package cmd

import (
	"fmt"
	"time"

	cli "github.com/urfave/cli/v2"

	"aws-mgmt/pkg/client"
)

const hibernateDesc = `Hibernate an EC2 instance.

The TIME string is the number of seconds to delay the hibernation, and defaults
to 10. "now" is an alias for 0.

If run on an EC2 instance with an appropriate IAM EC2 role, the instance will
be hibernated. Required IAM permissions include:
  - ec2:StopInstances

Alternatively, an instance ID must be specified: that instance will be
hibernated. Required IAM permissions include:
  - ec2:StopInstances
`

var HibernateApp = &cli.App{
	Name:            "hibernate",
	Usage:           "hibernate an instance",
	UsageText:       "hibernate [options] [TIME]",
	HideHelpCommand: true,
	Args:            true,
	ArgsUsage:       "[TIME]",
	Action:          hibernateFunc,
	Description:     hibernateDesc,
	Flags: []cli.Flag{
		&cli.StringFlag{
			Name:  "instance-id",
			Value: "",
			Usage: "set the instance id, defaults to the instance running this command",
		},
		&cli.StringFlag{
			Name:  "loglevel",
			Value: "error",
			Usage: "set the loglevel: debug, info, error",
		},
	},
}

var HibernateCommand = &cli.Command{
	Name:            "hibernate",
	Usage:           "hibernate an instance",
	UsageText:       "hibernate [options] [TIME]",
	HideHelpCommand: true,
	Args:            true,
	ArgsUsage:       "[TIME]",
	Action:          hibernateFunc,
	Description:     hibernateDesc,
	Flags: []cli.Flag{
		&cli.StringFlag{
			Name:  "instance-id",
			Value: "",
			Usage: "set the instance id, defaults to the instance running this command",
		},
		&cli.StringFlag{
			Name:  "loglevel",
			Value: "error",
			Usage: "set the loglevel: debug, info, error",
		},
	},
}

func hibernateFunc(ctx *cli.Context) error {

	// create logger
	log, err := createLogger(ctx.String("loglevel"))
	if err != nil {
		return fmt.Errorf("unable to create a logger, %w", err)
	}

	// set timer for shutdown
	timer, err := setTimer(ctx.Args().Get(0))
	if err != nil {
		return err
	}
	log.Debug("timer is set", "timer", timer)

	// create aws config
	cfg, err := client.CreateAWSConfig()
	if err != nil {
		return err
	}

	awsClient := client.NewAWSClient(
		client.SetConfig(cfg),
	)

	// determine instance id
	instance_id := ctx.String("instance-id")
	if instance_id == "" {
		instance_id, err = awsClient.GetInstanceID()
		if err != nil {
			return err
		}
	}
	log.Debug("instance id is set", "instance_id", instance_id)

	log.Info("waiting to hibernate", "timer", timer)
	time.Sleep(timer)

	// stop instance
	state, err := awsClient.StopInstance(instance_id, true)
	if err != nil {
		return fmt.Errorf("unable to stop instance, %w", err)
	}
	log.Info("hibernating instance", "instance_id", instance_id, "state", state)

	return nil
}

func setTimer(t string) (time.Duration, error) {
	var err error
	timer := time.Duration(10 * time.Second)
	if t != "" {
		if t == "now" {
			timer = time.Duration(0)
		} else {
			timer, err = time.ParseDuration(t + "s")
			if err != nil {
				return timer, fmt.Errorf("unable to set timer, %w", err)
			}
		}
	}
	return timer, nil
}