package keys

import (
	"errors"
	"fmt"
	"math/big"

	"github.com/sonr-io/crypto/core/curves"
)

// getEcdsaPoint builds an elliptic curve point from a compressed byte slice
func getEcdsaPoint(pubKey []byte) (*curves.EcPoint, error) {
	crv := curves.K256()
	x := new(big.Int).SetBytes(pubKey[1:33])
	y := new(big.Int).SetBytes(pubKey[33:])
	ecCurve, err := crv.ToEllipticCurve()
	if err != nil {
		return nil, fmt.Errorf("error converting curve: %v", err)
	}
	return &curves.EcPoint{X: x, Y: y, Curve: ecCurve}, nil
}

// DeserializeSecp256k1Signature deserializes an ECDSA signature from a byte slice
func deserializeSignature(sigBytes []byte) (*curves.EcdsaSignature, error) {
	if len(sigBytes) != 66 {
		return nil, errors.New("malformed signature: not the correct size")
	}
	sig := &curves.EcdsaSignature{
		V: int(sigBytes[0]),
		R: new(big.Int).SetBytes(sigBytes[1:33]),
		S: new(big.Int).SetBytes(sigBytes[33:66]),
	}
	return sig, nil
}