module NTimeLine

  # Pager is a class for search result summary.
  class Pager < Base
    attr_reader :total, :page, :page_count
    attr_accessor :request_params

    def initialize(doc) #:nodoc:
      summary = doc.root.elements["/response/result/summary"]
      @total = summary.elements["total"].text.to_i
      @page = summary.elements["page"].text.to_i
      @page_count = summary.elements["page_count"].text.to_i
    end

    # Goto a previous page.
    def prev
      if @page - 1 > 0
        params = @request_params.merge(:page => @page - 1)
        request(self.class::PATH, params, self.class)
      end
    end

    # Goto a next page.
    def next
      if @page < @page_count
        params = @request_params.merge(:page => @page + 1)
        request(self.class::PATH, params, self.class)
      end
    end

    # Goto a page at the number.
    # n:: page number
    def [](n)
      if n > 0 && n < @page_count
        params = @request_params.merge(:page => n)
        request(self.class::PATH, params, self.class)
      end
    end

    alias :size :page_count
  end

  # TimelinePager is a pager of timelines search result summary.
  class TimeLinePager < Pager
    PATH = "/timelines/search"

    attr_reader :timelines

    def initialize(doc) #:nodoc:
      super(doc)
      @timelines = []
      doc.root.each_element("/response/result/timelines/timeline") do |timeline|
        @timelines << TimeLine.new(timeline)
      end
    end
  end

  # ArticlePager is a pager of aritcles search result summary.
  class ArticlePager < Pager
    PATH = "/articles/search"

    attr_reader :articles

    def initialize(doc) #:nodoc:
      super(doc)
      @articles = []
      doc.root.each_element("/response/result/articles/article") do |article|
        @articles << Article.new(article)
      end
    end
  end
end