package command

import (
	"fmt"
	"io/fs"
	"os"
	"path"
	"strconv"
	"strings"

	"github.com/seaweedfs/seaweedfs/weed/glog"
	"github.com/seaweedfs/seaweedfs/weed/storage"
	"github.com/seaweedfs/seaweedfs/weed/storage/backend"
	"github.com/seaweedfs/seaweedfs/weed/storage/needle"
	"github.com/seaweedfs/seaweedfs/weed/storage/needle_map"
	"github.com/seaweedfs/seaweedfs/weed/storage/super_block"
	"github.com/seaweedfs/seaweedfs/weed/storage/types"
	"github.com/seaweedfs/seaweedfs/weed/util"
)

func init() {
	cmdFix.Run = runFix // break init cycle
}

var cmdFix = &Command{
	UsageLine: "fix [-remoteFile=false] [-volumeId=234] [-collection=bigData] /tmp",
	Short:     "run weed tool fix on files or whole folders to recreate index file(s) if corrupted",
	Long: `Fix runs the SeaweedFS fix command on local dat files ( or remote files) or whole folders to re-create the index .idx file. If fixing remote files, you need to synchronize master.toml to the same directory on the current node as on the master node.
  You Need to stop the volume server when running this command.
`,
}

var (
	fixVolumeCollection = cmdFix.Flag.String("collection", "", "an optional volume collection name, if specified only it will be processed")
	fixVolumeId         = cmdFix.Flag.Int64("volumeId", 0, "an optional volume id, if not 0 (default) only it will be processed")
	fixIncludeDeleted   = cmdFix.Flag.Bool("includeDeleted", true, "include deleted entries in the index file")
	fixIgnoreError      = cmdFix.Flag.Bool("ignoreError", false, "an optional, if true will be processed despite errors")
	fixRemoteFile       = cmdFix.Flag.Bool("remoteFile", false, "an optional, if true will not try to load the local .dat file, but only the remote file")
)

type VolumeFileScanner4Fix struct {
	version        needle.Version
	nm             *needle_map.MemDb
	nmDeleted      *needle_map.MemDb
	includeDeleted bool
}

func (scanner *VolumeFileScanner4Fix) VisitSuperBlock(superBlock super_block.SuperBlock) error {
	scanner.version = superBlock.Version
	return nil
}

func (scanner *VolumeFileScanner4Fix) ReadNeedleBody() bool {
	return false
}

func (scanner *VolumeFileScanner4Fix) VisitNeedle(n *needle.Needle, offset int64, needleHeader, needleBody []byte) error {
	glog.V(2).Infof("key %v offset %d size %d disk_size %d compressed %v", n.Id, offset, n.Size, n.DiskSize(scanner.version), n.IsCompressed())
	if n.Size.IsValid() {
		if pe := scanner.nm.Set(n.Id, types.ToOffset(offset), n.Size); pe != nil {
			return fmt.Errorf("saved %d with error %v", n.Size, pe)
		}
	} else {
		if scanner.includeDeleted {
			if pe := scanner.nmDeleted.Set(n.Id, types.ToOffset(offset), types.TombstoneFileSize); pe != nil {
				return fmt.Errorf("saved deleted %d with error %v", n.Size, pe)
			}
		} else {
			glog.V(2).Infof("skipping deleted file ...")
			return scanner.nm.Delete(n.Id)
		}
	}
	return nil
}

func runFix(cmd *Command, args []string) bool {
	for _, arg := range args {
		basePath, f := path.Split(util.ResolvePath(arg))
		if util.FolderExists(arg) {
			basePath = arg
			f = ""
		}

		files := []fs.DirEntry{}
		if f == "" {
			fileInfo, err := os.ReadDir(basePath)
			if err != nil {
				fmt.Println(err)
				return false
			}
			files = fileInfo
		} else {
			fileInfo, err := os.Stat(arg)
			if err != nil {
				fmt.Println(err)
				return false
			}
			files = []fs.DirEntry{fs.FileInfoToDirEntry(fileInfo)}
		}

		ext := ".dat"
		if *fixRemoteFile {
			ext = ".idx"
			util.LoadConfiguration("master", false)
			backend.LoadConfiguration(util.GetViper())
		}

		for _, file := range files {
			if !strings.HasSuffix(file.Name(), ext) {
				continue
			}
			if *fixVolumeCollection != "" {
				if !strings.HasPrefix(file.Name(), *fixVolumeCollection+"_") {
					continue
				}
			}
			baseFileName := file.Name()[:len(file.Name())-4]
			collection, volumeIdStr := "", baseFileName
			if sepIndex := strings.LastIndex(baseFileName, "_"); sepIndex > 0 {
				collection = baseFileName[:sepIndex]
				volumeIdStr = baseFileName[sepIndex+1:]
			}
			volumeId, parseErr := strconv.ParseInt(volumeIdStr, 10, 64)
			if parseErr != nil {
				fmt.Printf("Failed to parse volume id from %s: %v\n", baseFileName, parseErr)
				return false
			}
			if *fixVolumeId != 0 && *fixVolumeId != volumeId {
				continue
			}
			doFixOneVolume(basePath, baseFileName, collection, volumeId, *fixIncludeDeleted)
		}
	}
	return true
}

func SaveToIdx(scaner *VolumeFileScanner4Fix, idxName string) (ret error) {
	idxFile, err := os.OpenFile(idxName, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0644)
	if err != nil {
		return
	}
	defer func() {
		idxFile.Close()
	}()

	return scaner.nm.AscendingVisit(func(value needle_map.NeedleValue) error {
		_, err := idxFile.Write(value.ToBytes())
		if scaner.includeDeleted && err == nil {
			if deleted, ok := scaner.nmDeleted.Get(value.Key); ok {
				_, err = idxFile.Write(deleted.ToBytes())
			}
		}
		return err
	})
}

func doFixOneVolume(basepath string, baseFileName string, collection string, volumeId int64, fixIncludeDeleted bool) {
	indexFileName := path.Join(basepath, baseFileName+".idx")

	nm := needle_map.NewMemDb()
	nmDeleted := needle_map.NewMemDb()
	defer nm.Close()
	defer nmDeleted.Close()

	vid := needle.VolumeId(volumeId)
	scanner := &VolumeFileScanner4Fix{
		nm:             nm,
		nmDeleted:      nmDeleted,
		includeDeleted: fixIncludeDeleted,
	}

	if err := storage.ScanVolumeFile(basepath, collection, vid, storage.NeedleMapInMemory, scanner); err != nil {
		err := fmt.Errorf("scan .dat File: %w", err)
		if *fixIgnoreError {
			glog.Error(err)
		} else {
			glog.Fatal(err)
		}
	}

	if err := SaveToIdx(scanner, indexFileName); err != nil {
		err := fmt.Errorf("save to .idx File: %w", err)
		if *fixIgnoreError {
			glog.Error(err)
		} else {
			os.Remove(indexFileName)
			glog.Fatal(err)
		}
	}
}