/*
Copyright 2020 The Rook Authors. All rights reserved.

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 cleanup

import (
	"fmt"
	"strconv"
	"strings"
	"sync"

	"github.com/coreos/pkg/capnslog"
	cephv1 "github.com/rook/rook/pkg/apis/ceph.rook.io/v1"
	"github.com/rook/rook/pkg/clusterd"
	"github.com/rook/rook/pkg/daemon/ceph/client"
	"github.com/rook/rook/pkg/daemon/ceph/osd"
	oposd "github.com/rook/rook/pkg/operator/ceph/cluster/osd"
)

const (
	completeShredUtility = "shred"
)

var logger = capnslog.NewPackageLogger("github.com/rook/rook", "cleanup")

// DiskSanitizer is simple struct to old the context to execute the commands
type DiskSanitizer struct {
	context           *clusterd.Context
	clusterInfo       *client.ClusterInfo
	sanitizeDisksSpec *cephv1.SanitizeDisksSpec
}

// ShredCommand is a struct that defines a shred command with its arguments
type ShredCommand struct {
	command string
	args    []string
}

// NewDiskSanitizer is function that returns a full filled DiskSanitizer object
func NewDiskSanitizer(context *clusterd.Context, clusterInfo *client.ClusterInfo, sanitizeDisksSpec *cephv1.SanitizeDisksSpec) *DiskSanitizer {
	return &DiskSanitizer{
		context:           context,
		clusterInfo:       clusterInfo,
		sanitizeDisksSpec: sanitizeDisksSpec,
	}
}

// StartSanitizeDisks main entrypoint of the cleanup package
func (s *DiskSanitizer) StartSanitizeDisks() {
	// LVM based OSDs
	osdLVMList, err := osd.GetCephVolumeLVMOSDs(s.context, s.clusterInfo, s.clusterInfo.FSID, "", false, false)
	if err != nil {
		logger.Errorf("failed to list lvm osd(s). %v", err)
	} else {
		// Start the sanitizing sequence
		s.SanitizeLVMDisk(osdLVMList)
	}

	// Raw based OSDs
	osdRawList, err := osd.GetCephVolumeRawOSDs(s.context, s.clusterInfo, s.clusterInfo.FSID, "", "", "", false, true)
	if err != nil {
		logger.Errorf("failed to list raw osd(s). %v", err)
	} else {
		// Start the sanitizing sequence
		s.SanitizeRawDisk(osdRawList)
	}
}

func (s *DiskSanitizer) SanitizeRawDisk(osdRawList []oposd.OSDInfo) {
	// Initialize work group to wait for completion of all the go routine
	var wg sync.WaitGroup

	for _, osd := range osdRawList {
		logger.Infof("sanitizing osd %d disk %q", osd.ID, osd.BlockPath)

		// Increment the wait group counter
		wg.Add(1)

		// Put each sanitize in a go routine to speed things up
		go s.executeSanitizeCommand(osd, &wg)
	}

	wg.Wait()
}

func (s *DiskSanitizer) SanitizeLVMDisk(osdLVMList []oposd.OSDInfo) {
	// Initialize work group to wait for completion of all the go routine
	var wg sync.WaitGroup
	pvs := []string{}

	for _, osd := range osdLVMList {
		// Increment the wait group counter
		wg.Add(1)

		// Lookup the PV associated to the LV
		pvs = append(pvs, s.returnPVDevice(osd.BlockPath)[0])

		// run c-v
		go s.wipeLVM(osd.ID, &wg)
	}
	// Wait for ceph-volume to finish before wiping the remaining Physical Volume data
	wg.Wait()

	var wg2 sync.WaitGroup
	// purge remaining LVM2 metadata from PV
	for _, pv := range pvs {
		wg2.Add(1)
		go s.executeSanitizeCommand(oposd.OSDInfo{BlockPath: pv}, &wg2)
	}
	wg2.Wait()
}

func (s *DiskSanitizer) wipeLVM(osdID int, wg *sync.WaitGroup) {
	// On return, notify the WaitGroup that we’re done
	defer wg.Done()

	output, err := s.context.Executor.ExecuteCommandWithCombinedOutput("stdbuf", "-oL", "ceph-volume", "lvm", "zap", "--osd-id", strconv.Itoa(osdID), "--destroy")
	if err != nil {
		logger.Errorf("failed to sanitize osd %d. %s. %v", osdID, output, err)
	}

	logger.Infof("%s\n", output)
	logger.Infof("successfully sanitized lvm osd %d", osdID)
}

func (s *DiskSanitizer) returnPVDevice(disk string) []string {
	output, err := s.context.Executor.ExecuteCommandWithOutput("lvs", disk, "-o", "seg_pe_ranges", "--noheadings")
	if err != nil {
		logger.Errorf("failed to execute lvs command. %v", err)
		return []string{}
	}

	logger.Infof("output: %s", output)
	return strings.Split(output, ":")
}

func (s *DiskSanitizer) buildDataSource() string {
	return fmt.Sprintf("/dev/%s", s.sanitizeDisksSpec.DataSource.String())
}

func (s *DiskSanitizer) buildShredArgs(disk string) []string {
	var shredArgs []string

	// If data source is not zero, then let's add zeros at the end of the pass
	if s.sanitizeDisksSpec.DataSource != cephv1.SanitizeDataSourceZero {
		shredArgs = append(shredArgs, "--zero")
	}

	// If the data source for randomness is zero
	if s.sanitizeDisksSpec.DataSource == cephv1.SanitizeDataSourceZero {
		shredArgs = append(shredArgs, fmt.Sprintf("--random-source=%s", s.buildDataSource()))
	}

	shredArgs = append(shredArgs, []string{
		"--force",
		"--verbose",
		fmt.Sprintf("--iterations=%s", strconv.Itoa(int(s.sanitizeDisksSpec.Iteration))),
		disk,
	}...)

	return shredArgs
}

func (s *DiskSanitizer) buildQuickShredCommands(disk string) []ShredCommand {
	return []ShredCommand{
		{command: "ceph-volume", args: []string{"lvm", "zap", disk}},
	}
}

func (s *DiskSanitizer) buildShredCommands(disk string) []ShredCommand {
	var shredCommands []ShredCommand

	if s.sanitizeDisksSpec.Method == cephv1.SanitizeMethodQuick {
		return s.buildQuickShredCommands(disk)
	}

	if s.sanitizeDisksSpec.DataSource == cephv1.SanitizeDataSourceZero {
		shredCommands = append(shredCommands, ShredCommand{command: completeShredUtility, args: s.buildShredArgs(disk)})
		return shredCommands
	}

	shredCommands = append(shredCommands, ShredCommand{command: completeShredUtility, args: s.buildShredArgs(disk)})

	return shredCommands
}

func (s *DiskSanitizer) executeSanitizeCommand(osdInfo oposd.OSDInfo, wg *sync.WaitGroup) {
	// On return, notify the WaitGroup that we’re done
	defer wg.Done()

	// If the device is encrypted, get the real path and remove the dm device
	if osdInfo.Encrypted {
		realPath, err := osd.GetBackingDeviceForEncryptedBlock(s.context, osdInfo.BlockPath)
		if err != nil {
			logger.Errorf("failed to get backing device for encrypted block %q. %v", osdInfo.BlockPath, err)
		} else {
			err := osd.RemoveEncryptedDevice(s.context, osdInfo.BlockPath)
			if err != nil {
				logger.Errorf("failed to remove dm device %q. %v", osdInfo.BlockPath, err)
			}

			osdInfo.BlockPath = realPath
		}
	}

	for _, device := range []string{osdInfo.BlockPath, osdInfo.MetadataPath, osdInfo.WalPath} {
		if device == "" {
			continue
		}

		for _, shredCmd := range s.buildShredCommands(device) {
			output, err := s.context.Executor.ExecuteCommandWithCombinedOutput(shredCmd.command, shredCmd.args...)

			logger.Infof("%s\n", output)

			if err != nil {
				logger.Errorf("failed to execute sanitization command for osd disk %q. output: %s, error: %v", device, output, err)
			} else {
				logger.Infof("successfully executed sanitization command for osd disk %q", device)
			}
		}
	}
}