// Copyright (c) 2016-2020, The Monero Project
// 
// All rights reserved.
// 
// Redistribution and use in source and binary forms, with or without modification, are
// permitted provided that the following conditions are met:
// 
// 1. Redistributions of source code must retain the above copyright notice, this list of
//    conditions and the following disclaimer.
// 
// 2. 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.
// 
// 3. Neither the name of the copyright holder 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 HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#include <vector>
#include "misc_os_dependent.h"
#include "perf_timer.h"

#undef MONERO_DEFAULT_LOG_CATEGORY
#define MONERO_DEFAULT_LOG_CATEGORY "perf"

#define PERF_LOG_ALWAYS(level, cat, x) \
  el::base::Writer(level, el::Color::Default, __FILE__, __LINE__, ELPP_FUNC, el::base::DispatchAction::FileOnlyLog).construct(cat) << x
#define PERF_LOG(level, cat, x) \
  do { \
    if (ELPP->vRegistry()->allowed(level, cat)) PERF_LOG_ALWAYS(level, cat, x); \
  } while(0)

namespace tools
{
  uint64_t get_tick_count()
  {
#if defined(__x86_64__)
    uint32_t hi, lo;
    __asm__ volatile("rdtsc" : "=a"(lo), "=d"(hi));
    return (((uint64_t)hi) << 32) | (uint64_t)lo;
#else
    return epee::misc_utils::get_ns_count();
#endif
  }

#ifdef __x86_64__
  uint64_t get_ticks_per_ns()
  {
    uint64_t t0 = epee::misc_utils::get_ns_count(), t1;
    uint64_t r0 = get_tick_count();

    while (1)
    {
      t1 = epee::misc_utils::get_ns_count();
      if (t1 - t0 > 1*1000000000) break; // work one second
    }

    uint64_t r1 = get_tick_count();
    uint64_t tpns256 = 256 * (r1 - r0) / (t1 - t0);
    return tpns256 ? tpns256 : 1;
  }
#endif

#ifdef __x86_64__
  uint64_t ticks_per_ns = get_ticks_per_ns();
#endif

  uint64_t ticks_to_ns(uint64_t ticks)
  {
#if defined(__x86_64__)
    return 256 * ticks / ticks_per_ns;
#else
    return ticks;
#endif
  }
}

namespace tools
{

el::Level performance_timer_log_level = el::Level::Info;

static __thread std::vector<LoggingPerformanceTimer*> *performance_timers = NULL;

void set_performance_timer_log_level(el::Level level)
{
  if (level != el::Level::Debug && level != el::Level::Trace && level != el::Level::Info
   && level != el::Level::Warning && level != el::Level::Error && level != el::Level::Fatal)
  {
    MERROR("Wrong log level: " << el::LevelHelper::convertToString(level) << ", using Info");
    level = el::Level::Info;
  }
  performance_timer_log_level = level;
}

PerformanceTimer::PerformanceTimer(bool paused): started(true), paused(paused)
{
  if (paused)
    ticks = 0;
  else
    ticks = get_tick_count();
}

LoggingPerformanceTimer::LoggingPerformanceTimer(const std::string &s, const std::string &cat, uint64_t unit, el::Level l): PerformanceTimer(), name(s), cat(cat), unit(unit), level(l)
{
  const bool log = ELPP->vRegistry()->allowed(level, cat.c_str());
  if (!performance_timers)
  {
    if (log)
      PERF_LOG_ALWAYS(level, cat.c_str(), "PERF             ----------");
    performance_timers = new std::vector<LoggingPerformanceTimer*>();
    performance_timers->reserve(16); // how deep before realloc
  }
  else
  {
    LoggingPerformanceTimer *pt = performance_timers->back();
    if (!pt->started && !pt->paused)
    {
      if (log)
      {
        size_t size = 0; for (const auto *tmp: *performance_timers) if (!tmp->paused) ++size;
        PERF_LOG_ALWAYS(pt->level, cat.c_str(), "PERF           " << std::string((size-1) * 2, ' ') << "  " << pt->name);
      }
      pt->started = true;
    }
  }
  performance_timers->push_back(this);
}

PerformanceTimer::~PerformanceTimer()
{
  if (!paused)
    ticks = get_tick_count() - ticks;
}

LoggingPerformanceTimer::~LoggingPerformanceTimer()
{
  pause();
  performance_timers->pop_back();
  const bool log = ELPP->vRegistry()->allowed(level, cat.c_str());
  if (log)
  {
    char s[12];
    snprintf(s, sizeof(s), "%8llu  ", (unsigned long long)(ticks_to_ns(ticks) / (1000000000 / unit)));
    size_t size = 0; for (const auto *tmp: *performance_timers) if (!tmp->paused || tmp==this) ++size;
    PERF_LOG_ALWAYS(level, cat.c_str(), "PERF " << s << std::string(size * 2, ' ') << "  " << name);
  }
  if (performance_timers->empty())
  {
    delete performance_timers;
    performance_timers = NULL;
  }
}

void PerformanceTimer::pause()
{
  if (paused)
    return;
  ticks = get_tick_count() - ticks;
  paused = true;
}

void PerformanceTimer::resume()
{
  if (!paused)
    return;
  ticks = get_tick_count() - ticks;
  paused = false;
}

void PerformanceTimer::reset()
{
  if (paused)
    ticks = 0;
  else
    ticks = get_tick_count();
}

uint64_t PerformanceTimer::value() const
{
  uint64_t v = ticks;
  if (!paused)
    v = get_tick_count() - v;
  return ticks_to_ns(v);
}

}