package db

import (
	"github.com/prysmaticlabs/prysm/shared/bytesutil"
)

// The Schema will define how to store and retrieve data from the db.
// Currently we store blocks by prefixing `block` to their hash and
// using that as the key to store blocks.
// `block` + hash -> block
//
// We store the state using the state lookup key, and
// also the genesis block using the genesis lookup key.
// The canonical head is stored using the canonical head lookup key.

// The fields below define the suffix of keys in the db.
var (
	attestationBucket       = []byte("attestation-bucket")
	attestationTargetBucket = []byte("attestation-target-bucket")
	blockOperationsBucket   = []byte("block-operations-bucket")
	blockBucket             = []byte("block-bucket")
	mainChainBucket         = []byte("main-chain-bucket")
	histStateBucket         = []byte("historical-state-bucket")
	chainInfoBucket         = []byte("chain-info")
	validatorBucket         = []byte("validator")

	mainChainHeightKey      = []byte("chain-height")
	canonicalHeadKey        = []byte("canonical-head")
	stateLookupKey          = []byte("state")
	finalizedStateLookupKey = []byte("finalized-state")
	justifiedStateLookupKey = []byte("justified-state")
	finalizedBlockLookupKey = []byte("finalized-block")
	justifiedBlockLookupKey = []byte("justified-block")

	// DB internal use
	cleanupHistoryBucket = []byte("cleanup-history-bucket")
)

func encodeSlotNumberRoot(number uint64, root [32]byte) []byte {
	return append(bytesutil.Bytes8(number), root[:]...)
}

// encodeSlotNumber encodes a slot number as little-endian uint32.
func encodeSlotNumber(number uint64) []byte {
	return bytesutil.Bytes8(number)
}

// decodeSlotNumber returns a slot number which has been
// encoded as a little-endian uint32 in the byte array.
func decodeToSlotNumber(bytearray []byte) uint64 {
	return bytesutil.FromBytes8(bytearray)
}