package amazonec2

import (
	"crypto/md5"
	"crypto/rand"
	"fmt"
	"io"
	"io/ioutil"
	"net"
	"net/url"
	"strconv"
	"strings"
	"time"

	"github.com/aws/aws-sdk-go/aws"
	"github.com/aws/aws-sdk-go/aws/awserr"
	"github.com/aws/aws-sdk-go/aws/credentials"
	"github.com/aws/aws-sdk-go/aws/session"
	"github.com/aws/aws-sdk-go/service/ec2"
	"github.com/docker/machine/libmachine/drivers"
	"github.com/docker/machine/libmachine/log"
	"github.com/docker/machine/libmachine/mcnflag"
	"github.com/docker/machine/libmachine/mcnutils"
	"github.com/docker/machine/libmachine/ssh"
	"github.com/docker/machine/libmachine/state"
)

const (
	driverName               = "amazonec2"
	ipRange                  = "0.0.0.0/0"
	machineSecurityGroupName = "docker-machine"
	defaultAmiId             = "ami-615cb725"
	defaultRegion            = "us-east-1"
	defaultInstanceType      = "t2.micro"
	defaultDeviceName        = "/dev/sda1"
	defaultRootSize          = 16
	defaultVolumeType        = "gp2"
	defaultZone              = "a"
	defaultSecurityGroup     = machineSecurityGroupName
	defaultSSHUser           = "ubuntu"
	defaultSpotPrice         = "0.50"
)

const (
	keypairNotFoundCode = "InvalidKeyPair.NotFound"
)

var (
	dockerPort = 2376
	swarmPort  = 3376
)

type Driver struct {
	*drivers.BaseDriver
	Id                  string
	AccessKey           string
	SecretKey           string
	SessionToken        string
	Region              string
	AMI                 string
	SSHKeyID            int
	KeyName             string
	InstanceId          string
	InstanceType        string
	PrivateIPAddress    string
	SecurityGroupId     string
	SecurityGroupName   string
	Tags                string
	ReservationId       string
	DeviceName          string
	RootSize            int64
	VolumeType          string
	IamInstanceProfile  string
	VpcId               string
	SubnetId            string
	Zone                string
	keyPath             string
	RequestSpotInstance bool
	SpotPrice           string
	PrivateIPOnly       bool
	UsePrivateIP        bool
	Monitoring          bool
}

func (d *Driver) GetCreateFlags() []mcnflag.Flag {
	return []mcnflag.Flag{
		mcnflag.StringFlag{
			Name:   "amazonec2-access-key",
			Usage:  "AWS Access Key",
			EnvVar: "AWS_ACCESS_KEY_ID",
		},
		mcnflag.StringFlag{
			Name:   "amazonec2-secret-key",
			Usage:  "AWS Secret Key",
			EnvVar: "AWS_SECRET_ACCESS_KEY",
		},
		mcnflag.StringFlag{
			Name:   "amazonec2-session-token",
			Usage:  "AWS Session Token",
			EnvVar: "AWS_SESSION_TOKEN",
		},
		mcnflag.StringFlag{
			Name:   "amazonec2-ami",
			Usage:  "AWS machine image",
			EnvVar: "AWS_AMI",
		},
		mcnflag.StringFlag{
			Name:   "amazonec2-region",
			Usage:  "AWS region",
			Value:  defaultRegion,
			EnvVar: "AWS_DEFAULT_REGION",
		},
		mcnflag.StringFlag{
			Name:   "amazonec2-vpc-id",
			Usage:  "AWS VPC id",
			EnvVar: "AWS_VPC_ID",
		},
		mcnflag.StringFlag{
			Name:   "amazonec2-zone",
			Usage:  "AWS zone for instance (i.e. a,b,c,d,e)",
			Value:  defaultZone,
			EnvVar: "AWS_ZONE",
		},
		mcnflag.StringFlag{
			Name:   "amazonec2-subnet-id",
			Usage:  "AWS VPC subnet id",
			EnvVar: "AWS_SUBNET_ID",
		},
		mcnflag.StringFlag{
			Name:   "amazonec2-security-group",
			Usage:  "AWS VPC security group",
			Value:  defaultSecurityGroup,
			EnvVar: "AWS_SECURITY_GROUP",
		},
		mcnflag.StringFlag{
			Name:   "amazonec2-tags",
			Usage:  "AWS Tags (e.g. key1,value1,key2,value2)",
			EnvVar: "AWS_TAGS",
		},
		mcnflag.StringFlag{
			Name:   "amazonec2-instance-type",
			Usage:  "AWS instance type",
			Value:  defaultInstanceType,
			EnvVar: "AWS_INSTANCE_TYPE",
		},
		mcnflag.StringFlag{
			Name:   "amazonec2-device-name",
			Usage:  "AWS root device name",
			Value:  defaultDeviceName,
			EnvVar: "AWS_DEVICE_NAME",
		},
		mcnflag.IntFlag{
			Name:   "amazonec2-root-size",
			Usage:  "AWS root disk size (in GB)",
			Value:  defaultRootSize,
			EnvVar: "AWS_ROOT_SIZE",
		},
		mcnflag.StringFlag{
			Name:   "amazonec2-volume-type",
			Usage:  "Amazon EBS volume type",
			Value:  defaultVolumeType,
			EnvVar: "AWS_VOLUME_TYPE",
		},
		mcnflag.StringFlag{
			Name:   "amazonec2-iam-instance-profile",
			Usage:  "AWS IAM Instance Profile",
			EnvVar: "AWS_INSTANCE_PROFILE",
		},
		mcnflag.StringFlag{
			Name:   "amazonec2-ssh-user",
			Usage:  "Set the name of the ssh user",
			Value:  defaultSSHUser,
			EnvVar: "AWS_SSH_USER",
		},
		mcnflag.BoolFlag{
			Name:  "amazonec2-request-spot-instance",
			Usage: "Set this flag to request spot instance",
		},
		mcnflag.StringFlag{
			Name:  "amazonec2-spot-price",
			Usage: "AWS spot instance bid price (in dollar)",
			Value: defaultSpotPrice,
		},
		mcnflag.BoolFlag{
			Name:  "amazonec2-private-address-only",
			Usage: "Only use a private IP address",
		},
		mcnflag.BoolFlag{
			Name:  "amazonec2-use-private-address",
			Usage: "Force the usage of private IP address",
		},
		mcnflag.BoolFlag{
			Name:  "amazonec2-monitoring",
			Usage: "Set this flag to enable CloudWatch monitoring",
		},
	}
}

func NewDriver(hostName, storePath string) drivers.Driver {
	id := generateId()
	return &Driver{
		Id:                id,
		AMI:               defaultAmiId,
		Region:            defaultRegion,
		InstanceType:      defaultInstanceType,
		RootSize:          defaultRootSize,
		Zone:              defaultZone,
		SecurityGroupName: defaultSecurityGroup,
		SpotPrice:         defaultSpotPrice,
		BaseDriver: &drivers.BaseDriver{
			SSHUser:     defaultSSHUser,
			MachineName: hostName,
			StorePath:   storePath,
		},
	}
}

func (d *Driver) SetConfigFromFlags(flags drivers.DriverOptions) error {
	region, err := validateAwsRegion(flags.String("amazonec2-region"))
	if err != nil {
		return err
	}

	image := flags.String("amazonec2-ami")
	if len(image) == 0 {
		image = regionDetails[region].AmiId
	}

	d.AccessKey = flags.String("amazonec2-access-key")
	d.SecretKey = flags.String("amazonec2-secret-key")
	d.SessionToken = flags.String("amazonec2-session-token")
	d.Region = region
	d.AMI = image
	d.RequestSpotInstance = flags.Bool("amazonec2-request-spot-instance")
	d.SpotPrice = flags.String("amazonec2-spot-price")
	d.InstanceType = flags.String("amazonec2-instance-type")
	d.VpcId = flags.String("amazonec2-vpc-id")
	d.SubnetId = flags.String("amazonec2-subnet-id")
	d.SecurityGroupName = flags.String("amazonec2-security-group")
	d.Tags = flags.String("amazonec2-tags")
	zone := flags.String("amazonec2-zone")
	d.Zone = zone[:]
	d.DeviceName = flags.String("amazonec2-device-name")
	d.RootSize = int64(flags.Int("amazonec2-root-size"))
	d.VolumeType = flags.String("amazonec2-volume-type")
	d.IamInstanceProfile = flags.String("amazonec2-iam-instance-profile")
	d.SSHUser = flags.String("amazonec2-ssh-user")
	d.SSHPort = 22
	d.PrivateIPOnly = flags.Bool("amazonec2-private-address-only")
	d.UsePrivateIP = flags.Bool("amazonec2-use-private-address")
	d.Monitoring = flags.Bool("amazonec2-monitoring")
	d.SetSwarmConfigFromFlags(flags)

	if d.AccessKey == "" {
		return fmt.Errorf("amazonec2 driver requires the --amazonec2-access-key option")
	}

	if d.SecretKey == "" {
		return fmt.Errorf("amazonec2 driver requires the --amazonec2-secret-key option")
	}

	if d.SubnetId == "" && d.VpcId == "" {
		return fmt.Errorf("amazonec2 driver requires either the --amazonec2-subnet-id or --amazonec2-vpc-id option")
	}

	if d.SubnetId != "" && d.VpcId != "" {
		subnetFilter := []*ec2.Filter{
			{
				Name:   aws.String("subnet-id"),
				Values: []*string{&d.SubnetId},
			},
		}

		subnets, err := d.getClient().DescribeSubnets(&ec2.DescribeSubnetsInput{
			Filters: subnetFilter,
		})
		if err != nil {
			return err
		}

		if *subnets.Subnets[0].VpcId != d.VpcId {
			return fmt.Errorf("SubnetId: %s does not belong to VpcId: %s", d.SubnetId, d.VpcId)
		}
	}

	if d.isSwarmMaster() {
		u, err := url.Parse(d.SwarmHost)
		if err != nil {
			return fmt.Errorf("error parsing swarm host: %s", err)
		}

		parts := strings.Split(u.Host, ":")
		port, err := strconv.Atoi(parts[1])
		if err != nil {
			return err
		}

		swarmPort = port
	}

	return nil
}

// DriverName returns the name of the driver
func (d *Driver) DriverName() string {
	return driverName
}

func (d *Driver) checkPrereqs() error {
	// check for existing keypair
	key, err := d.getClient().DescribeKeyPairs(&ec2.DescribeKeyPairsInput{
		KeyNames: []*string{&d.MachineName},
	})
	if err != nil {
		if awsErr, ok := err.(awserr.Error); ok && awsErr.Code() == keypairNotFoundCode {
			// Not a real error for 'NotFound' since we're checking existance anyways
		} else {
			return err
		}
	}

	if err == nil && len(key.KeyPairs) != 0 {
		return fmt.Errorf("There is already a keypair with the name %s.  Please either remove that keypair or use a different machine name.", d.MachineName)
	}

	regionZone := d.Region + d.Zone
	if d.SubnetId == "" {
		filters := []*ec2.Filter{
			{
				Name:   aws.String("availability-zone"),
				Values: []*string{&regionZone},
			},
			{
				Name:   aws.String("vpc-id"),
				Values: []*string{&d.VpcId},
			},
		}

		subnets, err := d.getClient().DescribeSubnets(&ec2.DescribeSubnetsInput{
			Filters: filters,
		})
		if err != nil {
			return err
		}

		if len(subnets.Subnets) == 0 {
			return fmt.Errorf("unable to find a subnet in the zone: %s", regionZone)
		}

		d.SubnetId = *subnets.Subnets[0].SubnetId

		// try to find default
		if len(subnets.Subnets) > 1 {
			for _, subnet := range subnets.Subnets {
				if *subnet.DefaultForAz {
					d.SubnetId = *subnet.SubnetId
					break
				}
			}
		}
	}

	return nil
}

func (d *Driver) PreCreateCheck() error {
	return d.checkPrereqs()
}

func (d *Driver) instanceIpAvailable() bool {
	ip, err := d.GetIP()
	if err != nil {
		log.Debug(err)
	}
	if ip != "" {
		d.IPAddress = ip
		log.Debugf("Got the IP Address, it's %q", d.IPAddress)
		return true
	}
	return false
}

func (d *Driver) Create() error {
	if err := d.checkPrereqs(); err != nil {
		return err
	}

	log.Infof("Launching instance...")

	if err := d.createKeyPair(); err != nil {
		return fmt.Errorf("unable to create key pair: %s", err)
	}

	if err := d.configureSecurityGroup(d.SecurityGroupName); err != nil {
		return err
	}

	bdm := &ec2.BlockDeviceMapping{
		DeviceName: aws.String(d.DeviceName),
		Ebs: &ec2.EbsBlockDevice{
			VolumeSize:          aws.Int64(d.RootSize),
			VolumeType:          aws.String(d.VolumeType),
			DeleteOnTermination: aws.Bool(true),
		},
	}
	netSpecs := []*ec2.InstanceNetworkInterfaceSpecification{{
		DeviceIndex:              aws.Int64(0), // eth0
		Groups:                   []*string{&d.SecurityGroupId},
		SubnetId:                 &d.SubnetId,
		AssociatePublicIpAddress: aws.Bool(!d.PrivateIPOnly),
	}}

	regionZone := d.Region + d.Zone
	log.Debugf("launching instance in subnet %s", d.SubnetId)

	var instance *ec2.Instance

	if d.RequestSpotInstance {
		spotInstanceRequest, err := d.getClient().RequestSpotInstances(&ec2.RequestSpotInstancesInput{
			LaunchSpecification: &ec2.RequestSpotLaunchSpecification{
				ImageId: &d.AMI,
				Placement: &ec2.SpotPlacement{
					AvailabilityZone: &regionZone,
				},
				KeyName:           &d.KeyName,
				InstanceType:      &d.InstanceType,
				NetworkInterfaces: netSpecs,
				Monitoring:        &ec2.RunInstancesMonitoringEnabled{Enabled: aws.Bool(d.Monitoring)},
				IamInstanceProfile: &ec2.IamInstanceProfileSpecification{
					Name: &d.IamInstanceProfile,
				},
				BlockDeviceMappings: []*ec2.BlockDeviceMapping{bdm},
			},
			InstanceCount: aws.Int64(1),
			SpotPrice:     &d.SpotPrice,
		})
		if err != nil {
			return fmt.Errorf("Error request spot instance: %s", err)
		}

		log.Info("Waiting for spot instance...")
		err = d.getClient().WaitUntilSpotInstanceRequestFulfilled(&ec2.DescribeSpotInstanceRequestsInput{
			SpotInstanceRequestIds: []*string{spotInstanceRequest.SpotInstanceRequests[0].SpotInstanceRequestId},
		})
		if err != nil {
			return fmt.Errorf("Error fulfilling spot request: %v", err)
		}
		log.Info("Created spot instance request %v", *spotInstanceRequest.SpotInstanceRequests[0].SpotInstanceRequestId)
		// resolve instance id
		for i := 0; i < 3; i++ {
			// Even though the waiter succeeded, eventual consistency means we could
			// get a describe output that does not include this information. Try a
			// few times just in case
			var resolvedSpotInstance *ec2.DescribeSpotInstanceRequestsOutput
			resolvedSpotInstance, err = d.getClient().DescribeSpotInstanceRequests(&ec2.DescribeSpotInstanceRequestsInput{
				SpotInstanceRequestIds: []*string{spotInstanceRequest.SpotInstanceRequests[0].SpotInstanceRequestId},
			})
			if err != nil {
				// Unexpected; no need to retry
				return fmt.Errorf("Error describing previously made spot instance request: %v", err)
			}
			maybeInstanceId := resolvedSpotInstance.SpotInstanceRequests[0].InstanceId
			if maybeInstanceId != nil {
				var instances *ec2.DescribeInstancesOutput
				instances, err = d.getClient().DescribeInstances(&ec2.DescribeInstancesInput{
					InstanceIds: []*string{maybeInstanceId},
				})
				if err != nil {
					// Retry if we get an id from spot instance but EC2 doesn't recognize it yet; see above, eventual consistency possible
					continue
				}
				instance = instances.Reservations[0].Instances[0]
				err = nil
				break
			}
			time.Sleep(5 * time.Second)
		}

		if err != nil {
			return fmt.Errorf("Error resolving spot instance to real instance: %v", err)
		}
	} else {
		inst, err := d.getClient().RunInstances(&ec2.RunInstancesInput{
			ImageId:  &d.AMI,
			MinCount: aws.Int64(1),
			MaxCount: aws.Int64(1),
			Placement: &ec2.Placement{
				AvailabilityZone: &regionZone,
			},
			KeyName:           &d.KeyName,
			InstanceType:      &d.InstanceType,
			NetworkInterfaces: netSpecs,
			Monitoring:        &ec2.RunInstancesMonitoringEnabled{Enabled: aws.Bool(d.Monitoring)},
			IamInstanceProfile: &ec2.IamInstanceProfileSpecification{
				Name: &d.IamInstanceProfile,
			},
			BlockDeviceMappings: []*ec2.BlockDeviceMapping{bdm},
		})

		if err != nil {
			return fmt.Errorf("Error launching instance: %s", err)
		}
		instance = inst.Instances[0]
	}

	d.InstanceId = *instance.InstanceId

	log.Debug("waiting for ip address to become available")
	if err := mcnutils.WaitFor(d.instanceIpAvailable); err != nil {
		return err
	}

	if instance.PrivateIpAddress != nil {
		d.PrivateIPAddress = *instance.PrivateIpAddress
	}

	d.waitForInstance()

	log.Debugf("created instance ID %s, IP address %s, Private IP address %s",
		d.InstanceId,
		d.IPAddress,
		d.PrivateIPAddress,
	)

	log.Debug("Settings tags for instance")
	err := d.configureTags(d.Tags)

	if err != nil {
		return fmt.Errorf("Unable to tag instance %s: %s", d.InstanceId, err)
	}

	return nil
}

func (d *Driver) GetURL() (string, error) {
	ip, err := d.GetIP()
	if err != nil {
		return "", err
	}
	if ip == "" {
		return "", nil
	}
	return fmt.Sprintf("tcp://%s", net.JoinHostPort(ip, strconv.Itoa(dockerPort))), nil
}

func (d *Driver) GetIP() (string, error) {
	inst, err := d.getInstance()
	if err != nil {
		return "", err
	}

	if d.PrivateIPOnly {
		if inst.PrivateIpAddress == nil {
			return "", fmt.Errorf("No private IP for instance %v", *inst.InstanceId)
		}
		return *inst.PrivateIpAddress, nil
	}

	if d.UsePrivateIP {
		if inst.PrivateIpAddress == nil {
			return "", fmt.Errorf("No private IP for instance %v", *inst.InstanceId)
		}
		return *inst.PrivateIpAddress, nil
	}

	if inst.PublicIpAddress == nil {
		return "", fmt.Errorf("No IP for instance %v", *inst.InstanceId)
	}
	return *inst.PublicIpAddress, nil
}

func (d *Driver) GetState() (state.State, error) {
	inst, err := d.getInstance()
	if err != nil {
		return state.Error, err
	}
	switch *inst.State.Name {
	case ec2.InstanceStateNamePending:
		return state.Starting, nil
	case ec2.InstanceStateNameRunning:
		return state.Running, nil
	case ec2.InstanceStateNameStopping:
		return state.Stopping, nil
	case ec2.InstanceStateNameShuttingDown:
		return state.Stopping, nil
	case ec2.InstanceStateNameStopped:
		return state.Stopped, nil
	case ec2.InstanceStateNameTerminated:
		return state.Error, nil
	default:
		log.Warnf("unrecognized instance state: %v", *inst.State.Name)
		return state.Error, nil
	}
}

func (d *Driver) GetSSHHostname() (string, error) {
	// TODO: use @nathanleclaire retry func here (ehazlett)
	return d.GetIP()
}

func (d *Driver) GetSSHUsername() string {
	if d.SSHUser == "" {
		d.SSHUser = "ubuntu"
	}

	return d.SSHUser
}

func (d *Driver) Start() error {
	_, err := d.getClient().StartInstances(&ec2.StartInstancesInput{
		InstanceIds: []*string{&d.InstanceId},
	})
	if err != nil {
		return err
	}

	return d.waitForInstance()
}

func (d *Driver) Stop() error {
	_, err := d.getClient().StopInstances(&ec2.StopInstancesInput{
		InstanceIds: []*string{&d.InstanceId},
		Force:       aws.Bool(false),
	})
	return err
}

func (d *Driver) Restart() error {
	_, err := d.getClient().RebootInstances(&ec2.RebootInstancesInput{
		InstanceIds: []*string{&d.InstanceId},
	})
	return err
}

func (d *Driver) Kill() error {
	_, err := d.getClient().StopInstances(&ec2.StopInstancesInput{
		InstanceIds: []*string{&d.InstanceId},
		Force:       aws.Bool(true),
	})
	return err
}

func (d *Driver) Remove() error {
	if err := d.terminate(); err != nil {
		return fmt.Errorf("unable to terminate instance: %s", err)
	}

	// remove keypair
	if err := d.deleteKeyPair(); err != nil {
		return fmt.Errorf("unable to remove key pair: %s", err)
	}

	return nil
}

func (d *Driver) getClient() *ec2.EC2 {
	config := aws.NewConfig()
	config = config.WithRegion(d.Region)
	config = config.WithCredentials(credentials.NewStaticCredentials(d.AccessKey, d.SecretKey, d.SessionToken))
	return ec2.New(session.New(config))
}

func (d *Driver) getInstance() (*ec2.Instance, error) {
	instances, err := d.getClient().DescribeInstances(&ec2.DescribeInstancesInput{
		InstanceIds: []*string{&d.InstanceId},
	})
	if err != nil {
		return nil, err
	}
	return instances.Reservations[0].Instances[0], nil
}

func (d *Driver) instanceIsRunning() bool {
	st, err := d.GetState()
	if err != nil {
		log.Debug(err)
	}
	if st == state.Running {
		return true
	}
	return false
}

func (d *Driver) waitForInstance() error {
	if err := mcnutils.WaitFor(d.instanceIsRunning); err != nil {
		return err
	}

	return nil
}

func (d *Driver) createKeyPair() error {
	if err := ssh.GenerateSSHKey(d.GetSSHKeyPath()); err != nil {
		return err
	}

	publicKey, err := ioutil.ReadFile(d.GetSSHKeyPath() + ".pub")
	if err != nil {
		return err
	}

	keyName := d.MachineName

	log.Debugf("creating key pair: %s", keyName)
	_, err = d.getClient().ImportKeyPair(&ec2.ImportKeyPairInput{
		KeyName:           &keyName,
		PublicKeyMaterial: publicKey,
	})
	if err != nil {
		return err
	}
	d.KeyName = keyName
	return nil
}

func (d *Driver) terminate() error {
	if d.InstanceId == "" {
		return fmt.Errorf("unknown instance")
	}

	log.Debugf("terminating instance: %s", d.InstanceId)
	_, err := d.getClient().TerminateInstances(&ec2.TerminateInstancesInput{
		InstanceIds: []*string{&d.InstanceId},
	})
	if err != nil {
		return fmt.Errorf("unable to terminate instance: %s", err)
	}
	return nil
}

func (d *Driver) isSwarmMaster() bool {
	return d.SwarmMaster
}

func (d *Driver) securityGroupAvailableFunc(id string) func() bool {
	return func() bool {

		securityGroup, err := d.getClient().DescribeSecurityGroups(&ec2.DescribeSecurityGroupsInput{
			GroupIds: []*string{&id},
		})
		if err == nil && len(securityGroup.SecurityGroups) > 0 {
			return true
		} else if err == nil {
			log.Debugf("No security group with id %v found", id)
			return false
		}
		log.Debug(err)
		return false
	}
}

func (d *Driver) configureTags(tagGroups string) error {

	tags := []*ec2.Tag{}
	tags = append(tags, &ec2.Tag{
		Key:   aws.String("Name"),
		Value: &d.MachineName,
	})

	if tagGroups != "" {
		t := strings.Split(tagGroups, ",")
		if len(t) > 0 && len(t)%2 != 0 {
			log.Warnf("Tags are not key value in pairs. %d elements found", len(t))
		}
		for i := 0; i < len(t)-1; i += 2 {
			tags = append(tags, &ec2.Tag{
				Key:   &t[i],
				Value: &t[i+1],
			})
		}
	}

	_, err := d.getClient().CreateTags(&ec2.CreateTagsInput{
		Resources: []*string{&d.InstanceId},
		Tags:      tags,
	})

	if err != nil {
		return err
	}

	return nil
}

func (d *Driver) configureSecurityGroup(groupName string) error {
	log.Debugf("configuring security group in %s", d.VpcId)

	var group *ec2.SecurityGroup
	filters := []*ec2.Filter{
		{
			Name:   aws.String("group-name"),
			Values: []*string{&groupName},
		},
		{
			Name:   aws.String("vpc-id"),
			Values: []*string{&d.VpcId},
		},
	}
	groups, err := d.getClient().DescribeSecurityGroups(&ec2.DescribeSecurityGroupsInput{
		Filters: filters,
	})
	if err != nil {
		return err
	}

	if len(groups.SecurityGroups) > 0 {
		log.Debugf("found existing security group (%s) in %s", groupName, d.VpcId)
		group = groups.SecurityGroups[0]
	}

	// if not found, create
	if group == nil {
		log.Debugf("creating security group (%s) in %s", groupName, d.VpcId)
		groupResp, err := d.getClient().CreateSecurityGroup(&ec2.CreateSecurityGroupInput{
			GroupName:   &groupName,
			Description: aws.String("Docker Machine"),
			VpcId:       &d.VpcId,
		})
		if err != nil {
			return err
		}
		// Manually translate into the security group construct
		group = &ec2.SecurityGroup{
			GroupId:   groupResp.GroupId,
			VpcId:     aws.String(d.VpcId),
			GroupName: aws.String(groupName),
		}
		// wait until created (dat eventual consistency)
		log.Debugf("waiting for group (%s) to become available", *group.GroupId)
		if err := mcnutils.WaitFor(d.securityGroupAvailableFunc(*group.GroupId)); err != nil {
			return err
		}
	}

	d.SecurityGroupId = *group.GroupId

	perms := d.configureSecurityGroupPermissions(group)

	if len(perms) != 0 {
		log.Debugf("authorizing group %s with permissions: %v", groupName, perms)
		_, err := d.getClient().AuthorizeSecurityGroupIngress(&ec2.AuthorizeSecurityGroupIngressInput{
			GroupId:       group.GroupId,
			IpPermissions: perms,
		})
		if err != nil {
			return err
		}
	}

	return nil
}

func (d *Driver) configureSecurityGroupPermissions(group *ec2.SecurityGroup) []*ec2.IpPermission {
	hasSshPort := false
	hasDockerPort := false
	hasSwarmPort := false
	for _, p := range group.IpPermissions {
		switch *p.FromPort {
		case 22:
			hasSshPort = true
		case int64(dockerPort):
			hasDockerPort = true
		case int64(swarmPort):
			hasSwarmPort = true
		}
	}

	perms := []*ec2.IpPermission{}

	if !hasSshPort {
		perms = append(perms, &ec2.IpPermission{
			IpProtocol: aws.String("tcp"),
			FromPort:   aws.Int64(22),
			ToPort:     aws.Int64(22),
			IpRanges:   []*ec2.IpRange{{CidrIp: aws.String(ipRange)}},
		})
	}

	if !hasDockerPort {
		perms = append(perms, &ec2.IpPermission{
			IpProtocol: aws.String("tcp"),
			FromPort:   aws.Int64(int64(dockerPort)),
			ToPort:     aws.Int64(int64(dockerPort)),
			IpRanges:   []*ec2.IpRange{{CidrIp: aws.String(ipRange)}},
		})
	}

	if !hasSwarmPort && d.SwarmMaster {
		perms = append(perms, &ec2.IpPermission{
			IpProtocol: aws.String("tcp"),
			FromPort:   aws.Int64(int64(swarmPort)),
			ToPort:     aws.Int64(int64(swarmPort)),
			IpRanges:   []*ec2.IpRange{{CidrIp: aws.String(ipRange)}},
		})
	}

	log.Debugf("configuring security group authorization for %s", ipRange)

	return perms
}

func (d *Driver) deleteSecurityGroup() error {
	log.Debugf("deleting security group %s", d.SecurityGroupId)

	_, err := d.getClient().DeleteSecurityGroup(&ec2.DeleteSecurityGroupInput{
		GroupId: &d.SecurityGroupId,
	})
	if err != nil {
		return err
	}

	return nil
}

func (d *Driver) deleteKeyPair() error {
	log.Debugf("deleting key pair: %s", d.KeyName)

	_, err := d.getClient().DeleteKeyPair(&ec2.DeleteKeyPairInput{
		KeyName: &d.KeyName,
	})
	if err != nil {
		return err
	}

	return nil
}

func generateId() string {
	rb := make([]byte, 10)
	_, err := rand.Read(rb)
	if err != nil {
		log.Warnf("Unable to generate id: %s", err)
	}

	h := md5.New()
	io.WriteString(h, string(rb))
	return fmt.Sprintf("%x", h.Sum(nil))
}