module ActiveRecord
  class Relation
    delegate :delete, :to_sql, :to => :relation
    CLAUSES_METHODS = ["where", "join", "project", "group", "order", "take", "skip"].freeze
    attr_reader :relation, :klass

    def initialize(klass, table = nil)
      @klass = klass
      @relation = Arel::Table.new(table || @klass.table_name)
    end

    def to_a
      @klass.find_by_sql(@relation.to_sql)
    end

    def first
      @relation = @relation.take(1)
      to_a.first
    end

    for clause in CLAUSES_METHODS
      class_eval %{
        def #{clause}(_#{clause})
          @relation = @relation.#{clause}(_#{clause}) if _#{clause}
          self
        end
      }
    end

    private
      def method_missing(method, *args, &block)
        if @relation.respond_to?(method)
          @relation.send(method, *args, &block)
        elsif Array.instance_methods.include?(method.to_s)
          to_a.send(method, *args, &block)
        end
      end
  end
end