module Nitro

# Scaffolding is one facet of Nitro's Rapid Application 
# Develpoment (RAD) features. The scaffolder automatically 
# generates common code for managed object and their 
# controllers.

module Scaffold

  # Automatically enchant all entities?
  
  setting :enchant_all_entities, :default => true, :doc => 'Automatically enchant all entities?'
    
  module ClassMethods
    
    # 'Enchant' a class (typically a managed class). A 
    # collection of useful methods are magically added to the 
    # class and/or the class instances.
    #
    # to_s
    # to_href
    # to_link
    # to_edit_href
    # to_admin_href
    #
    #--
    # to_xxx is used instead of xxx in an attempt to avoid 
    # colisions with user defined methods.
    #++
    
    def enchant *classes
      for c in classes
        enchant_class c
      end
    end

    #--
    # Actually enchant the given class. Override this method
    # to customize for your application. The string calculation
    # code is deliberatly dynamic to work with Ruby's OO 
    # features.
    #++
    
    def enchant_class klass
      # to_s
            
      if klass.respond_to? :title
        define_instance_method klass, :to_s, %{ title }, force = true      
      elsif klass.respond_to? :name
        define_instance_method klass, :to_s, %{ name }, force = true      
      end
    
      # to_href
      # ex: blog/articles/23
      
      define_instance_method klass, :to_href, %{
        "\#{self.class.ann.self.controller.mount_path}/\#{self.class.name.underscore.pluralize}/\#{oid}"
      }

      # to_link
      # ex: <a href="blog/articles/23">The article's title</a>
      
      define_instance_method klass, :to_link, %{
        %|<a href="\#{to_href}">\#{to_s}</a>|
      }
                    
      # to_edit_href
      # ex: admin/articles/edit/23

      define_instance_method klass, :to_admin_href, %{
        "\#{AdminController.mount_path}/\#{self.class.name.underscore.pluralize}/edit/\#{oid}"
      }

      if defined? AdminController
        # to_admin_href
        # ex: admin/articles/list

        define_instance_method klass, :to_admin_href, %{
          "\#{AdminController.mount_path}/\#{self.class.name.underscore.pluralize}/list"
        }
                      
        # to_admin_href
        # ex: admin/articles/list

        define_class_method klass, :to_admin_href, %{
          "\#{AdminController.mount_path}/\#{self.name.underscore.pluralize}/list"
        }
      end
    end

  private
  
    #--
    # This helper defines an instance method for the 
    # scaffolded class. The method is only defined if the klass
    # does not already respond to it.
    #++
    
    def define_instance_method klass, meth, body, force = false
      unless force or klass.instance_methods.include? meth.to_s
        klass.module_eval %{
          def #{meth}
            #{body}
          end
        }
      end
    end

    #--
    # This helper defines an class method for the 
    # scaffolded class. The method is only defined if the klass
    # does not already respond to it.
    #++
    
    def define_class_method klass, meth, body
      unless klass.respond_to? meth.to_s
        klass.module_eval %{
          def self.#{meth}
            #{body}
          end
        }
      end
    end
    
  end
  
  def self.included base
    base.extend ClassMethods  
  end
  
  # Make the Scaffold module also work as a singleton, ie:
  #
  # Scaffold.enchant Article, Category
  
  extend ClassMethods
  
end

end

# * George Moschovitis <gm@navel.gr>