/*
 * Copyright (c) 2020, Ali Mohammad Pur <ali.mpfard@gmail.com>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this
 *    list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#pragma once

#include <AK/String.h>
#include <AK/StringBuilder.h>
#include <LibCrypto/Hash/HashFunction.h>

namespace Crypto {
namespace Hash {

namespace SHA256Constants {
constexpr static u32 RoundConstants[64] {
    0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5,
    0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
    0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3,
    0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
    0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc,
    0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
    0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7,
    0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
    0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13,
    0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
    0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3,
    0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
    0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5,
    0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
    0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208,
    0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2
};

constexpr static u32 InitializationHashes[8] = {
    0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a,
    0x510e527f, 0x9b05688c, 0x1f83d9ab, 0x5be0cd19
};
}

namespace SHA512Constants {
constexpr static u64 RoundConstants[80] {
    0x428a2f98d728ae22, 0x7137449123ef65cd, 0xb5c0fbcfec4d3b2f, 0xe9b5dba58189dbbc, 0x3956c25bf348b538,
    0x59f111f1b605d019, 0x923f82a4af194f9b, 0xab1c5ed5da6d8118, 0xd807aa98a3030242, 0x12835b0145706fbe,
    0x243185be4ee4b28c, 0x550c7dc3d5ffb4e2, 0x72be5d74f27b896f, 0x80deb1fe3b1696b1, 0x9bdc06a725c71235,
    0xc19bf174cf692694, 0xe49b69c19ef14ad2, 0xefbe4786384f25e3, 0x0fc19dc68b8cd5b5, 0x240ca1cc77ac9c65,
    0x2de92c6f592b0275, 0x4a7484aa6ea6e483, 0x5cb0a9dcbd41fbd4, 0x76f988da831153b5, 0x983e5152ee66dfab,
    0xa831c66d2db43210, 0xb00327c898fb213f, 0xbf597fc7beef0ee4, 0xc6e00bf33da88fc2, 0xd5a79147930aa725,
    0x06ca6351e003826f, 0x142929670a0e6e70, 0x27b70a8546d22ffc, 0x2e1b21385c26c926, 0x4d2c6dfc5ac42aed,
    0x53380d139d95b3df, 0x650a73548baf63de, 0x766a0abb3c77b2a8, 0x81c2c92e47edaee6, 0x92722c851482353b,
    0xa2bfe8a14cf10364, 0xa81a664bbc423001, 0xc24b8b70d0f89791, 0xc76c51a30654be30, 0xd192e819d6ef5218,
    0xd69906245565a910, 0xf40e35855771202a, 0x106aa07032bbd1b8, 0x19a4c116b8d2d0c8, 0x1e376c085141ab53,
    0x2748774cdf8eeb99, 0x34b0bcb5e19b48a8, 0x391c0cb3c5c95a63, 0x4ed8aa4ae3418acb, 0x5b9cca4f7763e373,
    0x682e6ff3d6b2b8a3, 0x748f82ee5defb2fc, 0x78a5636f43172f60, 0x84c87814a1f0ab72, 0x8cc702081a6439ec,
    0x90befffa23631e28, 0xa4506cebde82bde9, 0xbef9a3f7b2c67915, 0xc67178f2e372532b, 0xca273eceea26619c,
    0xd186b8c721c0c207, 0xeada7dd6cde0eb1e, 0xf57d4f7fee6ed178, 0x06f067aa72176fba, 0x0a637dc5a2c898a6,
    0x113f9804bef90dae, 0x1b710b35131c471b, 0x28db77f523047d84, 0x32caab7b40c72493, 0x3c9ebe0a15c9bebc,
    0x431d67c49c100d4c, 0x4cc5d4becb3e42b6, 0x597f299cfc657e2a, 0x5fcb6fab3ad6faec, 0x6c44198c4a475817
};

constexpr static u64 InitializationHashes[8] = {
    0x6a09e667f3bcc908, 0xbb67ae8584caa73b, 0x3c6ef372fe94f82b, 0xa54ff53a5f1d36f1,
    0x510e527fade682d1, 0x9b05688c2b3e6c1f, 0x1f83d9abfb41bd6b, 0x5be0cd19137e2179
};
}

template<size_t Bytes>
struct SHA2Digest {
    u8 data[Bytes];
    constexpr static size_t Size = Bytes;
    const u8* immutable_data() const { return data; }
    size_t data_length() { return Bytes; }
};

// FIXME: I want template<size_t BlockSize> but the compiler gets confused
class SHA256 final : public HashFunction<512, SHA2Digest<256 / 8>> {
public:
    SHA256()
    {
        reset();
    }

    virtual void update(const u8*, size_t) override;

    virtual void update(const ByteBuffer& buffer) override { update(buffer.data(), buffer.size()); };
    virtual void update(const StringView& string) override { update((const u8*)string.characters_without_null_termination(), string.length()); };

    virtual DigestType digest() override;
    virtual DigestType peek() override;

    inline static DigestType hash(const u8* data, size_t length)
    {
        SHA256 sha;
        sha.update(data, length);
        return sha.digest();
    }

    inline static DigestType hash(const ByteBuffer& buffer) { return hash(buffer.data(), buffer.size()); }
    inline static DigestType hash(const StringView& buffer) { return hash((const u8*)buffer.characters_without_null_termination(), buffer.length()); }

    virtual String class_name() const override
    {
        StringBuilder builder;
        builder.append("SHA");
        builder.appendf("%zu", this->DigestSize * 8);
        return builder.build();
    };
    inline virtual void reset() override
    {
        m_data_length = 0;
        m_bit_length = 0;
        for (size_t i = 0; i < 8; ++i)
            m_state[i] = SHA256Constants::InitializationHashes[i];
    }

private:
    inline void transform(const u8*);

    u8 m_data_buffer[BlockSize];
    size_t m_data_length { 0 };

    u64 m_bit_length { 0 };
    u32 m_state[8];

    constexpr static auto FinalBlockDataSize = BlockSize - 8;
    constexpr static auto Rounds = 64;
};

class SHA512 final : public HashFunction<1024, SHA2Digest<512 / 8>> {
public:
    SHA512()
    {
        reset();
    }

    virtual void update(const u8*, size_t) override;

    virtual void update(const ByteBuffer& buffer) override { update(buffer.data(), buffer.size()); };
    virtual void update(const StringView& string) override { update((const u8*)string.characters_without_null_termination(), string.length()); };

    virtual DigestType digest() override;
    virtual DigestType peek() override;

    inline static DigestType hash(const u8* data, size_t length)
    {
        SHA512 sha;
        sha.update(data, length);
        return sha.digest();
    }

    inline static DigestType hash(const ByteBuffer& buffer) { return hash(buffer.data(), buffer.size()); }
    inline static DigestType hash(const StringView& buffer) { return hash((const u8*)buffer.characters_without_null_termination(), buffer.length()); }

    virtual String class_name() const override
    {
        StringBuilder builder;
        builder.append("SHA");
        builder.appendf("%zu", this->DigestSize * 8);
        return builder.build();
    };
    inline virtual void reset() override
    {
        m_data_length = 0;
        m_bit_length = 0;
        for (size_t i = 0; i < 8; ++i)
            m_state[i] = SHA512Constants::InitializationHashes[i];
    }

private:
    inline void transform(const u8*);

    u8 m_data_buffer[BlockSize];
    size_t m_data_length { 0 };

    u64 m_bit_length { 0 };
    u64 m_state[8];

    constexpr static auto FinalBlockDataSize = BlockSize - 8;
    constexpr static auto Rounds = 80;
};

}
}
