class Mechanize
  ##
  # This class manages history for your mechanize object.
  class History < Array
    attr_accessor :max_size

    def initialize(max_size = nil)
      @max_size       = max_size
      @history_index  = {}
    end

    def initialize_copy(orig)
      super
      @history_index = orig.instance_variable_get(:@history_index).dup
    end

    def push(page, uri = nil)
      super(page)
      @history_index[(uri ? uri : page.uri).to_s] = page
      if @max_size && self.length > @max_size
        while self.length > @max_size
          self.shift
        end
      end
      self
    end
    alias :<< :push

    def visited?(url)
      ! visited_page(url).nil?
    end

    def visited_page(url)
      @history_index[(url.respond_to?(:uri) ? url.uri : url).to_s]
    end

    def clear
      @history_index.clear
      super
    end

    def shift
      return nil if length == 0
      page    = self[0]
      self[0] = nil
      super
      remove_from_index(page)
      page
    end

    def pop
      return nil if length == 0
      page = super
      remove_from_index(page)
      page
    end

    private
    def remove_from_index(page)
      @history_index.each do |k,v|
        @history_index.delete(k) if v == page
      end
    end
  end
end