package iskra

import "git.smesh.lol/iskradb/lattice"

// Stage tags prepended to the key's high byte.
const (
	StageSRC uint8 = 0x01
	StageAST uint8 = 0x02
	StageIR  uint8 = 0x03
	StageASM uint8 = 0x04
	StageBIN uint8 = 0x05
)

// MakeKey encodes stage in the high 8 bits and the FNV hash in the lower 56
// bits of Key[0], with Key[1] = 0. This preserves existing stage-based
// semantics as a 128-bit lattice.Key (same collision rate as before, but
// compatible with the updated iskradb interface).
// MakeCodeKey encodes a code-lattice stage+FNV key.
// Renamed from MakeKey to make room for MakeKey(domain, coord, word) in coord.mx.
func MakeCodeKey(stage uint8, hash uint64) lattice.Key {
	return lattice.Key{(uint64(stage) << 56) | (hash & 0x00FFFFFFFFFFFFFF), 0}
}

func KeyStage(key lattice.Key) uint8 {
	return uint8(key[0] >> 56)
}

func KeyHash(key lattice.Key) uint64 {
	return key[0] & 0x00FFFFFFFFFFFFFF
}

// NameKey builds a lattice.Key from stage and the segment's name.
func NameKey(stage uint8, name string) lattice.Key {
	return MakeCodeKey(stage, HashBytes([]byte(name)))
}

func StageName(s uint8) string {
	switch s {
	case StageSRC:
		return "SRC"
	case StageAST:
		return "AST"
	case StageIR:
		return "IR"
	case StageASM:
		return "ASM"
	case StageBIN:
		return "BIN"
	}
	return "?"
}