/****************************
 * evaluate() function decides if given position is terminal (checkmate,
 * stalemate, ...) , if not, seeks it in the hash table, if not
 * present, calls dynamic (search()) or static (static_eval()) evaluation.
 * This also handles extensions.
 ******************/

#include "phalanx.h"

#define EXTENSION_BASE 80

#define NULL_MOVE_PRUNING

#define RECAPTURE_EXTENSIONS
#define PEE_EXTENSIONS     /* entering kings+pawns endgame extends */
#define CHECK_EXTENSIONS
#define PAWNPUSH_EXTENSIONS

#define minmv (P_VALUE)

/* 12 moves to draw: the static evaluation goes to zero */
#define RULE_50_CLOSE 24

/**
***   Phalanx uses very simple implementation of static-eval cache.
***   It eats 512 kB and makes it about 10% faster on a 486.
**/
#undef CACHE
#ifdef CACHE
unsigned * C; /* 64k entries of 4 bytes: 256kB */
#endif



void initcache(void)
{
#ifdef CACHE
C = malloc(0x10000*sizeof(unsigned)); /* 64k entries of 8 bytes: 512kB */
if( C==NULL ) { puts("cannot alloc static eval cache!"); exit(0); }
#endif
}


tsearchnode S[MAXPLY];

static inline int approx_eval(void)
{
S[Ply].psnl = - S[Ply-1].psnl;

S[Ply].devi = S[Ply-1].devi*2/3 + abs(S[Ply].psnl)/8;
if( G[Counter-1].m.in2 ) S[Ply].devi += 60; else S[Ply].devi += 40;

/* pawn promotions should mostly trigger full static eval in the child node,
 * and avoid the lazy one, otherwise the engine delays promotions due to
 * the high bonus for the pawn on the 7th row. */
if(
	( G[Counter-1].m.in1 == WP && G[Counter-1].m.to >= A7 )
	||
	( G[Counter-1].m.in1 == BP && G[Counter-1].m.to <= H2 )
  )
	S[Ply].devi += 3*P_VALUE;

return G[Counter].mtrl - G[Counter].xmtrl + S[Ply].psnl;
}



int static_eval(void)
{

int positional;
int r50 = 100 - G[Counter].rule50;
int material = G[Counter].mtrl-G[Counter].xmtrl;

#ifdef CACHE
if( ( ( C[ 0x0000FFFF & G[Counter].hashboard ] ^ G[Counter].hashboard )
    & 0xFFFF0000 ) == 0 )
{
unsigned * cc = C + ( 0x0000FFFF & G[Counter].hashboard );
Wknow.prune = (((*cc)&0x00004FFF)!=0);
Bknow.prune = (((*cc)&0x00008FFF)!=0);
return ( (*cc) & 0x00003FFF ) ;
}
#endif

positional = score_position();

if( r50 < RULE_50_CLOSE )
{ positional = positional * r50 / RULE_50_CLOSE;
  material = material * r50 / RULE_50_CLOSE;
}

#undef RAISE
#ifdef RAISE
/* Inbalanced material: take positional bonus seriously */
if( abs(material) > 200 )
{
	int m = abs(material) - 200;
	if( m > 1000 ) m=1000;
#ifdef SCORING
	if( Scoring )
		printf(
		" (   ) inbalanced material, positional raised: %i -> %i\n",
		positional, positional + positional*m/500 );
#endif
	positional =        positional + positional*m/500;
}
#endif

#ifdef CACHE
{
unsigned * cc = C + ( 0x0000FFFF & G[Counter].hashboard );
*cc = ( 0xFFFF0000 & G[Counter].hashboard ) | ( material+positional );
if( Wknow.prune ) *cc |= 0x00004000; else *cc &= (0xFFFFFFFF-0x00004000);
if( Bknow.prune ) *cc |= 0x00008000; else *cc &= (0xFFFFFFFF-0x00008000);
}
#endif

S[Ply].psnl = positional;
S[Ply].devi = 0;

#undef debug
#ifdef debug
if(abs(positional)>600)
{ Scoring = 1; score_position(); Scoring = 0;
  printboard(); printf("[%i,%i,%i]",material,positional,score_position());
  getchar();
}
#endif

return material+positional;

}



inline int repetition( int n )
{
	int i;
	int r=0;
	unsigned board = G[Counter].hashboard;
	for( i=Counter-2; i>=0; i-=2 )
	{
		if( G[i].hashboard == board ) if( ++r == n ) return 1;
		if( G[i].rule50 <= 1 ) break;
	}
	return 0;
}



int material_draw( void )
{
	int i, n=2;

	for( i=L[WKP].next; i!=0; i=L[i].next )
	switch( B[i] )
	{	case WQ: case WR: case WP: return 0;
		default: n--; if( n==0 ) return 0;
	}

	for( i=L[BKP].next; i!=0; i=L[i].next )
	switch( B[i] )
	{	case BQ: case BR: case BP: return 0;
		default: n--; if( n==0 ) return 0;
	}

	return 1;
}



/*****************************************************************/

int evaluate( int Alpha, int Beta )
{

static int timeslice = 2000;
static int polslice = 4000;
int result;
tmove m[256]; int n;  /* moves and number of moves */
thashentry *t;
int check;
int lastiter;
int totmat = Totmat = G[Counter].mtrl+G[Counter].xmtrl;

if(Ply%2) lastiter = -LastIter; else lastiter = LastIter;

Nodes++;

if( Flag.level == fixedtime || Flag.level == timecontrol )
if( ( Nodes % timeslice ) == 0 && !Flag.analyze )
{
	extern long T1;
	int t = Flag.centiseconds - ptime() + T1;

	if( t < 0 ) { if( Flag.ponder >= 2 ) Flag.ponder = 3; else Abort = 2; }
	else
	if( t != Flag.centiseconds )
	timeslice =
	  Nodes * t / ( Flag.centiseconds - t ) * 2 / 3;

	if( timeslice > 5*Flag.centiseconds ) timeslice = 5*Flag.centiseconds;
	if( timeslice < 50 ) timeslice=50;
}

{
	static int64 lnodes = 0;
	if( lnodes + polslice < Nodes || Nodes == 1 )
	{
		static long lptime = 0;
		long nptime = ptime();

		if( nptime == lptime ) nptime++;

		if( nptime - lptime < 100 ) polslice = polslice*11/10;
		else { polslice = polslice*10/11; }

		lptime = nptime;

		if( Flag.post && !Flag.xboard ) verboseline();

if(Flag.polling)
{

#if defined(__GNUC__) && !defined(__MINGW32__)
  static fd_set readfds;
  static struct timeval tv;
  int data;

  FD_ZERO (&readfds);
  FD_SET (fileno(stdin), &readfds);
  tv.tv_sec=0;
  tv.tv_usec=0;
  select(16, &readfds, 0, 0, &tv);
  data=FD_ISSET(fileno(stdin), &readfds);
  if(data)
  {
	if(polslice<8000 || Flag.analyze) polslice=4000; else polslice/=2;
	interrupt(0);
  }

#else

 /* Credit here goes to Dr Oliver Brausch for the code from his
  * program Olithink.  Some rewriting has been done by CMF, but not much
  * as I have absolutely no idea whatsoever what this does.
  * I think the original code is from Crafty by Prof. Robert Hyatt. [JA] */

  static int init = 0, pipe;
  static HANDLE inh;
  DWORD dw;

  /* If we're running under XBoard then we can't use _kbhit() as the input commands
   * are sent to us directly over the internal pipe */
  if (Flag.xboard>0) {
#if defined(FILE_CNT)
    if (stdin->_cnt > 0) return stdin->_cnt;
#endif
    if (!init) {
      init = 1;
      inh = GetStdHandle(STD_INPUT_HANDLE);
      pipe = !GetConsoleMode(inh, &dw);
      if (!pipe) {
        SetConsoleMode(inh, dw & ~(ENABLE_MOUSE_INPUT | ENABLE_WINDOW_INPUT));
        FlushConsoleInputBuffer(inh);
      }
    }
    if (pipe) {
      if (!PeekNamedPipe(inh, NULL, 0, NULL, &dw, NULL)) return 1;
      return dw;
    }
    else {
      GetNumberOfConsoleInputEvents(inh, &dw);
      return dw <= 1 ? 0 : dw;
    }
  }
  else return _kbhit();

#endif

}

/*
		if( Flag.analyze )
		printf("stat01: %d %d %d %d %d\n",0,Nodes,A_d,A_i,A_n);
*/

		lnodes = Nodes;
	}
}

if( Ply >= MAXPLY-2 )
{ PV[Ply][Ply].from=0; return G[Counter].mtrl-G[Counter].xmtrl; }

if( G[Counter].rule50 >= 100 ) /* 50 moves draw */
{ PV[Ply][Ply].from=0; return DRAW; }

/* insufficient material draw */
if( G[Counter].mtrl<400 && G[Counter].mtrl<400 )
if( material_draw() )
{ PV[Ply][Ply].from=0; return DRAW; }

if( G[Counter].rule50 >= 3 )
if( repetition(1) ) /* third rep. draw */
{
	int j;
	int ext=0;
	PV[Ply][Ply].from=0;

	for( j=Counter-1; j>Counter-Ply; j-=2 )
	{ ext += G[j-1].m.dch - G[j].m.dch; }

	if( ext > 0 )
	{
		if( ext > 500 ) ext=500;
		ext += Ply*20;
	}
	else if( ext < 0 )
	{
		if( ext < -500 ) ext=-500;
		ext -= Ply*20;
	}

	/* Speculative drawscore
	 * Human players sometimes play a wild sacrifice leading to unclear
	 * lines, making sure they could achieve a repetition draw at least.
	 * This is the same speculative heuristics:
	 * Repetition draw is scored as a slight advantage to the side that
	 * forced the repetition, ie. that had less extensions in the path,
	 * that's why we count the cumulative extension above. The deeper
	 * in the tree this happens, the higher speculative bonus we give,
	 * that is the Ply*20 above. However, if the remaining Depth is large,
	 * we pull the score back closer to the DRAW score, because with
	 * the larger Depth we should be able to find something better
	 * than draw.
	 */
	return DRAW + ext/(15+max(-5,Depth/10));
}

/********************************************************************
 *     Now it is time to look into the hashtable.
 ********************************************************************/
if( SizeHT == 0 || Depth<0 ) t = NULL;
else
if( (t=seekHT()) != NULL )
if( Age == t->age || Beta-Alpha == 1 )
if( t->depth >= Depth || ( Depth<300 && abs(t->value)>CHECKMATE-1000 ) )
{
	int val = t->value;
	if( val > CHECKMATE-1000 ) val -= Ply;
	else if( val < -CHECKMATE+1000 ) val += Ply;

	switch( t->result )
	{
	case no_cut:                    /* `true value', good_score */
		PV[Ply][Ply].from=0; return val;
	break;
	case alpha_cut:                 /* `this or less', failed_low */
		if( val <= Alpha ) { PV[Ply][Ply].from=0; return Alpha; }
	break;
	case beta_cut:                  /* `this or more', failed_high */
		if( val >= Beta ) { PV[Ply][Ply].from=0; return Beta; }
	break;
	}
}
/***** End of hashtable stuff *****/

#undef nodef
#ifdef nodef
{
static int64 int good=0, all=0;
if( t!=NULL && t->move!=0 ) good++;
all++;
if( all%100000 == 0 && all!=0 )
printf("hit percentage = %lld.%02lld%%\n",good*100/all,good*10000/all%100);
}
#endif

if( Ply<2 )	/* called from rootsearch() */
	S[Ply].check = check = checktest(Color);
else		/* called from search() and the checktest() has been run */
	check = S[Ply].check;

if( Depth>0 || check )
{

	if(Depth<=0) result = approx_eval();
	else         result = static_eval();

#define FORWARD_PRUNING
#ifdef  FORWARD_PRUNING
/*
 * A simple forward pruning:
 * The Depth is low and the static evaluation is over [Alpha plus margin]
 * Our king is safe (khung<limit) and we don't have much hung material.
 * Let's lift Alpha and prune if it gets >= Beta.
 * This works quite fine for larger Depths than 200 (2 plies) as well, 
 * tested with limit 600 on a set of positions and it's still finding
 * everything and in a shorter time, but I'm keeping the depth limit
 * conservative for now.
 * This is similar to what the old Phalanx XXII had, except now
 * we use the margin.
 */
	if(	!check
		&& Depth < 200
		&& (	Color==WHITE
			?
			( Wknow.hung<14 && Wknow.khung<6 )
			:
			( Bknow.hung<14 && Bknow.khung<6 )
		   )
	  )
	{
		int r = result - (P_VALUE+Depth)/10;
		if( r>=Beta ) { PV[Ply][Ply].from=0; return Beta; }
		if( r>Alpha ) Alpha=r;
	}
#endif /* FORWARD_PRUNING */


/*
if(    Depth<1500 && Depth>0
    && Beta-Alpha==1 && !check
    && result < Beta-P_VALUE-Depth )
{
	generate_legal_checks(m,&n);
	if( n==0 ) { result=Alpha; goto end; }
}
else
*/
	generate_legal_moves(m,&n,check);

	/** Return, if there is no legal move - checkmate or stalemate **/
	if(n==0)
	{
		PV[Ply][Ply].from=0;
		if(check) return Ply-CHECKMATE;
		else return DRAW;
	}

#ifdef NULL_MOVE_PRUNING
	if(
		Depth > 100
		&& ( result >= Beta || Depth > 350 )
		&& ! FollowPV
		&& ! check
		&& n>4
		&& ( (Color==WHITE) ? (Wknow.q||Wknow.r||Wknow.b||Wknow.n>1)
		                    : (Bknow.q||Bknow.r||Bknow.b||Bknow.n>1) )
		&& G[Counter-1].m.special != NULL_MOVE  /* prev. node not nm */
		&& ( t==NULL || t->depth <= Depth-350
		  || t->result==beta_cut || t->value >= Beta )
	)
	{
		int value;
		int olddepth = Depth;

		G[Counter].m.in1 = 0; /* disable en passant */
		G[Counter].m.special = NULL_MOVE;
		G[Counter].m.to = 2;
		Counter ++; Ply ++;
		G[Counter].castling = G[Counter-1].castling;
		G[Counter].rule50 = G[Counter-1].rule50 + 1;
		G[Counter].hashboard =
			HASH_COLOR ^ G[Counter-1].hashboard;
		G[Counter].mtrl = G[Counter-1].xmtrl;
		G[Counter].xmtrl = G[Counter-1].mtrl;
		Color = enemy(Color);
		S[Ply].check=0;

		/* reduction depends on number of moves generated */
		/* n=20 ... R=2, n=40 ... R=3, n=50 ... R=3.5 */
		Depth -= 200 + n*5;

		if(Depth<0) Depth=0; else Depth -= Depth/4;
		value = -evaluate(-Beta, -Beta+1);

		Color = enemy(Color);
		Counter --; Ply --;
		Depth = olddepth;
		Totmat = totmat;

		if( value >= Beta ) { result = Beta; goto end; }
	}
#endif

#define PROBCUT
#ifdef PROBCUT
#define MRGN 190
/*
 *  If we have a capture that can get us above Beta+MRGN, we try to
 *  search the capturing move at a reduced depth and with raised Beta.
 *  If we then get a fail high, the previous opponent move was likely
 *  a blunder and we can prune this node.
 *  This is complementary to null move pruning. Null move can prune many
 *  weak moves, but not those that create a threat, e.g. unprotected rook
 *  attacks queen - null move allows capturing the queen and thus cannot
 *  prune the silly attack, whereas in ProbCut queen captures the rook,
 *  confirms with the reduced search that the previous opponent move
 *  was a blunder and prunes.
 */

if( Depth>350 && Beta-Alpha==1 && !check )
{
	int i;
	int r = Alpha;
	int olddepth = Depth;

	Depth-= 350;

	for( i=0; i!=n; i++ )
	if( m[i].in2 && result+Values[m[i].in2>>4] >= Beta+MRGN )
	{
		do_move(m+i); S[Ply].check=checktest(Color);
		r = - evaluate( -Beta-MRGN, -Beta-MRGN+1 );
		undo_move(m+i);
		if( r>=Beta+MRGN ) break;
	}
	Depth = olddepth;

	if( r>= Beta+MRGN ) { result = Beta; goto end; }
}

#endif /* PROBCUT */

#ifdef CHECK_EXTENSIONS
	if( check && Depth>0 )
	{
		int newdch, i;

		/* We compute the extension from the depth remaining (Depth)
		 * and number of legal moves available (n) */
		newdch =
			   EXTENSION_BASE - 20
			 - 3000/(Depth+100) /* 30..0 */
			 - 200/(n*(n+1)); /* 1~100,2~33,3~16,..0 */

		if( result<=lastiter-50 || result <= -250 )  /* losing anyway */
			newdch = (newdch+100)/2; /* smaller extension, 50% */

		for( i=0; i!=n; i++ )
			if( m[i].in2 ) m[i].dch = (newdch+100)/2; /* capture */
			else m[i].dch = newdch;
	}
#endif

#ifdef PAWNPUSH_EXTENSIONS
	if( Totmat < 4000 )
	if(result<lastiter+50 && result<250)  /* winning anyway: dont extend */
	{
		int i;
		for( i=0; i!=n; i++ )
		if( piece(m[i].in2a) == PAWN
		 && m[i].special == 0
		 && ( ( Color==WHITE && m[i].to >= A6 )
		   || ( Color==BLACK && m[i].to <= H3 ) ) )
		{
			int j;
			int support=0;
			int newdch=EXTENSION_BASE;

			if( Color == WHITE )
			{

				for( j=m[i].to+10; j<=H7; j+=10 )
				if( B[j-1]==BP
				 || B[j]==BP
				 || B[j+1]==BP )
				goto no_push_extension;

				for( j=m[i].to; j<=H8; j+=10 )
				{
					if( B[j] ) support--;
					if( see(B,m[i].from,j) < 0 )
						support--;
					else	support++;
				}
			}
			else
			{
				for( j=m[i].to-10; j>=A2; j-=10 )
				if( B[j-1]==WP
				 || B[j]==WP
				 || B[j+1]==WP )
				goto no_push_extension;

				for( j=m[i].to; j>=A1; j-=10 )
				{
					if( B[j] ) support--;
					if( see(B,m[i].from,j) < 0 )
						support--;
					else	support++;
				}
			}

			newdch += Depth/20 + Totmat/100 - 30*support;

			switch( m[i].to/10 )
			{ case 8: case 3:
			  if(support>0) newdch -= 20*support+10; break; }

			if( newdch < m[i].dch )
			{ m[i].dch = newdch; }

			no_push_extension:;
		}
	}
#endif

#ifdef RECAPTURE_EXTENSIONS
	if( Depth>0 && G[Counter-1].m.in2 )
	if( result<lastiter+50 && result<250 )   /* winning anyway: dont */
	{
		int i, t=G[Counter-1].m.to;
		int v1 = Values[ G[Counter-1].m.in1 >> 4 ];
		int v2 = Values[ G[Counter-1].m.in2 >> 4 ];
		int newdch;

		if( Depth <= 200 )
			newdch = EXTENSION_BASE-30;
		else
			newdch = EXTENSION_BASE-20;

		if( min(v1,v2) > 400 || G[Counter].mtrl < Q_VALUE )
			newdch -= 70;
		else
		if( min(v1,v2) > 200 || G[Counter].mtrl < (Q_VALUE+N_VALUE) )
			newdch -= 45;

		/* recaptures depth bonus */
		for( i=0; i!=n; i++ )
		if( m[i].to == t )
		if( m[i].dch > newdch )
/*		if( Depth<=100 || see(B,m[i].from,m[i].to) >= v1 ) */
			m[i].dch = newdch;
	}
#endif

#ifdef PEE_EXTENSIONS
	if( Depth > 200
	 && G[Counter].mtrl <= (8*P_VALUE)
	 && G[Counter].xmtrl <= (8*P_VALUE+Q_VALUE)
	 && G[Counter-1].m.in2 > KNIGHT )
	{
		int i;
		int target=0;
		int cdch;

		for( i=L[L[Color].next].next; i!=0; i=L[i].next )
		if( B[i] >= KNIGHT ) goto nopee;

		for( i=L[L[enemy(Color)].next].next; i!=0; i=L[i].next )
		if( B[i] >= KNIGHT )
		{ if( target ) goto nopee; else target=i; }

		if( ! target ) goto nopee;

		if( G[Counter-1].m.in2 >= QUEEN ) cdch = min(Depth,450);
		else cdch = min(Depth*2/3,350);

		for( i=0; i!=n; i++ )
		if( m[i].to == target )
		{ m[i].dch -= cdch;
		  /* printboard(NULL); printm(m[i],NULL); getchar(); */ }

		nopee:;
	}
#endif

#ifdef ETTC
if( Depth > 200 && SizeHT != 0 )
{
	extern void do_hash(tmove *), undo_hash(tmove *);

	int i;
	for( i=0; i!=n; i++ )
	{
		thashentry *t;
		do_hash(m+i);

		if( (t=seekHT()) != NULL )
		if( t->depth >= Depth )
		if( t->result != beta_cut )
		{
			int val = -t->value;
			if( val > CHECKMATE-100 ) val -= Ply;
			else if( val < -CHECKMATE+100 ) val += Ply;

			if( val > Alpha )
			{
				if( val >= Beta )
				{
					undo_hash(m+i);
					G[Counter].m = m[i];
					PV[Ply][Ply] = m[i];
					PV[Ply][Ply+1].from = 0;
					result = Beta; goto end;
				}
				Alpha=val;
			}
		}
		undo_hash(m+i);
	}
}
#endif

}
else
{	/*** Quiescence search ***/

	result = approx_eval();

	if( ( result < Beta+S[Ply].devi && result > Alpha-S[Ply].devi )
	 || Totmat<=(B_VALUE+P_VALUE) || Ply<2 )
	result = static_eval();

	if( result >= Beta ) return result;

	if( result <= Alpha-(Q_VALUE+minmv) && Depth <= -100 )
	{ return Alpha; }

#ifdef QCAPSONLY
	generate_legal_captures(m,&n,Alpha-result-minmv);
#else
	/* What to generate? Only captures or also safe checks? */
	if(    G[Counter].mtrl-G[Counter].xmtrl < 400
	    && Depth > -100
	)
		generate_legal_checks(m,&n);
	else
		generate_legal_captures(m,&n,Alpha-result-minmv);
#endif
}

/*** Compute heuristic values of moves ***/
add_killer( m, n, t );

PV[Ply][Ply].from = 0;

if( Flag.nps )
{
	if( Flag.easy )
	{ if( n>10 && Flag.easy<=100 ) blunder(m,&n); }

	/* timecontrol fix */
	if( polslice > Flag.easy+200 ) polslice=Flag.easy+200;

	/* Now limit the NPS, lowest value is 100.
	 * For higher values of nps levels like 50000 nps, there's no need
	 * to check for the limit and call ptime() at every node,
	 * hence the condition below */
	if( Nodes%(1+Flag.nps/500)==0 )
	{
		int nps_actual = Nodes*100/max(ptime()-T1,1);
		if( nps_actual > Flag.nps && !Abort ) usleep(100000);
	}
}

/*** Full-width search ***/
if( Depth>0 || check )
{
	result = search(m,n,Alpha,Beta);
}
else /*** Quiescence ***/
{
	if( result > Alpha )
		result = search(m,n,result,Beta);
	else
		result = search(m,n,Alpha,Beta);
}

end:

if( result>=Beta && Depth>0 )
	write_killer( G[Counter].m.from, G[Counter].m.to );

if( SizeHT != 0 && Depth >= 0 && Abort == 0 ) writeHT( result, Alpha, Beta );

/**
***    Check learning file.
***    This should be done before search.  It is here only for
***    timing heuristics stability problem that needs better
***    solution.
**/
if( Depth > 300 && Flag.learn )
if( Depth > 400 || Ply<3 )
{
	int lresult = rlearn();
	if( lresult != NOVALUE )
	{ PV[Ply][Ply].from=0;
	  if( lresult > CHECKMATE-1000 )  lresult -= Ply;
	  if( lresult < -CHECKMATE+1000 ) lresult += Ply;
	  result = lresult;
	}
}

return result;

}