//===--- Marshallers.cpp ----------------------------------------*- C++ -*-===//

//

// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.

// See https://llvm.org/LICENSE.txt for license information.

// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

//

//===----------------------------------------------------------------------===//

#include "Marshallers.h"

#include "llvm/ADT/ArrayRef.h"

#include "llvm/ADT/Optional.h"

#include "llvm/ADT/StringRef.h"

#include "llvm/Support/Regex.h"

#include <string>

static llvm::Optional<std::string>

getBestGuess(llvm::StringRef Search, llvm::ArrayRef<llvm::StringRef> Allowed,

             llvm::StringRef DropPrefix = "", unsigned MaxEditDistance = 3) {

  if (MaxEditDistance != ~0U)

    ++MaxEditDistance;

  llvm::StringRef Res;

  for (const llvm::StringRef &Item : Allowed) {

    if (Item.equals_lower(Search)) {

      assert(!Item.equals(Search) && "This should be handled earlier on.");

      MaxEditDistance = 1;

      Res = Item;

      continue;

    }

    unsigned Distance = Item.edit_distance(Search);

    if (Distance < MaxEditDistance) {

      MaxEditDistance = Distance;

      Res = Item;

    }

  }

  if (!Res.empty())

    return Res.str();

  if (!DropPrefix.empty()) {

    --MaxEditDistance; // Treat dropping the prefix as 1 edit

    for (const llvm::StringRef &Item : Allowed) {

      auto NoPrefix = Item;

      if (!NoPrefix.consume_front(DropPrefix))

        continue;

      if (NoPrefix.equals_lower(Search)) {

        if (NoPrefix.equals(Search))

          return Item.str();

        MaxEditDistance = 1;

        Res = Item;

        continue;

      }

      unsigned Distance = NoPrefix.edit_distance(Search);

      if (Distance < MaxEditDistance) {

        MaxEditDistance = Distance;

        Res = Item;

      }

    }

    if (!Res.empty())

      return Res.str();

  }

  return llvm::None;

}

llvm::Optional<std::string>

clang::ast_matchers::dynamic::internal::ArgTypeTraits<

    clang::attr::Kind>::getBestGuess(const VariantValue &Value) {

  static constexpr llvm::StringRef Allowed[] = {

#define ATTR(X) "attr::" #X,

#include "clang/Basic/AttrList.inc"

  };

  if (Value.isString())

    return ::getBestGuess(Value.getString(), llvm::makeArrayRef(Allowed),

                          "attr::");

  return llvm::None;

}

llvm::Optional<std::string>

clang::ast_matchers::dynamic::internal::ArgTypeTraits<

    clang::CastKind>::getBestGuess(const VariantValue &Value) {

  static constexpr llvm::StringRef Allowed[] = {

#define CAST_OPERATION(Name) "CK_" #Name,

#include "clang/AST/OperationKinds.def"

  };

  if (Value.isString())

    return ::getBestGuess(Value.getString(), llvm::makeArrayRef(Allowed),

                          "CK_");

  return llvm::None;

}

llvm::Optional<std::string>

clang::ast_matchers::dynamic::internal::ArgTypeTraits<

    clang::OpenMPClauseKind>::getBestGuess(const VariantValue &Value) {

  static constexpr llvm::StringRef Allowed[] = {

#define OMP_CLAUSE_CLASS(Enum, Str, Class) #Enum,

#include "llvm/Frontend/OpenMP/OMPKinds.def"

  };

  if (Value.isString())

    return ::getBestGuess(Value.getString(), llvm::makeArrayRef(Allowed),

                          "OMPC_");

  return llvm::None;

}

llvm::Optional<std::string>

clang::ast_matchers::dynamic::internal::ArgTypeTraits<

    clang::UnaryExprOrTypeTrait>::getBestGuess(const VariantValue &Value) {

  static constexpr llvm::StringRef Allowed[] = {

#define UNARY_EXPR_OR_TYPE_TRAIT(Spelling, Name, Key) "UETT_" #Name,

#define CXX11_UNARY_EXPR_OR_TYPE_TRAIT(Spelling, Name, Key) "UETT_" #Name,

#include "clang/Basic/TokenKinds.def"

  };

  if (Value.isString())

    return ::getBestGuess(Value.getString(), llvm::makeArrayRef(Allowed),

                          "UETT_");

  return llvm::None;

}

static constexpr std::pair<llvm::StringRef, llvm::Regex::RegexFlags>

    RegexMap[] = {

        {"NoFlags", llvm::Regex::RegexFlags::NoFlags},

        {"IgnoreCase", llvm::Regex::RegexFlags::IgnoreCase},

        {"Newline", llvm::Regex::RegexFlags::Newline},

        {"BasicRegex", llvm::Regex::RegexFlags::BasicRegex},

};

static llvm::Optional<llvm::Regex::RegexFlags>

getRegexFlag(llvm::StringRef Flag) {

  for (const auto &StringFlag : RegexMap) {

    if (Flag == StringFlag.first)

      return StringFlag.second;

  }

  return llvm::None;

}

static llvm::Optional<llvm::StringRef>

getCloseRegexMatch(llvm::StringRef Flag) {

  for (const auto &StringFlag : RegexMap) {

    if (Flag.edit_distance(StringFlag.first) < 3)

      return StringFlag.first;

  }

  return llvm::None;

}

llvm::Optional<llvm::Regex::RegexFlags>

clang::ast_matchers::dynamic::internal::ArgTypeTraits<

    llvm::Regex::RegexFlags>::getFlags(llvm::StringRef Flags) {

  llvm::Optional<llvm::Regex::RegexFlags> Flag;

  SmallVector<StringRef, 4> Split;

  Flags.split(Split, '|', -1, false);

  for (StringRef OrFlag : Split) {

    if (llvm::Optional<llvm::Regex::RegexFlags> NextFlag =

            getRegexFlag(OrFlag.trim()))

      Flag = Flag.getValueOr(llvm::Regex::NoFlags) | *NextFlag;

    else

      return None;

  }

  return Flag;

}

llvm::Optional<std::string>

clang::ast_matchers::dynamic::internal::ArgTypeTraits<

    llvm::Regex::RegexFlags>::getBestGuess(const VariantValue &Value) {

  if (!Value.isString())

    return llvm::None;

  SmallVector<StringRef, 4> Split;

  llvm::StringRef(Value.getString()).split(Split, '|', -1, false);

  for (llvm::StringRef &Flag : Split) {

    if (llvm::Optional<llvm::StringRef> BestGuess =

            getCloseRegexMatch(Flag.trim()))

      Flag = *BestGuess;

    else

      return None;

  }

  if (Split.empty())

    return None;

  return llvm::join(Split, " | ");

}