more work on paginators

app/logical/post_sets/base.rb

@@ -0,0 +1,37 @@
+module PostSets
+  class Base
+    def has_wiki?
+      false
+    end
+    
+    def wiki_page
+      nil
+    end
+    
+    def presenter
+      @presenter ||= PostSetPresenter.new(self)
+    end
+    
+    def is_single_tag?
+      false
+    end
+    
+    def tag
+      tag_string
+    end
+    
+    def arbitrary_sql_order_clause(ids, table_name)
+      if ids.empty?
+        return "#{table_name}.id desc"
+      end
+      
+      conditions = []
+      
+      ids.each_with_index do |x, n|
+        conditions << "when #{x} then #{n}"
+      end
+      
+      "case #{table_name}.id " + conditions.join(" ") + " end"
+    end
+  end
+end

app/logical/post_sets/favorite.rb

@@ -0,0 +1,24 @@
+module PostSets
+  class Favorite < Base
+    attr_reader :user, :page, :favorites, :posts
+    
+    def initialize(params)
+      @user = ::User.find(params[:id])
+      @page = [params[:page].to_i, 1].max
+      @favorites = ::Favorite.model_for(@user.id).for_user(@user.id).paginate(page)
+      @posts = ::Post.where("id in (?)", post_ids).order(arbitrary_sql_order_clause(post_ids, "posts")).paginate("a0")
+    end
+    
+    def post_ids
+      @post_ids ||= favorites.map(&:post_id)
+    end
+    
+    def offset
+      (page - 1) * records_per_page
+    end
+    
+    def tag_string
+      @tag_string ||= "fav:#{user.name}"
+    end
+  end
+end

app/logical/post_sets/post.rb

@@ -1,5 +1,5 @@
 module PostSets
-  class Post
+  class Post < Base
     attr_reader :tags, :page, :posts
     
     def initialize(params)
@@ -31,13 +31,5 @@ module PostSets
     def is_single_tag?
       tags.size == 1
     end
-    
-    def tag
-      tag_string
-    end
-    
-    def presenter
-      @presenter ||= PostSetPresenter.new(self)
-    end
   end
 end