module PgsqlStatsHelper
  def pages_to_human_size(pages)
    number_to_human_size(pages * 8.kilobytes)
  end
  
  def percentage_bar(text, percent, options = {})
    percent = 0 unless percent.finite?
    percent = [[ 0, percent.to_i ].max, 100].min
    if options.keys.first.is_a?(Range)
      for range in options.keys
        if range === percent
          bar_class = options[range][:bar_class]
          bar_style = options[range][:bar_style]
          text_class = options[range][:text_class]
          text_style = options[range][:text_style]
          break
        end
      end
    else
      bar_class = options[:bar_class]
      bar_style = options[:bar_style]
      text_class = options[:text_class]
      text_style = options[:text_style]
    end
    
    bar_options = {}
    bar_options.merge!(:class => bar_class) if bar_class
    bar_options.merge!(:style => "position: absolute; left:0; width: #{percent}%; overflow: hidden; z-index: -1; #{bar_style}")
    text_options = {}
    text_options.merge!(:class => text_class) if text_class
    text_options.merge!(:style => "z-index: 1; #{text_style}")

    content_tag(:div,
                content_tag(:span, " ", bar_options) + content_tag(:span, text, text_options),
                :style => "width: 100%; height: 100%; position: relative; z-index: 1;")
  end

  def analysis_results(entity)
    if entity.respond_to?(:analysis) && analysis = entity.analysis
      results = ""

      if analysis.consider_adding_index?
        results << content_tag(:div,
                               PgsqlStats::Analysis.analysis_hint_proc.call(@template),
                               :title => "This table may benefit from the addition of an index.",
                               :class => "analysishint")
      end

      if analysis.consider_dropping_index?
        results << content_tag(:div,
                               PgsqlStats::Analysis.analysis_hint_proc.call(@template),
                               :title => "This index does not appear to be frequently used in queries.  You might consider dropping it to improve insert/update performance.",
                               :class => "analysishint")
      end
    end
  end
end