I am using Sunspot and Will_paginate for search in my application and don't how to have my search results start out with certain ordering conditions.

The model I am searching is the UserPrice model and want my :price and :purchase_date in descending order or lowest price to highest and present date to past:

class UserPrice < ActiveRecord::Base
  attr_accessible :price, :product_name, :purchase_date
  belongs_to :product

  # Sunspot configuration
  searchable do
    text :product_name do
        product.name
    end
  end
end

class SearchController < ApplicationController

  def index
    @search = UserPrice.search do
      fulltext params[:search]
      paginate(:per_page => 5, :page => params[:page])
    end
    @user_prices = @search.results
  end
end

Even though I don't know how, I'm not sure if I would use Sunspot or Will_paginate to sort by order of price and purchase date. How would I achieve this though?

Thank you.

UPDATE

I try to use the order_by method but not sure how the model would look now.

class SearchController < ApplicationController

  def index
    @search = UserPrice.search do
      fulltext params[:search]
      paginate(:per_page => 5, :page => params[:page])
      facet(:business_retail_store_id)
      facet(:business_online_store_id)
      order_by :price, :desc
      order_by :purchase_date, :desc
    end
    @user_prices = @search.results
  end
end

Not sure why having the following in my controller:

order_by :price, :desc
order_by :purchase_date, :desc

I get the error:

Sunspot::UnrecognizedFieldError in SearchController#index

No field configured for UserPrice with name 'price'

This doesn't make sense to me since I do have these fields inside of my UserPrice model and in my database. How do I fix this?