# USAGE: Hash.from_xml:(YOUR_XML_STRING)
# modified from 
# http://stackoverflow.com/questions/1230741/
# convert-a-nokogiri-document-to-a-ruby-hash/1231297#1231297
class DarwinCore
  module XmlReader
    class << self

      def from_xml(xml_io) 
        result = Nokogiri::XML(xml_io)
        return { result.root.name.to_sym => xml_node_to_hash(result.root)} 
      end

      private
      def xml_node_to_hash(node) 
        # If we are at the root of the document, start the hash 
        if node.element?
          prepare_node_element(node)
        else 
          return prepare(node.content.to_s) 
        end 
      end          
      
      def add_attributes(node, result_hash)
        if node.attributes != {}
          result_hash[:attributes] = {}
          node.attributes.keys.each do |key|
            result_hash[:attributes][node.attributes[key].name.to_sym] = 
              prepare(node.attributes[key].value)
          end
        end
      end

      def prepare_node_element(node)
        result_hash = {}
        add_attributes(node, result_hash)
        if node.children.size > 0
          result_hash = add_children(node, result_hash)
        end 
        result_hash
      end
      
      def add_children(node, result_hash)
        node.children.each do |child| 
          result = xml_node_to_hash(child) 

          if child.name == "text"
            text = handle_text(child, result)
            return text if text
          elsif result_hash[child.name.to_sym]
            handle_child_node(child, result_hash, result)
          else 
            result_hash[child.name.to_sym] = prepare(result)
          end
        end
        result_hash
      end

      def handle_child_node(child, result_hash, result)
        if result_hash[child.name.to_sym].is_a?(Object::Array)
          result_hash[child.name.to_sym] << prepare(result)
        else
          result_hash[child.name.to_sym] = 
            [result_hash[child.name.to_sym]] << prepare(result)
        end
      end

      def handle_text(child, result)
        unless child.next_sibling || child.previous_sibling
          prepare(result)
        end
      end

      def prepare(data)
        (data.class == String && data.to_i.to_s == data) ? data.to_i : data
      end

    end
  end
end