//
// 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 "extra/fuzzer/fuzzer_input.hpp"
#include <immer/flex_vector.hpp>
#include <immer/flex_vector_transient.hpp>
#include <immer/heap/gc_heap.hpp>
#include <immer/refcount/no_refcount_policy.hpp>
#include <array>
#include <iostream>
#include <catch.hpp>

#define IMMER_FUZZED_TRACE_ENABLE 0

#if IMMER_FUZZED_TRACE_ENABLE
#define IMMER_FUZZED_TRACE(...) std::cout << __VA_ARGS__ << std::endl;
#else
#define IMMER_FUZZED_TRACE(...)
#endif

using gc_memory = immer::memory_policy<
    immer::heap_policy<immer::gc_heap>,
    immer::no_refcount_policy,
    immer::gc_transience_policy,
    false>;

namespace {

template <std::size_t VarCount = 4, unsigned Bits = 2>
int run_input(const std::uint8_t* data, std::size_t size)
{
    using vector_t    = immer::flex_vector<int, gc_memory, Bits, Bits>;
    using transient_t = typename vector_t::transient_type;
    using size_t   = std::uint8_t;

    auto vs = std::array<vector_t, VarCount>{};
    auto ts = std::array<transient_t, VarCount>{};

#if IMMER_FUZZED_TRACE_ENABLE
    std::cout << "/// new test run" << std::endl;
    for (auto i = 0; i < VarCount; ++i)
        std::cout << "auto v" << i << " = vector_t{};" << std::endl;
    for (auto i = 0; i < VarCount; ++i)
        std::cout << "auto t" << i << " = transient_t{};" << std::endl;
#endif

    auto is_valid_var = [&] (auto idx) {
        return idx >= 0 && idx < VarCount;
    };
    auto is_valid_var_neq = [](auto other) {
        return [=] (auto idx) {
            return idx >= 0 && idx < VarCount && idx != other;
        };
    };
    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(); };
    };
    auto can_concat = [] (auto&& v1, auto&& v2) {
        using size_type = decltype(v1.size());
        auto max = std::numeric_limits<size_type>::max() >> (Bits * 4);
        return v1.size() < max && v2.size() < max;
    };

    return fuzzer_input{data, size}.run([&] (auto& in)
    {
        enum ops {
            op_transient,
            op_persistent,
            op_push_back,
            op_update,
            op_take,
            op_drop,
            op_concat,
            op_push_back_mut,
            op_update_mut,
            op_take_mut,
            op_drop_mut,
            op_prepend_mut,
            op_prepend_mut_move,
            op_append_mut,
            op_append_mut_move,
        };
        auto dst = read<std::uint8_t>(in, is_valid_var);
        switch (read<char>(in))
        {
        case op_transient: {
            auto src = read<std::uint8_t>(in, is_valid_var);
            IMMER_FUZZED_TRACE(
                "t" << +dst << " = v" << +src << ".transient();");
            ts[dst] = vs[src].transient();
            break;
        }
        case op_persistent: {
            auto src = read<std::uint8_t>(in, is_valid_var);
            IMMER_FUZZED_TRACE(
                "v" << +dst << " = t" << +src << ".persistent();");
            vs[dst] = ts[src].persistent();
            break;
        }
        case op_push_back: {
            auto src = read<std::uint8_t>(in, is_valid_var);
            IMMER_FUZZED_TRACE(
                "v" << +dst << " = v" << +src <<
                ".push_back(42);");
            vs[dst] = vs[src].push_back(42);
            break;
        }
        case op_update: {
            auto src = read<std::uint8_t>(in, is_valid_var);
            auto idx = read<size_t>(in, is_valid_index(vs[src]));
            IMMER_FUZZED_TRACE(
                "v" << +dst << " = v" << +src <<
                ".update(" << +idx << ", [] (auto x) { return x + 1; });");
            vs[dst] = vs[src].update(idx, [] (auto x) { return x + 1; });
            break;
        }
        case op_take: {
            auto src = read<std::uint8_t>(in, is_valid_var);
            auto idx = read<size_t>(in, is_valid_size(vs[src]));
            IMMER_FUZZED_TRACE(
                "v" << +dst << " = v" << +src <<
                ".take(" << +idx << ");");
            vs[dst] = vs[src].take(idx);
            break;
        }
        case op_drop: {
            auto src = read<std::uint8_t>(in, is_valid_var);
            auto idx = read<size_t>(in, is_valid_size(vs[src]));
            IMMER_FUZZED_TRACE(
                "v" << +dst << " = v" << +src <<
                ".take(" << +idx << ");");
            vs[dst] = vs[src].drop(idx);
            break;
        }
        case op_concat: {
            auto src = read<std::uint8_t>(in, is_valid_var);
            auto src2 = read<std::uint8_t>(in, is_valid_var);
            if (can_concat(vs[src], vs[src2])) {
                IMMER_FUZZED_TRACE(
                    "v" << +dst << " = v" << +src << " + v" << +src2 << ";");
                vs[dst] = vs[src] + vs[src2];
            }
            break;
        }
        case op_push_back_mut: {
            IMMER_FUZZED_TRACE("t" << +dst << ".push_back(13);");
            ts[dst].push_back(13);
            break;
        }
        case op_update_mut: {
            auto idx = read<size_t>(in, is_valid_index(ts[dst]));
            IMMER_FUZZED_TRACE(
                "t" << +dst << ".update("
                << +idx << ", [] (auto x) { return x + 1; });");
            ts[dst].update(idx, [] (auto x) { return x + 1; });
            break;
        }
        case op_take_mut: {
            auto idx = read<size_t>(in, is_valid_size(ts[dst]));
            IMMER_FUZZED_TRACE("t" << +dst << ").take(" << +idx << ");");
            ts[dst].take(idx);
            break;
        }
        case op_prepend_mut: {
            auto src = read<std::uint8_t>(in, is_valid_var_neq(dst));
            if (can_concat(ts[dst], ts[src])) {
                IMMER_FUZZED_TRACE(
                    "t" << +dst << ".prepend(t" << +src << ");");
                ts[dst].prepend(ts[src]);
            }
            break;
        }
        case op_prepend_mut_move: {
            auto src = read<std::uint8_t>(in, is_valid_var_neq(dst));
            if (can_concat(ts[dst], ts[src])) {
                IMMER_FUZZED_TRACE(
                    "t" << +dst << ".prepend(std::move(t" << +src << "));"
                    << " t" << +src << " = {};");
                ts[dst].prepend(std::move(ts[src]));
                ts[src] = {};
            }
            break;
        }
        case op_append_mut: {
            auto src = read<std::uint8_t>(in, is_valid_var_neq(dst));
            if (can_concat(ts[dst], ts[src])) {
                IMMER_FUZZED_TRACE(
                    "t" << +dst << ".append(t" << +src << ");");
                ts[dst].append(ts[src]);
            }
            break;
        }
        case op_append_mut_move: {
            auto src = read<std::uint8_t>(in, is_valid_var_neq(dst));
            if (can_concat(ts[dst], ts[src])) {
                IMMER_FUZZED_TRACE(
                    "t" << +dst << ".append(std::move(t" << +src << "));"
                    << " t" << +src << " = {};");
                ts[dst].append(std::move(ts[src]));
                ts[src] = {};
            }
            break;
        }
        default:
            break;
        };
        return true;
    });
}

} // anonymous

TEST_CASE("bug: concatenating transients")
{
    // When concatenating two transients vectors the nodes from the
    // argument become aliased in the result.  As such, we need to
    // reset the identitiy of the argument.
    SECTION("simplified")
    {
        using vector_t = immer::flex_vector<int, gc_memory, 2, 2>;
        auto t0 = vector_t{}.transient();
        t0.push_back(42);
        t0.push_back(42);
        t0.push_back(42);
        t0.push_back(42);
        t0.push_back(42);
        t0.push_back(42);
        auto t1 = t0;
        t1.append(t0);
        t1.append(t0);
        t0.append(t1);
        t1.append(t0);
    }

    SECTION("")
    {
        constexpr std::uint8_t input[] = {
            0x2,0x2,0x2,0x2,0x29,0x32,0x0,0x0,0x2,0x2,0x2,0x2,0x2,0x2,0x2,0x2,0x2,0x2,0x2,0x2,0x6,0x2,0x2,0x2,0x2,0x2,0x6,0x2,0x2,0x2,0x0,0x38,0x2,0x0,0x0,0x2,0x2,0xd,0x0,0x0,0x3b,0xff,0x3a,0x2,0xd,0xd,0x2,0x0,0x0,0x10,0xe,0x0,0xd,0x0,0x0,0x2,0x2,0xd,0x0,0x1,0x5,
        };
        CHECK(run_input(input, sizeof(input)) == 0);
    }
}

TEST_CASE("bug: concatenating moved transients")
{
    // A moved from concatenated transient is totally smashed, we can
    // not do anything with it but reasign...
    SECTION("simplified")
    {
        using vector_t = immer::flex_vector<int, gc_memory, 2, 2>;
        using transient_t = typename vector_t::transient_type;
        auto v0 = vector_t{};
        auto t0 = transient_t{};
        auto t2 = transient_t{};
        v0 = v0.push_back(42);
        t2 = v0.transient();
        v0 = v0 + v0;
        v0 = v0 + v0;
        v0 = v0 + v0;
        v0 = v0 + v0;
        t0 = v0.transient();
        t0 = v0.transient();
        t0.append(std::move(t2)); t2 = {};
        t2.append(std::move(t0));
    }

    SECTION("")
    {
        constexpr std::uint8_t input[] = {
            0x0,0x2,0x0,0x2,0x0,0x0,0x0,0x6,0x0,0x0,0x0,0x6,0x0,0x0,0x0,0x9d,0x0,0x6,0x0,0x0,0x0,0x6,0x0,0x0,0x0,0x9d,0x28,0x0,0x0,0x0,0x0,0x0,0xf7,0xc5,0x0,0xa,0xa,0x0,0xfa,0xe7,0xff,0xe7,0xff,0x0,0xe,0x2,0x9,0x0,0x28,0x2,0xe,0x0,0x0,0x2,0xd,0x0,0x0,0x28,0x0,0xd,0x2,0x5,0x0,0x2,
        };
        CHECK(run_input(input, sizeof(input)) == 0);
    }

    SECTION("simplified")
    {
        using vector_t = immer::flex_vector<int, gc_memory, 2, 2>;
        using transient_t = typename vector_t::transient_type;
        auto v0 = vector_t{};
        auto t0 = transient_t{};
        auto t2 = transient_t{};
        v0 = v0.push_back(42);
        v0 = v0.push_back(42);
        v0 = v0 + v0;
        t0 = v0.transient();
        t2.prepend(std::move(t0)); t0 = {};
        t0 = v0.transient();
        t0.push_back(13);
        t2.append(std::move(t0)); t0 = {};
        t0 = v0.transient();
        t0.push_back(13);
        t2.prepend(std::move(t0)); t0 = {};
    }

    SECTION("")
    {
        return;
        constexpr std::uint8_t input[] = {
            0x0,0x2,0x0,0x0,0x2,0xb7,0x1,0x36,0x40,0x0,0x0,0x0,0x0,0xb6,0x0,0x2,0x0,0x0,0x6,0xe,0x0,0x0,0xfe,0x0,0x0,0xff,0x0,0x2,0xc,0xff,0xfc,0x29,0x0,0x0,0x0,0x0,0x0,0x7,0x2,0xe,0xff,0xfc,0x29,0x0,0x0,0x0,0x0,0x0,0x7,0x3,0x0,0x0,0x2,0xc,0x2,0xc,0x0,0xd,0x0,0x0,0x0,0x0,0x25,0x6,
        };
        CHECK(run_input(input, sizeof(input)) == 0);
    }
}

TEST_CASE("bug: aegsdas")
{
    SECTION("simplified")
    {
        using vector_t = immer::flex_vector<int, gc_memory, 2, 2>;
        using transient_t = typename vector_t::transient_type;
        auto v2 = vector_t{};
        auto t0 = transient_t{};
        auto t1 = transient_t{};
        v2 = v2.push_back(42);
        v2 = v2.push_back(42);
        v2 = v2.push_back(42);
        v2 = v2.push_back(42);
        v2 = v2.push_back(42);
        t0 = v2.transient();
        t1.prepend(t0);
        t1.prepend(t0);
        t1.prepend(t0);
        t0.prepend(std::move(t1)); t1 = {};
    }

    SECTION("")
    {
        constexpr std::uint8_t input[] = {
            0xff,0xff,0x2,0x2,0x2,0x2,0x2,0x2,0x2,0x2,0x2,0x82,0x2,0x2,0x2,0x2,0x2,0x2,0x0,0x0,0x3d,0x0,0x0,0x0,0x2,0x84,0x0,0x3b,0x1,0xb,0x0,0xa,0x1,0xb,0x0,0x0,0x3,0x2,0x0,0x3b,0x1,0xb,0x1,0x0,0x0,0xc,0xb,0x1,0x8,0xff,0xff,0xfc,0xfd,0x0,0x3b,0x3,0x2,0x0,0x3b,0x1,0x9,0x1,0x3b,
        };
        CHECK(run_input(input, sizeof(input)) == 0);
    }
}