sort latest books

app/controllers/books_controller.rb

@@ -10,7 +10,7 @@ class BooksController < ApplicationController
 	end
 
 	def index
-		@books = Book.where(initial_filter).order(:sort)
+		@books = Book.where(initial_filter).order(sort_col)
 			.paginate(page: params[:page], per_page: session[:current_per_page])
 		@title = "Books"
 		respond_to do |format|
@@ -24,4 +24,12 @@ class BooksController < ApplicationController
 		redirect_to "/calibre/#{url_encode(@book.path)}/cover.jpg"
 	end
 
+	private
+	def sort_col
+		if session[:sort] == "latest"
+			return { last_modified: :desc }
+		end
+		:sort
+	end
+
 end

app/helpers/preferences_helper.rb

@@ -5,12 +5,13 @@ module PreferencesHelper
 		["UPPER(sort) LIKE ?", session[:initial] + "%"] if session[:initial]
 	end
 
-	# update preferences (per_page, initial)
+	# update preferences (per_page, initial, sort)
 	def preferences
 		session[:current_per_page] = params[:per_page] ? params[:per_page].to_i : (session[:current_per_page] || WillPaginate.per_page)
 		if params[:initial] 
 			session[:initial] = (params[:initial] == "reset" ? nil : params[:initial])
 		end
+		session[:sort] = params[:sort]
 	end
 
 end

app/views/books/_index.html.erb

@@ -1,4 +1,13 @@
+<div class="panel panel-default">
+	<div class="panel-heading">
+		<h3 class="panel-title">Filter</h3>
+	</div>
+	<div class="panel-body">
+<% isLatest = session[:sort] == "latest" %>
+<%= link_to "Latest", url_for(sort: (isLatest ? "alpha" : "latest")), class: "btn btn-default btn-sm " + (isLatest ? " active" : ""), remote: true %>
 <%= render'layouts/initials' %>
+	</div>
+</div>
 <%= will_paginate class: "center" %>
 
 <table class="table table-striped authors">