class Kramdown::Converter::Html

def add_syntax_highlighter_to_class_attr(attr, lang = nil)
  (attr['class'] = (attr['class'] || '') + " highlighter-#{@options[:syntax_highlighter]}").lstrip!
  attr['class'].sub!(/\blanguage-\S+|(^)/) { "language-#{lang}#{$1 ? ' ' : ''}" } if lang
end

def convert(el, indent = -@indent)
  send(DISPATCHER[el.type], el, indent)
end

def convert_a(el, indent)
  format_as_span_html(el.type, el.attr, inner(el, indent))
end

def convert_abbreviation(el, _indent)
  title = @root.options[:abbrev_defs][el.value]
  attr = @root.options[:abbrev_attr][el.value].dup
  attr['title'] = title unless title.empty?
  format_as_span_html("abbr", attr, el.value)
end

def convert_blank(_el, _indent)
  "\n"
end

def convert_blockquote(el, indent)
  format_as_indented_block_html(el.type, el.attr, inner(el, indent), indent)
end

def convert_br(_el, _indent)
  "<br />"
end

def convert_codeblock(el, indent)
  attr = el.attr.dup
  lang = extract_code_language!(attr)
  hl_opts = {}
  highlighted_code = highlight_code(el.value, el.options[:lang] || lang, :block, hl_opts)
  if highlighted_code
    add_syntax_highlighter_to_class_attr(attr, lang || hl_opts[:default_lang])
    "#{' ' * indent}<div#{html_attributes(attr)}>#{highlighted_code}#{' ' * indent}</div>\n"
  else
    result = escape_html(el.value)
    result.chomp!
    if el.attr['class'].to_s =~ /\bshow-whitespaces\b/
      result.gsub!(/(?:(^[ \t]+)|([ \t]+$)|([ \t]+))/) do |m|
        suffix = ($1 ? '-l' : ($2 ? '-r' : ''))
        m.scan(/./).map do |c|
          case c
          when "\t" then "<span class=\"ws-tab#{suffix}\">\t</span>"
          when " " then "<span class=\"ws-space#{suffix}\">&#8901;</span>"
          end
        end.join('')
      end
    end
    code_attr = {}
    code_attr['class'] = "language-#{lang}" if lang
    "#{' ' * indent}<pre#{html_attributes(attr)}>" \
      "<code#{html_attributes(code_attr)}>#{result}\n</code></pre>\n"
  end
end

def convert_codespan(el, _indent)
  attr = el.attr.dup
  lang = extract_code_language(attr)
  hl_opts = {}
  result = highlight_code(el.value, lang, :span, hl_opts)
  if result
    add_syntax_highlighter_to_class_attr(attr, hl_opts[:default_lang])
  else
    result = escape_html(el.value)
  end
  format_as_span_html('code', attr, result)
end

def convert_comment(el, indent)
  if el.options[:category] == :block
    "#{' ' * indent}<!-- #{el.value} -->\n"
  else
    "<!-- #{el.value} -->"
  end
end

def convert_dl(el, indent)
  format_as_indented_block_html(el.type, el.attr, inner(el, indent), indent)
end

def convert_dt(el, indent)
  attr = el.attr.dup
  @stack.last.options[:ial][:refs].each do |ref|
    if ref =~ /\Aauto_ids(?:-([\w-]+))?/
      attr['id'] = "#{$1}#{basic_generate_id(el.options[:raw_text])}".lstrip
      break
    end
  end if !attr['id'] && @stack.last.options[:ial] && @stack.last.options[:ial][:refs]
  format_as_block_html(el.type, attr, inner(el, indent), indent)
end

def convert_em(el, indent)
  format_as_span_html(el.type, el.attr, inner(el, indent))
end

def convert_entity(el, _indent)
  entity_to_str(el.value, el.options[:original])
end

def convert_footnote(el, _indent)
  repeat = ''
  name = @options[:footnote_prefix] + el.options[:name]
  if (footnote = @footnotes_by_name[name])
    number = footnote[2]
    repeat = ":#{footnote[3] += 1}"
  else
    number = @footnote_counter
    @footnote_counter += 1
    @footnotes << [name, el.value, number, 0]
    @footnotes_by_name[name] = @footnotes.last
  end
  "<sup id=\"fnref:#{name}#{repeat}\">" \
    "<a href=\"#fn:#{name}\" class=\"footnote\">" \
    "#{number}</a></sup>"
end

def convert_header(el, indent)
  attr = el.attr.dup
  if @options[:auto_ids] && !attr['id']
    attr['id'] = generate_id(el.options[:raw_text])
  end
  @toc << [el.options[:level], attr['id'], el.children] if attr['id'] && in_toc?(el)
  level = output_header_level(el.options[:level])
  format_as_block_html("h#{level}", attr, inner(el, indent), indent)
end

def convert_hr(el, indent)
  "#{' ' * indent}<hr#{html_attributes(el.attr)} />\n"
end

def convert_html_element(el, indent)
  res = inner(el, indent)
  if el.options[:category] == :span
    "<#{el.value}#{html_attributes(el.attr)}" + \
      (res.empty? && HTML_ELEMENTS_WITHOUT_BODY.include?(el.value) ? " />" : ">#{res}</#{el.value}>")
  else
    output = +''
    if @stack.last.type != :html_element || @stack.last.options[:content_model] != :raw
      output << ' ' * indent
    end
    output << "<#{el.value}#{html_attributes(el.attr)}"
    if el.options[:is_closed] && el.options[:content_model] == :raw
      output << " />"
    elsif !res.empty? && el.options[:content_model] != :block
      output << ">#{res}</#{el.value}>"
    elsif !res.empty?
      output << ">\n#{res.chomp}\n" << ' ' * indent << "</#{el.value}>"
    elsif HTML_ELEMENTS_WITHOUT_BODY.include?(el.value)
      output << " />"
    else
      output << "></#{el.value}>"
    end
    output << "\n" if @stack.last.type != :html_element || @stack.last.options[:content_model] != :raw
    output
  end
end

def convert_img(el, _indent)
  "<img#{html_attributes(el.attr)} />"
end

def convert_li(el, indent)
  output = ' ' * indent << "<#{el.type}" << html_attributes(el.attr) << ">"
  res = inner(el, indent)
  if el.children.empty? || (el.children.first.type == :p && el.children.first.options[:transparent])
    output << res << (res =~ /\n\Z/ ? ' ' * indent : '')
  else
    output << "\n" << res << ' ' * indent
  end
  output << "</#{el.type}>\n"
end

def convert_math(el, indent)
  if (result = format_math(el, indent: indent))
    result
  else
    attr = el.attr.dup
    attr['class'] = "#{attr['class']} kdmath".lstrip
    if el.options[:category] == :block
      format_as_block_html('div', attr, "$$\n#{el.value}\n$$", indent)
    else
      format_as_span_html('span', attr, "$#{el.value}$")
    end
  end
end

def convert_p(el, indent)
  if el.options[:transparent]
    inner(el, indent)
  elsif el.children.size == 1 && el.children.first.type == :img &&
      el.children.first.options[:ial]&.[](:refs)&.include?('standalone')
    convert_standalone_image(el.children.first, indent)
  else
    format_as_block_html(el.type, el.attr, inner(el, indent), indent)
  end
end

def convert_raw(el, _indent)
  if !el.options[:type] || el.options[:type].empty? || el.options[:type].include?('html')
    el.value + (el.options[:category] == :block ? "\n" : '')
  else
    ''
  end
end

def convert_root(el, indent)
  result = inner(el, indent)
  if @footnote_location
    result.sub!(/#{@footnote_location}/, footnote_content.gsub(/\\/, "\\\\\\\\"))
  else
    result << footnote_content
  end
  if @toc_code
    toc_tree = generate_toc_tree(@toc, @toc_code[0], @toc_code[1] || {})
    text = if !toc_tree.children.empty?
             convert(toc_tree, 0)
           else
             ''
           end
    result.sub!(/#{@toc_code.last}/, text.gsub(/\\/, "\\\\\\\\"))
  end
  result
end

def convert_smart_quote(el, _indent)
  entity_to_str(smart_quote_entity(el))
end

def convert_standalone_image(el, indent)
  attr = el.attr.dup
  figure_attr = {}
  figure_attr['class'] = attr.delete('class') if attr.key?('class')
  figure_attr['id'] = attr.delete('id') if attr.key?('id')
  body = "#{' ' * (indent + @indent)}<img#{html_attributes(attr)} />\n" \
    "#{' ' * (indent + @indent)}<figcaption>#{attr['alt']}</figcaption>\n"
  format_as_indented_block_html("figure", figure_attr, body, indent)
end

def convert_table(el, indent)
  format_as_indented_block_html(el.type, el.attr, inner(el, indent), indent)
end

def convert_td(el, indent)
  res = inner(el, indent)
  type = (@stack[-2].type == :thead ? :th : :td)
  attr = el.attr
  alignment = @stack[-3].options[:alignment][@stack.last.children.index(el)]
  if alignment != :default
    attr = el.attr.dup
    attr['style'] = (attr.key?('style') ? "#{attr['style']}; " : '') + "text-align: #{alignment}"
  end
  format_as_block_html(type, attr, res.empty? ? entity_to_str(ENTITY_NBSP) : res, indent)
end

def convert_text(el, _indent)
  escape_html(el.value, :text)
end

def convert_typographic_sym(el, _indent)
  if (result = @options[:typographic_symbols][el.value])
    escape_html(result, :text)
  else
    TYPOGRAPHIC_SYMS[el.value].map {|e| entity_to_str(e) }.join('')
  end
end

def convert_ul(el, indent)
  if !@toc_code && (el.options[:ial][:refs].include?('toc') rescue nil)
    @toc_code = [el.type, el.attr, (0..128).to_a.map { rand(36).to_s(36) }.join]
    @toc_code.last
  elsif !@footnote_location && el.options[:ial] && (el.options[:ial][:refs] || []).include?('footnotes')
    @footnote_location = (0..128).to_a.map { rand(36).to_s(36) }.join
  else
    format_as_indented_block_html(el.type, el.attr, inner(el, indent), indent)
  end
end

def convert_xml_comment(el, indent)
  if el.options[:category] == :block &&
      (@stack.last.type != :html_element || @stack.last.options[:content_model] != :raw)
    ' ' * indent << el.value << "\n"
  else
    el.value
  end
end

def fix_for_toc_entry(elements)
  remove_footnotes(elements)
  unwrap_links(elements)
  elements
end

def footnote_content
  ol = Element.new(:ol)
  ol.attr['start'] = @footnote_start if @footnote_start != 1
  i = 0
  backlink_text = escape_html(@options[:footnote_backlink], :text)
  while i < @footnotes.length
    name, data, _, repeat = *@footnotes[i]
    li = Element.new(:li, nil, 'id' => "fn:#{name}")
    li.children = Marshal.load(Marshal.dump(data.children))
    para = nil
    if li.children.last.type == :p || @options[:footnote_backlink_inline]
      parent = li
      while !parent.children.empty? && ![:p, :header].include?(parent.children.last.type)
        parent = parent.children.last
      end
      para = parent.children.last
      insert_space = true
    end
    unless para
      li.children << (para = Element.new(:p))
      insert_space = false
    end
    unless @options[:footnote_backlink].empty?
      nbsp = entity_to_str(ENTITY_NBSP)
      value = sprintf(FOOTNOTE_BACKLINK_FMT, (insert_space ? nbsp : ''), name, backlink_text)
      para.children << Element.new(:raw, value)
      (1..repeat).each do |index|
        value = sprintf(FOOTNOTE_BACKLINK_FMT, nbsp, "#{name}:#{index}",
                        "#{backlink_text}<sup>#{index + 1}</sup>")
        para.children << Element.new(:raw, value)
      end
    end
    ol.children << Element.new(:raw, convert(li, 4))
    i += 1
  end
  if ol.children.empty?
    ''
  else
    format_as_indented_block_html('div', {class: "footnotes"}, convert(ol, 2), 0)
  end
end

def format_as_block_html(name, attr, body, indent)
  "#{' ' * indent}<#{name}#{html_attributes(attr)}>#{body}</#{name}>\n"
end

def format_as_indented_block_html(name, attr, body, indent)
  "#{' ' * indent}<#{name}#{html_attributes(attr)}>\n#{body}#{' ' * indent}</#{name}>\n"
end

def format_as_span_html(name, attr, body)
  "<#{name}#{html_attributes(attr)}>#{body}</#{name}>"
end

def generate_toc_tree(toc, type, attr)
  sections = Element.new(type, nil, attr.dup)
  sections.attr['id'] ||= 'markdown-toc'
  stack = []
  toc.each do |level, id, children|
    li = Element.new(:li, nil, nil, level: level)
    li.children << Element.new(:p, nil, nil, transparent: true)
    a = Element.new(:a, nil)
    a.attr['href'] = "##{id}"
    a.attr['id'] = "#{sections.attr['id']}-#{id}"
    a.children.concat(fix_for_toc_entry(Marshal.load(Marshal.dump(children))))
    li.children.last.children << a
    li.children << Element.new(type)
    success = false
    until success
      if stack.empty?
        sections.children << li
        stack << li
        success = true
      elsif stack.last.options[:level] < li.options[:level]
        stack.last.children.last.children << li
        stack << li
        success = true
      else
        item = stack.pop
        item.children.pop if item.children.last.children.empty?
      end
    end
  end
  until stack.empty?
    item = stack.pop
    item.children.pop if item.children.last.children.empty?
  end
  sections
end

def initialize(root, options)
  super
  @footnote_counter = @footnote_start = @options[:footnote_nr]
  @footnotes = []
  @footnotes_by_name = {}
  @footnote_location = nil
  @toc = []
  @toc_code = nil
  @indent = 2
  @stack = []
end

def inner(el, indent)
  result = +''
  indent += @indent
  @stack.push(el)
  el.children.each do |inner_el|
    result << send(DISPATCHER[inner_el.type], inner_el, indent)
  end
  @stack.pop
  result
end

def obfuscate(text)
  result = +''
  text.each_byte do |b|
    result << (b > 128 ? b.chr : sprintf("&#%03d;", b))
  end
  result.force_encoding(text.encoding)
  result
end

def remove_footnotes(elements)
  elements.delete_if do |c|
    remove_footnotes(c.children)
    c.type == :footnote
  end
end

def unwrap_links(elements)
  elements.map! do |c|
    unwrap_links(c.children)
    c.type == :a ? c.children : c
  end.flatten!
end