/*
GoCheese -- Python private package repository and caching proxy
Copyright (C) 2019-2021 Elena Balakhonova <balakhonova_e@riseup.net>

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, version 3 of the License.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

package main

import (
	"crypto/sha256"
	"crypto/subtle"
	"encoding/hex"
	"fmt"
)

type SHA256AuthData []byte

func (expectedPasword SHA256AuthData) Auth(password string) bool {
	hash := sha256.Sum256([]byte(password))
	return subtle.ConstantTimeCompare(hash[:], []byte(expectedPasword)) == 1
}

func parseSHA256(params string) (Auther, error) {
	if len(params) != 64 {
		return nil, fmt.Errorf("sha256 parameters %q have wrong format", params)
	}
	hash, err := hex.DecodeString(params)
	return SHA256AuthData(hash), err
}