package common

import (
	"fmt"

	"github.com/aws/aws-sdk-go/aws/awserr"
	"github.com/aws/aws-sdk-go/service/ec2"
	"github.com/hashicorp/packer/common"
	"github.com/hashicorp/packer/packer"
	"github.com/mitchellh/multistep"
)

type StepStopEBSBackedInstance struct {
	Skip                bool
	DisableStopInstance bool
}

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

	// Skip when it is a spot instance
	if s.Skip {
		return multistep.ActionContinue
	}

	var err error

	if !s.DisableStopInstance {
		// Stop the instance so we can create an AMI from it
		ui.Say("Stopping the source instance...")

		// Amazon EC2 API follows an eventual consistency model.

		// This means that if you run a command to modify or describe a resource
		// that you just created, its ID might not have propagated throughout
		// the system, and you will get an error responding that the resource
		// does not exist.

		// Work around this by retrying a few times, up to about 5 minutes.
		err := common.Retry(10, 60, 6, func(i uint) (bool, error) {
			ui.Message(fmt.Sprintf("Stopping instance, attempt %d", i+1))

			_, err = ec2conn.StopInstances(&ec2.StopInstancesInput{
				InstanceIds: []*string{instance.InstanceId},
			})

			if err == nil {
				// success
				return true, nil
			}

			if awsErr, ok := err.(awserr.Error); ok {
				if awsErr.Code() == "InvalidInstanceID.NotFound" {
					ui.Message(fmt.Sprintf(
						"Error stopping instance; will retry ..."+
							"Error: %s", err))
					// retry
					return false, nil
				}
			}
			// errored, but not in expected way. Don't want to retry
			return true, err
		})

		if err != nil {
			err := fmt.Errorf("Error stopping instance: %s", err)
			state.Put("error", err)
			ui.Error(err.Error())
			return multistep.ActionHalt
		}

	} else {
		ui.Say("Automatic instance stop disabled. Please stop instance manually.")
	}

	// Wait for the instance to actually stop
	ui.Say("Waiting for the instance to stop...")
	err = ec2conn.WaitUntilInstanceStopped(&ec2.DescribeInstancesInput{
		InstanceIds: []*string{instance.InstanceId},
	})

	if err != nil {
		err := fmt.Errorf("Error waiting for instance to stop: %s", err)
		state.Put("error", err)
		ui.Error(err.Error())
		return multistep.ActionHalt
	}

	return multistep.ActionContinue
}

func (s *StepStopEBSBackedInstance) Cleanup(multistep.StateBag) {
	// No cleanup...
}