# 
# Copyright (c) 2006 Michael Koziarski
# 
# Permission is hereby granted, free of charge, to any person obtaining a copy of
# this software and associated documentation files (the "Software"), to deal in the
# Software without restriction, including without limitation the rights to use,
# copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
# Software, and to permit persons to whom the Software is furnished to do so,
# subject to the following conditions:
# 
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
# 
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
# FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
# COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
# AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

require 'rubygems'
require 'xml/libxml'

class FasterXmlSimple
  class << self
    def xml_in(string, options={})
      new(string, options).out
    end
  end
  
  attr_reader :doc, :options, :current_element
  
  def initialize(string, options)
    @doc             = parse(string)
    @options         = default_options.merge options
    @current_element = nil
  end
  
  def out
    {doc.root.name => collapse(doc.root, doc.root.name)}
  end
  
  private
    def default_options
      {'contentkey' => '__content__', 'forcearray' => []}
    end
  
    def collapse(element, key_name)
      result = hash_of_attributes(element) 
      if text_node? element
        text = collapse_text(element)
        result.merge!(content_key => text) if text =~ /\S/
      elsif element.children?
        element.inject(result) do |hash, child|
          (hash[child.name] ||= []) << collapse(child, element.name) unless child.text?
          hash
        end
      end
      return nil if result.empty?
      # Compact them to ensure it complies with the user's requests
      inline_single_element_arrays(result) 
      suppress_empty(result) if suppress_empty?

      result
    end
  
    def content_key
      options['contentkey']
    end
  
    def force_array?(key_name)
      options['forcearray'].include?(key_name)
    end
  
    def inline_single_element_arrays(result)
      result.each do |key, value|
        if value.size == 1 && value.is_a?(Array) && !force_array?(key)
          result[key] = value.first
        end
      end    
    end
  
    def suppress_empty(result)
      result.delete content_key if result[content_key] !~ /\S/ 
    end
  
    def suppress_empty?
      options.has_key? 'suppressempty'
    end
  
    # a text node is one with 1 or more child nodes which are
    # text nodes, and no non-text children
    def text_node?(element)
      !element.text? && element.all? {|c| c.text?}
    end
  
    # takes a text node, and collapses it into a string
    def collapse_text(element)
      element.map {|c| c.content } * ''
    end
  
    def hash_of_attributes(element)
      result = {}
      element.each_attr do |attribute| 
        name = attribute.name
        name = [attribute.ns, attribute.name].join(':') if attribute.ns?
        result[name] = attribute.value 
      end
      result
    end
  
    def parse(string)
      XML::Parser.string(string).parse
    end
end