module PermanentRecords

  def self.included(base)
    base.extend Scopes
    base.send :include, InstanceMethods
    base.alias_method_chain :destroy, :permanent_record
  end
  
  module Scopes
    def with_deleted
      with_scope :find => {:conditions => "#{quoted_table_name}.deleted_at IS NOT NULL"} do
        yield
      end
    end
    
    def with_not_deleted
      with_scope :find => {:conditions => "#{quoted_table_name}.deleted_at IS NULL"} do
        yield
      end
    end
    
    # this next bit is basically stolen from the scope_out plugin
    [:deleted, :not_deleted].each do |name|
      define_method "find_#{name}" do |*args|
        send("with_#{name}") { find(*args) }
      end

      define_method "count_#{name}" do |*args|
        send("with_#{name}") { count(*args) }
      end

      define_method "calculate_#{name}" do |*args|
        send("with_#{name}") { calculate(*args) }
      end

      define_method "find_all_#{name}" do |*args|
        send("with_#{name}") { find(:all, *args) }
      end
    end
  end
  
  module InstanceMethods
    
    def is_permanent?
      respond_to?(:deleted_at)
    end
    
    def deleted?
      deleted_at if is_permanent?
    end
    
    def revive
      set_deleted_at nil
    end
    
    def set_deleted_at(value)
      return self unless is_permanent?
      record = self.class.find(id)
      record.update_attribute(:deleted_at, value)
      @attributes, @attributes_cache = record.attributes, record.attributes
      self
    end
    
    def destroy_with_permanent_record(force = nil)
      return destroy_without_permanent_record if :force == force || !is_permanent?
      unless deleted?
        set_deleted_at Time.now
        freeze
      end
      self
    end
  end
end