module Rails
  module Generators
    module MigrationHelper
      include Rails::Generators::Migration

      module ClassMethods    
        def migration_lookup_at(dirname) #:nodoc:
          Dir.glob("#{dirname}/[0-9]*_*.rb")
        end

        def migration_exists?(dirname, file_name) #:nodoc:
          migration_lookup_at(dirname).grep(/\d+_#{file_name}.rb$/).first
        end

        def current_migration_number(dirname) #:nodoc:
          migration_lookup_at(dirname).collect do |file|
            File.basename(file).split("_").first.to_i
          end.max.to_i
        end

        def next_migration_number(dirname) #:nodoc:
          orm = Rails.configuration.generators.options[:rails][:orm]
          require "rails/generators/#{orm}"
          "#{orm.to_s.camelize}::Generators::Base".constantize.next_migration_number(dirname)
        rescue
          raise NotImplementedError
        end
      end         

      def self.included(base) #:nodoc: 
        base.extend ClassMethods      
      end

      def info msg
        Rails.logger.info msg
      end
      
      def migration(options)
        migration_template "create_users.erb", "db/migrations/#{name}"
      end
    end
  end
end