// Copyright (c) 2020 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#include <crypto/poly1305.h>
#include <test/fuzz/FuzzedDataProvider.h>
#include <test/fuzz/fuzz.h>
#include <test/fuzz/util.h>

#include <cstdint>
#include <vector>

FUZZ_TARGET(crypto_poly1305)
{
    FuzzedDataProvider fuzzed_data_provider{buffer.data(), buffer.size()};

    const std::vector<uint8_t> key = ConsumeFixedLengthByteVector(fuzzed_data_provider, Poly1305::KEYLEN);
    const std::vector<uint8_t> in = ConsumeRandomLengthByteVector(fuzzed_data_provider);

    std::vector<std::byte> tag_out(Poly1305::TAGLEN);
    Poly1305{MakeByteSpan(key)}.Update(MakeByteSpan(in)).Finalize(tag_out);
}


FUZZ_TARGET(crypto_poly1305_split)
{
    FuzzedDataProvider provider{buffer.data(), buffer.size()};

    // Read key and instantiate two Poly1305 objects with it.
    auto key = provider.ConsumeBytes<std::byte>(Poly1305::KEYLEN);
    key.resize(Poly1305::KEYLEN);
    Poly1305 poly_full{key}, poly_split{key};

    // Vector that holds all bytes processed so far.
    std::vector<std::byte> total_input;

    // Process input in pieces.
    LIMITED_WHILE(provider.remaining_bytes(), 100) {
        auto in = provider.ConsumeRandomLengthString();
        poly_split.Update(MakeByteSpan(in));
        // Update total_input to match what was processed.
        total_input.insert(total_input.end(), MakeByteSpan(in).begin(), MakeByteSpan(in).end());
    }

    // Process entire input at once.
    poly_full.Update(total_input);

    // Verify both agree.
    std::array<std::byte, Poly1305::TAGLEN> tag_split, tag_full;
    poly_split.Finalize(tag_split);
    poly_full.Finalize(tag_full);
    assert(tag_full == tag_split);
}