (path = node.attributes['path'])
      # QUESTION should we use refid as fallback text instead? (like the html5 backend?)
      %(<link xl:href="#{node.target}">#{node.text || path}</link>)
    else
      linkend = node.attributes['fragment'] || node.target
      (text = node.text) ? %(<link linkend="#{linkend}">#{text}</link>) : %(<xref linkend="#{linkend}"/>)
    end
  when :link
    %(<link xl:href="#{node.target}">#{node.text}</link>)
  when :bibref
    %(<anchor#{common_attributes node.id, nil, "[#{node.reftext || node.id}]"}/>#{text})
  else
    logger.warn %(unknown anchor type: #{node.type.inspect})
    nil
  end
end

def convert_inline_break node
  %(#{node.text}<?asciidoc-br?>)
end

def convert_inline_button node
  %(<guibutton>#{node.text}</guibutton>)
end

def convert_inline_callout node
  %(<co#{common_attributes node.id}/>)
end

def convert_inline_footnote node
  if node.type == :xref
    %(<footnoteref linkend="#{node.target}"/>)
  else
    %(<footnote#{common_attributes node.id}><simpara>#{node.text}</simpara></footnote>)
  end
end

def convert_inline_image node
  width_attribute = (node.attr? 'width') ? %( contentwidth="#{node.attr 'width'}") : ''
  depth_attribute = (node.attr? 'height') ? %( contentdepth="#{node.attr 'height'}") : ''
  %(<inlinemediaobject>
mageobject>
magedata fileref="#{node.type == 'icon' ? (node.icon_uri node.target) : (node.image_uri node.target)}"#{width_attribute}#{depth_attribute}/>
imageobject>
extobject><phrase>#{node.alt}</phrase></textobject>
inlinemediaobject>)
end

def convert_inline_indexterm node
  if (see = node.attr 'see')
    rel = %(\n<see>#{see}</see>)
  elsif (see_also_list = node.attr 'see-also')
    rel = see_also_list.map {|see_also| %(\n<seealso>#{see_also}</seealso>) }.join
  else
    rel = ''
  end
  if node.type == :visible
    %(<indexterm>
rimary>#{node.text}</primary>#{rel}
indexterm>#{node.text})
  else
    if (numterms = (terms = node.attr 'terms').size) > 2
      %(<indexterm>
rimary>#{terms[0]}</primary><secondary>#{terms[1]}</secondary><tertiary>#{terms[2]}</tertiary>#{rel}
indexterm>#{(node.document.option? 'indexterm-promotion') ? %[
ndexterm>
rimary>#{terms[1]}</primary><secondary>#{terms[2]}</secondary>
indexterm>
ndexterm>
rimary>#{terms[2]}</primary>
indexterm>] : ''})
    elsif numterms > 1
      %(<indexterm>
rimary>#{terms[0]}</primary><secondary>#{terms[1]}</secondary>#{rel}
indexterm>#{(node.document.option?  'indexterm-promotion') ? %[
ndexterm>
rimary>#{terms[1]}</primary>
indexterm>] : ''})
    else
      %(<indexterm>
rimary>#{terms[0]}</primary>#{rel}
indexterm>)
    end
  end
end

def convert_inline_kbd node
  if (keys = node.attr 'keys').size == 1
    %(<keycap>#{keys[0]}</keycap>)
  else
    %(<keycombo><keycap>#{keys.join '</keycap><keycap>'}</keycap></keycombo>)
  end
end

def convert_inline_menu node
  menu = node.attr 'menu'
  if (submenus = node.attr 'submenus').empty?
    if (menuitem = node.attr 'menuitem')
      %(<menuchoice><guimenu>#{menu}</guimenu> <guimenuitem>#{menuitem}</guimenuitem></menuchoice>)
    else
      %(<guimenu>#{menu}</guimenu>)
    end
  else
    %(<menuchoice><guimenu>#{menu}</guimenu> <guisubmenu>#{submenus.join '</guisubmenu> <guisubmenu>'}</guisubmenu> <guimenuitem>#{node.attr 'menuitem'}</guimenuitem></menuchoice>)
  end
end

def convert_inline_quoted node
  if (type = node.type) == :asciimath
    # NOTE fop requires jeuclid to process mathml markup
    asciimath_available? ? %(<inlineequation>#{(::AsciiMath.parse node.text).to_mathml 'mml:', 'xmlns:mml' => 'http://www.w3.org/1998/Math/MathML'}</inlineequation>) : %(<inlineequation><mathphrase><![CDATA[#{node.text}]]></mathphrase></inlineequation>)
  elsif type == :latexmath
    # unhandled math; pass source to alt and required mathphrase element; dblatex will process alt as LaTeX math
    %(<inlineequation><alt><![CDATA[#{equation = node.text}]]></alt><mathphrase><![CDATA[#{equation}]]></mathphrase></inlineequation>)
  else
    open, close, supports_phrase = QUOTE_TAGS[type]
    text = node.text
    if node.role
      if supports_phrase
        quoted_text = %(#{open}<phrase role="#{node.role}">#{text}</phrase>#{close})
      else
        quoted_text = %(#{open.chop} role="#{node.role}">#{text}#{close})
      end
    else
      quoted_text = %(#{open}#{text}#{close})
    end
    node.id ? %(<anchor#{common_attributes node.id, nil, text}/>#{quoted_text}) : quoted_text
  end
end

def convert_listing node
  informal = !node.title?
  common_attrs = common_attributes node.id, node.role, node.reftext
  if node.style == 'source'
    if (attrs = node.attributes).key? 'linenums'
      numbering_attrs = (attrs.key? 'start') ? %( linenumbering="numbered" startinglinenumber="#{attrs['start'].to_i}") : ' linenumbering="numbered"'
    else
      numbering_attrs = ' linenumbering="unnumbered"'
    end
    if attrs.key? 'language'
      wrapped_content = %(<programlisting#{informal ? common_attrs : ''} language="#{attrs['language']}"#{numbering_attrs}>#{node.content}</programlisting>)
    else
      wrapped_content = %(<screen#{informal ? common_attrs : ''}#{numbering_attrs}>#{node.content}</screen>)
    end
  else
    wrapped_content = %(<screen#{informal ? common_attrs : ''}>#{node.content}</screen>)
  end
  informal ? wrapped_content : %(<formalpara#{common_attrs}>
itle>#{node.title}</title>
ara>
wrapped_content}
para>
formalpara>)
end

def convert_literal node
  if node.title?
    %(<formalpara#{common_attributes node.id, node.role, node.reftext}>
itle>#{node.title}</title>
ara>
iterallayout class="monospaced">#{node.content}</literallayout>
para>
formalpara>)
  else
    %(<literallayout#{common_attributes node.id, node.role, node.reftext} class="monospaced">#{node.content}</literallayout>)
  end
end

def convert_olist node
  result = []
  num_attribute = node.style ? %( numeration="#{node.style}") : ''
  start_attribute = (node.attr? 'start') ? %( startingnumber="#{node.attr 'start'}") : ''
  result << %(<orderedlist#{common_attributes node.id, node.role, node.reftext}#{num_attribute}#{start_attribute}>)
  result << %(<title>#{node.title}</title>) if node.title?
  node.items.each do |item|
    result << %(<listitem#{common_attributes item.id, item.role}>)
    result << %(<simpara>#{item.text}</simpara>)
    result << item.content if item.blocks?
    result << '</listitem>'
  end
  result << %(</orderedlist>)
  result.join LF
end

def convert_open node
  case node.style
  when '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
      %(<abstract>
title_tag node}#{enclose_content node}
abstract>)
    end
  when 'partintro'
    unless 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
      %(<partintro#{common_attributes node.id, node.role, node.reftext}>
title_tag node}#{enclose_content node}
partintro>)
    end
  else
    reftext = node.reftext if (id = node.id)
    role = node.role
    if node.title?
      %(<formalpara#{common_attributes id, role, reftext}>
itle>#{node.title}</title>
ara>#{content_spacer = node.content_model == :compound ? LF : ''}#{node.content}#{content_spacer}</para>
formalpara>)
    elsif id || role
      if node.content_model == :compound
        %(<para#{common_attributes id, role, reftext}>
node.content}
para>)
      else
        %(<simpara#{common_attributes id, role, reftext}>#{node.content}</simpara>)
      end
    else
      enclose_content node
    end
  end
end

def convert_page_break node
  '<simpara><?asciidoc-pagebreak?></simpara>'
end

def convert_paragraph node
  if node.title?
    %(<formalpara#{common_attributes node.id, node.role, node.reftext}>
itle>#{node.title}</title>
ara>#{node.content}</para>
formalpara>)
  else
    %(<simpara#{common_attributes node.id, node.role, node.reftext}>#{node.content}</simpara>)
  end
end

def convert_preamble node
  if node.document.doctype == 'book'
    %(<preface#{common_attributes node.id, node.role, node.reftext}>
title_tag node, false}#{node.content}
preface>)
  else
    node.content
  end
end

def convert_quote node
  blockquote_tag(node, (node.has_role? 'epigraph') && 'epigraph') { enclose_content node }
end

def convert_section node
  if node.document.doctype == 'manpage'
    tag_name = MANPAGE_SECTION_TAGS[tag_name = node.sectname] || tag_name
  else
    tag_name = node.sectname
  end
  title_el = node.special && (node.option? 'untitled') ? '' : %(<title>#{node.title}</title>\n)
  %(<#{tag_name}#{common_attributes node.id, node.role, node.reftext}>
title_el}#{node.content}
#{tag_name}>)
end

def convert_sidebar node
  %(<sidebar#{common_attributes node.id, node.role, node.reftext}>
title_tag node}#{enclose_content node}
sidebar>)
end

def convert_stem node
  if (idx = node.subs.index :specialcharacters)
    node.subs.delete_at idx
    equation = node.content || ''
    idx > 0 ? (node.subs.insert idx, :specialcharacters) : (node.subs.unshift :specialcharacters)
  else
    equation = node.content || ''
  end
  if node.style == 'asciimath'
    # NOTE fop requires jeuclid to process mathml markup
    equation_data = asciimath_available? ? ((::AsciiMath.parse equation).to_mathml 'mml:', 'xmlns:mml' => 'http://www.w3.org/1998/Math/MathML') : %(<mathphrase><![CDATA[#{equation}]]></mathphrase>)
  else
    # unhandled math; pass source to alt and required mathphrase element; dblatex will process alt as LaTeX math
    equation_data = %(<alt><![CDATA[#{equation}]]></alt>
athphrase><![CDATA[#{equation}]]></mathphrase>)
  end
  if node.title?
    %(<equation#{common_attributes node.id, node.role, node.reftext}>
itle>#{node.title}</title>
equation_data}
equation>)
  else
    # WARNING dblatex displays the <informalequation> element inline instead of block as documented (except w/ mathml)
    %(<informalequation#{common_attributes node.id, node.role, node.reftext}>
equation_data}
informalequation>)
  end
end

def convert_table node
  has_body = false
  result = []
  pgwide_attribute = (node.option? 'pgwide') ? ' pgwide="1"' : ''
  if (frame = node.attr 'frame', 'all', 'table-frame') == 'ends'
    frame = 'topbot'
  end
  grid = node.attr 'grid', nil, 'table-grid'
  result << %(<#{tag_name = node.title? ? 'table' : 'informaltable'}#{common_attributes node.id, node.role, node.reftext}#{pgwide_attribute} frame="#{frame}" rowsep="#{['none', 'cols'].include?(grid) ? 0 : 1}" colsep="#{['none', 'rows'].include?(grid) ? 0 : 1}"#{(node.attr? 'orientation', 'landscape', 'table-orientation') ? ' orient="land"' : ''}>)
  if (node.option? 'unbreakable')
    result << '<?dbfo keep-together="always"?>'
  elsif (node.option? 'breakable')
    result << '<?dbfo keep-together="auto"?>'
  end
  result << %(<title>#{node.title}</title>) if tag_name == 'table'
  col_width_key = if (width = (node.attr? 'width') ? (node.attr 'width') : nil)
    TABLE_PI_NAMES.each do |pi_name|
      result << %(<?#{pi_name} table-width="#{width}"?>)
    end
    'colabswidth'
  else
    'colpcwidth'
  end
  result << %(<tgroup cols="#{node.attr 'colcount'}">)
  node.columns.each do |col|
    result << %(<colspec colname="col_#{col.attr 'colnumber'}" colwidth="#{col.attr col_width_key}*"/>)
  end
  node.rows.to_h.each do |tsec, rows|
    next if rows.empty?
    has_body = true if tsec == :body
    result << %(<t#{tsec}>)
    rows.each do |row|
      result << '<row>'
      row.each do |cell|
        halign_attribute = (cell.attr? 'halign') ? %( align="#{cell.attr 'halign'}") : ''
        valign_attribute = (cell.attr? 'valign') ? %( valign="#{cell.attr 'valign'}") : ''
        colspan_attribute = cell.colspan ? %( namest="col_#{colnum = cell.column.attr 'colnumber'}" nameend="col_#{colnum + cell.colspan - 1}") : ''
        rowspan_attribute = cell.rowspan ? %( morerows="#{cell.rowspan - 1}") : ''
        # NOTE <entry> may not have whitespace (e.g., line breaks) as a direct descendant according to DocBook rules
        entry_start = %(<entry#{halign_attribute}#{valign_attribute}#{colspan_attribute}#{rowspan_attribute}>)
        if tsec == :head
          cell_content = cell.text
        else
          case cell.style
          when :asciidoc
            cell_content = cell.content
          when :literal
            cell_content = %(<literallayout class="monospaced">#{cell.text}</literallayout>)
          when :header
            cell_content = (cell_content = cell.content).empty? ? '' : %(<simpara><emphasis role="strong">#{cell_content.join '</emphasis></simpara><simpara><emphasis role="strong">'}</emphasis></simpara>)
          else
            cell_content = (cell_content = cell.content).empty? ? '' : %(<simpara>#{cell_content.join '</simpara><simpara>'}</simpara>)
          end
        end
        entry_end = (node.document.attr? 'cellbgcolor') ? %(<?dbfo bgcolor="#{node.document.attr 'cellbgcolor'}"?></entry>) : '</entry>'
        result << %(#{entry_start}#{cell_content}#{entry_end})
      end
      result << '</row>'
    end
    result << %(</t#{tsec}>)
  end
  result << '</tgroup>'
  result << %(</#{tag_name}>)
  logger.warn 'tables must have at least one body row' unless has_body
  result.join LF
end

def convert_thematic_break node
  '<simpara><?asciidoc-hr?></simpara>'
end

def convert_ulist node
  result = []
  if node.style == 'bibliography'
    result << %(<bibliodiv#{common_attributes node.id, node.role, node.reftext}>)
    result << %(<title>#{node.title}</title>) if node.title?
    node.items.each do |item|
      result << '<bibliomixed>'
      result << %(<bibliomisc>#{item.text}</bibliomisc>)
      result << item.content if item.blocks?
      result << '</bibliomixed>'
    end
    result << '</bibliodiv>'
  else
    mark_type = (checklist = node.option? 'checklist') ? 'none' : node.style
    mark_attribute = mark_type ? %( mark="#{mark_type}") : ''
    result << %(<itemizedlist#{common_attributes node.id, node.role, node.reftext}#{mark_attribute}>)
    result << %(<title>#{node.title}</title>) if node.title?
    node.items.each do |item|
      text_marker = (item.attr? 'checked') ? '&#10003; ' : '&#10063; ' if checklist && (item.attr? 'checkbox')
      result << %(<listitem#{common_attributes item.id, item.role}>)
      result << %(<simpara>#{text_marker || ''}#{item.text}</simpara>)
      result << item.content if item.blocks?
      result << '</listitem>'
    end
    result << '</itemizedlist>'
  end
  result.join LF
end

def convert_verse node
  blockquote_tag(node, (node.has_role? 'epigraph') && 'epigraph') { %(<literallayout>#{node.content}</literallayout>) }
end

def cover_tag doc, face, use_placeholder = false
  if (cover_image = doc.attr %(#{face}-cover-image))
    width_attr = ''
    depth_attr = ''
    if (cover_image.include? ':') && ImageMacroRx =~ cover_image
      attrlist = $2
      cover_image = doc.image_uri $1
      unless attrlist.empty?
        attrs = (AttributeList.new attrlist).parse ['alt', 'width', 'height']
        if attrs.key? 'scaledwidth'
          # NOTE scalefit="1" is the default in this case
          width_attr = %( width="#{attrs['scaledwidth']}")
        else
          width_attr = %( contentwidth="#{attrs['width']}") if attrs.key? 'width'
          depth_attr = %( contentdepth="#{attrs['height']}") if attrs.key? 'height'
        end
      end
    end
    %(<cover role="#{face}">
ediaobject>
mageobject>
magedata fileref="#{cover_image}"#{width_attr}#{depth_attr}/>
imageobject>
mediaobject>
cover>)
  elsif use_placeholder
    %(<cover role="#{face}"/>)
  end
end

def document_info_tag doc
  result = ['<info>']
  unless doc.notitle
    if (title = doc.doctitle partition: true, use_fallback: true).subtitle?
      result << %(<title>#{title.main}</title>
ubtitle>#{title.subtitle}</subtitle>)
    else
      result << %(<title>#{title}</title>)
    end
  end
  if (date = (doc.attr? 'revdate') ? (doc.attr 'revdate') : ((doc.attr? 'reproducible') ? nil : (doc.attr 'docdate')))
    result << %(<date>#{date}</date>)
  end
  if doc.attr? 'copyright'
    CopyrightRx =~ (doc.attr 'copyright')
    result << '<copyright>'
    result << %(<holder>#{$1}</holder>)
    result << %(<year>#{$2}</year>) if $2
    result << '</copyright>'
  end
  if doc.header?
    unless (authors = doc.authors).empty?
      if authors.size > 1
        result << '<authorgroup>'
        authors.each {|author| result << (author_tag doc, author) }
        result << '</authorgroup>'
      else
        result << (author_tag doc, (author = authors[0]))
        result << %(<authorinitials>#{author.initials}</authorinitials>) if author.initials
      end
    end
    if (doc.attr? 'revdate') && ((doc.attr? 'revnumber') || (doc.attr? 'revremark'))
      result << %(<revhistory>
evision>)
      result << %(<revnumber>#{doc.attr 'revnumber'}</revnumber>) if doc.attr? 'revnumber'
      result << %(<date>#{doc.attr 'revdate'}</date>) if doc.attr? 'revdate'
      result << %(<authorinitials>#{doc.attr 'authorinitials'}</authorinitials>) if doc.attr? 'authorinitials'
      result << %(<revremark>#{doc.attr 'revremark'}</revremark>) if doc.attr? 'revremark'
      result << %(</revision>
revhistory>)
    end
    if (doc.attr? 'front-cover-image') || (doc.attr? 'back-cover-image')
      if (back_cover_tag = cover_tag doc, 'back')
        result << (cover_tag doc, 'front', true)
        result << back_cover_tag
      elsif (front_cover_tag = cover_tag doc, 'front')
        result << front_cover_tag
      end
    end
    result << %(<orgname>#{doc.attr 'orgname'}</orgname>) if doc.attr? 'orgname'
    unless (docinfo_content = doc.docinfo).empty?
      result << docinfo_content
    end
  end
  result << '</info>'
  if doc.doctype == 'manpage'
    result << '<refmeta>'
    result << %(<refentrytitle>#{doc.attr 'mantitle'}</refentrytitle>) if doc.attr? 'mantitle'
    result << %(<manvolnum>#{doc.attr 'manvolnum'}</manvolnum>) if doc.attr? 'manvolnum'
    result << %(<refmiscinfo class="source">#{doc.attr 'mansource', '&#160;'}</refmiscinfo>)
    result << %(<refmiscinfo class="manual">#{doc.attr 'manmanual', '&#160;'}</refmiscinfo>)
    result << '</refmeta>'
    result << '<refnamediv>'
    result += (doc.attr 'mannames').map {|n| %(<refname>#{n}</refname>) } if doc.attr? 'mannames'
    result << %(<refpurpose>#{doc.attr 'manpurpose'}</refpurpose>) if doc.attr? 'manpurpose'
    result << '</refnamediv>'
  end
  result.join LF
end

def enclose_content node
  node.content_model == :compound ? node.content : %(<simpara>#{node.content}</simpara>)
end

def initialize backend, opts = {}
  @backend = backend
  init_backend_traits basebackend: 'docbook', filetype: 'xml', outfilesuffix: '.xml', supports_templates: true
end

def load_asciimath
  (defined? ::AsciiMath.parse) ? :loaded : (Helpers.require_library 'asciimath', true, :warn).nil? ? :unavailable : :loaded
end

def title_tag node, optional = true
  !optional || node.title? ? %(<title>#{node.title}</title>\n) : ''
end