module FormHelpers
  # params is an array of hashes for ordering.  has structure is described 
  # in the usage msg
  def self.auto_form(params=[], objs=[])
    msg =<<EOF
    params should contain keys for commands to execute.  Where
    each command key should begin with ':command_' and end with 'element_name'
    which maps to a valid element definition.  objs should be an array
    of element objects.  We will dynamically see which object the associated
    command maps to.
EOF
    
    raise ArgumentError, msg unless params.nitems > 0 && objs.nitems > 0
    
    checkbox_state=[true, false]
    params.each { |i|
      
      objs.each {|o|
        key = i.keys.first
        value = i.values.first
        next unless key.to_s =~ /^command_/

        object_class=''
        current=''
        element = key.to_s.split('command_').last
        if o.respond_to?(element)
          eval "object_class = o.#{element}.class.to_s"
          if object_class =~ /checkbox/i
            raise ArgumentError unless checkbox_state.include?(value)
            eval "current = o.#{element}.checked?"
            o.send(element).set(value)
          if object_class =~ /radio/i
            if value
              o.send(element).check
            else
              o.send(element).uncheck              
            end
          end
          elsif object_class =~ /selectlist/i
            o.send(element).select(value)
          elsif object_class =~ /textfield/i
            # skip if key supplied but empty string or nil
            o.send(element).set(value) #unless value != ''
          elsif object_class =~ /button|link|image/i
            eval "o.#{element}.#{value}"
          end
          
        end
      }
    }
  end
end