// SPDX-License-Identifier: Apache-2.0

// SPDX-FileCopyrightText: Copyright The WasmEdge Authors

#ifdef WASMEDGE_BUILD_FUZZING

#include "driver/fuzzPO.h"

#include "common/spdlog.h"

#include "common/version.h"

#include "po/argument_parser.h"

#include <algorithm>

#include <array>

#include <cstdio>

#include <type_traits>

#include <utility>

#include <vector>

namespace {

template <class Key, class Value, class Hash, class BinaryPredicate>

class SkipTable {

private:

  using UnsignedKey = std::make_unsigned_t<Key>;

  std::array<Value,

             static_cast<std::size_t>(std::numeric_limits<UnsignedKey>::max()) +

                 1u>

      Table;

public:

  SkipTable(std::size_t, Value Default, Hash, BinaryPredicate) {

    std::fill_n(Table.begin(), Table.size(), Default);

  }

  void insert(const Key &K, Value V) { Table[static_cast<UnsignedKey>(K)] = V; }

  const Value &at(const Key &K) const {

    return Table[static_cast<UnsignedKey>(K)];

  }

};

template <class RandomIt1,

          class Hash =

              std::hash<typename std::iterator_traits<RandomIt1>::value_type>,

          class BinaryPredicate = std::equal_to<>>

class BoyerMooreHorspoolSearcher {

private:

  using Key = typename std::iterator_traits<RandomIt1>::value_type;

  using Value = typename std::iterator_traits<RandomIt1>::difference_type;

  static_assert(std::is_integral_v<Key> && sizeof(Key) == 1 &&

                std::is_same_v<Hash, std::hash<Key>> &&

                std::is_same_v<BinaryPredicate, std::equal_to<>>);

  using SkipTableType = SkipTable<Key, Value, Hash, BinaryPredicate>;

public:

  BoyerMooreHorspoolSearcher(RandomIt1 First, RandomIt1 Last, Hash HF = Hash(),

                             BinaryPredicate Pred = BinaryPredicate())

      : Pattern(First), PatternLength(std::distance(First, Last)), Pred(Pred),

        Table(PatternLength, PatternLength, HF, Pred) {

    if (First != Last) {

      --Last;

      for (Value I = 0; First != Last; ++First, ++I) {

        Table.insert(*First, PatternLength - 1 - I);

      }

    }

  }

  template <class RandomIt2>

  std::pair<RandomIt2, RandomIt2> operator()(RandomIt2 First,

                                             RandomIt2 Last) const {

    static_assert(

        std::is_same_v<

            std::remove_cv_t<std::remove_reference_t<

                typename std::iterator_traits<RandomIt1>::value_type>>,

            std::remove_cv_t<std::remove_reference_t<

                typename std::iterator_traits<RandomIt2>::value_type>>>,

        "Corpus and Pattern iterators must point to the same type");

    if (First == Last) {

      // empty corpus

      return {Last, Last};

    }

    if (PatternLength == 0) {

      // empty pattern

      return {First, First};

    }

    // the pattern is larger than the corpus

    if (PatternLength > std::distance(First, Last)) {

      return {Last, Last};

    }

    RandomIt2 Curr = First;

    const RandomIt2 End = Last - PatternLength;

    while (Curr <= End) {

      Value J = PatternLength;

      while (Pred(Pattern[J - 1], Curr[J - 1])) {

        --J;

        if (J == 0) {

          // found

          return {Curr, Curr + PatternLength};

        }

      }

      const auto K = Curr[PatternLength - 1];

      const auto D = Table.at(K);

      Curr += D;

    }

    return {Last, Last};

  }

private:

  RandomIt1 Pattern;

  Value PatternLength;

  BinaryPredicate Pred;

  SkipTableType Table;

};

} // namespace

namespace WasmEdge {

namespace Driver {

int FuzzPO(const uint8_t *Data, size_t Size) noexcept {

  using namespace std::literals;

  std::ios::sync_with_stdio(false);

  spdlog::set_level(spdlog::level::info);

  PO::Option<std::string> SoName(PO::Description("Wasm or so file"sv),

                                 PO::MetaVar("WASM_OR_SO"sv));

  PO::List<std::string> Args(PO::Description("Execution arguments"sv),

                             PO::MetaVar("ARG"sv));

  PO::Option<PO::Toggle> Reactor(PO::Description(

      "Enable reactor mode. Reactor mode calls `_initialize` if exported."));

  PO::List<std::string> Dir(

      PO::Description(

          "Binding directories into WASI virtual filesystem. Each directories "

          "can specified as --dir `guest_path:host_path`, where `guest_path` "

          "specifies the path that will correspond to `host_path` for calls "

          "like `fopen` in the guest."sv),

      PO::MetaVar("PREOPEN_DIRS"sv));

  PO::List<std::string> Env(

      PO::Description(

          "Environ variables. Each variable can be specified as --env `NAME=VALUE`."sv),

      PO::MetaVar("ENVS"sv));

  PO::Option<PO::Toggle> PropWASM1(

      PO::Description("Set as WASM 1.0 standard."sv));

  PO::Option<PO::Toggle> PropWASM2(

      PO::Description("Set as WASM 2.0 standard."sv));

  PO::Option<PO::Toggle> PropWASM3(

      PO::Description("Set as WASM 3.0 standard (default)."sv));

  PO::Option<PO::Toggle> PropMutGlobals(

      PO::Description("Disable Import/Export of mutable globals proposal"sv));

  PO::Option<PO::Toggle> PropNonTrapF2IConvs(PO::Description(

      "Disable Non-trapping float-to-int conversions proposal"sv));

  PO::Option<PO::Toggle> PropSignExtendOps(

      PO::Description("Disable Sign-extension operators proposal"sv));

  PO::Option<PO::Toggle> PropMultiValue(

      PO::Description("Disable Multi-value proposal"sv));

  PO::Option<PO::Toggle> PropBulkMemOps(

      PO::Description("Disable Bulk memory operations proposal"sv));

  PO::Option<PO::Toggle> PropRefTypes(

      PO::Description("Disable Reference types proposal"sv));

  PO::Option<PO::Toggle> PropSIMD(PO::Description("Disable SIMD proposal"sv));

  PO::Option<PO::Toggle> PropTailCall(

      PO::Description("Disable Tail-call proposal"sv));

  PO::Option<PO::Toggle> PropExtendConst(

      PO::Description("Disable Extended-const proposal"sv));

  PO::Option<PO::Toggle> PropFunctionReference(

      PO::Description("Disable Function Reference proposal"sv));

  PO::Option<PO::Toggle> PropGC(PO::Description("Disable GC proposal"sv));

  PO::Option<PO::Toggle> PropMultiMem(

      PO::Description("Disable Multiple memories proposal"sv));

  PO::Option<PO::Toggle> PropRelaxedSIMD(

      PO::Description("Disable Relaxed SIMD proposal"sv));

  PO::Option<PO::Toggle> PropExceptionHandling(

      PO::Description("Disable Exception handling proposal"sv));

  // TODO: MEMORY64 - enable the option.

  // PO::Option<PO::Toggle> PropMemory64(

  //     PO::Description("Disable Memory64 proposal"sv));

  PO::Option<PO::Toggle> PropThreads(

      PO::Description("Enable Threads proposal"sv));

  PO::Option<PO::Toggle> PropComponent(PO::Description(

      "Enable Component Model proposal, this is experimental"sv));

  PO::Option<PO::Toggle> PropAll(PO::Description("Enable all features"sv));

  PO::Option<PO::Toggle> ConfEnableInstructionCounting(PO::Description(

      "Enable generating code for counting Wasm instructions executed."sv));

  PO::Option<PO::Toggle> ConfEnableGasMeasuring(PO::Description(

      "Enable generating code for counting gas burned during execution."sv));

  PO::Option<PO::Toggle> ConfEnableTimeMeasuring(PO::Description(

      "Enable generating code for counting time during execution."sv));

  PO::Option<PO::Toggle> ConfEnableAllStatistics(PO::Description(

      "Enable generating code for all statistics options include instruction counting, gas measuring, and execution time"sv));

  PO::Option<uint64_t> TimeLim(

      PO::Description(

          "Limitation of maximum time(in milliseconds) for execution, default value is 0 for no limitations"sv),

      PO::MetaVar("TIMEOUT"sv), PO::DefaultValue<uint64_t>(0));

  PO::List<int> GasLim(

      PO::Description(

          "Limitation of execution gas. Upper bound can be specified as --gas-limit `GAS_LIMIT`."sv),

      PO::MetaVar("GAS_LIMIT"sv));

  PO::List<int> MemLim(

      PO::Description(

          "Limitation of pages(as size of 64 KiB) in every memory instance. Upper bound can be specified as --memory-page-limit `PAGE_COUNT`."sv),

      PO::MetaVar("PAGE_COUNT"sv));

  PO::List<std::string> ForbiddenPlugins(

      PO::Description("List of plugins to ignore."sv), PO::MetaVar("NAMES"sv));

  auto Parser = PO::ArgumentParser();

  Parser.add_option(SoName)

      .add_option(Args)

      .add_option("reactor"sv, Reactor)

      .add_option("dir"sv, Dir)

      .add_option("env"sv, Env)

      .add_option("wasm-1"sv, PropWASM1)

      .add_option("wasm-2"sv, PropWASM2)

      .add_option("wasm-3"sv, PropWASM3)

      .add_option("disable-import-export-mut-globals"sv, PropMutGlobals)

      .add_option("disable-non-trap-float-to-int"sv, PropNonTrapF2IConvs)

      .add_option("disable-sign-extension-operators"sv, PropSignExtendOps)

      .add_option("disable-multi-value"sv, PropMultiValue)

      .add_option("disable-bulk-memory"sv, PropBulkMemOps)

      .add_option("disable-reference-types"sv, PropRefTypes)

      .add_option("disable-simd"sv, PropSIMD)

      .add_option("disable-tail-call"sv, PropTailCall)

      .add_option("disable-extended-const"sv, PropExtendConst)

      .add_option("disable-function-reference"sv, PropFunctionReference)

      .add_option("disable-gc"sv, PropGC)

      .add_option("disable-multi-memory"sv, PropMultiMem)

      .add_option("disable-relaxed-simd"sv, PropRelaxedSIMD)

      .add_option("disable-exception-handling"sv, PropExceptionHandling)

      // TODO: MEMORY64 - enable the option.

      // .add_option("disable-memory64"sv, PropMemory64)

      .add_option("enable-threads"sv, PropThreads)

      .add_option("enable-component"sv, PropComponent)

      .add_option("enable-all"sv, PropAll)

      .add_option("time-limit"sv, TimeLim)

      .add_option("gas-limit"sv, GasLim)

      .add_option("memory-page-limit"sv, MemLim)

      .add_option("forbidden-plugin"sv, ForbiddenPlugins);

  static constexpr const std::array<char, 4> Separator = {'\xde', '\xad',

                                                          '\xbe', '\xef'};

  static const BoyerMooreHorspoolSearcher Searcher(Separator.begin(),

                                                   Separator.end());

  Span<const char> RawArgs(reinterpret_cast<const char *>(Data), Size);

  std::vector<std::string> ArgvStr;

  std::vector<const char *> Argv;

  while (!RawArgs.empty()) {

    const auto It = std::search(RawArgs.begin(), RawArgs.end(), Searcher);

    ArgvStr.emplace_back(RawArgs.begin(), It);

    RawArgs = RawArgs.subspan(std::min<size_t>(

        std::distance(RawArgs.begin(), It) + 4, RawArgs.size()));

  }

  for (const auto &Arg : ArgvStr) {

    Argv.push_back(Arg.c_str());

  }

  std::unique_ptr<std::FILE, decltype(&std::fclose)> Out{

      std::fopen("/dev/null", "w"), std::fclose};

  if (!Parser.parse(Out.get(), Argv.size(), Argv.data())) {

    return EXIT_FAILURE;

  }

  if (Parser.isVersion()) {

    fmt::print(Out.get(), "{} version {}\n"sv, Argv.empty() ? "" : Argv[0],

               kVersionString);

    return EXIT_SUCCESS;

  }

  return EXIT_SUCCESS;

}

} // namespace Driver

} // namespace WasmEdge

#endif