//

// immer: immutable data structures for C++

// Copyright (C) 2016, 2017, 2018 Juan Pedro Bolivar Puente

//

// This software is distributed under the Boost Software License, Version 1.0.

// See accompanying file LICENSE or copy at http://boost.org/LICENSE_1_0.txt

//

#include "fuzzer_input.hpp"

#include <immer/array.hpp>

#include <array>

extern "C" int LLVMFuzzerTestOneInput(const std::uint8_t* data,

                                      std::size_t size)

{

    constexpr auto var_count = 4;

    using array_t = immer::array<int, immer::default_memory_policy>;

    using size_t  = std::uint8_t;

    auto vars = std::array<array_t, var_count>{};

    auto is_valid_var   = [&](auto idx) { return idx >= 0 && idx < var_count; };

    auto is_valid_index = [](auto& v) {

        return [&](auto idx) { return idx >= 0 && idx < v.size(); };

    };

    auto is_valid_size = [](auto& v) {

        return [&](auto idx) { return idx >= 0 && idx <= v.size(); };

    };

    // limit doing immutable pushes on vectors that are too big already to

    // prevent timeouts

    auto too_big = [](auto&& v) { return v.size() > (std::size_t{1} << 10); };

    return fuzzer_input{data, size}.run([&](auto& in) {

        enum ops

        {

            op_push_back,

            op_update,

            op_take,

            op_push_back_move,

            op_update_move,

            op_take_move,

        };

        auto src = read<char>(in, is_valid_var);

        auto dst = read<char>(in, is_valid_var);

        switch (read<char>(in)) {

        case op_push_back: {

            if (!too_big(vars[src]))

                vars[dst] = vars[src].push_back(42);

            break;

        }

        case op_update: {

            auto idx  = read<size_t>(in, is_valid_index(vars[src]));

            vars[dst] = vars[src].update(idx, [](auto x) { return x + 1; });

            break;

        }

        case op_take: {

            auto idx  = read<size_t>(in, is_valid_size(vars[src]));

            vars[dst] = vars[src].take(idx);

            break;

        }

        case op_push_back_move: {

            if (!too_big(vars[src]))

                vars[dst] = std::move(vars[src]).push_back(12);

            break;

        }

        case op_update_move: {

            auto idx = read<size_t>(in, is_valid_index(vars[src]));

            vars[dst] =

                std::move(vars[src]).update(idx, [](auto x) { return x + 1; });

            break;

        }

        case op_take_move: {

            auto idx  = read<size_t>(in, is_valid_size(vars[src]));

            vars[dst] = std::move(vars[src]).take(idx);

            break;

        }

        default:

            break;

        };

        return true;

    });

}