fixes #805

app/presenters/post_set_presenters/popular.rb

@@ -31,6 +31,83 @@ module PostSetPresenters
       1.month.since(date)
     end
     
+    def link_rel_for_scale?(template, scale)
+      (template.params[:scale].blank? && scale == "day") || template.params[:scale].to_s.include?(scale)
+    end
+    
+    def next_date_for_scale(scale)
+      case scale
+      when "Day"
+        next_day
+        
+      when "Week"
+        next_week
+        
+      when "Month"
+        next_month
+        
+      else
+        nil
+      end
+    end
+
+    def prev_date_for_scale(scale)
+      case scale
+      when "Day"
+        prev_day
+        
+      when "Week"
+        prev_week
+        
+      when "Month"
+        prev_month
+        
+      else
+        nil
+      end
+    end
+    
+    def nav_links_for_scale(template, scale)
+      html = []
+      html << '<span class="period">'
+      html << template.link_to(
+        "&laquo;prev".html_safe, 
+        template.popular_explore_posts_path(
+          :date => prev_date_for_scale(scale), 
+          :scale => scale.downcase
+        ),
+        :rel => (link_rel_for_scale?(template, scale.downcase) ? "prev" : nil)
+      )
+      html << template.link_to(
+        scale, 
+        template.popular_explore_posts_path(
+          :date => date, 
+          :scale => scale.downcase
+        ), 
+        :class => "desc"
+      )
+      html << template.link_to(
+        "next&raquo;".html_safe, 
+        template.popular_explore_posts_path(
+          :date => next_date_for_scale(scale), 
+          :scale => scale.downcase
+        ),
+        :rel => (link_rel_for_scale?(template, scale.downcase) ? "next" : nil)
+      )
+      html << '</span>'
+      html.join("\n").html_safe
+    end
+    
+    def nav_links(template)
+      html =  []
+      html << '<p id="popular-nav-links">'
+      html << nav_links_for_scale(template, "Day")
+      html << nav_links_for_scale(template, "Week")
+      html << nav_links_for_scale(template, "Month")
+      html << '</p>'
+      html.join("\n").html_safe
+    end
+    
     def range_text
       if min_date == max_date
         date.strftime("%B %d, %Y")