// Copyright (c) 2016 Tigera, Inc. All rights reserved.
//
// 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 hash

import (
	"crypto"
	"encoding/base64"
)

// MakeUniqueID uses a secure hash to create a unique ID from content.
// The hash is prefixed with "<prefix>:".
func MakeUniqueID(prefix, content string) string {
	hash := crypto.SHA224.New()
	bytes := []byte(prefix + ":" + content)
	written, err := hash.Write(bytes)
	if err != nil {
		panic(err)
	}
	if written != len(bytes) {
		panic("Failed to write to Hash")
	}
	hashBytes := hash.Sum(make([]byte, 0, hash.Size()))
	return prefix + ":" + base64.RawURLEncoding.EncodeToString(hashBytes)
}