// ChildFileIds returns the IDs of all Files that have parent refs to the given file.
func (d *DriveDB) ChildFileIds(fileId string) ([]string, error) {
	var ids []string
	d.iters.Add(1)
	batch := new(leveldb.Batch)
	iter := d.db.NewIterator(util.BytesPrefix(childKey(fileId)), nil)
	for iter.Next() {
		pidcid := deKey(string(iter.Key()))
		cid := pidcid[len(fileId)+1:]
		found, err := d.db.Has(fileKey(cid), nil)
		if err == nil && found {
			ids = append(ids, cid)
		} else {
			batch.Delete(iter.Key())
		}
	}
	iter.Release()
	d.iters.Done()
	if batch.Len() > 0 {
		err := d.db.Write(batch, nil)
		if err != nil {
			log.Printf("error writing to db: %v", err)
		}
	}
	return ids, iter.Error()
}

// DeleteDataWithPrefix deletes all service data such as service metadata, items and payloads.
func (ds *LevelDBStorage) DeleteDataWithPrefix(prefix string) int {
	ds.FlushCache()
	ds.saveLock.Lock()
	defer ds.saveLock.Unlock()

	limitCounter := 0
	total := 0
	iter := ds.IterData(prefix)
	wb := new(leveldb.Batch)

	for iter.Valid() {
		total++
		if limitCounter < 1000 {
			wb.Delete(iter.GetKey())
			limitCounter++
		} else {
			limitCounter = 0
			ds.db.Write(wb, nil)
			wb.Reset()
		}
		iter.Next()
	}

	ds.db.Write(wb, nil)
	return total
}

func (self dbSync) saveInDb(mult map[string]string) {
	batch := new(leveldb.Batch)
	for k, v := range mult {
		batch.Put([]byte(k), []byte(v))
	}
	self.Db.Write(batch, nil)
}

func msetnx(v resp.CommandArgs, ex *CommandExtras) error {
	if len(v) == 0 || len(v)%2 != 0 {
		return resp.NewError(ErrFmtWrongNumberArgument, "msetnx").WriteTo(ex.Buffer)
	}

	batch := new(leveldb.Batch)
	for i := 0; i < len(v); {
		batch.Put(v[i], v[i+1])
		i += 2
	}

	ex.DB.Lock()
	defer ex.DB.Unlock()

	for i := 0; i < len(v); {
		_, err := ex.DB.Get(v[i])
		if err != nil && err != leveldb.ErrNotFound {
			return err
		}
		if err != leveldb.ErrNotFound {
			return resp.ZeroInteger.WriteTo(ex.Buffer)
		}
		i += 2
	}

	if err := ex.DB.WriteBatch(batch); err != nil {
		return err
	}
	return resp.OneInteger.WriteTo(ex.Buffer)
}

func (self dbSync) multiDeleteDb(ks []string) {
	batch := new(leveldb.Batch)
	for _, k := range ks {
		batch.Delete([]byte(k))
	}
	self.Db.Write(batch, nil)
}

// PersistReceivedRecords save the info about which records we've already seen
func (p *LevelDBPersister) PersistReceivedRecords(comp StreamID, records []*Record) error {
	batch := new(leveldb.Batch)
	for _, r := range records {
		batch.Put([]byte(fmt.Sprintf(receivedKeyFormat, comp, r.ID)), nil)
	}
	return p.db.Write(batch, nil)
}

// PutReceipts stores the receipts in the current database
func PutReceipts(db common.Database, receipts types.Receipts) error {
	batch := new(leveldb.Batch)
	_, batchWrite := db.(*ethdb.LDBDatabase)

	for _, receipt := range receipts {
		storageReceipt := (*types.ReceiptForStorage)(receipt)
		bytes, err := rlp.EncodeToBytes(storageReceipt)
		if err != nil {
			return err
		}

		if batchWrite {
			batch.Put(append(receiptsPre, receipt.TxHash[:]...), bytes)
		} else {
			err = db.Put(append(receiptsPre, receipt.TxHash[:]...), bytes)
			if err != nil {
				return err
			}
		}
	}
	if db, ok := db.(*ethdb.LDBDatabase); ok {
		if err := db.LDB().Write(batch, nil); err != nil {
			return err
		}
	}

	return nil
}

// childFileIds returns a map containing IDs of all Files that have parent
// refs to the given file.  The returned map keys are IDs, and the map values
// indicate if the child is a directory.
func (d *DriveDB) childFileIds(fileId string) (map[string]bool, error) {
	ids := make(map[string]bool)
	d.iters.Add(1)
	batch := new(leveldb.Batch)
	iter := d.db.NewIterator(util.BytesPrefix(childKeyPrefix(fileId)), nil)
	for iter.Next() {
		pidcid := deKey(string(iter.Key()))
		cid := pidcid[len(fileId)+1:]
		if gdriveFile, err := d.FileById(cid); err != nil {
			log.Printf("unknown fileId %v: %v", fileId, err)
			batch.Delete(iter.Key())
		} else {
			ids[cid] = gdriveFile.MimeType == driveFolderMimeType
		}
	}
	iter.Release()
	d.iters.Done()
	if batch.Len() > 0 {
		err := d.db.Write(batch, nil)
		if err != nil {
			log.Printf("error writing to db: %v", err)
		}
	}
	return ids, iter.Error()
}

func (l *LevelDb) Put(id DbKey, aliases []DbKey, value []byte) error {

	// Lazy Open
	if err := l.open(); err != nil {
		return err
	}

	batch := new(leveldb.Batch)
	idb := id.ToBytes("kv")
	batch.Put(idb, value)
	if aliases != nil {
		for _, alias := range aliases {
			batch.Put(alias.ToBytes("lo"), idb)
		}
	}

	err := l.db.Write(batch, nil)

	// If the file is corrupt, just nuke and act like we didn't find anything
	if l.nukeIfCorrupt(err) {
		err = nil
	}

	return err
}

func clearItems(db *leveldb.DB) error {
	snap, err := db.GetSnapshot()
	if err != nil {
		return err
	}
	defer snap.Release()

	// Iterate over k2

	it := snap.NewIterator(util.BytesPrefix([]byte{1}), nil)
	defer it.Release()

	batch := new(leveldb.Batch)
	for it.Next() {
		k1 := it.Key()
		k2 := it.Value()

		// k2 should exist
		_, err := snap.Get(k2, nil)
		if err != nil {
			return err
		}

		// Delete the k1 => k2 mapping first
		batch.Delete(k1)
		// Then the k2 => data mapping
		batch.Delete(k2)
	}
	if testing.Verbose() {
		log.Printf("batch write (clear) %p", batch)
	}
	return db.Write(batch, nil)
}

// flush a leveldb batch to database and reset batch to 0
func cacheFlush(db *leveldb.DB, batch *leveldb.Batch) {
	err := db.Write(batch, nil)
	if err != nil {
		log.Fatal(err)
	}
	batch.Reset()
}

func (ds *LevelDBStorage) DeleteData(id ...string) error {
	wb := new(leveldb.Batch)
	for _, i := range id {
		wb.Delete(enc.UnsafeStringToBytes(i))
	}
	return ds.db.Write(wb, nil)
}

func (server *Server) deleteMessages(uid *[32]byte, messageList []*[32]byte) error {
	batch := new(leveldb.Batch)
	for _, messageID := range messageList {
		key := append(append([]byte{'m'}, uid[:]...), messageID[:]...)
		batch.Delete(key)
	}
	return server.database.Write(batch, wO_sync)
}

func (l *internalLevelDBStore) putBatch(b *leveldb.Batch, numBytes int) {
	l.concurrentWriteLimit <- struct{}{}
	err := l.db.Write(b, nil)
	d.Chk.NoError(err)
	l.putCount += int64(b.Len())
	l.putBytes += int64(numBytes)
	<-l.concurrentWriteLimit
}

func ldbCheckGlobals(db *leveldb.DB, folder []byte) {
	defer runtime.GC()

	snap, err := db.GetSnapshot()
	if err != nil {
		panic(err)
	}
	l.Debugf("created snapshot %p", snap)
	defer func() {
		l.Debugf("close snapshot %p", snap)
		snap.Release()
	}()

	start := globalKey(folder, nil)
	limit := globalKey(folder, []byte{0xff, 0xff, 0xff, 0xff})
	dbi := snap.NewIterator(&util.Range{Start: start, Limit: limit}, nil)
	defer dbi.Release()

	batch := new(leveldb.Batch)
	l.Debugf("new batch %p", batch)

	var fk []byte
	for dbi.Next() {
		gk := dbi.Key()
		var vl versionList
		err := vl.UnmarshalXDR(dbi.Value())
		if err != nil {
			panic(err)
		}

		// Check the global version list for consistency. An issue in previous
		// versions of goleveldb could result in reordered writes so that
		// there are global entries pointing to no longer existing files. Here
		// we find those and clear them out.

		name := globalKeyName(gk)
		var newVL versionList
		for _, version := range vl.versions {
			fk = deviceKeyInto(fk[:cap(fk)], folder, version.device, name)
			l.Debugf("snap.Get %p %x", snap, fk)
			_, err := snap.Get(fk, nil)
			if err == leveldb.ErrNotFound {
				continue
			}
			if err != nil {
				panic(err)
			}
			newVL.versions = append(newVL.versions, version)
		}

		if len(newVL.versions) != len(vl.versions) {
			l.Infof("db repair: rewriting global version list for %x %x", gk[1:1+64], gk[1+64:])
			batch.Put(dbi.Key(), newVL.MustMarshalXDR())
		}
	}
	l.Debugf("db check completed for %q", folder)
	db.Write(batch, nil)
}

func (ldb *LevelDB) delete(keys [][]byte) {
	batch := new(leveldb.Batch)
	for _, key := range keys {
		batch.Delete(key)
	}
	if err := ldb.db.Write(batch, nil); err != nil && err != leveldb.ErrNotFound {
		panic(err)
	}
}

// Discard block map state, removing the given files
func (m *BlockMap) Discard(files []protocol.FileInfo) error {
	batch := new(leveldb.Batch)
	for _, file := range files {
		for _, block := range file.Blocks {
			batch.Delete(m.blockKey(block.Hash, file.Name))
		}
	}
	return m.db.Write(batch, nil)
}

func (server *Server) newKeys(uid *[32]byte, keyList [][]byte) error {
	batch := new(leveldb.Batch)
	for _, key := range keyList {
		keyHash := sha256.Sum256(key)
		dbKey := append(append([]byte{'k'}, uid[:]...), keyHash[:]...)
		batch.Put(dbKey, key)
	}
	return server.database.Write(batch, wO_sync)
}

// Fix repairs incorrect blockmap entries, removing the old entry and
// replacing it with a new entry for the given block
func (f *BlockFinder) Fix(folder, file string, index int32, oldHash, newHash []byte) error {
	buf := make([]byte, 4)
	binary.BigEndian.PutUint32(buf, uint32(index))

	batch := new(leveldb.Batch)
	batch.Delete(blockKeyInto(nil, oldHash, folder, file))
	batch.Put(blockKeyInto(nil, newHash, folder, file), buf)
	return f.db.Write(batch, nil)
}

func main() {
	olddb, err := Open(os.Args[1])
	if err != nil {
		panic(err)
	}
	newdb, err := Open(os.Args[2])
	if err != nil {
		panic(err)
	}

	iter := olddb.NewIterator(&util.Range{Start: nil, Limit: nil}, nil)

	totalBitset := 0
	totalMsgpack := 0

	rows := 0

	var batch *leveldb.Batch
	batch = new(leveldb.Batch)
	for iter.Next() {
		key := iter.Key()
		value := iter.Value()
		if bytes.HasPrefix(key, []byte("doc:")) {
			batch.Put(key, value)
			continue
		}
		bs := bitset.New(8)
		bs.ReadFrom(bytes.NewBuffer(value))
		var docIDs []uint
		for i, e := bs.NextSet(0); e; i, e = bs.NextSet(i + 1) {
			docIDs = append(docIDs, i)
		}
		b, err := msgpack.Marshal(delta_encode(docIDs))
		if err != nil {
			panic(err)
		}
		//fmt.Printf("bitset size is %d\n", len(value))
		//fmt.Printf("msgpack size is %d\n", len(b))

		totalBitset += len(value)
		totalMsgpack += len(b)
		batch.Put(key, b)
		if rows%10000 == 0 {
			log.Print("rows ", rows)
			newdb.Write(batch, nil)
			batch = new(leveldb.Batch)
		}
		rows++

	}
	fmt.Printf("bitset size is %d\n", totalBitset)
	fmt.Printf("msgpack size is %d\n", totalMsgpack)
	newdb.Write(batch, nil)
	newdb.CompactRange(util.Range{Start: nil, Limit: nil})

}