package chroot

import (
	"fmt"
	"log"

	"github.com/aws/aws-sdk-go/aws"
	"github.com/aws/aws-sdk-go/service/ec2"
	"github.com/mitchellh/multistep"
	awscommon "github.com/mitchellh/packer/builder/amazon/common"
	"github.com/mitchellh/packer/packer"
)

// StepCreateVolume creates a new volume from the snapshot of the root
// device of the AMI.
//
// Produces:
//   volume_id string - The ID of the created volume
type StepCreateVolume struct {
	volumeId       string
	RootVolumeSize int64
}

func (s *StepCreateVolume) Run(state multistep.StateBag) multistep.StepAction {
	ec2conn := state.Get("ec2").(*ec2.EC2)
	image := state.Get("source_image").(*ec2.Image)
	instance := state.Get("instance").(*ec2.Instance)
	ui := state.Get("ui").(packer.Ui)

	// Determine the root device snapshot
	log.Printf("Searching for root device of the image (%s)", *image.RootDeviceName)
	var rootDevice *ec2.BlockDeviceMapping
	for _, device := range image.BlockDeviceMappings {
		if *device.DeviceName == *image.RootDeviceName {
			rootDevice = device
			break
		}
	}

	if rootDevice == nil {
		err := fmt.Errorf("Couldn't find root device!")
		state.Put("error", err)
		ui.Error(err.Error())
		return multistep.ActionHalt
	}

	ui.Say("Creating the root volume...")
	vs := *rootDevice.Ebs.VolumeSize
	if s.RootVolumeSize > *rootDevice.Ebs.VolumeSize {
		vs = s.RootVolumeSize
	}
	createVolume := &ec2.CreateVolumeInput{
		AvailabilityZone: instance.Placement.AvailabilityZone,
		Size:             aws.Int64(vs),
		SnapshotId:       rootDevice.Ebs.SnapshotId,
		VolumeType:       rootDevice.Ebs.VolumeType,
		Iops:             rootDevice.Ebs.Iops,
	}
	log.Printf("Create args: %+v", createVolume)

	createVolumeResp, err := ec2conn.CreateVolume(createVolume)
	if err != nil {
		err := fmt.Errorf("Error creating root volume: %s", err)
		state.Put("error", err)
		ui.Error(err.Error())
		return multistep.ActionHalt
	}

	// Set the volume ID so we remember to delete it later
	s.volumeId = *createVolumeResp.VolumeId
	log.Printf("Volume ID: %s", s.volumeId)

	// Wait for the volume to become ready
	stateChange := awscommon.StateChangeConf{
		Pending:   []string{"creating"},
		StepState: state,
		Target:    "available",
		Refresh: func() (interface{}, string, error) {
			resp, err := ec2conn.DescribeVolumes(&ec2.DescribeVolumesInput{VolumeIds: []*string{&s.volumeId}})
			if err != nil {
				return nil, "", err
			}

			v := resp.Volumes[0]
			return v, *v.State, nil
		},
	}

	_, err = awscommon.WaitForState(&stateChange)
	if err != nil {
		err := fmt.Errorf("Error waiting for volume: %s", err)
		state.Put("error", err)
		ui.Error(err.Error())
		return multistep.ActionHalt
	}

	state.Put("volume_id", s.volumeId)
	return multistep.ActionContinue
}

func (s *StepCreateVolume) Cleanup(state multistep.StateBag) {
	if s.volumeId == "" {
		return
	}

	ec2conn := state.Get("ec2").(*ec2.EC2)
	ui := state.Get("ui").(packer.Ui)

	ui.Say("Deleting the created EBS volume...")
	_, err := ec2conn.DeleteVolume(&ec2.DeleteVolumeInput{VolumeId: &s.volumeId})
	if err != nil {
		ui.Error(fmt.Sprintf("Error deleting EBS volume: %s", err))
	}
}