// Ceres Solver - A fast non-linear least squares minimizer
// Copyright 2023 Google Inc. All rights reserved.
// http://ceres-solver.org/
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// * Redistributions of source code must retain the above copyright notice,
//   this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above copyright notice,
//   this list of conditions and the following disclaimer in the documentation
//   and/or other materials provided with the distribution.
// * Neither the name of Google Inc. nor the names of its contributors may be
//   used to endorse or promote products derived from this software without
//   specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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// POSSIBILITY OF SUCH DAMAGE.
//
// Author: strandmark@google.com (Petter Strandmark)

#include "ceres/wall_time.h"

#include <ctime>

#include "absl/log/log.h"
#include "absl/strings/str_format.h"
#include "ceres/internal/config.h"

#ifdef _WIN32
#include <windows.h>
#else
#include <sys/time.h>
#endif

namespace ceres::internal {

double WallTimeInSeconds() {
#ifdef _WIN32
  LARGE_INTEGER count;
  LARGE_INTEGER frequency;
  QueryPerformanceCounter(&count);
  QueryPerformanceFrequency(&frequency);
  return static_cast<double>(count.QuadPart) /
         static_cast<double>(frequency.QuadPart);
#else
  timeval time_val;
  gettimeofday(&time_val, nullptr);
  return (time_val.tv_sec + time_val.tv_usec * 1e-6);
#endif
}

EventLogger::EventLogger(const std::string& logger_name) {
  if (!VLOG_IS_ON(3)) {
    return;
  }

  start_time_ = WallTimeInSeconds();
  last_event_time_ = start_time_;
  events_ = absl::StrFormat(
      "\n%s\n                                        Delta   Cumulative\n",
      logger_name);
}

EventLogger::~EventLogger() {
  if (!VLOG_IS_ON(3)) {
    return;
  }
  AddEvent("Total");
  VLOG(3) << "\n" << events_ << "\n";
}

void EventLogger::AddEvent(const std::string& event_name) {
  if (!VLOG_IS_ON(3)) {
    return;
  }

  const double current_time = WallTimeInSeconds();
  const double relative_time_delta = current_time - last_event_time_;
  const double absolute_time_delta = current_time - start_time_;
  last_event_time_ = current_time;

  absl::StrAppendFormat(&events_,
                        "  %30s : %10.5f   %10.5f\n",
                        event_name,
                        relative_time_delta,
                        absolute_time_delta);
}

}  // namespace ceres::internal