//go:generate struct-markdown

package ebssurrogate

import (
	"errors"

	"github.com/hashicorp/packer/packer-plugin-sdk/template/interpolate"
)

type RootBlockDevice struct {
	SourceDeviceName string `mapstructure:"source_device_name"`
	// The device name exposed to the instance (for
	// example, /dev/sdh or xvdh). Required for every device in the block
	// device mapping.
	DeviceName string `mapstructure:"device_name" required:"false"`
	// Indicates whether the EBS volume is
	// deleted on instance termination. Default false. NOTE: If this
	// value is not explicitly set to true and volumes are not cleaned up by
	// an alternative method, additional volumes will accumulate after every
	// build.
	DeleteOnTermination bool `mapstructure:"delete_on_termination" required:"false"`
	// The number of I/O operations per second (IOPS) that
	// the volume supports. See the documentation on
	// IOPs
	// for more information
	IOPS int64 `mapstructure:"iops" required:"false"`
	// The volume type. gp2 for General Purpose
	// (SSD) volumes, io1 for Provisioned IOPS (SSD) volumes, st1 for
	// Throughput Optimized HDD, sc1 for Cold HDD, and standard for
	// Magnetic volumes.
	VolumeType string `mapstructure:"volume_type" required:"false"`
	// The size of the volume, in GiB. Required if
	// not specifying a snapshot_id.
	VolumeSize int64 `mapstructure:"volume_size" required:"false"`
}

func (c *RootBlockDevice) Prepare(ctx *interpolate.Context) []error {
	var errs []error

	if c.SourceDeviceName == "" {
		errs = append(errs, errors.New("source_device_name for the root_device must be specified"))
	}

	if c.DeviceName == "" {
		errs = append(errs, errors.New("device_name for the root_device must be specified"))
	}

	if c.VolumeType == "gp2" && c.IOPS != 0 {
		errs = append(errs, errors.New("iops may not be specified for a gp2 volume"))
	}

	if c.IOPS < 0 {
		errs = append(errs, errors.New("iops must be greater than 0"))
	}

	if c.VolumeSize < 0 {
		errs = append(errs, errors.New("volume_size must be greater than 0"))
	}

	if len(errs) > 0 {
		return errs
	}

	return nil
}