class AWS::EC2::InstanceCollection

def [] id
  super
end

def count_options options
  min = max = 1
  count = options[:count]
  case count
  when Range
    min = count.begin
    max = (count.exclude_end? ? count.end - 1 : count.end)
  when Integer
    min = max = count
  end
  { :min_count => min, :max_count => max }
end

def create options = {}
  if profile = options.delete(:iam_instance_profile)
    profile = case profile
    when /^arn:aws:iam::/ then { :arn => profile }
    when String then { :name => profile }
    when Hash then profile
    else 
      msg = "expected a name or ARN string for :iam_instance_profile"
    end
    options[:iam_instance_profile] = profile
  end
  if image = options.delete(:image)
    options[:image_id] = image.id
  end
  if kernel = options.delete(:kernel)
    options[:kernel_id] = kernel.id
  end
  if ramdisk = options.delete(:ramdisk)
    options[:ramdisk_id] = ramdisk.id
  end
  if key_pair = options.delete(:key_pair)
    options[:key_name] = key_pair.name
  end
  options = count_options(options).merge(options)
  options.delete(:count)
  options[:user_data] = Base64.encode64(options[:user_data]).strip if
    options[:user_data]
  options[:block_device_mappings] =
    translate_block_device_mappings(options[:block_device_mappings]) if
    options[:block_device_mappings]
  options[:monitoring] = { :enabled => true } if
    options[:monitoring_enabled]
  options.delete(:monitoring_enabled)
  placement = {}
  if options[:availability_zone]
    placement[:availability_zone] = options[:availability_zone].to_s
    options.delete(:availability_zone)
  end
  if options[:dedicated_tenancy]
    placement[:tenancy] = 'dedicated' 
    options.delete(:dedicated_tenancy)
  end
  options[:placement] = placement unless placement.empty?
  if subnet_id = subnet_id_option(options)
    options[:subnet_id] = subnet_id
  end
  security_group_opts(options)
  options[:client_token] = UUIDTools::UUID.timestamp_create.to_s
  resp = client.run_instances(options)
  if options[:min_count] == options[:max_count] and
      options[:min_count] == 1
    self[resp.instances_set.first.instance_id]
  else
    resp.instances_set.map do |i|
      self[i.instance_id]
    end
  end
end

def each(&block)
  response = filtered_request(:describe_instances)
  response.reservation_set.each do |reservation|
    reservation.instances_set.each do |i|
      yield(Instance.new(i.instance_id, :config => config))
    end
  end
end

def member_class
  Instance
end

def security_group_opts options
  ids = []
  names = []
  Array(options.delete(:security_group_ids)).each do |g|
    ids << g
  end
  # this may be security group objects or names
  Array(options.delete(:security_groups)).each do |g|
    case g
    when String        then names << g
    when SecurityGroup then ids << g.id
    else
      raise ArgumentError, ':security_groups may only contain ' +
        'security group names, ids or objects'
    end
  end
  return if ids.empty? and names.empty?
  if options[:subnet_id]
    # vpc instances only accepts security group ids, so any group
    # names must be converted to ids, which requires a service
    # request
    unless names.empty?
      ec2 = EC2.new(:config => config)
      groups = ec2.security_groups.filter('group-name', names)
      ids += groups.collect{|g| g.id }
    end
    options[:security_group_ids] = ids
  else
    # non-vpc instances accept both group names and ids, so 
    # we accept whichever
    options[:security_groups] = names unless names.empty?
    options[:security_group_ids] = ids unless ids.empty?
  end
end