Ajax, will_paginate, sort, search

I'm trying to get search, sort, will_paginate and ajax working
together. I've seen lots of will_paginate and ajax, but not with
search and sort.

I've got the search and sort part working ok, but the will_paginate
brings back the entire page from the ajax call, and also i can't seem
to get the data back from will_paginate properly (i.e. the page number
changes, but the data items do not change properly - e.g. if there are
5 items with 3 per page, and we move to page 2, then the first two
items from page 1 remain and the third is delete, but it moves to page
2 in the pagination). I also have problems passing the sort and search
criteria with the will_paginate ajax call)

view code index.html.erb

<label for="item_name">Filter on item name  : </label>
<%= text_field_tag("search", params['search'], :size => 10 ) %>
<img alt="spinner" id="spinner" src="/images/ajax-loader.gif"
style="display:none" />
<%= observe_field "search", :update => "", # :frequency => 0.5,
        :with => "search", :url => { :controller => "companies", :action =>
"search" },
        :loading => "Element.show('spinner')",
        :complete => "Element.hide('spinner')" %>
<div id="container">
                <%= render :partial => 'contents' %>
</div>

view code _contents.html.erb

<table>
 <thead>
  <tr>
      <td <%= sort _td_class_helper "reg_number" %>>
        <%= sort_link_helper "Reg Number", "reg_number" %>
      </td>
      <td <%= sort_td_class_helper "name" %>>
        <%= sort_link_helper "Name", "company_name" %>
      </td>
      <td <%= sort_td_class_helper "city" %>>
        <%= sort_link_helper "City", "city" %>
      </td>
      <td <%= sort_td_class_helper "country" %>>
        <%= sort_link_helper "Country", "country" %>
      </td>
  </tr>
  </thead>
  <tbody>
<% if @companies.size == 0 %>
<p>No Companies found...</p>
<% else %>
    <% @companies.each do |company| %>
    <tr class="<%= cycle("even","odd") %>">
      <td><%=h company.company_registered_number %></td>
      <td><%= link_to company.company_name, :action => "show", :id =>
company.id %></td>
      <td><%=h company.city %></td>
          <td><%=h company.country.country %></td>
    </tr>
<% end %>
  </tbody>
</table>
<p>
<%= will_paginate(@companies, :renderer =>
"RemoteLinkRenderer",:remote => { :update => '',  :action =>
'search', :params => { 'search' => params[:search], 'sort' =>
params[:sort] }})%>
</p>
<% end %>

model

def self.search(search, page, sortby)
        sort = case sortby
           when "company_name"  then "companies.company_name"
           when "reg_number"   then
"companies.company_registered_number"
           when "city" then "companies.city"
           when "country" then "countries.country"
           when "company_name_reverse"  then "companies.company_name
DESC"
           when "reg_number_reverse"   then
"companies.company_registered_number DESC"
           when "city_reverse" then "companies.city DESC"
           when "country_reverse" then "countries.country DESC"
           end
        paginate(:per_page => 3, :page => page,  :include =>
'country',
           :conditions => ['company_name like ? and companies.id !=
0', "%#{search}%" ], :order => sort)
end

Controller

  def search
    @companies = Company.search(params[:search], params[:page],
params[:sort])
:order => 'company_registered_number ASC')
     respond_to do |format|
      format.js{
        render :update do |page|
          page['container'].replace_html :partial => "contents"
          end
      }
    end
  end

application_helper

  def sort_td_class_helper(param)
    result = 'class="sortup"' if params[:sort] == param
    result = 'class="sortdown"' if params[:sort] == param + "_reverse"
    return result
  end
  def sort_link_helper(text, param)
    key = param
    key += "_reverse" if params[:sort] == param
    options = {
      :url => { :params => params.merge({:action => 'search',:sort =>
key, :page => nil})},
      :update => '',
      :before => "Element.show('spinner')",
      :success => "Element.hide('spinner')"
    }
    html_options = {
      :title => "Sort by this field",
      :href => url_for(:params => params.merge({:action =>
'search',:sort => key, :page => nil}))
    }
    logger.info " options #{options} html_options #{html_options}"
    link_to_remote(text, options, html_options)
  end

# app/helpers/remote_link_renderer.rb

class RemoteLinkRenderer < WillPaginate::LinkRenderer
  def prepare(collection, options, template)
    @remote = options.delete(:remote) || {}
    super
  end
protected
  def page_link(page, text, attributes = {})
    @template.link_to_remote(text, {:url => url_for(page), :method
=> :get}.merge(@remote))
  end
end