module Protobuf::Encoder

def encode(stream, message)
  # FIXME make this not as ghetto
  raise NotInitializedError, "Message %s is not initialized (one or more fields is improperly set): %s" % [message.class.name, JSON.parse(message.to_json)] unless message.initialized?
  
  message.each_field do |field, value|
    next unless message.has_field?(field.name)
    if field.repeated?
      if field.packed?
        key = (field.tag << 3) | WireType::LENGTH_DELIMITED
        packed_value = value.map {|val| field.encode(val) }.join
        stream.write(Field::VarintField.encode(key))
        stream.write(Field::VarintField.encode(packed_value.size))
        stream.write(packed_value)
      else
        value.each do |val|
          write_pair(stream, field, val)
        end
      end
    else
      write_pair(stream, field, value)
    end
  end
end

def write_pair(stream, field, value)
  key = (field.tag << 3) | field.wire_type
  key_bytes = Field::VarintField.encode(key)
  stream.write(key_bytes)
  bytes = field.encode(value)
  stream.write(bytes)
end