/*
Copyright 2018 The Ceph-CSI Authors.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package rbd

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"os"
	"strconv"
	"strings"
	"time"

	"github.com/ceph/ceph-csi/internal/util"
	"github.com/ceph/ceph-csi/internal/util/log"

	"github.com/container-storage-interface/spec/lib/go/csi"
	"k8s.io/apimachinery/pkg/util/wait"
)

const (
	rbdTonbd  = "rbd-nbd"
	moduleNbd = "nbd"

	accessTypeKRbd = "krbd"
	accessTypeNbd  = "nbd"

	rbd = "rbd"

	// Output strings returned during invocation of "rbd unmap --device-type... <imageSpec>" when
	// image is not found to be mapped. Used to ignore errors when attempting to unmap such images.
	// The %s format specifier should contain the <imageSpec> string
	// NOTE: When using devicePath instead of imageSpec, the error strings are different.
	rbdUnmapCmdkRbdMissingMap = "rbd: %s: not a mapped image or snapshot"
	rbdUnmapCmdNbdMissingMap  = "rbd-nbd: %s is not mapped"
	rbdMapConnectionTimeout   = "Connection timed out"

	defaultNbdReAttachTimeout = 300 /* in seconds */
	defaultNbdIOTimeout       = 0   /* do not abort the requests */

	// The default way of creating nbd devices via rbd-nbd is through the
	// legacy ioctl interface, to take advantage of netlink features we
	// should specify `try-netlink` flag explicitly.
	useNbdNetlink = "try-netlink"

	// `reattach-timeout` of rbd-nbd is to tweak NBD_ATTR_DEAD_CONN_TIMEOUT.
	// It specifies how long the device should be held waiting for the
	// userspace process to come back to life.
	setNbdReattach = "reattach-timeout"

	// `io-timeout` of rbd-nbd is to tweak NBD_ATTR_TIMEOUT. It specifies
	// how long the IO should wait to get handled before bailing out.
	setNbdIOTimeout = "io-timeout"
)

var (
	hasNBD              = true
	hasNBDCookieSupport = false

	kernelCookieSupport = []util.KernelVersion{
		{
			Version:      5,
			PatchLevel:   14,
			SubLevel:     0,
			ExtraVersion: 0,
			Distribution: "",
			Backport:     false,
		}, // standard 5.14+ versions
		{
			Version:      4,
			PatchLevel:   18,
			SubLevel:     0,
			ExtraVersion: 365,
			Distribution: ".el8",
			Backport:     true,
		}, // CentOS-8.x
	}
)

// rbdDeviceInfo strongly typed JSON spec for rbd device list output (of type krbd).
type rbdDeviceInfo struct {
	ID             string `json:"id"`
	Pool           string `json:"pool"`
	RadosNamespace string `json:"namespace"`
	Name           string `json:"name"`
	Device         string `json:"device"`
}

// nbdDeviceInfo strongly typed JSON spec for rbd-nbd device list output (of type nbd)
// NOTE: There is a bug in rbd output that returns id as number for nbd, and string for krbd, thus
// requiring 2 different JSON structures to unmarshal the output.
// NOTE: image key is "name" in krbd output and "image" in nbd output, which is another difference.
type nbdDeviceInfo struct {
	ID             int64  `json:"id"`
	Pool           string `json:"pool"`
	RadosNamespace string `json:"namespace"`
	Name           string `json:"image"`
	Device         string `json:"device"`
}

type detachRBDImageArgs struct {
	imageOrDeviceSpec string
	isImageSpec       bool
	isNbd             bool
	encrypted         bool
	volumeID          string
	unmapOptions      string
	logDir            string
	logStrategy       string
}

// rbdGetDeviceList queries rbd about mapped devices and returns a list of rbdDeviceInfo
// It will selectively list devices mapped using krbd or nbd as specified by accessType.
func rbdGetDeviceList(ctx context.Context, accessType string) ([]rbdDeviceInfo, error) {
	// rbd device list --format json --device-type [krbd|nbd]
	var (
		rbdDeviceList []rbdDeviceInfo
		nbdDeviceList []nbdDeviceInfo
	)

	stdout, _, err := util.ExecCommand(ctx, rbd, "device", "list", "--format="+"json", "--device-type", accessType)
	if err != nil {
		return nil, fmt.Errorf("error getting device list from rbd for devices of type (%s): %w", accessType, err)
	}

	if accessType == accessTypeKRbd {
		err = json.Unmarshal([]byte(stdout), &rbdDeviceList)
	} else {
		err = json.Unmarshal([]byte(stdout), &nbdDeviceList)
	}
	if err != nil {
		return nil, fmt.Errorf(
			"error to parse JSON output of device list for devices of type (%s): %w",
			accessType,
			err)
	}

	// convert output to a rbdDeviceInfo list for consumers
	if accessType == accessTypeNbd {
		for _, device := range nbdDeviceList {
			rbdDeviceList = append(
				rbdDeviceList,
				rbdDeviceInfo{
					ID:             strconv.FormatInt(device.ID, 10),
					Pool:           device.Pool,
					RadosNamespace: device.RadosNamespace,
					Name:           device.Name,
					Device:         device.Device,
				})
		}
	}

	return rbdDeviceList, nil
}

// findDeviceMappingImage finds a devicePath, if available, based on image spec (pool/{namespace/}image) on the node.
func findDeviceMappingImage(ctx context.Context, pool, namespace, image string, useNbdDriver bool) (string, bool) {
	accessType := accessTypeKRbd
	if useNbdDriver {
		accessType = accessTypeNbd
	}

	imageSpec := fmt.Sprintf("%s/%s", pool, image)
	if namespace != "" {
		imageSpec = fmt.Sprintf("%s/%s/%s", pool, namespace, image)
	}

	rbdDeviceList, err := rbdGetDeviceList(ctx, accessType)
	if err != nil {
		log.WarningLog(ctx, "failed to determine if image (%s) is mapped to a device (%v)", imageSpec, err)

		return "", false
	}

	for _, device := range rbdDeviceList {
		if device.Name == image && device.Pool == pool && device.RadosNamespace == namespace {
			return device.Device, true
		}
	}

	return "", false
}

// Stat a path, if it doesn't exist, retry maxRetries times.
func waitForPath(ctx context.Context, pool, namespace, image string, maxRetries int, useNbdDriver bool) (string, bool) {
	for i := 0; i < maxRetries; i++ {
		if i != 0 {
			time.Sleep(time.Second)
		}

		device, found := findDeviceMappingImage(ctx, pool, namespace, image, useNbdDriver)
		if found {
			return device, found
		}
	}

	return "", false
}

// SetRbdNbdToolFeatures sets features available with rbd-nbd, and NBD module
// loaded status.
func SetRbdNbdToolFeatures() {
	var stderr string
	// check if the module is loaded or compiled in
	_, err := os.Stat(fmt.Sprintf("/sys/module/%s", moduleNbd))
	if os.IsNotExist(err) {
		// try to load the module
		_, stderr, err = util.ExecCommand(context.TODO(), "modprobe", moduleNbd)
		if err != nil {
			hasNBD = false
			log.WarningLogMsg("nbd modprobe failed (%v): %q", err, stderr)

			return
		}
	}
	log.DefaultLog("nbd module loaded")

	// fetch the current running kernel info
	release, err := util.GetKernelVersion()
	if err != nil {
		log.WarningLogMsg("fetching current kernel version failed (%v)", err)

		return
	}
	if !util.CheckKernelSupport(release, kernelCookieSupport) {
		log.WarningLogMsg("kernel version %q doesn't support cookie feature", release)

		return
	}
	log.DefaultLog("kernel version %q supports cookie feature", release)

	// check if the rbd-nbd tool supports cookie
	stdout, stderr, err := util.ExecCommand(context.TODO(), rbdTonbd, "--help")
	if err != nil || stderr != "" {
		hasNBD = false
		log.WarningLogMsg("running rbd-nbd --help failed with error:%v, stderr:%s", err, stderr)

		return
	}
	if !strings.Contains(stdout, "--cookie") {
		log.WarningLogMsg("rbd-nbd tool doesn't support cookie feature")

		return
	}
	hasNBDCookieSupport = true
	log.DefaultLog("rbd-nbd tool supports cookie feature")
}

// parseMapOptions helps parse formatted mapOptions and unmapOptions and
// returns mounter specific options.
func parseMapOptions(mapOptions string) (string, string, error) {
	var krbdMapOptions, nbdMapOptions string
	for _, item := range strings.Split(mapOptions, ";") {
		var mounter, options string
		if item == "" {
			continue
		}
		s := strings.SplitN(item, ":", 2)
		if len(s) == 1 {
			options = strings.TrimSpace(s[0])
			krbdMapOptions = options
		} else {
			// options might also contain values delimited with ":", in this
			// case mounter type MUST be specified.
			// ex: krbd:read_from_replica=localize,crush_location=zone:zone1;
			mounter = strings.TrimSpace(s[0])
			options = strings.TrimSpace(s[1])
			switch strings.ToLower(mounter) {
			case accessTypeKRbd:
				krbdMapOptions = options
			case accessTypeNbd:
				nbdMapOptions = options
			default:
				return "", "", fmt.Errorf("unknown mounter type: %q, please specify mounter type", mounter)
			}
		}
	}

	return krbdMapOptions, nbdMapOptions, nil
}

// getMapOptions is a wrapper func, calls parse map/unmap funcs and feeds the
// rbdVolume object.
func getMapOptions(req *csi.NodeStageVolumeRequest, rv *rbdVolume) error {
	krbdMapOptions, nbdMapOptions, err := parseMapOptions(req.GetVolumeContext()["mapOptions"])
	if err != nil {
		return err
	}
	krbdUnmapOptions, nbdUnmapOptions, err := parseMapOptions(req.GetVolumeContext()["unmapOptions"])
	if err != nil {
		return err
	}
	if rv.Mounter == rbdDefaultMounter {
		rv.MapOptions = krbdMapOptions
		rv.UnmapOptions = krbdUnmapOptions
	} else if rv.Mounter == rbdNbdMounter {
		rv.MapOptions = nbdMapOptions
		rv.UnmapOptions = nbdUnmapOptions
	}

	return nil
}

func attachRBDImage(ctx context.Context, volOptions *rbdVolume, device string, cr *util.Credentials) (string, error) {
	var err error

	image := volOptions.RbdImageName
	useNBD := false
	if volOptions.Mounter == rbdTonbd && hasNBD {
		useNBD = true
	}

	devicePath, found := waitForPath(ctx, volOptions.Pool, volOptions.RadosNamespace, image, 1, useNBD)
	if !found {
		backoff := wait.Backoff{
			Duration: rbdImageWatcherInitDelay,
			Factor:   rbdImageWatcherFactor,
			Steps:    rbdImageWatcherSteps,
		}

		err = waitForrbdImage(ctx, backoff, volOptions)

		if err != nil {
			return "", err
		}
		devicePath, err = createPath(ctx, volOptions, device, cr)
	}

	return devicePath, err
}

func appendNbdDeviceTypeAndOptions(cmdArgs []string, userOptions, cookie string) []string {
	cmdArgs = append(cmdArgs, "--device-type", accessTypeNbd)

	isUnmap := CheckSliceContains(cmdArgs, "unmap")
	if !isUnmap {
		if !strings.Contains(userOptions, useNbdNetlink) {
			cmdArgs = append(cmdArgs, "--options", useNbdNetlink)
		}
		if !strings.Contains(userOptions, setNbdReattach) {
			cmdArgs = append(cmdArgs, "--options", fmt.Sprintf("%s=%d", setNbdReattach, defaultNbdReAttachTimeout))
		}
		if !strings.Contains(userOptions, setNbdIOTimeout) {
			cmdArgs = append(cmdArgs, "--options", fmt.Sprintf("%s=%d", setNbdIOTimeout, defaultNbdIOTimeout))
		}

		if hasNBDCookieSupport {
			cmdArgs = append(cmdArgs, "--options", fmt.Sprintf("cookie=%s", cookie))
		}
	}

	if userOptions != "" {
		// userOptions is appended after, possibly overriding the above
		// default options.
		cmdArgs = append(cmdArgs, "--options", userOptions)
	}

	return cmdArgs
}

func appendKRbdDeviceTypeAndOptions(cmdArgs []string, userOptions string) []string {
	// Enable mapping and unmapping images from a non-initial network
	// namespace (e.g. for Multus CNI).  The network namespace must be
	// owned by the initial user namespace.
	cmdArgs = append(cmdArgs, "--device-type", accessTypeKRbd, "--options", "noudev")

	if userOptions != "" {
		// userOptions is appended after, possibly overriding the above
		// default options.
		cmdArgs = append(cmdArgs, "--options", userOptions)
	}

	return cmdArgs
}

// appendRbdNbdCliOptions append mandatory options and convert list of useroptions
// provided for rbd integrated cli to rbd-nbd cli format specific.
func appendRbdNbdCliOptions(cmdArgs []string, userOptions, cookie string) []string {
	if !strings.Contains(userOptions, useNbdNetlink) {
		cmdArgs = append(cmdArgs, fmt.Sprintf("--%s", useNbdNetlink))
	}
	if !strings.Contains(userOptions, setNbdReattach) {
		cmdArgs = append(cmdArgs, fmt.Sprintf("--%s=%d", setNbdReattach, defaultNbdReAttachTimeout))
	}
	if !strings.Contains(userOptions, setNbdIOTimeout) {
		cmdArgs = append(cmdArgs, fmt.Sprintf("--%s=%d", setNbdIOTimeout, defaultNbdIOTimeout))
	}
	if hasNBDCookieSupport {
		cmdArgs = append(cmdArgs, fmt.Sprintf("--cookie=%s", cookie))
	}
	if userOptions != "" {
		options := strings.Split(userOptions, ",")
		for _, opt := range options {
			cmdArgs = append(cmdArgs, fmt.Sprintf("--%s", opt))
		}
	}

	return cmdArgs
}

func createPath(ctx context.Context, volOpt *rbdVolume, device string, cr *util.Credentials) (string, error) {
	isNbd := false
	imagePath := volOpt.String()

	log.TraceLog(ctx, "rbd: map mon %s", volOpt.Monitors)

	mapArgs := []string{
		"--id", cr.ID,
		"-m", volOpt.Monitors,
		"--keyfile=" + cr.KeyFile,
	}

	// Choose access protocol
	if volOpt.Mounter == rbdTonbd && hasNBD {
		isNbd = true
	}

	if isNbd {
		mapArgs = append(mapArgs, "--log-file",
			getCephClientLogFileName(volOpt.VolID, volOpt.LogDir, "rbd-nbd"))
	}

	cli := rbd
	if device != "" {
		// TODO: use rbd cli for attach/detach in the future
		cli = rbdNbdMounter
		mapArgs = append(mapArgs, "attach", imagePath, "--device", device)
		mapArgs = appendRbdNbdCliOptions(mapArgs, volOpt.MapOptions, volOpt.VolID)
	} else {
		mapArgs = append(mapArgs, "map", imagePath)
		if isNbd {
			mapArgs = appendNbdDeviceTypeAndOptions(mapArgs, volOpt.MapOptions, volOpt.VolID)
		} else {
			mapArgs = appendKRbdDeviceTypeAndOptions(mapArgs, volOpt.MapOptions)
		}
	}

	if volOpt.readOnly {
		mapArgs = append(mapArgs, "--read-only")
	}

	var (
		stdout string
		stderr string
		err    error
	)

	if volOpt.NetNamespaceFilePath != "" {
		stdout, stderr, err = util.ExecuteCommandWithNSEnter(ctx, volOpt.NetNamespaceFilePath, cli, mapArgs...)
	} else {
		stdout, stderr, err = util.ExecCommand(ctx, cli, mapArgs...)
	}
	if err != nil {
		log.WarningLog(ctx, "rbd: map error %v, rbd output: %s", err, stderr)
		// unmap rbd image if connection timeout
		if strings.Contains(err.Error(), rbdMapConnectionTimeout) {
			dArgs := detachRBDImageArgs{
				imageOrDeviceSpec: imagePath,
				isImageSpec:       true,
				isNbd:             isNbd,
				encrypted:         volOpt.isEncrypted(),
				volumeID:          volOpt.VolID,
				unmapOptions:      volOpt.UnmapOptions,
				logDir:            volOpt.LogDir,
				logStrategy:       volOpt.LogStrategy,
			}
			detErr := detachRBDImageOrDeviceSpec(ctx, &dArgs)
			if detErr != nil {
				log.WarningLog(ctx, "rbd: %s unmap error %v", imagePath, detErr)
			}
		}

		return "", fmt.Errorf("rbd: map failed with error %w, rbd error output: %s", err, stderr)
	}
	devicePath := strings.TrimSuffix(stdout, "\n")

	return devicePath, nil
}

func waitForrbdImage(ctx context.Context, backoff wait.Backoff, volOptions *rbdVolume) error {
	imagePath := volOptions.String()

	err := wait.ExponentialBackoff(backoff, func() (bool, error) {
		used, err := volOptions.isInUse()
		if err != nil {
			return false, fmt.Errorf("fail to check rbd image status: (%w)", err)
		}
		if (volOptions.DisableInUseChecks) && (used) {
			log.UsefulLog(ctx, "valid multi-node attach requested, ignoring watcher in-use result")

			return used, nil
		}

		return !used, nil
	})
	// return error if rbd image has not become available for the specified timeout
	if errors.Is(err, wait.ErrWaitTimeout) {
		return fmt.Errorf("rbd image %s is still being used", imagePath)
	}
	// return error if any other errors were encountered during waiting for the image to become available
	return err
}

func detachRBDDevice(ctx context.Context, devicePath, volumeID, unmapOptions string, encrypted bool) error {
	nbdType := false
	if strings.HasPrefix(devicePath, "/dev/nbd") {
		nbdType = true
	}

	dArgs := detachRBDImageArgs{
		imageOrDeviceSpec: devicePath,
		isImageSpec:       false,
		isNbd:             nbdType,
		encrypted:         encrypted,
		volumeID:          volumeID,
		unmapOptions:      unmapOptions,
	}

	return detachRBDImageOrDeviceSpec(ctx, &dArgs)
}

// detachRBDImageOrDeviceSpec detaches an rbd imageSpec or devicePath, with additional checking
// when imageSpec is used to decide if image is already unmapped.
func detachRBDImageOrDeviceSpec(
	ctx context.Context,
	dArgs *detachRBDImageArgs,
) error {
	if dArgs.encrypted {
		mapperFile, mapperPath := util.VolumeMapper(dArgs.volumeID)
		mappedDevice, mapper, err := util.DeviceEncryptionStatus(ctx, mapperPath)
		if err != nil {
			log.ErrorLog(ctx, "error determining LUKS device on %s, %s: %s",
				mapperPath, dArgs.imageOrDeviceSpec, err)

			return err
		}
		if len(mapper) > 0 {
			// mapper found, so it is open Luks device
			err = util.CloseEncryptedVolume(ctx, mapperFile)
			if err != nil {
				log.ErrorLog(ctx, "error closing LUKS device on %s, %s: %s",
					mapperPath, dArgs.imageOrDeviceSpec, err)

				return err
			}
			dArgs.imageOrDeviceSpec = mappedDevice
		}
	}

	unmapArgs := []string{"unmap", dArgs.imageOrDeviceSpec}
	if dArgs.isNbd {
		unmapArgs = appendNbdDeviceTypeAndOptions(unmapArgs, dArgs.unmapOptions, dArgs.volumeID)
	} else {
		unmapArgs = appendKRbdDeviceTypeAndOptions(unmapArgs, dArgs.unmapOptions)
	}

	_, stderr, err := util.ExecCommand(ctx, rbd, unmapArgs...)
	if err != nil {
		// Messages for krbd and nbd differ, hence checking either of them for missing mapping
		// This is not applicable when a device path is passed in
		if dArgs.isImageSpec &&
			(strings.Contains(stderr, fmt.Sprintf(rbdUnmapCmdkRbdMissingMap, dArgs.imageOrDeviceSpec)) ||
				strings.Contains(stderr, fmt.Sprintf(rbdUnmapCmdNbdMissingMap, dArgs.imageOrDeviceSpec))) {
			// Devices found not to be mapped are treated as a successful detach
			log.TraceLog(ctx, "image or device spec (%s) not mapped", dArgs.imageOrDeviceSpec)

			return nil
		}

		return fmt.Errorf("rbd: unmap for spec (%s) failed (%w): (%s)", dArgs.imageOrDeviceSpec, err, stderr)
	}
	if dArgs.isNbd && dArgs.logDir != "" {
		logFile := getCephClientLogFileName(dArgs.volumeID, dArgs.logDir, "rbd-nbd")
		go strategicActionOnLogFile(ctx, dArgs.logStrategy, logFile)
	}

	return nil
}