class MathematicalTreeprocessor

# File lib/asciidoctor-mathematical/extension.rb, line 112
def handle_inline_stem(node, text, mathematical, image_output_dir, image_target_dir, format, inline)
  document = node.document
  source_modified = false

  return [text, source_modified] unless document.attr? 'stem'

  to_html = document.basebackend? 'html'

  default_equation_type = document.attr('stem').include?('tex') ? :latexmath : :asciimath

  # TODO skip passthroughs in the source (e.g., +stem:[x^2]+)
  if text && text.include?(':') && (text.include?('stem:') || text.include?('math:'))
    text = text.gsub(StemInlineMacroRx) do
      if (m = $~)[0].start_with? '\\'
        next m[0][1..-1]
      end

      next '' if (eq_data = m[3].rstrip).empty?

      equation_type = default_equation_type if (equation_type = m[1].to_sym) == :stem
      if equation_type == :asciimath
        eq_data = AsciiMath.parse(eq_data).to_latex
      else # :latexmath
        eq_data = eq_data.gsub('\]', ']')
        subs = m[2].nil_or_empty? ? (to_html ? [:specialcharacters] : []) : (node.resolve_pass_subs m[2])
        eq_data = node.apply_subs eq_data, subs unless subs.empty?
      end

      source_modified = true
      img_target, img_width, img_height = make_equ_image eq_data, nil, true, mathematical, image_output_dir, image_target_dir, format, inline
      if inline
        %(pass:[<span class="steminline">#{img_target}</span>])
      else
        %(image:#{img_target}[width=#{img_width},height=#{img_height}])
      end
    end
  end

  [text, source_modified]
end

# File lib/asciidoctor-mathematical/extension.rb, line 89
def handle_prose_block(prose, mathematical, image_output_dir, image_target_dir, format, inline)
  if prose.context == :list_item || prose.context == :table_cell
    use_text_property = true
    text = prose.instance_variable_get :@text
  else
    text = prose.lines * LineFeed
  end
  text, source_modified = handle_inline_stem prose, text, mathematical, image_output_dir, image_target_dir, format, inline
  if source_modified
    if use_text_property
      prose.text = text
    else
      prose.lines = text.split LineFeed
    end
  end
end

# File lib/asciidoctor-mathematical/extension.rb, line 106
def handle_section_title(sect, mathematical, image_output_dir, image_target_dir, format, inline)
  text = sect.instance_variable_get :@title
  text, source_modified = handle_inline_stem sect, text, mathematical, image_output_dir, image_target_dir, format, inline
  sect.title = text if source_modified
end

# File lib/asciidoctor-mathematical/extension.rb, line 53
def handle_stem_block(stem, mathematical, image_output_dir, image_target_dir, format, inline)
  equation_type = stem.style.to_sym

  case equation_type
  when :latexmath
    content = stem.content
  when :asciimath
    content = AsciiMath.parse(stem.content).to_latex
  else
    return
  end

  img_target, img_width, img_height = make_equ_image content, stem.id, false, mathematical, image_output_dir, image_target_dir, format, inline

  parent = stem.parent
  if inline
    stem_image = create_pass_block parent, %{<div class="stemblock"> #{img_target} </div>}, {}
    parent.blocks[parent.blocks.index stem] = stem_image
  else
    alt_text = stem.attr 'alt', (equation_type == :latexmath ? %($$#{content}$$) : %(`#{content}`))
    attrs = {'target' => img_target, 'alt' => alt_text, 'align' => 'center'}
    # NOTE: The following setups the *intended width and height in pixel* for png images, which can be different that that of the generated image when PPIs larger than 72.0 is used.
    if format == :png
      attrs['width'] = %(#{img_width})
      attrs['height'] = %(#{img_height})
    end
    parent = stem.parent
    stem_image = create_image_block parent, attrs
    stem_image.id = stem.id if stem.id
    if (title = stem.attributes['title'])
      stem_image.title = title
    end
    parent.blocks[parent.blocks.index stem] = stem_image
  end
end

# File lib/asciidoctor-mathematical/extension.rb, line 175
def image_output_and_target_dir(doc)
  output_dir = doc.attr('imagesoutdir')
  if output_dir
    if doc.attr('imagesdir').nil_or_empty?
      target_dir = output_dir
    else
      # When imagesdir attribute is set, every relative path is prefixed with it. So the real target dir shall then be relative to the imagesdir, instead of being relative to document root.
      abs_imagesdir = ::Pathname.new doc.normalize_system_path(doc.attr('imagesdir'))
      abs_outdir = ::Pathname.new doc.normalize_system_path(output_dir)
      target_dir = abs_outdir.relative_path_from(abs_imagesdir).to_s
    end
  else
    output_dir = doc.attr('imagesdir')
    # since we store images directly to imagesdir, target dir shall be NULL and asciidoctor converters will prefix imagesdir.
    target_dir = "."
  end

  output_dir = doc.normalize_system_path(output_dir, doc.attr('docdir'))
  return [output_dir, target_dir]
end

# File lib/asciidoctor-mathematical/extension.rb, line 153
def make_equ_image(equ_data, equ_id, equ_inline, mathematical, image_output_dir, image_target_dir, format, inline)
  input = equ_inline ? %($#{equ_data}$) : %($$#{equ_data}$$)

  # TODO: Handle exceptions.
  result = mathematical.parse input
  if inline
    result[:data]
  else
    unless equ_id
      equ_id = %(stem-#{::Digest::MD5.hexdigest input})
    end
    image_ext = %(.#{format})
    img_target = %(#{equ_id}#{image_ext})
    img_file = ::File.join image_output_dir, img_target

    ::IO.write img_file, result[:data]

    img_target = ::File.join image_target_dir, img_target unless image_target_dir == '.'
    [img_target, result[:width], result[:height]]
  end
end

# File lib/asciidoctor-mathematical/extension.rb, line 12
def process document
  return unless document.attr? 'stem'
  
  format = ((document.attr 'mathematical-format') || 'png').to_sym
  unless format == :png || format == :svg
    warn %(Unknown format '#{format}', retreat to 'png')
    format = :png
  end
  ppi = ((document.attr 'mathematical-ppi') || '300.0').to_f
  ppi = format == :png ? ppi : 72.0
  inline = document.attr 'mathematical-inline'
  if inline && format == :png
    warn 'Can\'t use mathematical-inline together with mathematical-format=png'
  end
  # The no-args constructor defaults to SVG and standard delimiters ($..$ for inline, $$..$$ for block)
  mathematical = ::Mathematical.new format: format, ppi: ppi
  unless inline
    image_output_dir, image_target_dir = image_output_and_target_dir document
    ::Asciidoctor::Helpers.mkdir_p image_output_dir unless ::File.directory? image_output_dir
  end

  (document.find_by context: :stem, traverse_documents: true).each do |stem|
    handle_stem_block stem, mathematical, image_output_dir, image_target_dir, format, inline
  end

  document.find_by(traverse_documents: true) {|b|
    (b.content_model == :simple && (b.subs.include? :macros)) || b.context == :list_item
  }.each do |prose|
    handle_prose_block prose, mathematical, image_output_dir, image_target_dir, format, inline
  end

  (document.find_by content: :section).each do |sect|
    handle_section_title sect, mathematical, image_output_dir, image_target_dir, format, inline
  end

  document.remove_attr 'stem'
  (document.instance_variable_get :@header_attributes).delete 'stem' rescue nil

  nil
end