/* protocol.cpp

   GNU Chess engine

   Copyright (C) 2001-2015 Free Software Foundation, Inc.

   This program 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.

   This program 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/>.
*/


// protocol.cpp

// includes

#include <cstdarg>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <pthread.h>

#include "board.h"
#include "book.h"
#include "eval.h"
#include "fen.h"
#include "material.h"
#include "move.h"
#include "move_do.h"
#include "move_legal.h"
#include "option.h"
#include "pawn.h"
#include "posix.h"
#include "protocol.h"
#include "pst.h"
#include "search.h"
#include "trans.h"
#include "util.h"
#include "config.h"

// constants

namespace engine {

static const double NormalRatio = 1.0;
static const double PonderRatio = 1.25;

// variables

static bool Init;

static bool Searching; // search in progress?
static bool Infinite; // infinite or ponder mode?
static bool Delay; // postpone "bestmove" in infinite/ponder mode?

extern bool UseTrans;

// Streams used for communication with the adapter

extern FILE *pipefd_a2e_0_stream;
extern FILE *pipefd_e2a_1_stream;

// prototypes

static void init              ();
static void loop_step         ();

static void parse_go          (char string[]);
static void parse_position    (char string[]);
static void parse_setoption   (char string[]);

static void send_best_move    ();

static bool string_equal      (const char s1[], const char s2[]);
static bool string_start_with (const char s1[], const char s2[]);

// functions

// loop()

void loop() {

   // init (to help debugging)

   Init = false;

   Searching = false;
   Infinite = false;
   Delay = false;

   search_clear();

   board_from_fen(SearchInput->board,StartFen);

   // loop

   while (true) loop_step();
}

// init()

static void init() {

   if (!Init) {

      // late initialisation

      Init = true;

      if (option_get_bool("OwnBook")) {
         book_open(option_get_string("BookFile"));
      }

      trans_alloc(Trans);

      pawn_init();
      pawn_alloc();

      material_init();
      material_alloc();

      pst_init();
      eval_init();
   }
}

// event()

void event() {

   while (!SearchInfo->stop && input_available()) loop_step();
}

// loop_step()

static void loop_step() {

   char string[65536];

   // read a line

   get(string,65536);

   // parse

   if (false) {

   } else if (string_start_with(string,"debug ")) {

      // dummy

   } else if (string_start_with(string,"go ")) {

      if (!Searching && !Delay) {
         init();
         parse_go(string);
      } else {
         ASSERT(false);
      }

   } else if (string_equal(string,"isready")) {

      if (!Searching && !Delay) {
         init();
      }

      send("readyok"); // no need to wait when searching (dixit SMK)

   } else if (string_equal(string,"ponderhit")) {

      if (Searching) {

         ASSERT(Infinite);

         SearchInput->infinite = false;
         Infinite = false;

      } else if (Delay) {

         send_best_move();
         Delay = false;

      } else {

         ASSERT(false);
      }

   } else if (string_start_with(string,"position ")) {

      if (!Searching && !Delay) {
         init();
         parse_position(string);
      } else {
         ASSERT(false);
      }

   } else if (string_equal(string,"quit")) {

      ASSERT(!Searching);
      ASSERT(!Delay);

      //exit(EXIT_SUCCESS);
      pthread_exit(NULL);

   } else if (string_start_with(string,"setoption ")) {

      if (!Searching && !Delay) {
         parse_setoption(string);
      } else {
         ASSERT(false);
      }

   } else if (string_equal(string,"stop")) {

      if (Searching) {

         SearchInfo->stop = true;
         Infinite = false;

      } else if (Delay) {

         send_best_move();
         Delay = false;
      }

   } else if (string_equal(string,"uci")) {

      ASSERT(!Searching);
      ASSERT(!Delay);

      send("id name GNU Chess " VERSION);
      send("id author GNU Chess team");

      option_list();

      send("uciok");

   } else if (string_equal(string,"ucinewgame")) {

      if (!Searching && !Delay && Init) {
         trans_clear(Trans);
      } else {
         ASSERT(false);
      }

   } else if (string_equal(string,"hashon")) {

      UseTrans = true;

   } else if (string_equal(string,"hashoff")) {

      UseTrans = false;

   }
}

// parse_go()

static void parse_go(char string[]) {

   const char * ptr;
   bool infinite, ponder;
   int depth, mate, movestogo;
   sint64 nodes;
   double binc, btime, movetime, winc, wtime;
   double time, inc;
   double time_max, alloc;

   // init

   infinite = false;
   ponder = false;

   depth = -1;
   mate = -1;
   movestogo = -1;

   nodes = -1;

   binc = -1.0;
   btime = -1.0;
   movetime = -1.0;
   winc = -1.0;
   wtime = -1.0;

   // parse

   ptr = strtok(string," "); // skip "go"

   for (ptr = strtok(NULL," "); ptr != NULL; ptr = strtok(NULL," ")) {

      if (false) {

      } else if (string_equal(ptr,"binc")) {

         ptr = strtok(NULL," ");
         if (ptr == NULL) my_fatal("parse_go(): missing argument\n");

         binc = double(atoi(ptr)) / 1000.0;
         ASSERT(binc>=0.0);

      } else if (string_equal(ptr,"btime")) {

         ptr = strtok(NULL," ");
         if (ptr == NULL) my_fatal("parse_go(): missing argument\n");

         btime = double(atoi(ptr)) / 1000.0;
         ASSERT(btime>=0.0);

      } else if (string_equal(ptr,"depth")) {

         ptr = strtok(NULL," ");
         if (ptr == NULL) my_fatal("parse_go(): missing argument\n");

         depth = atoi(ptr);
         ASSERT(depth>=0);

      } else if (string_equal(ptr,"infinite")) {

         infinite = true;

      } else if (string_equal(ptr,"mate")) {

         ptr = strtok(NULL," ");
         if (ptr == NULL) my_fatal("parse_go(): missing argument\n");

         mate = atoi(ptr);
         ASSERT(mate>=0);

      } else if (string_equal(ptr,"movestogo")) {

         ptr = strtok(NULL," ");
         if (ptr == NULL) my_fatal("parse_go(): missing argument\n");

         movestogo = atoi(ptr);
         ASSERT(movestogo>=0);

      } else if (string_equal(ptr,"movetime")) {

         ptr = strtok(NULL," ");
         if (ptr == NULL) my_fatal("parse_go(): missing argument\n");

         movetime = double(atoi(ptr)) / 1000.0;
         ASSERT(movetime>=0.0);

      } else if (string_equal(ptr,"nodes")) {

         ptr = strtok(NULL," ");
         if (ptr == NULL) my_fatal("parse_go(): missing argument\n");

         nodes = my_atoll(ptr);
         ASSERT(nodes>=0);

      } else if (string_equal(ptr,"ponder")) {

         ponder = true;

      } else if (string_equal(ptr,"searchmoves")) {

         // dummy

      } else if (string_equal(ptr,"winc")) {

         ptr = strtok(NULL," ");
         if (ptr == NULL) my_fatal("parse_go(): missing argument\n");

         winc = double(atoi(ptr)) / 1000.0;
         ASSERT(winc>=0.0);

      } else if (string_equal(ptr,"wtime")) {

         ptr = strtok(NULL," ");
         if (ptr == NULL) my_fatal("parse_go(): missing argument\n");

         wtime = double(atoi(ptr)) / 1000.0;
         ASSERT(wtime>=0.0);
      }
   }

   // init

   search_clear();

   // depth limit

   if (depth >= 0) {
      SearchInput->depth_is_limited = true;
      SearchInput->depth_limit = depth;
   } else if (mate >= 0) {
      SearchInput->depth_is_limited = true;
      SearchInput->depth_limit = mate * 2 - 1; // HACK: move -> ply
   }

   // time limit

   if (COLOUR_IS_WHITE(SearchInput->board->turn)) {
      time = wtime;
      inc = winc;
   } else {
      time = btime;
      inc = binc;
   }

   if (movestogo <= 0 || movestogo > 30) movestogo = 30; // HACK
   if (inc < 0.0) inc = 0.0;

   if (movetime >= 0.0) {

      // fixed time

      SearchInput->time_is_limited = true;
      SearchInput->time_limit_1 = movetime * 5.0; // HACK to avoid early exit
      SearchInput->time_limit_2 = movetime;

   } else if (time >= 0.0) {

      // dynamic allocation

      time_max = time * 0.95 - 1.0;
      if (time_max < 0.0) time_max = 0.0;

      SearchInput->time_is_limited = true;

      alloc = (time_max + inc * double(movestogo-1)) / double(movestogo);
      alloc *= (option_get_bool("Ponder") ? PonderRatio : NormalRatio);
      if (alloc > time_max) alloc = time_max;
      SearchInput->time_limit_1 = alloc;

      alloc = (time_max + inc * double(movestogo-1)) * 0.5;
      if (alloc < SearchInput->time_limit_1) alloc = SearchInput->time_limit_1;
      if (alloc > time_max) alloc = time_max;
      SearchInput->time_limit_2 = alloc;
   }

   if (infinite || ponder) SearchInput->infinite = true;

   // search

   ASSERT(!Searching);
   ASSERT(!Delay);

   Searching = true;
   Infinite = infinite || ponder;
   Delay = false;

   search();
   search_update_current();

   ASSERT(Searching);
   ASSERT(!Delay);

   Searching = false;
   Delay = Infinite;

   if (!Delay) send_best_move();
}

// parse_position()

static void parse_position(char string[]) {

   const char * fen;
   char * moves;
   const char * ptr;
   char move_string[256];
   int move;
   undo_t undo[1];

   // init

   fen = strstr(string,"fen ");
   moves = strstr(string,"moves ");

   // start position

   if (fen != NULL) { // "fen" present

      if (moves != NULL) { // "moves" present
         ASSERT(moves>fen);
         moves[-1] = '\0'; // dirty, but so is UCI
      }

      board_from_fen(SearchInput->board,fen+4); // CHANGE ME

   } else {

      // HACK: assumes startpos

      board_from_fen(SearchInput->board,StartFen);
   }

   // moves

   if (moves != NULL) { // "moves" present

      ptr = moves + 6;

      while (*ptr != '\0') {

         move_string[0] = *ptr++;
         move_string[1] = *ptr++;
         move_string[2] = *ptr++;
         move_string[3] = *ptr++;

         if (*ptr == '\0' || *ptr == ' ') {
            move_string[4] = '\0';
         } else { // promote
            move_string[4] = *ptr++;
            move_string[5] = '\0';
         }

         move = move_from_string(move_string,SearchInput->board);

         move_do(SearchInput->board,move,undo);

         while (*ptr == ' ') ptr++;
      }
   }
}

// parse_setoption()

static void parse_setoption(char string[]) {

   const char * name;
   char * value;

   // init

   name = strstr(string,"name ");
   value = strstr(string,"value ");

   if (name == NULL || value == NULL || name >= value) return; // ignore buttons

   value[-1] = '\0'; // HACK
   name += 5;
   value += 6;

   // update

   option_set(name,value);

   // update transposition-table size if needed

   if (Init && my_string_equal(name,"Hash")) { // Init => already allocated

      ASSERT(!Searching);

      if (option_get_int("Hash") >= 4) {
         trans_free(Trans);
         trans_alloc(Trans);
      }
   }
}

// send_best_move()

static void send_best_move() {

   double time, speed, cpu;
   sint64 node_nb;
   char move_string[256];
   char ponder_string[256];
   int move;
   mv_t * pv;

   // info

   // HACK: should be in search.cpp

   time = SearchCurrent->time;
   speed = SearchCurrent->speed;
   cpu = SearchCurrent->cpu;
   node_nb = SearchCurrent->node_nb;

   send("info time %.0f nodes " S64_FORMAT " nps %.0f cpuload %.0f",time*1000.0,node_nb,speed,cpu*1000.0);

   trans_stats(Trans);
   // pawn_stats();
   // material_stats();

   // best move

   move = SearchBest->move;
   pv = SearchBest->pv;

   move_to_string(move,move_string,256);

   if (pv[0] == move && move_is_ok(pv[1])) {
      move_to_string(pv[1],ponder_string,256);
      send("bestmove %s ponder %s",move_string,ponder_string);
   } else {
      send("bestmove %s",move_string);
   }
}

// get()

void get(char string[], int size) {

   ASSERT(string!=NULL);
   ASSERT(size>=65536);

   if (!my_file_read_line(pipefd_a2e_0_stream,string,size)) { // EOF
      exit(EXIT_SUCCESS);
   }
}

// send()

void send(const char format[], ...) {

   va_list arg_list;
   char string[4096];

   ASSERT(format!=NULL);

   va_start(arg_list,format);
   vsprintf(string,format,arg_list);
   va_end(arg_list);

   fprintf(pipefd_e2a_1_stream,"%s\n",string);
}

// string_equal()

static bool string_equal(const char s1[], const char s2[]) {

   ASSERT(s1!=NULL);
   ASSERT(s2!=NULL);

   return strcmp(s1,s2) == 0;
}

// string_start_with()

static bool string_start_with(const char s1[], const char s2[]) {

   ASSERT(s1!=NULL);
   ASSERT(s2!=NULL);

   return strstr(s1,s2) == s1;
}

}  // namespace engine

// end of protocol.cpp

