class DotHelper

# File lib/dothtml/dot_helper.rb, line 114
def self.detect_language(contents, language = nil)
  language || ((contents =~ DOT_REGEX) ? 'dot' : 'neato')
end

# File lib/dothtml/dot_helper.rb, line 118
  def self.enhance(contents, language)
    if contents =~ GRAPH_REGEX
      contents
    elsif language == 'dot'
      <<-GRAPH
      digraph {
        #{contents}
      }
      GRAPH
    else
      <<-GRAPH
      graph {
        #{contents}
      }
      GRAPH
    end
  end

# File lib/dothtml/dot_helper.rb, line 136
def self.from_dot(contents, language = 'dot')
  language = detect_language(contents, language)
  contents = enhance(contents, language)
  new(svg_from_dot(contents, language))
end

# File lib/dothtml/dot_helper.rb, line 110
def self.from_dotfile(filename)
  new(svg_from_dot(File.read(filename)))
end

# File lib/dothtml/dot_helper.rb, line 10
def initialize(svg_contents)
  @svg_contents = svg_contents
end

# File lib/dothtml/dot_helper.rb, line 142
def self.svg_from_dot(contents, language = 'dot')
  Open3.popen3("#{language} -Tsvg") do |stdin, stdout, stderr|
    stdout.binmode
    stdin.print contents
    stdin.close

    err = stderr.read
    if !err.nil? && !err.strip.empty?
      raise "Error from graphviz:\n#{err}"
    end

    stdout.read.tap { |str| str.force_encoding 'UTF-8' }
  end
end

# File lib/dothtml/dot_helper.rb, line 37
def descriptions?
  #dom.css("")
end

# File lib/dothtml/dot_helper.rb, line 18
def dom
  @dom ||= parse_dom(@svg_contents)
end

# File lib/dothtml/dot_helper.rb, line 87
def embed_images
  node.children.before(images)
  self
end

# File lib/dothtml/dot_helper.rb, line 29
def extractChoices
end

# File lib/dothtml/dot_helper.rb, line 41
def extractTitle
  dom.css("title").first.content()
end

# File lib/dothtml/dot_helper.rb, line 79
def extract_id_class(old_id)
  if old_id =~ /(.*?) ?class=["']?(.*?)['"]?$/
    [$1, $2]
  else
    [old_id]
  end
end

# File lib/dothtml/dot_helper.rb, line 50
def images
  embedded_images = Set.new

  defs = dom.create_element("def")

  # assuming the images are the correct size, declare their size
  dom.css("image").each do |img|
    file_name = img.attributes["href"].value
    id = file_name.split(".").first.split("/").last
    if file_name =~ /\.svg$/ && ! embedded_images.include?(file_name)
      src = parse_dom(File.read(file_name)).at("svg")
      g = dom.create_element("g", id: id,
        width: src["width"], height: src["height"])
      defs.add_child(g)
      src.children.each do |child|
        g.add_child(child.clone)
      end
      embedded_images << file_name
    end

    img.name="use"
    img.attributes["href"].value="##{id}"
    #img.attributes["width"].remove
    #img.attributes["height"].remove
    #img.attributes["preserveAspectRatio"].remove
  end
  defs
end

# File lib/dothtml/dot_helper.rb, line 97
def node
  dom.at("svg")
end

# File lib/dothtml/dot_helper.rb, line 14
def parse_dom(contents)
  Nokogiri::XML.parse(contents)
end

# File lib/dothtml/dot_helper.rb, line 92
def remove_comments
  dom.xpath('//comment()').each { |comment| comment.remove }
  self
end

# File lib/dothtml/dot_helper.rb, line 102
def to_xml
  node.to_xml
end

# File lib/dothtml/dot_helper.rb, line 106
def write(file_name, template_name, locals)
  File.write(file_name, Tilt.new(template_name).render(binding, locals))
end