// Copyright 2026 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package hpke

import (
	"github.com/tink-crypto/tink-go/v2/hybrid/internal/xwing"
)

// xWingKEM implements interface kem for X-Wing.
type xWingKEM struct{}

var _ kem = (*xWingKEM)(nil)

func newXWingKEM() (*xWingKEM, error) {
	return &xWingKEM{}, nil
}

func (x *xWingKEM) encapsulate(recipientPubKey []byte) (sharedSecret, senderPubKey []byte, err error) {
	return xwing.Encapsulate(recipientPubKey)
}

func (x *xWingKEM) decapsulate(encapsulatedKey, recipientPrivKey []byte) ([]byte, error) {
	return xwing.Decapsulate(encapsulatedKey, recipientPrivKey)
}

func (x *xWingKEM) id() KEMID { return XWing }

func (x *xWingKEM) encapsulatedKeyLength() int { return kemLengths[XWing].nEnc }
