/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */

/*

 * This file is part of the LibreOffice project.

 *

 * This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/.

 */

#pragma once

#include <comphelper/comphelperdllapi.h>

#include <rtl/digest.h>

#include <memory>

#include <string>

#include <vector>

namespace rtl {

    class OUString;

}

namespace comphelper {

enum class HashType

{

    MD5,

    SHA1,

    SHA256,

    SHA384,

    SHA512

};

const sal_uInt32 MD5_HASH_LENGTH = RTL_DIGEST_LENGTH_MD5;

const sal_uInt32 SHA1_HASH_LENGTH = RTL_DIGEST_LENGTH_SHA1;

const sal_uInt32 SHA256_HASH_LENGTH = 32;

const sal_uInt32 SHA384_HASH_LENGTH = 48;

const sal_uInt32 SHA512_HASH_LENGTH = 64;

struct HashImpl;

COMPHELPER_DLLPUBLIC std::string hashToString(const std::vector<unsigned char>& rHash);

class COMPHELPER_DLLPUBLIC Hash

{

private:

    std::unique_ptr<HashImpl> mpImpl;

public:

    enum class IterCount

    {

        NONE,       /// Iteration count not added to hash iterations.

        PREPEND,    /// Iteration count prepended to hash iterations.

        APPEND      /// Iteration count appended to hash iterations.

    };

    Hash(HashType eType);

    ~Hash();

    void update(const void* pInput, size_t length);

    void update(std::vector<unsigned char> const& rInput)

    {

        update(rInput.data(), rInput.size());

    }

    void initialize();

    std::vector<unsigned char> finalize();

    static std::vector<unsigned char> calculateHash(const void* pInput, size_t length, HashType eType);

    /** Calculate hash value with salt (pSalt,nSaltLen) prepended to password

        (pInput,nLength) and repeated iterations run if nSpinCount>0.

        This implements the algorithms as specified in

        https://msdn.microsoft.com/en-us/library/dd920692 or

        https://msdn.microsoft.com/en-us/library/dd924776 and

        https://msdn.microsoft.com/en-us/library/dd925430

        @param  pSalt

                may be nullptr thus no salt prepended

        @param  nSpinCount

                If >0, repeat nSpinCount iterations. For each iteration, the

                previous iteration's result plus a 4 byte value (0-based,

                little endian) containing the number of the iteration prepended

                or appended to the hash value is the input for the next

                iteration.

        @param  eIterCount

                If IterCount::APPEND, append iteration count as per

                https://msdn.microsoft.com/en-us/library/dd920692

                If IterCount::PREPEND, prepend iteration count as per

                https://msdn.microsoft.com/en-us/library/dd924776 and

                https://msdn.microsoft.com/en-us/library/dd925430

                If IterCount::NONE, do not add the iteration count to hash

                iterations.

        @return the raw hash value

     */

    static std::vector<unsigned char> calculateHash(

            const void* pInput, size_t nLength,

            const void* pSalt, size_t nSaltLen,

            sal_uInt32 nSpinCount,

            IterCount eIterCount,

            HashType eType);

    /** Convenience function to calculate a salted hash with iterations.

        @param  rPassword

                UTF-16 encoded string, hashed byte-wise as unsigned char.

        @param  rSaltValue

                Salt that will be prepended to password data.

     */

    static std::vector<unsigned char> calculateHash(

            std::u16string_view rPassword,

            const std::vector<unsigned char>& rSaltValue,

            sal_uInt32 nSpinCount,

            IterCount eIterCount,

            HashType eType);

    size_t getLength() const;

};

}

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