the previous and next posts are now supplied in json of the presenter; give the template creator a default value

app/models/post.rb

@@ -68,6 +68,14 @@ class Post < ActiveRecord::Base
     joins(:likes).where(:likes => {:author_id => person.id})
   }
 
+  def self.next(post)
+    where("posts.id > ?", post.id)
+  end
+
+  def self.previous(post)
+    where("posts.id < ?", post.id)
+  end
+
   def post_type
     self.class.name
   end

app/presenters/post_presenter.rb

@@ -1,16 +1,50 @@
 require File.join(File.dirname(__FILE__), '..', '..', 'lib', 'template_picker')
 
 class PostPresenter
-  attr_accessor :post
+  attr_accessor :post, :current_user
 
-  def initialize(post)
+  def initialize(post, current_user = nil)
     self.post = post
+    self.current_user = current_user
   end
 
   def to_json(options = {})
     {
-      :post => self.post.as_api_response(:backbone),
+      :post => self.post.as_api_response(:backbone).update(
+        { :next_post => next_post_url,
+      :previous_post => previous_post_url}),
       :templateName => TemplatePicker.new(self.post).template_name
     }
   end
+
+ 
+  def next_post_url
+    if n = next_post
+      Rails.application.routes.url_helpers.post_path(n)
+    end
+  end
+
+  def previous_post_url
+    if p = previous_post
+      Rails.application.routes.url_helpers.post_path(p)
+    end
+  end
+
+  def next_post
+    post_base.next(post).first
+  end
+
+  def previous_post
+    post_base.previous(post).first
+  end
+
+  protected
+
+  def post_base 
+    if current_user
+      Post.owned_or_visible_by_user(current_user)
+    else
+      Post.all_public
+    end
+  end
 end

app/views/posts/show.html.haml

@@ -6,24 +6,7 @@
   = post_page_title @post
 
 - content_for :head do
-  =javascript_include_tag 'vendor/bootstrap/bootstrap-transition', 'vendor/bootstrap/bootstrap-modal'
+  = javascript_include_tag 'vendor/bootstrap/bootstrap-transition', 'vendor/bootstrap/bootstrap-modal', 'posts-show'
-
-:javascript
-  $(function(){
-    $(document).keypress(function(event){
-        $('#text').focus();
-        $('#comment').modal();
-      });
-
-    $(document).keydown(function(e){
-      if (e.keyCode == 37) {
-         window.location = $('#back').attr('href');
-      }else if(e.keyCode == 39) {
-         window.location = $('#forward').attr('href');
-      }
-    });
-  });
-
 .header
   .header-container
     #post-author.media
@@ -72,8 +55,8 @@
 
 #post-content
 
-= link_to image_tag('arrow-left.png'), post_path(@post.id-1), :class => 'nav-arrow left', :id => 'back'
+= link_to image_tag('arrow-left.png'), '#', :class => 'nav-arrow left', :id => 'back'
-= link_to image_tag('arrow-right.png'), post_path(@post.id+1), :class => 'nav-arrow right', :id => 'forward'
+= link_to image_tag('arrow-right.png'), '#', :class => 'nav-arrow right', :id => 'forward'
 
 #comment.modal.fade
   .modal-header

lib/diaspora/shareable.rb

@@ -52,6 +52,9 @@ module Diaspora
       end
     end
 
+
+
+
     def diaspora_handle
       read_attribute(:diaspora_handle) || self.author.diaspora_handle
     end

lib/template_picker.rb

@@ -14,9 +14,11 @@ class TemplatePicker
   end
 
   def template_name
-    for template in TEMPLATES
+    TEMPLATES.each do |template|
       return template.gsub("_", '-') if self.send("#{template}?".to_sym)
     end
+
+    'status' #default
   end
 
   def status_with_photo_backdrop?

public/javascripts/app/views/single_post_view.js

@@ -1,5 +1,11 @@
 app.views.SinglePost = app.views.Post.extend({
 
-  className : "loaded"
+  className : "loaded",
+  next_arrow: $('#forward'),
+  previous_arrow: $('#back'),
 
+  postRenderTemplate : function() {
+    $('#forward').attr('href', this.model.get('next_post'));
+    $('#back').attr('href', this.model.get('previous_post'));
+  }
 });

public/javascripts/posts-show.js

@@ -0,0 +1,14 @@
+$(function(){
+  $(document).keypress(function(event){
+      $('#text').focus();
+      $('#comment').modal();
+    });
+
+  $(document).keydown(function(e){
+    if (e.keyCode == 37) {
+       window.location = $('#back').attr('href');
+    }else if(e.keyCode == 39) {
+       window.location = $('#forward').attr('href');
+    }
+  });
+});

spec/lib/template_picker_spec.rb

@@ -2,7 +2,10 @@ require File.join(File.dirname(__FILE__), '..', '..', 'lib', 'template_picker')
 
 describe TemplatePicker do
   before do
-    @post_stubs = {:photos => stub(:present? => true, :size => 2), :o_embed_cache => stub(:present? => true), :text? => true, :text => stub(:length => 400)}
+    @post_stubs = {:type => 'StatusMessage', :photos => stub(:size => 2), 
+                   :o_embed_cache => stub(:present? => true), 
+                   :text? => true, :text => stub(:length => 400)
+                  }
   end
 
   let(:post) {
@@ -16,11 +19,13 @@ describe TemplatePicker do
 
   describe '#template_name' do
     it 'returns the coolest template if the post has lots of cool stuff' do
-      puts TemplatePicker.new(post).template_name
+      TemplatePicker.new(post).template_name.should_not be_nil
     end
   end
+
   describe '#status_with_photo_backdrop?' do
-    it 'is true if the post contains a photo and text' do
+    it 'is true if the post contains a single photo and text' do
+      @post_stubs.merge!(:photos => stub(:size => 1))
       TemplatePicker.new(post).should be_status_with_photo_backdrop
     end
   end
@@ -48,6 +53,7 @@ describe TemplatePicker do
       @post_stubs.merge!(:photos => stub(:size => 1))
       TemplatePicker.new(post).should be_photo_backdrop
     end
+
   end
 
   describe '#status?' do