/* SPDX-License-Identifier: MIT
 *
 * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
 */

package service

import (
	"fmt"
	"golang.org/x/sys/windows"
	"syscall"
)

type Error uint32

const (
	ErrorSuccess Error = iota
	ErrorRingloggerOpen
	ErrorLoadConfiguration
	ErrorCreateWintun
	ErrorDetermineWintunName
	ErrorUAPIListen
	ErrorUAPISerialization
	ErrorDeviceSetConfig
	ErrorBindSocketsToDefaultRoutes
	ErrorSetNetConfig
	ErrorDetermineExecutablePath
	ErrorFindAdministratorsSID
	ErrorOpenNULFile
	ErrorTrackTunnels
	ErrorEnumerateSessions
	ErrorWin32
)

func (e Error) Error() string {
	switch e {
	case ErrorSuccess:
		return "No error."
	case ErrorRingloggerOpen:
		return "Unable to open log file."
	case ErrorDetermineExecutablePath:
		return "Unable to determine path of running executable."
	case ErrorLoadConfiguration:
		return "Unable to load configuration from path."
	case ErrorCreateWintun:
		return "Unable to create Wintun device."
	case ErrorDetermineWintunName:
		return "Unable to determine Wintun name."
	case ErrorUAPIListen:
		return "Unable to listen on named pipe."
	case ErrorUAPISerialization:
		return "Unable to serialize configuration into uapi form."
	case ErrorDeviceSetConfig:
		return "Unable to set device configuration."
	case ErrorBindSocketsToDefaultRoutes:
		return "Unable to bind sockets to default route."
	case ErrorSetNetConfig:
		return "Unable to set interface addresses, routes, dns, and/or adapter settings."
	case ErrorFindAdministratorsSID:
		return "Unable to find Administrators SID."
	case ErrorOpenNULFile:
		return "Unable to open NUL file."
	case ErrorTrackTunnels:
		return "Unable to track existing tunnels."
	case ErrorEnumerateSessions:
		return "Unable to enumerate current sessions."
	case ErrorWin32:
		return "An internal Windows error has occurred."
	default:
		return "An unknown error has occurred."
	}
}

func determineErrorCode(err error, serviceError Error) (bool, uint32) {
	if syserr, ok := err.(syscall.Errno); ok {
		return false, uint32(syserr)
	} else if serviceError != ErrorSuccess {
		return true, uint32(serviceError)
	} else {
		return false, windows.NO_ERROR
	}
}

func combineErrors(err error, serviceError Error) error {
	if serviceError != ErrorSuccess {
		if err != nil {
			return fmt.Errorf("%v: %v", serviceError, err)
		} else {
			return serviceError
		}
	}
	return err
}

const (
	serviceDOES_NOT_EXIST    uint32 = 0x00000424
	serviceMARKED_FOR_DELETE uint32 = 0x00000430
	serviceNEVER_STARTED     uint32 = 0x00000435
)