class Spec::Matchers::MatchArray

def description
  "contain exactly #{_pretty_print(@expected)}"
end

def difference_between_arrays(array_1, array_2)
  difference = array_1.dup
  array_2.each do |element|
    if index = difference.index(element)
      difference.delete_at(index)
    end
  end
  difference
end

def failure_message_for_should
  message =  "expected collection contained:  #{safe_sort(@expected).inspect}\n"
  message += "actual collection contained:    #{safe_sort(@actual).inspect}\n"
  message += "the missing elements were:      #{safe_sort(@missing_items).inspect}\n" unless @missing_items.empty?
  message += "the extra elements were:        #{safe_sort(@extra_items).inspect}\n"   unless @extra_items.empty?
  message
end

def failure_message_for_should_not
  "Matcher does not support should_not"
end

def initialize(expected)
  @expected = expected
end

def matches?(actual)
  @actual = actual        
  @extra_items = difference_between_arrays(@actual, @expected)
  @missing_items = difference_between_arrays(@expected, @actual)
  @extra_items.empty? & @missing_items.empty?
end

def safe_sort(array)
  array.all?{|item| item.respond_to?(:<=>)} ? array.sort : array
end