/// \file MetaAddress.cpp

//
// This file is distributed under the MIT License. See LICENSE.md for details.
//

#include "llvm/IR/Constants.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/Module.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/raw_ostream.h"

#include "revng/Support/IRHelpers.h"
#include "revng/Support/MetaAddress.h"

using namespace llvm;

Constant *MetaAddress::toValue(llvm::Module *M) const {
  return getUniqueString(M, toString());
}

MetaAddress MetaAddress::fromValue(Value *V) {
  return MetaAddress::fromString(extractFromConstantStringPtr(V));
}

Instruction *MetaAddress::composeIntegerPC(IRBuilderBase &B,
                                           Value *AddressValue,
                                           Value *EpochValue,
                                           Value *AddressSpaceValue,
                                           Value *TypeValue) {
  llvm::Type *Int128 = B.getInt128Ty();
  auto Load128 = [&B, Int128](Value *V) { return B.CreateZExt(V, Int128); };

  auto *Epoch = B.CreateShl(Load128(EpochValue), 64);
  auto *AddressSpace = B.CreateShl(Load128(AddressSpaceValue), 64 + 32);
  auto *Type = B.CreateShl(Load128(TypeValue), 64 + 32 + 16);
  auto *Composed = B.CreateAdd(Load128(AddressValue),
                               B.CreateAdd(Epoch,
                                           B.CreateAdd(AddressSpace, Type)));

  return cast<Instruction>(Composed);
}

MetaAddress MetaAddress::decomposeIntegerPC(ConstantInt *Value) {
  return decomposeIntegerPC(Value->getValue());
}

MetaAddress MetaAddress::decomposeIntegerPC(const APInt &Value) {
  revng_assert(Value.getBitWidth() == 128);
  uint64_t Lower = (Value & UINT64_MAX).getLimitedValue();
  uint64_t Upper = Value.lshr(64).getLimitedValue();

  MetaAddress Result;
  Result.Address = Lower;
  Result.Epoch = Upper & 0xFFFFFFFF;
  Result.AddressSpace = (Upper >> 32) & 0xFFFF;
  Result.Type = static_cast<MetaAddressType::Values>(Upper >> (32 + 16));
  Result.validate();

  return Result;
}

static std::string toStringImpl(const MetaAddress &Address,
                                std::optional<llvm::Triple::ArchType> Arch,
                                llvm::StringRef Separator) {
  if (Address.isInvalid())
    return Separator.str() += "Invalid";

  bool ShouldPrintTheType = true;
  if (Arch.has_value()) {
    // Assert if `Arch` is not supported.
    static_cast<void>(MetaAddressType::genericFromArch(Arch.value()));

    if (Address.arch().has_value() && Address.arch().value() == Arch.value())
      ShouldPrintTheType = false;
  }

  std::string Result;
  {
    raw_string_ostream Stream(Result);
    Stream << "0x" << Twine::utohexstr(Address.address());
    if (ShouldPrintTheType)
      Stream << Separator << MetaAddressType::toString(Address.type());
    if (not Address.isDefaultEpoch())
      Stream << Separator << Address.epoch();
    if (not Address.isDefaultAddressSpace())
      Stream << Separator << Address.addressSpace();
  }

  return Result;
}

std::string
MetaAddress::toString(std::optional<llvm::Triple::ArchType> Arch) const {
  return toStringImpl(*this, Arch, Separator);
}

std::string
MetaAddress::toIdentifier(std::optional<llvm::Triple::ArchType> Arch) const {
  return toStringImpl(*this, Arch, "_");
}

MetaAddress MetaAddress::fromString(StringRef Text) {
  revng_assert(Text.size() > Separator.size());
  if (Text.take_front(Separator.size()) == Separator)
    if (Text.drop_front(Separator.size()) == "Invalid")
      return MetaAddress::invalid();

  MetaAddress Result;

  SmallVector<StringRef, 4> Parts;
  Text.split(Parts, Separator);

  if (Parts.size() < 2 or Parts.size() > 4)
    return MetaAddress::invalid();

  bool Error;
  uint64_t Value;

  Error = Parts[0].getAsInteger(0, Result.Address);
  if (Error)
    return MetaAddress::invalid();

  Result.Type = MetaAddressType::fromString(Parts[1]);
  if (Result.type() == MetaAddressType::Invalid)
    return MetaAddress::invalid();

  Result.Epoch = 0;
  if (Parts.size() >= 3 and Parts[2].size() > 0) {
    Error = Parts[2].getAsInteger(0, Result.Epoch);
    if (Error)
      return MetaAddress::invalid();
  }

  Result.AddressSpace = 0;
  if (Parts.size() == 4 and Parts[3].size() > 0) {
    Error = Parts[3].getAsInteger(0, Result.AddressSpace);
    if (Error)
      return MetaAddress::invalid();
  }

  Result.validate();

  return Result;
}