package govmtools

import (
	"fmt"
	"github.com/ptrcnull/vsock"
	"golang.org/x/sys/unix"
)

type PacketType uint32
const (
	PacketTypeData PacketType = iota + 1
	PacketTypePing
)

type FieldID uint32
const (
	FieldIDType FieldID = iota + 1
	FieldIDPayload
	FieldIDFastClose
)

type FieldType uint32
const (
	FieldEmpty FieldType = iota
	FieldInt64
	FieldString
	FieldInt64List
	FieldStringList
	FieldMax
)

type GuestInfoType uint32
const (
	GuestInfoError GuestInfoType = iota
	GuestInfoDnsName
	GuestInfoIpAddress
	GuestInfoDiskFreeSpace
	GuestInfoBuildNumber
	GuestInfoOsNameFull
	GuestInfoOsName
	GuestInfoUptime
	GuestInfoMemory
	GuestInfoIpAddressV2
	GuestInfoIpAddressV3
	GuestInfoOsDetailed
	GuestInfoMax
)

const GuestConnectPort = 976
const ContextID = unix.VMADDR_CID_HYPERVISOR

type Socket struct {
	conn *vsock.Conn
}

func NewSocket() (*Socket, error) {
	conn, err := vsock.Dial(ContextID, GuestConnectPort)
	if err != nil {
		return nil, fmt.Errorf("connect: %w", err)
	}

	return &Socket{
		conn: conn,
	}, nil
}

func (s *Socket) SendCommand(cmd string) error {
	err := s.WritePacket([]Field{
		{
			Type:  FieldInt64,
			ID:    FieldIDType,
			Value: PacketTypeData,
		},
		{
			Type: FieldEmpty,
		},
		{
			Type:  FieldString,
			ID:    FieldIDPayload,
			Value: cmd,
		},
	})
	if err != nil {
		return fmt.Errorf("write packet: %w", err)
	}

	res, err := s.ReadPacket()
	if err != nil {
		return fmt.Errorf("read packet: %w", err)
	}
	if len(res) != 1 {
		return fmt.Errorf("unexpected response length: %d", len(res))
	}
	field := res[0]
	if field.Type != FieldString {
		return fmt.Errorf("unexpected response type: %d", field.Type)
	}
	if field.ID != FieldIDPayload {
		return fmt.Errorf("unexpected response id: %d", field.ID)
	}

	response := field.Value.(string)
	if response != "1 " {
		return fmt.Errorf("unexpected response: %s", response)
	}

	return nil
}

func (s *Socket) SetGuestInfo(messageType GuestInfoType, message string) {
	s.MustSendCommand(fmt.Sprintf("SetGuestInfo  %d %s", messageType, message))
}

func (s *Socket) MustSendCommand(cmd string) {
	err := s.SendCommand(cmd)
	if err != nil {
		panic(err)
	}
}

func (s *Socket) ReportVersionData() error {
	data := []string{
		"description " + Name + " " + Version + " build " + BuildNumber,
		"versionString " + Version,
		"versionNumber " + VersionNumber,
		"buildNumber " + BuildNumber,
	}

	for _, value := range data {
		err := s.SendCommand("info-set guestinfo.vmtools." + value + "\x00")
		if err != nil {
			return fmt.Errorf("send: %w", err)
		}
	}

	return nil
}