//===- offload_impl.hpp- Implementation helpers for the Offload library ---===//
//
// 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
//
//===----------------------------------------------------------------------===//
#pragma once

#include "PluginInterface.h"
#include <OffloadAPI.h>
#include <iostream>
#include <memory>
#include <optional>
#include <set>
#include <string>
#include <unordered_set>
#include <vector>

#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/StringSet.h"
#include "llvm/Support/Error.h"

namespace llvm {
namespace offload {
bool isTracingEnabled();
bool isValidationEnabled();
bool isOffloadInitialized();
} // namespace offload
} // namespace llvm

// Use the StringSet container to efficiently deduplicate repeated error
// strings (e.g. if the same error is hit constantly in a long running program)
llvm::StringSet<> &errorStrs();

// Use an unordered_set to avoid duplicates of error structs themselves.
// We cannot store the structs directly as returned pointers to them must always
// be valid, and a rehash of the set may invalidate them. This requires
// custom hash and equal_to function objects.
using ErrPtrT = std::unique_ptr<ol_error_struct_t>;
struct ErrPtrEqual {
  bool operator()(const ErrPtrT &lhs, const ErrPtrT &rhs) const {
    if (!lhs && !rhs) {
      return true;
    }
    if (!lhs || !rhs) {
      return false;
    }

    bool StrsEqual = false;
    if (lhs->Details == NULL && rhs->Details == NULL) {
      StrsEqual = true;
    } else if (lhs->Details != NULL && rhs->Details != NULL) {
      StrsEqual = (std::strcmp(lhs->Details, rhs->Details) == 0);
    }
    return (lhs->Code == rhs->Code) && StrsEqual;
  }
};
struct ErrPtrHash {
  size_t operator()(const ErrPtrT &e) const {
    if (!e) {
      // We shouldn't store empty errors (i.e. success), but just in case
      return 0lu;
    } else {
      return std::hash<int>{}(e->Code);
    }
  }
};
using ErrSetT = std::unordered_set<ErrPtrT, ErrPtrHash, ErrPtrEqual>;
ErrSetT &errors();

namespace {
ol_errc_t GetErrorCode(std::error_code Code) {
  if (Code.category() ==
      error::make_error_code(error::ErrorCode::SUCCESS).category())
    return static_cast<ol_errc_t>(Code.value());

  return OL_ERRC_UNKNOWN;
}
} // namespace

inline ol_result_t llvmErrorToOffloadError(llvm::Error &&Err) {
  if (!Err) {
    // No error
    return nullptr;
  }

  ol_errc_t ErrCode;
  llvm::StringRef Details;

  llvm::handleAllErrors(std::move(Err), [&](llvm::StringError &Err) {
    ErrCode = GetErrorCode(Err.convertToErrorCode());
    Details = errorStrs().insert(Err.getMessage()).first->getKeyData();
  });

  auto NewErr = std::unique_ptr<ol_error_struct_t>(
      new ol_error_struct_t{ErrCode, Details.data()});
  return errors().emplace(std::move(NewErr)).first->get();
}