package cryptoutil

import (
	"bytes"
	"crypto"
	"crypto/ecdsa"
	"crypto/ed25519"
	"crypto/rsa"
	"fmt"
)

func PublicKeyEqual(a, b crypto.PublicKey) (bool, error) {
	switch a := a.(type) {
	case *rsa.PublicKey:
		rsaPublicKey, ok := b.(*rsa.PublicKey)
		return ok && RSAPublicKeyEqual(a, rsaPublicKey), nil
	case *ecdsa.PublicKey:
		ecdsaPublicKey, ok := b.(*ecdsa.PublicKey)
		return ok && ECDSAPublicKeyEqual(a, ecdsaPublicKey), nil
	case ed25519.PublicKey:
		ed25519PublicKey, ok := b.(ed25519.PublicKey)
		return ok && bytes.Equal(a, ed25519PublicKey), nil
	default:
		return false, fmt.Errorf("unsupported public key type %T", a)
	}
}

func RSAPublicKeyEqual(a, b *rsa.PublicKey) bool {
	return a.E == b.E && a.N.Cmp(b.N) == 0
}

func ECDSAPublicKeyEqual(a, b *ecdsa.PublicKey) bool {
	return a.Curve == b.Curve && a.X.Cmp(b.X) == 0 && a.Y.Cmp(b.Y) == 0
}