class Arbre::HTML::Tag

def add_class(class_names)
  class_list.add class_names
end

def attributes_html
  attributes.any? ? " " + attributes.to_html : nil
end

def build(*args)
  super
  attributes = args.extract_options!
  self.content = args.first if args.first
  set_for_attribute(attributes.delete(:for))
  attributes.each do |key, value|
    set_attribute(key, value)
  end
end

def child_is_text?
  children.size == 1 && children.first.is_a?(TextNode)
end

def class_list
  get_attribute(:class) || set_attribute(:class, ClassList.new)
end

def class_names
  class_list.to_html
end

def default_id_for_prefix
  nil
end

def get_attribute(name)
  @attributes[name.to_sym]
end

def has_attribute?(name)
  @attributes.has_key?(name.to_sym)
end

def id
  get_attribute(:id)
end

def id!
  return id if id
  self.id = object_id.to_s
  id
end

def id=(id)
  set_attribute(:id, id)
end

def indent(open_tag, child_content, close_tag)
  spaces = ' ' * indent_level * INDENT_SIZE
  html = ""
  if no_child? || child_is_text?
    if self_closing_tag?
      html << spaces << open_tag.sub( />$/, '/>' )
    else
      # one line
      html << spaces << open_tag << child_content << close_tag
    end
  else
    # multiple lines
    html << spaces << open_tag << "\n"
    html << child_content # the child takes care of its own spaces
    html << spaces << close_tag
  end
  html << "\n"
  html
end

def initialize(*)
  super
  @attributes = Attributes.new
end

def no_child?
  children.empty?
end

def remove_attribute(name)
  @attributes.delete(name.to_sym)
end

def remove_class(class_names)
  class_list.delete(class_names)
end

def self_closing_tag?
  %w|meta link|.include?(tag_name)
end

def set_attribute(name, value)
  @attributes[name.to_sym] = value
end

def set_for_attribute(record)
  return unless record
  set_attribute :id, ActionController::RecordIdentifier.dom_id(record, default_id_for_prefix)
  add_class ActionController::RecordIdentifier.dom_class(record)
end

def to_html
  indent("<#{tag_name}#{attributes_html}>", content, "</#{tag_name}>").html_safe
end