/*
  Stockfish, a UCI chess playing engine derived from Glaurung 2.1
  Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
  Copyright (C) 2008-2012 Marco Costalba, Joona Kiiski, Tord Romstad

  Stockfish is free software: you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 3 of the License, or
  (at your option) any later version.

  Stockfish is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#include <iomanip>
#include <iostream>
#include <sstream>

#include "misc.h"
#include "thread.h"

#if defined(__hpux)
#    include <sys/pstat.h>
#endif

using namespace std;

/// Version number. If Version is left empty, then Tag plus current
/// date (in the format YYMMDD) is used as a version number.

static const string Version = "2.3.1";
static const string Tag = "";


/// engine_info() returns the full name of the current Stockfish version.
/// This will be either "Stockfish YYMMDD" (where YYMMDD is the date when
/// the program was compiled) or "Stockfish <version number>", depending
/// on whether Version is empty.

const string engine_info(bool to_uci) {

  const string months("Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec");
  const string cpu64(Is64Bit ? " 64bit" : "");
  const string popcnt(HasPopCnt ? " SSE4.2" : "");

  string month, day, year;
  stringstream s, date(__DATE__); // From compiler, format is "Sep 21 2008"

  s << "Stockfish " << Version;

  if (Version.empty())
  {
      date >> month >> day >> year;

      s << Tag << setfill('0') << " " << year.substr(2)
        << setw(2) << (1 + months.find(month) / 4) << setw(2) << day;
  }

  s << cpu64 << popcnt << (to_uci ? "\nid author ": " by ")
    << "Tord Romstad, Marco Costalba and Joona Kiiski";

  return s.str();
}


/// Convert system time to milliseconds. That's all we need.

Time::point Time::now() {
  sys_time_t t; system_time(&t); return time_to_msec(t);
}


/// Debug functions used mainly to collect run-time statistics

static uint64_t hits[2], means[2];

void dbg_hit_on(bool b) { hits[0]++; if (b) hits[1]++; }
void dbg_hit_on_c(bool c, bool b) { if (c) dbg_hit_on(b); }
void dbg_mean_of(int v) { means[0]++; means[1] += v; }

void dbg_print() {

  if (hits[0])
      cerr << "Total " << hits[0] << " Hits " << hits[1]
           << " hit rate (%) " << 100 * hits[1] / hits[0] << endl;

  if (means[0])
      cerr << "Total " << means[0] << " Mean "
           << (float)means[1] / means[0] << endl;
}


/// Our fancy logging facility. The trick here is to replace cin.rdbuf() and
/// cout.rdbuf() with two Tie objects that tie cin and cout to a file stream. We
/// can toggle the logging of std::cout and std:cin at runtime while preserving
/// usual i/o functionality and without changing a single line of code!
/// Idea from http://groups.google.com/group/comp.lang.c++/msg/1d941c0f26ea0d81

struct Tie: public streambuf { // MSVC requires splitted streambuf for cin and cout

  Tie(streambuf* b, ofstream* f) : buf(b), file(f) {}

  int sync() { return file->rdbuf()->pubsync(), buf->pubsync(); }
  int overflow(int c) { return log(buf->sputc((char)c), "<< "); }
  int underflow() { return buf->sgetc(); }
  int uflow() { return log(buf->sbumpc(), ">> "); }

  streambuf* buf;
  ofstream* file;

  int log(int c, const char* prefix) {

    static int last = '\n';

    if (last == '\n')
        file->rdbuf()->sputn(prefix, 3);

    return last = file->rdbuf()->sputc((char)c);
  }
};

class Logger {

  Logger() : in(cin.rdbuf(), &file), out(cout.rdbuf(), &file) {}
 ~Logger() { start(false); }

  ofstream file;
  Tie in, out;

public:
  static void start(bool b) {

    static Logger l;

    if (b && !l.file.is_open())
    {
        l.file.open("io_log.txt", ifstream::out | ifstream::app);
        cin.rdbuf(&l.in);
        cout.rdbuf(&l.out);
    }
    else if (!b && l.file.is_open())
    {
        cout.rdbuf(l.out.buf);
        cin.rdbuf(l.in.buf);
        l.file.close();
    }
  }
};


/// Used to serialize access to std::cout to avoid multiple threads to write at
/// the same time.

std::ostream& operator<<(std::ostream& os, SyncCout sc) {

  static Mutex m;

  if (sc == io_lock)
      m.lock();

  if (sc == io_unlock)
      m.unlock();

  return os;
}


/// Trampoline helper to avoid moving Logger to misc.h
void start_logger(bool b) { Logger::start(b); }


/// cpu_count() tries to detect the number of CPU cores

int cpu_count() {

#if defined(_WIN32) || defined(_WIN64)
  SYSTEM_INFO s;
  GetSystemInfo(&s);
  return s.dwNumberOfProcessors;
#else

#  if defined(_SC_NPROCESSORS_ONLN)
  return sysconf(_SC_NPROCESSORS_ONLN);
#  elif defined(__hpux)
  struct pst_dynamic psd;
  if (pstat_getdynamic(&psd, sizeof(psd), (size_t)1, 0) == -1)
      return 1;
  return psd.psd_proc_cnt;
#  else
  return 1;
#  endif

#endif
}


/// timed_wait() waits for msec milliseconds. It is mainly an helper to wrap
/// conversion from milliseconds to struct timespec, as used by pthreads.

void timed_wait(WaitCondition& sleepCond, Lock& sleepLock, int msec) {

#if defined(_WIN32) || defined(_WIN64)
  int tm = msec;
#else
  timespec ts, *tm = &ts;
  uint64_t ms = Time::now() + msec;

  ts.tv_sec = ms / 1000;
  ts.tv_nsec = (ms % 1000) * 1000000LL;
#endif

  cond_timedwait(sleepCond, sleepLock, tm);
}


/// prefetch() preloads the given address in L1/L2 cache. This is a non
/// blocking function and do not stalls the CPU waiting for data to be
/// loaded from memory, that can be quite slow.
#if defined(NO_PREFETCH)

void prefetch(char*) {}

#else

#   include <xmmintrin.h>

void prefetch(char* addr) {

#  if defined(__INTEL_COMPILER) || defined(__ICL)
   // This hack prevents prefetches to be optimized away by
   // Intel compiler. Both MSVC and gcc seems not affected.
   __asm__ ("");
#  endif

  _mm_prefetch(addr, _MM_HINT_T2);
  _mm_prefetch(addr+64, _MM_HINT_T2); // 64 bytes ahead
}

#endif