package devicepath

import (
	"errors"
	"strings"
)

type DeviceNodeType uint8

const (
	HardwareDevicePath               DeviceNodeType = 0x01
	ACPIDevicePath                   DeviceNodeType = 0x02
	MessagingDevicePath              DeviceNodeType = 0x03
	MediaDevicePath                  DeviceNodeType = 0x04
	BIOSBootSpecificationsDevicePath DeviceNodeType = 0x05
	EndOfHardwareDevicePath          DeviceNodeType = 0x7F
)

type DeviceNodeSubType uint8

const (
	PCIHardware DeviceNodeSubType = 0x01
)

const (
	SATAMessaging DeviceNodeSubType = 18
)

const EndOfEntireDevicePath DeviceNodeSubType = 0xFF

const ACPISubType DeviceNodeSubType = 1

const HardDriveSubType DeviceNodeSubType = 1

type DevicePathNode interface {
	Type() DeviceNodeType
	SubType() DeviceNodeSubType
	ParseString(raw string) error
	String() string
	Bytes() []byte
}

var ErrPathComplete = errors.New("device path already complete")

type DevicePath struct {
	nodes []DevicePathNode
}

func (dp *DevicePath) complete() bool {
	return len(dp.nodes) > 0 && dp.nodes[len(dp.nodes)-1].Type() == EndOfHardwareDevicePath
}

func (dp *DevicePath) PushNode(node DevicePathNode) error {
	if dp.complete() {
		return ErrPathComplete
	}
	dp.nodes = append(dp.nodes, node)
	return nil
}

func (dp *DevicePath) String() string {
	var res []string
	for _, node := range dp.nodes {
		if node.String() != "" {
			res = append(res, node.String())
		}
	}
	return strings.Join(res, "/")
}