// updateSSRtxRecord updates an SSRtx record in the SSRtx records bucket.
func updateSSRtxRecord(tx walletdb.Tx, hash *chainhash.Hash,
	record *ssrtxRecord) error {
	// Fetch the current content of the key.
	// Possible buggy behaviour: If deserialization fails,
	// we won't detect it here. We assume we're throwing
	// ErrSSRtxsNotFound.
	oldRecords, _ := fetchSSRtxRecords(tx, hash)

	// Don't reinsert records we already have.
	if ssrtxRecordExistsInRecords(record, oldRecords) {
		return nil
	}

	bucket := tx.RootBucket().Bucket(ssrtxRecordsBucketName)

	var records []*ssrtxRecord
	// Either create a slice if currently nothing exists for this
	// key in the db, or append the entry to the slice.
	if oldRecords == nil {
		records = make([]*ssrtxRecord, 1)
		records[0] = record
	} else {
		records = append(oldRecords, record)
	}

	// Write the serialized SSRtxs keyed by the sstx hash.
	serializedSSRtxsRecords := serializeSSRtxRecords(records)

	err := bucket.Put(hash.Bytes(), serializedSSRtxsRecords)
	if err != nil {
		str := fmt.Sprintf("failed to store ssrtx records '%s'", hash)
		return stakeStoreError(ErrDatabase, str, err)
	}
	return nil
}

// FetchHeightRange looks up a range of blocks by the start and ending
// heights.  Fetch is inclusive of the start height and exclusive of the
// ending height. To fetch all hashes from the start height until no
// more are present, use the special id `AllShas'.
func (db *LevelDb) FetchHeightRange(startHeight, endHeight int64) (rshalist []chainhash.Hash, err error) {
	db.dbLock.Lock()
	defer db.dbLock.Unlock()

	var endidx int64
	if endHeight == database.AllShas {
		endidx = startHeight + 500
	} else {
		endidx = endHeight
	}

	shalist := make([]chainhash.Hash, 0, endidx-startHeight)
	for height := startHeight; height < endidx; height++ {
		// TODO(drahn) fix blkFile from height

		key := int64ToKey(height)
		blkVal, lerr := db.lDb.Get(key, db.ro)
		if lerr != nil {
			break
		}

		var sha chainhash.Hash
		sha.SetBytes(blkVal[0:32])
		shalist = append(shalist, sha)
	}

	if err != nil {
		return
	}
	//log.Tracef("FetchIdxRange idx %v %v returned %v shas err %v", startHeight, endHeight, len(shalist), err)

	return shalist, nil
}

func parsesha(argstr string) (argtype int, height int64, psha *chainhash.Hash, err error) {
	var sha chainhash.Hash

	var hashbuf string

	switch len(argstr) {
	case 64:
		hashbuf = argstr
	case 66:
		if argstr[0:2] != "0x" {
			log.Infof("prefix is %v", argstr[0:2])
			err = ErrBadShaPrefix
			return
		}
		hashbuf = argstr[2:]
	default:
		if len(argstr) <= 16 {
			// assume value is height
			argtype = ArgHeight
			var h int
			h, err = strconv.Atoi(argstr)
			if err == nil {
				height = int64(h)
				return
			}
			log.Infof("Unable to parse height %v, err %v", height, err)
		}
		err = ErrBadShaLen
		return
	}

	var buf [32]byte
	for idx, ch := range hashbuf {
		var val rune

		switch {
		case ch >= '0' && ch <= '9':
			val = ch - '0'
		case ch >= 'a' && ch <= 'f':
			val = ch - 'a' + rune(10)
		case ch >= 'A' && ch <= 'F':
			val = ch - 'A' + rune(10)
		default:
			err = ErrBadShaChar
			return
		}
		b := buf[31-idx/2]
		if idx&1 == 1 {
			b |= byte(val)
		} else {
			b |= (byte(val) << 4)
		}
		buf[31-idx/2] = b
	}
	sha.SetBytes(buf[0:32])
	psha = &sha
	return
}

// GetBlockAsync returns an instance of a type that can be used to get the
// result of the RPC at some future time by invoking the Receive function on the
// returned instance.
//
// See GetBlock for the blocking version and more details.
func (c *Client) GetBlockAsync(blockHash *chainhash.Hash) FutureGetBlockResult {
	hash := ""
	if blockHash != nil {
		hash = blockHash.String()
	}

	cmd := dcrjson.NewGetBlockCmd(hash, dcrjson.Bool(false), nil)
	return c.sendCmd(cmd)
}

// hashInSlice returns whether a hash exists in a slice or not.
func hashInSlice(h *chainhash.Hash, list []*chainhash.Hash) bool {
	for _, hash := range list {
		if h.IsEqual(hash) {
			return true
		}
	}

	return false
}

// GetHeadersAsync returns an instance of a type that can be used to get the result
// of the RPC at some future time by invoking the Receive function on the returned instance.
//
// See GetHeaders for the blocking version and more details.
func (c *Client) GetHeadersAsync(blockLocators []chainhash.Hash, hashStop *chainhash.Hash) FutureGetHeadersResult {
	concatenatedLocators := make([]byte, chainhash.HashSize*len(blockLocators))
	for i := range blockLocators {
		copy(concatenatedLocators[i*chainhash.HashSize:], blockLocators[i][:])
	}
	cmd := dcrjson.NewGetHeadersCmd(hex.EncodeToString(concatenatedLocators),
		hashStop.String())
	return c.sendCmd(cmd)
}

// GetRawTransactionAsync returns an instance of a type that can be used to get
// the result of the RPC at some future time by invoking the Receive function on
// the returned instance.
//
// See GetRawTransaction for the blocking version and more details.
func (c *Client) GetRawTransactionAsync(txHash *chainhash.Hash) FutureGetRawTransactionResult {
	hash := ""
	if txHash != nil {
		hash = txHash.String()
	}

	cmd := dcrjson.NewGetRawTransactionCmd(hash, dcrjson.Int(0))
	return c.sendCmd(cmd)
}

// GetTxOutAsync returns an instance of a type that can be used to get
// the result of the RPC at some future time by invoking the Receive function on
// the returned instance.
//
// See GetTxOut for the blocking version and more details.
func (c *Client) GetTxOutAsync(txHash *chainhash.Hash, index uint32, mempool bool) FutureGetTxOutResult {
	hash := ""
	if txHash != nil {
		hash = txHash.String()
	}

	cmd := dcrjson.NewGetTxOutCmd(hash, index, &mempool)
	return c.sendCmd(cmd)
}

// GetBlockVerboseAsync returns an instance of a type that can be used to get
// the result of the RPC at some future time by invoking the Receive function on
// the returned instance.
//
// See GetBlockVerbose for the blocking version and more details.
func (c *Client) GetBlockVerboseAsync(blockHash *chainhash.Hash, verboseTx bool) FutureGetBlockVerboseResult {
	hash := ""
	if blockHash != nil {
		hash = blockHash.String()
	}

	cmd := dcrjson.NewGetBlockCmd(hash, dcrjson.Bool(true), &verboseTx)
	return c.sendCmd(cmd)
}

// fetchSStxRecord retrieves a tx record from the sstx records bucket
// with the given hash.
func fetchSStxRecord(tx walletdb.Tx, hash *chainhash.Hash) (*sstxRecord, error) {
	bucket := tx.RootBucket().Bucket(sstxRecordsBucketName)

	key := hash.Bytes()
	val := bucket.Get(key)
	if val == nil {
		str := fmt.Sprintf("missing sstx record for hash '%s'", hash.String())
		return nil, stakeStoreError(ErrSStxNotFound, str, nil)
	}

	return deserializeSStxRecord(val)
}

func assertAddrIndexTipIsUpdated(db database.Db, t *testing.T, newestSha *chainhash.Hash, newestBlockIdx int64) {
	// Safe to ignore error, since height will be < 0 in "error" case.
	sha, height, _ := db.FetchAddrIndexTip()
	if newestBlockIdx != height {
		t.Fatalf("Height of address index tip failed to update, "+
			"expected %v, got %v", newestBlockIdx, height)
	}
	if !bytes.Equal(newestSha.Bytes(), sha.Bytes()) {
		t.Fatalf("Sha of address index tip failed to update, "+
			"expected %v, got %v", newestSha, sha)
	}
}

// fetchSSRtxRecords retrieves SSRtx records from the SSRtxRecords bucket with
// the given hash.
func fetchSSRtxRecords(ns walletdb.ReadBucket, hash *chainhash.Hash) ([]*ssrtxRecord,
	error) {

	bucket := ns.NestedReadBucket(ssrtxRecordsBucketName)

	key := hash.Bytes()
	val := bucket.Get(key)
	if val == nil {
		str := fmt.Sprintf("missing ssrtx records for hash '%s'", hash.String())
		return nil, stakeStoreError(ErrSSRtxsNotFound, str, nil)
	}

	return deserializeSSRtxRecords(val)
}

// fetchSStxRecordSStxTicketHash160 retrieves a ticket 0th output script or
// pubkeyhash from the sstx records bucket with the given hash.
func fetchSStxRecordSStxTicketHash160(ns walletdb.ReadBucket,
	hash *chainhash.Hash) (hash160 []byte, p2sh bool, err error) {

	bucket := ns.NestedReadBucket(sstxRecordsBucketName)

	key := hash.Bytes()
	val := bucket.Get(key)
	if val == nil {
		str := fmt.Sprintf("missing sstx record for hash '%s'", hash.String())
		return nil, false, stakeStoreError(ErrSStxNotFound, str, nil)
	}

	return deserializeSStxTicketHash160(val)
}

// fetchBlockShaByHeight returns a block hash based on its height in the
// block chain.
func (db *LevelDb) fetchBlockShaByHeight(height int64) (rsha *chainhash.Hash, err error) {
	key := int64ToKey(height)

	blkVal, err := db.lDb.Get(key, db.ro)
	if err != nil {
		log.Tracef("failed to find height %v", height)
		return // exists ???
	}

	var sha chainhash.Hash
	sha.SetBytes(blkVal[0:32])

	return &sha, nil
}

// fetchAddrIndexTip returns the last block height and block sha to be indexed.
// Meta-data about the address tip is currently cached in memory, and will be
// updated accordingly by functions that modify the state. This function is
// used on start up to load the info into memory. Callers will use the public
// version of this function below, which returns our cached copy.
func (db *LevelDb) fetchAddrIndexTip() (*chainhash.Hash, int64, error) {
	db.dbLock.Lock()
	defer db.dbLock.Unlock()

	data, err := db.lDb.Get(addrIndexMetaDataKey, db.ro)
	if err != nil {
		return &chainhash.Hash{}, -1, database.ErrAddrIndexDoesNotExist
	}

	var blkSha chainhash.Hash
	blkSha.SetBytes(data[0:32])

	blkHeight := binary.LittleEndian.Uint64(data[32:])

	return &blkSha, int64(blkHeight), nil
}

// newDummyCredit creates a new credit with the given hash and outpointIdx,
// locked to the votingpool address identified by the given
// series/index/branch.
func newDummyCredit(t *testing.T, pool *Pool, series uint32, index Index, branch Branch,
	txSha []byte, outpointIdx uint32) credit {
	var hash chainhash.Hash
	if err := hash.SetBytes(txSha); err != nil {
		t.Fatal(err)
	}
	// Ensure the address defined by the given series/branch/index is present on
	// the set of used addresses as that's a requirement of WithdrawalAddress.
	TstEnsureUsedAddr(t, pool, series, branch, index)
	addr := TstNewWithdrawalAddress(t, pool, series, branch, index)
	c := wtxmgr.Credit{
		OutPoint: wire.OutPoint{
			Hash:  hash,
			Index: outpointIdx,
		},
	}
	return newCredit(c, *addr)
}

// removeStakePoolInvalUserTickets removes the ticket hash from the inval
// ticket bucket.
func removeStakePoolInvalUserTickets(ns walletdb.ReadWriteBucket, scriptHash [20]byte,
	record *chainhash.Hash) error {

	// Fetch the current content of the key.
	// Possible buggy behaviour: If deserialization fails,
	// we won't detect it here. We assume we're throwing
	// ErrPoolUserInvalTcktsNotFound.
	oldRecords, _ := fetchStakePoolUserInvalTickets(ns, scriptHash)

	// Don't need to remove records that don't exist.
	if !duplicateExistsInInvalTickets(record, oldRecords) {
		return nil
	}

	var newRecords []*chainhash.Hash
	for i := range oldRecords {
		if record.IsEqual(oldRecords[i]) {
			newRecords = append(oldRecords[:i:i], oldRecords[i+1:]...)
		}
	}

	if newRecords == nil {
		return nil
	}

	bucket := ns.NestedReadWriteBucket(metaBucketName)
	key := make([]byte, stakePoolInvalidPrefixSize+scriptHashSize)
	copy(key[0:stakePoolInvalidPrefixSize], stakePoolInvalidPrefix)
	copy(key[stakePoolInvalidPrefixSize:stakePoolInvalidPrefixSize+scriptHashSize],
		scriptHash[:])

	// Write the serialized invalid user ticket hashes.
	serializedRecords := serializeUserInvalTickets(newRecords)

	err := bucket.Put(key, serializedRecords)
	if err != nil {
		str := fmt.Sprintf("failed to store pool user invalid ticket "+
			"records '%x'", scriptHash)
		return stakeStoreError(ErrDatabase, str, err)
	}

	return nil
}

// updateSStxRecordVoteBits updates an individual ticket's intended voteBits
// which are used to override the default voteBits when voting.
func updateSStxRecordVoteBits(ns walletdb.ReadWriteBucket, hash *chainhash.Hash,
	voteBits stake.VoteBits) error {
	if len(voteBits.ExtendedBits) > stake.MaxSingleBytePushLength-2 {
		str := fmt.Sprintf("voteBitsExt too long (got %v bytes, want max %v)",
			len(voteBits.ExtendedBits), stake.MaxSingleBytePushLength-2)
		return stakeStoreError(ErrData, str, nil)
	}

	bucket := ns.NestedReadWriteBucket(sstxRecordsBucketName)

	key := hash.Bytes()
	val := bucket.Get(key)
	if val == nil {
		str := fmt.Sprintf("missing sstx record for hash '%s'", hash.String())
		return stakeStoreError(ErrSStxNotFound, str, nil)
	}
	valLen := len(val)
	valCopy := make([]byte, valLen, valLen)
	copy(valCopy, val)

	// Move the cursor to the voteBits position and rewrite it.
	curPos := 0
	curPos += int64Size
	curPos += int32Size

	// Write the intended votebits length (uint8).
	valCopy[curPos] = byte(int16Size + len(voteBits.ExtendedBits))
	curPos += int8Size

	// Write the first two bytes for the intended votebits.
	byteOrder.PutUint16(valCopy[curPos:curPos+int16Size], voteBits.Bits)
	curPos += int16Size

	// Copy the remaining data from voteBitsExt.
	copy(valCopy[curPos:], voteBits.ExtendedBits[:])

	err := bucket.Put(key, valCopy)
	if err != nil {
		str := fmt.Sprintf("failed to update sstxrecord votebits for '%s'", hash)
		return stakeStoreError(ErrDatabase, str, err)
	}
	return nil
}

// fetchSStxRecordVoteBits fetches an individual ticket's intended voteBits
// which are used to override the default voteBits when voting.
func fetchSStxRecordVoteBits(ns walletdb.ReadBucket, hash *chainhash.Hash) (bool,
	stake.VoteBits, error) {

	bucket := ns.NestedReadBucket(sstxRecordsBucketName)

	key := hash.Bytes()
	val := bucket.Get(key)
	if val == nil {
		str := fmt.Sprintf("missing sstx record for hash '%s'", hash.String())
		return false, stake.VoteBits{}, stakeStoreError(ErrSStxNotFound, str, nil)
	}
	valLen := len(val)
	valCopy := make([]byte, valLen, valLen)
	copy(valCopy, val)

	// Move the cursor to the voteBits position and rewrite it.
	curPos := 0
	curPos += int64Size
	curPos += int32Size

	// Read the intended votebits length (uint8). If it is unset, return now.
	// Check it for sanity.
	voteBitsLen := uint8(val[curPos])
	if voteBitsLen == 0 {
		return false, stake.VoteBits{}, nil
	}
	if voteBitsLen < 2 || voteBitsLen > stake.MaxSingleBytePushLength {
		str := fmt.Sprintf("corrupt votebits length '%v'", voteBitsLen)
		return false, stake.VoteBits{}, stakeStoreError(ErrData, str, nil)
	}
	curPos += int8Size

	// Read the first two bytes for the intended votebits.
	voteBits := byteOrder.Uint16(valCopy[curPos : curPos+int16Size])
	curPos += int16Size

	// Retrieve the extended vote bits.
	voteBitsExt := make([]byte, voteBitsLen-int16Size)
	copy(voteBitsExt[:], valCopy[curPos:(curPos+int(voteBitsLen)-int16Size)])

	return true, stake.VoteBits{Bits: voteBits, ExtendedBits: voteBitsExt}, nil
}

// GenerateSSGenBlockRef generates an OP_RETURN push for the block header hash and
// height which the block votes on.
func GenerateSSGenBlockRef(blockHash chainhash.Hash, height uint32) ([]byte,
	error) {
	// Prefix
	dataPushes := []byte{
		0x6a, // OP_RETURN
		0x24, // OP_DATA_36
	}

	// Serialize the block hash and height
	blockHashBytes := blockHash.Bytes()
	blockHeightBytes := make([]byte, 4)
	binary.LittleEndian.PutUint32(blockHeightBytes, height)

	blockData := append(blockHashBytes, blockHeightBytes...)

	// Concatenate the prefix and block data
	blockDataOut := append(dataPushes, blockData...)

	return blockDataOut, nil
}