// Copyright (c) 2021 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 <minisketch.h>

#include <node/minisketchwrapper.h>

#include <test/fuzz/FuzzedDataProvider.h>

#include <test/fuzz/fuzz.h>

#include <test/fuzz/util.h>

#include <util/check.h>

#include <map>

#include <numeric>

namespace {

Minisketch MakeFuzzMinisketch32(size_t capacity, uint32_t impl)

{

    return Assert(Minisketch(32, impl, capacity));

}

} // namespace

FUZZ_TARGET(minisketch)

{

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

    const auto capacity{fuzzed_data_provider.ConsumeIntegralInRange<size_t>(1, 200)};

    const uint32_t impl{fuzzed_data_provider.ConsumeIntegralInRange<uint32_t>(0, Minisketch::MaxImplementation())};

    if (!Minisketch::ImplementationSupported(32, impl)) return;

    Minisketch sketch_a{MakeFuzzMinisketch32(capacity, impl)};

    Minisketch sketch_b{MakeFuzzMinisketch32(capacity, impl)};

    sketch_a.SetSeed(fuzzed_data_provider.ConsumeIntegral<uint64_t>());

    sketch_b.SetSeed(fuzzed_data_provider.ConsumeIntegral<uint64_t>());

    // Fill two sets and keep the difference in a map

    std::map<uint32_t, bool> diff;

    LIMITED_WHILE(fuzzed_data_provider.ConsumeBool(), 10000)

    {

        const auto entry{fuzzed_data_provider.ConsumeIntegralInRange<uint32_t>(1, std::numeric_limits<uint32_t>::max() - 1)};

        const auto KeepDiff{[&] {

            bool& mut{diff[entry]};

            mut = !mut;

        }};

        CallOneOf(

            fuzzed_data_provider,

            [&] {

                sketch_a.Add(entry);

                KeepDiff();

            },

            [&] {

                sketch_b.Add(entry);

                KeepDiff();

            },

            [&] {

                sketch_a.Add(entry);

                sketch_b.Add(entry);

            });

    }

    const auto num_diff{std::accumulate(diff.begin(), diff.end(), size_t{0}, [](auto n, const auto& e) { return n + e.second; })};

    Minisketch sketch_ar{MakeFuzzMinisketch32(capacity, impl)};

    Minisketch sketch_br{MakeFuzzMinisketch32(capacity, impl)};

    sketch_ar.SetSeed(fuzzed_data_provider.ConsumeIntegral<uint64_t>());

    sketch_br.SetSeed(fuzzed_data_provider.ConsumeIntegral<uint64_t>());

    sketch_ar.Deserialize(sketch_a.Serialize());

    sketch_br.Deserialize(sketch_b.Serialize());

    Minisketch sketch_diff{std::move(fuzzed_data_provider.ConsumeBool() ? sketch_a : sketch_ar)};

    sketch_diff.Merge(fuzzed_data_provider.ConsumeBool() ? sketch_b : sketch_br);

    if (capacity >= num_diff) {

        const auto max_elements{fuzzed_data_provider.ConsumeIntegralInRange<size_t>(num_diff, capacity)};

        const auto dec{*Assert(sketch_diff.Decode(max_elements))};

        Assert(dec.size() == num_diff);

        for (auto d : dec) {

            Assert(diff.at(d));

        }

    }

}