/*
Copyright 2025 Peter Kurfer.

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 jwk

import (
	"encoding/base64"
	"encoding/json"
)

type KeyType string

const (
	KeyTypeEC            KeyType = "EC"
	KeyTypeRSA           KeyType = "RSA"
	KeyTypeOctetSequence KeyType = "oct"
)

type Algorithm string

const (
	AlgorithmNone  Algorithm = ""
	AlgorithmHS256 Algorithm = "HS256"
	AlgorithmHS384 Algorithm = "HS384"
	AlgorithmHS512 Algorithm = "HS512"
)

var _ json.Marshaler = (*SymmetricKey)(nil)

type SymmetricKey struct {
	Algorithm Algorithm
	Key       []byte
}

// MarshalJSON implements json.Marshaler.
func (s SymmetricKey) MarshalJSON() ([]byte, error) {
	if s.Algorithm == AlgorithmNone {
		s.Algorithm = AlgorithmHS256
	}
	tmp := struct {
		KeyType   KeyType   `json:"kty"`
		Algorithm Algorithm `json:"alg"`
		Key       string    `json:"k"`
	}{
		KeyType:   KeyTypeOctetSequence,
		Algorithm: s.Algorithm,
		Key:       base64.RawURLEncoding.EncodeToString(s.Key),
	}

	return json.Marshal(tmp)
}