package merkletree

import (
	"math/big"

	"github.com/iden3/go-iden3-crypto/poseidon"
)

// HashElems performs a poseidon hash over the array of ElemBytes, currently we
// are using 2 elements.  Uses poseidon.Hash to be compatible with the circom
// circuits implementations.
func HashElems(elems ...*big.Int) (*Hash, error) {
	poseidonHash, err := poseidon.Hash(elems)
	if err != nil {
		return nil, err
	}
	return NewHashFromBigInt(poseidonHash), nil
}

// HashElemsKey performs a poseidon hash over the array of ElemBytes, currently
// we are using 2 elements.
func HashElemsKey(key *big.Int, elems ...*big.Int) (*Hash, error) {
	if key == nil {
		key = new(big.Int).SetInt64(0)
	}
	bi := make([]*big.Int, 3)
	copy(bi[:], elems)
	bi[2] = key
	poseidonHash, err := poseidon.Hash(bi)
	if err != nil {
		return nil, err
	}
	return NewHashFromBigInt(poseidonHash), nil
}