#ifndef CAFFE2_CORE_LOGGING_IS_NOT_GOOGLE_GLOG_H_
#define CAFFE2_CORE_LOGGING_IS_NOT_GOOGLE_GLOG_H_

#include <chrono>
#include <climits>
#include <ctime>
#include <iomanip>
#include <string>
#include <fstream>
#include <set>
#include <sstream>
#include <vector>

#include "caffe2/core/flags.h"

// Log severity level constants.
const int FATAL   = 3;
#if !defined(_MSC_VER) || !defined(ERROR)
// Windows defines the ERROR macro already, and as a result we will
// simply use that one. The downside is that one will now mix LOG(INFO)
// and LOG(ERROR) because ERROR is defined to be zero. Anyway, the
// recommended way is to use glog so fixing this is a low-pri item.
const int ERROR   = 2;
#endif
const int WARNING = 1;
const int INFO    = 0;
const char CAFFE2_SEVERITY_PREFIX[] = "FEWIV";

namespace caffe2 {
class MessageLogger {
 public:
  MessageLogger(const char *file, int line, int severity);
  ~MessageLogger();
  // Return the stream associated with the logger object.
  std::stringstream &stream() { return stream_; }

 private:
  // When there is a fatal log, we simply abort.
  void DealWithFatal() { abort(); }

  const char* tag_;
  std::stringstream stream_;
  int severity_;
};

// This class is used to explicitly ignore values in the conditional
// logging macros.  This avoids compiler warnings like "value computed
// is not used" and "statement has no effect".
class LoggerVoidify {
 public:
  LoggerVoidify() { }
  // This has to be an operator with a precedence lower than << but
  // higher than ?:
  void operator&(const std::ostream &s) { }
};

// Log a message and terminate.
template<class T>
void LogMessageFatal(const char *file, int line, const T &message) {
  MessageLogger(file, line, FATAL).stream() << message;
}

// Helpers for CHECK_NOTNULL(). Two are necessary to support both raw pointers
// and smart pointers.
template <typename T>
T& CheckNotNullCommon(const char *file, int line, const char *names, T& t) {
  if (t == nullptr) {
    LogMessageFatal(file, line, std::string(names));
  }
  return t;
}

template <typename T>
T* CheckNotNull(const char *file, int line, const char *names, T* t) {
  return CheckNotNullCommon(file, line, names, t);
}

template <typename T>
T& CheckNotNull(const char *file, int line, const char *names, T& t) {
  return CheckNotNullCommon(file, line, names, t);
}
}  // namespace caffe2

// ---------------------- Logging Macro definitions --------------------------


static_assert(CAFFE2_LOG_THRESHOLD <= FATAL,
              "CAFFE2_LOG_THRESHOLD should at most be FATAL.");
// If n is under the compile time caffe log threshold, The _CAFFE_LOG(n)
// should not generate anything in optimized code.
#define LOG(n) \
  if (n >= CAFFE2_LOG_THRESHOLD) \
    ::caffe2::MessageLogger((char*)__FILE__, __LINE__, n).stream()
#define VLOG(n) LOG((-n))

#define LOG_IF(n, condition)                    \
  if (n >= CAFFE2_LOG_THRESHOLD && (condition)) \
  ::caffe2::MessageLogger((char*)__FILE__, __LINE__, n).stream()
#define VLOG_IF(n, condition) LOG_IF((-n), (condition))

// Log only if condition is met.  Otherwise evaluates to void.
#define FATAL_IF(condition) \
  condition ? (void) 0 : ::caffe2::LoggerVoidify() & \
      ::caffe2::MessageLogger((char*)__FILE__, __LINE__, FATAL).stream()

// Check for a given boolean condition.
#define CHECK(condition) FATAL_IF(condition) \
        << "Check failed: " #condition " "

#ifndef NDEBUG
// Debug only version of CHECK
#define DCHECK(condition) FATAL_IF(condition) \
        << "Check failed: " #condition " "
#else
// Optimized version - generates no code.
#define DCHECK(condition) if(false) CHECK(condition)
#endif  // NDEBUG

#define CHECK_OP(val1, val2, op) FATAL_IF((val1 op val2)) \
  << "Check failed: " #val1 " " #op " " #val2 " "

// Check_op macro definitions
#define CHECK_EQ(val1, val2) CHECK_OP(val1, val2, ==)
#define CHECK_NE(val1, val2) CHECK_OP(val1, val2, !=)
#define CHECK_LE(val1, val2) CHECK_OP(val1, val2, <=)
#define CHECK_LT(val1, val2) CHECK_OP(val1, val2, <)
#define CHECK_GE(val1, val2) CHECK_OP(val1, val2, >=)
#define CHECK_GT(val1, val2) CHECK_OP(val1, val2, >)

#ifndef NDEBUG
// Debug only versions of CHECK_OP macros.
#define DCHECK_EQ(val1, val2) CHECK_OP(val1, val2, ==)
#define DCHECK_NE(val1, val2) CHECK_OP(val1, val2, !=)
#define DCHECK_LE(val1, val2) CHECK_OP(val1, val2, <=)
#define DCHECK_LT(val1, val2) CHECK_OP(val1, val2, <)
#define DCHECK_GE(val1, val2) CHECK_OP(val1, val2, >=)
#define DCHECK_GT(val1, val2) CHECK_OP(val1, val2, >)
#else  // !NDEBUG
// These versions generate no code in optimized mode.
#define DCHECK_EQ(val1, val2) if(false) CHECK_OP(val1, val2, ==)
#define DCHECK_NE(val1, val2) if(false) CHECK_OP(val1, val2, !=)
#define DCHECK_LE(val1, val2) if(false) CHECK_OP(val1, val2, <=)
#define DCHECK_LT(val1, val2) if(false) CHECK_OP(val1, val2, <)
#define DCHECK_GE(val1, val2) if(false) CHECK_OP(val1, val2, >=)
#define DCHECK_GT(val1, val2) if(false) CHECK_OP(val1, val2, >)
#endif  // NDEBUG

// Check that a pointer is not null.
#define CHECK_NOTNULL(val) \
  ::caffe2::CheckNotNull( \
      __FILE__, __LINE__, "Check failed: '" #val "' Must be non NULL", (val))

#ifndef NDEBUG
// Debug only version of CHECK_NOTNULL
#define DCHECK_NOTNULL(val) \
  ::caffe2::CheckNotNull( \
      __FILE__, __LINE__, "Check failed: '" #val "' Must be non NULL", (val))
#else  // !NDEBUG
// Optimized version - generates no code.
#define DCHECK_NOTNULL(val) if (false) CHECK_NOTNULL(val)
#endif  // NDEBUG

// ---------------------- Support for std objects --------------------------
// These are adapted from glog to support a limited set of logging capability
// for STL objects.

namespace caffe2 {
// Forward declare these two, and define them after all the container streams
// operators so that we can recurse from pair -> container -> container -> pair
// properly.
template<class First, class Second>
std::ostream& operator<<(
    std::ostream& out, const std::pair<First, Second>& p);
template <class Iter>
void PrintSequence(std::ostream& ss, Iter begin, Iter end);

#define INSTANTIATE_FOR_CONTAINER(container) \
template <class... Types> \
std::ostream& operator<<( \
    std::ostream& out, const container<Types...>& seq) { \
  PrintSequence(out, seq.begin(), seq.end()); \
  return out; \
}

INSTANTIATE_FOR_CONTAINER(std::vector)
INSTANTIATE_FOR_CONTAINER(std::map)
INSTANTIATE_FOR_CONTAINER(std::set)
#undef INSTANTIATE_FOR_CONTAINER

template<class First, class Second>
inline std::ostream& operator<<(
    std::ostream& out, const std::pair<First, Second>& p) {
  out << '(' << p.first << ", " << p.second << ')';
  return out;
}

template <class Iter>
inline void PrintSequence(std::ostream& out, Iter begin, Iter end) {
  // Output at most 100 elements -- appropriate if used for logging.
  for (int i = 0; begin != end && i < 100; ++i, ++begin) {
    if (i > 0) out << ' ';
    out << *begin;
  }
  if (begin != end) {
    out << " ...";
  }
}
}  // namespace caffe2

#endif  // CAFFE2_CORE_LOGGING_IS_NOT_GOOGLE_GLOG_H_
