/* algcheck.c
 *
 */

/*
    fics - An internet chess server.
    Copyright (C) 1993  Richard V. Nash

    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 2 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.
*/

/* Revision history:
   name		email		yy/mm/dd	Change
   Richard Nash	              	93/10/22	Created
*/

#include "stdinclude.h"
#include "common.h"

#include "algcheck.h"
#include "board.h"
#include "movecheck.h"
#include "utils.h"

/* Well, lets see if I can list the possibilities
 * Piece moves
 * Ne4
 * Nxe4
 * Nce4
 * Ncxe4
 * R2f3
 * R2xf3
 * Special pawn moves
 * e4
 * ed
 * exd
 * exd5
 * ed5
 * Drop moves (bughouse, board edit)
 * P@f7 P*f7
 * #f7 #Nf7
 * (o-o, o-o-o) Castling is handled earlier, so don't worry about that
 * Of course any of these can have a + or ++ or = string on the end, just
 * cut that off.
 */

/* f - file
 * r - rank
 * p - piece
 * x - x
 * @ - drop character (bughouse)
 */
char *alg_list[] = {
  "fxfr", "pxfr",		/* These two get confused in case of bishop */
  "ffr", "pfr",			/* These two get confused in case of bishop */
  "pffr",
  "pfxfr",
  "prfr",
  "prxfr",
  "fr",
  "ff",
  "fxf",
  "p@fr",
  "#fr",
  "#pfr",
  NULL
};

#define ALG_UNKNOWN -1
/* #define ALG_DROP    -2	IanO: this is in board.h, used in movecheck.c */

PRIVATE int get_move_info(char *str, int *piece, int *ff, int *fr, int *tf, int *tr, int *bishconfusion)
{
  char tmp[1024];
  char *s;
  int i, j, len;
  char c;
  int matchVal = -1;
  int lpiece, lff, lfr, ltf, ltr;

  *bishconfusion = 0;
  strcpy(tmp, str);
  if ((s = index(tmp, '+'))) {	/* Cut off any check marks */
    *s = '\0';
  }
  if ((s = index(tmp, '='))) {	/* Cut off any promotion marks */
    *s = '\0';
  }
  *piece = *ff = *fr = *tf = *tr = ALG_UNKNOWN;
  len = strlen(tmp);
  for (i = 0; alg_list[i]; i++) {
    lpiece = lff = lfr = ltf = ltr = ALG_UNKNOWN;
    if (strlen(alg_list[i]) != len)
      continue;
    for (j = len - 1; j >= 0; j--) {
      switch (alg_list[i][j]) {
      case 'f':
	if ((tmp[j] < 'a') || (tmp[j] > 'h'))
	  goto nomatch;
	if (ltf == ALG_UNKNOWN)
	  ltf = tmp[j] - 'a';
	else
	  lff = tmp[j] - 'a';
	break;
      case 'r':
	if ((tmp[j] < '1') || (tmp[j] > '8'))
	  goto nomatch;
	if (ltr == ALG_UNKNOWN)
	  ltr = tmp[j] - '1';
	else
	  lfr = tmp[j] - '1';
	break;
      case 'p':
	if (isupper(tmp[j]))
	  c = tolower(tmp[j]);
	else
	  c = tmp[j];
	if (c == 'k')
	  lpiece = KING;
	else if (c == 'q')
	  lpiece = QUEEN;
	else if (c == 'r')
	  lpiece = ROOK;
	else if (c == 'b')
	  lpiece = BISHOP;
	else if (c == 'n')
	  lpiece = KNIGHT;
	else if (c == 'p')
	  lpiece = PAWN;
	else
	  goto nomatch;
	break;
      case 'x':
	if ((tmp[j] != 'x') && (tmp[j] != 'X'))
	  goto nomatch;
	break;
      case '@':
	if (tmp[j] != '@' && tmp[j] != '*')
	  goto nomatch;
	lff = lfr = ALG_DROP;
	break;
      case '#':
	if (tmp[j] != '#')
	  goto nomatch;
	lff = lfr = ALG_DROP;
	break;
      default:
	fprintf(stderr, "Unknown character in algebraic parsing\n");
	break;
      }
    }
    if (lpiece == ALG_UNKNOWN)
      lpiece = PAWN;
    if (lpiece == PAWN && (lfr == ALG_UNKNOWN)) {	/* ffr or ff */
      if (lff != ALG_UNKNOWN) {
	if (lff == ltf)
	  goto nomatch;
	if ((lff - ltf != 1) && (ltf - lff != 1))
	  goto nomatch;
      }
    }
    *piece = lpiece;		/* We have a match */
    *tf = ltf;
    *tr = ltr;
    *ff = lff;
    *fr = lfr;
    if (matchVal != -1) {
      /* We have two matches, it must be that Bxc4 vs. bxc4 problem */
      /* Or it could be the Bc4 vs bc4 problem */
      *bishconfusion = 1;
    }
    matchVal = i;
nomatch:;
  }
  if (matchVal != -1)
    return MS_ALG;
  else
    return MS_NOTMOVE;
}

PUBLIC int alg_is_move(char *mstr)
{
  int piece, ff, fr, tf, tr, bc;

  return get_move_info(mstr, &piece, &ff, &fr, &tf, &tr, &bc);
}

/* We already know it is algebraic, get the move squares */
PUBLIC int alg_parse_move(char *mstr, game_state_t * gs, move_t * mt)
{
  int f, r, tmpr, posf, posr, posr2;
  int piece, ff, fr, tf, tr, bc;

  if (get_move_info(mstr, &piece, &ff, &fr, &tf, &tr, &bc) != MS_ALG) {
    fprintf(stderr, "FICS: Shouldn't try to algebraicly parse non-algabraic move string.\n");
    return MOVE_ILLEGAL;
  }
  /* Resolve ambiguities in to-ness */
  if (tf == ALG_UNKNOWN)
    return MOVE_AMBIGUOUS;	/* Must always know to file */
  if (tr == ALG_UNKNOWN) {
    posr = posr2 = ALG_UNKNOWN;
    if (piece != PAWN)
      return MOVE_AMBIGUOUS;
    if (ff == ALG_UNKNOWN)
      return MOVE_AMBIGUOUS;
    /* Need to find pawn on ff that can take to tf and fill in ranks */
    for (InitPieceLoop(gs->board, &f, &r, gs->onMove);
	 NextPieceLoop(gs->board, &f, &r, gs->onMove);) {
      if ((ff != ALG_UNKNOWN) && (ff != f))
	continue;
      if (piecetype(gs->board[f][r]) != piece)
	continue;
      if (gs->onMove == WHITE) {
	tmpr = r + 1;
      } else {
	tmpr = r - 1;
      }
/*      if ((gs->board[tf][tmpr] == NOPIECE) ||
          (iscolor(gs->board[tf][tmpr], gs->onMove))) continue;*/
/* patch from Soso, added by Sparky 3/16/95                    */
      if (gs->board[tf][tmpr] == NOPIECE) {
	if ((gs->ep_possible[((gs->onMove == WHITE) ? 0 : 1)][ff]) != (tf - ff))
	  continue;
      } else {
	if (iscolor(gs->board[tf][tmpr], gs->onMove))
	  continue;
      }

      if (legal_andcheck_move(gs, f, r, tf, tmpr)) {
	if ((posr != ALG_UNKNOWN) && (posr2 != ALG_UNKNOWN))
	  return MOVE_AMBIGUOUS;
	posr = tmpr;
	posr2 = r;
      }
    }
    tr = posr;
    fr = posr2;
  } else if (bc) {		/* Could be bxc4 or Bxc4, tr is known */
    ff = ALG_UNKNOWN;
    fr = ALG_UNKNOWN;
    for (InitPieceLoop(gs->board, &f, &r, gs->onMove);
	 NextPieceLoop(gs->board, &f, &r, gs->onMove);) {
      if ((piecetype(gs->board[f][r]) != PAWN) && (piecetype(gs->board[f][r]) != BISHOP))
	continue;
      if (legal_andcheck_move(gs, f, r, tf, tr)) {
	if ((piecetype(gs->board[f][r]) == PAWN) && (f != 1))
	  continue;
	if ((ff != ALG_UNKNOWN) && (fr != ALG_UNKNOWN))
	  return (MOVE_AMBIGUOUS);
	ff = f;
	fr = r;
      }
    }
  } else {			/* The from position is unknown */
    posf = ALG_UNKNOWN;
    posr = ALG_UNKNOWN;
    if ((ff == ALG_UNKNOWN) || (fr == ALG_UNKNOWN)) {
      /* Need to find a piece that can go to tf, tr */
      for (InitPieceLoop(gs->board, &f, &r, gs->onMove);
	   NextPieceLoop(gs->board, &f, &r, gs->onMove);) {
	if ((ff != ALG_UNKNOWN) && (ff != f))
	  continue;
	if ((fr != ALG_UNKNOWN) && (fr != r))
	  continue;
	if (piecetype(gs->board[f][r]) != piece)
	  continue;
	if (legal_andcheck_move(gs, f, r, tf, tr)) {
	  if ((posf != ALG_UNKNOWN) && (posr != ALG_UNKNOWN))
	    return MOVE_AMBIGUOUS;
	  posf = f;
	  posr = r;
	}
      }
    } else if (ff == ALG_DROP) {
      if (legal_andcheck_move(gs, ALG_DROP, piece, tf, tr)) {
	posf = ALG_DROP;
	posr = piece;
      }
    }
    ff = posf;
    fr = posr;
  }
  if ((tf == ALG_UNKNOWN) || (tr == ALG_UNKNOWN) ||
      (ff == ALG_UNKNOWN) || (fr == ALG_UNKNOWN))
    return MOVE_ILLEGAL;
  mt->fromFile = ff;
  mt->fromRank = fr;
  mt->toFile = tf;
  mt->toRank = tr;
  return MOVE_OK;
}

/*
 * Soso: rewrote alg_unparse function.  Algebraic deparser - sets the
 * 'mStr' variable with move description in short notation. Used in
 * last move report and in 'moves' command.
 */
PUBLIC char *
alg_unparse(game_state_t *gs, move_t *mt)
{
	char		tmp[20] = { '\0' };
	game_state_t	fakeMove;
	int		ambig, r_ambig, f_ambig;
	int		piece, f, r;
	static char	mStr[20] = { '\0' };

	if (mt->fromFile == ALG_DROP) {
		piece = mt->fromRank;
	} else {
		piece = piecetype(gs->board[mt->fromFile][mt->fromRank]);
	}

	if (piece == KING && (mt->fromFile == 4 && mt->toFile == 6)) {
		strcpy(mStr, "O-O");
		goto check;
	}

	if (piece == KING && (mt->fromFile == 4 && mt->toFile == 2)) {
		strcpy(mStr, "O-O-O");
		goto check;
	}

	strcpy(mStr, "");

	switch (piece) {
	case PAWN:
		if (mt->fromFile == ALG_DROP) {
			strcpy(mStr,"P");
		} else if (mt->fromFile != mt->toFile) {
			sprintf(tmp, "%c", (mt->fromFile + 'a'));
			strcpy(mStr, tmp);
		}
		break;
	case KNIGHT:
		strcpy(mStr, "N");
		break;
	case BISHOP:
		strcpy(mStr, "B");
		break;
	case ROOK:
		strcpy(mStr, "R");
		break;
	case QUEEN:
		strcpy(mStr, "Q");
		break;
	case KING:
		strcpy(mStr, "K");
		break;
	default:
		strcpy(mStr, "");
		break;
	} /* switch */

	if (mt->fromFile == ALG_DROP) {
		strcat(mStr, DROP_STR);
	} else {
		/*
		 * Checks for ambiguity in short notation (Ncb3, R8e8
		 * or so.)
		 */

		if (piece != PAWN) {
			ambig = r_ambig = f_ambig = 0;

			for (r = 0; r < 8; r++) {
				for (f = 0; f < 8; f++) {
					if (gs->board[f][r] != NOPIECE &&
					    iscolor(gs->board[f][r], gs->onMove) &&
					    piecetype(gs->board[f][r]) == piece &&
					    (f != mt->fromFile ||
					    r != mt->fromRank)) {
						if (legal_move(gs, f, r,
						    mt->toFile, mt->toRank)) {
							fakeMove = *gs;
							fakeMove.board[f][r] =
							    NOPIECE;
							fakeMove.onMove =
							    CToggle(fakeMove.onMove);

							gs->onMove =
							    CToggle(gs->onMove);

							/*
							 * New
							 * bracketing
							 * below to
							 * try to fix
							 * 'ambiguous
							 * move' bug.
							 */
							if (in_check(gs) ||
							    !in_check(&fakeMove))
								ambig++;

							if (f == mt->fromFile) {
								f_ambig++;
								ambig++;
							}
							if (r == mt->fromRank) {
								r_ambig++;
								ambig++;
							}

							gs->onMove =
							    CToggle(gs->onMove);
						}
					}
				} /* for */
			} /* for */

			if (ambig > 0) {
				/*
				 * Ambiguity in short notation. need
				 * to add file, rank or _both_ in
				 * notation.
				 */

				if (f_ambig == 0) {
					sprintf(tmp, "%c",
					    (mt->fromFile + 'a'));
					strcat(mStr, tmp);
				} else if (r_ambig == 0) {
					sprintf(tmp, "%d", (mt->fromRank + 1));
					strcat(mStr, tmp);
				} else {
					sprintf(tmp, "%c%d",
					    (mt->fromFile + 'a'),
					    (mt->fromRank + 1));
					strcat(mStr, tmp);
				}
			}
		}

		if (gs->board[mt->toFile][mt->toRank] != NOPIECE ||
		    (piece == PAWN && mt->fromFile != mt->toFile))
			strcat(mStr, "x");
	}

	sprintf(tmp, "%c%d", mt->toFile + 'a', mt->toRank + 1);
	strcat(mStr, tmp);

	if (piece == PAWN && mt->piecePromotionTo != NOPIECE) {
		strcat(mStr, "="); /* = before promoting piece */

		switch (piecetype(mt->piecePromotionTo)) {
		case KNIGHT:
			strcat(mStr, "N");
			break;
		case BISHOP:
			strcat(mStr, "B");
			break;
		case ROOK:
			strcat(mStr, "R");
			break;
		case QUEEN:
			strcat(mStr, "Q");
			break;
		default:
			break;
		}
	}

  check:;

	fakeMove = *gs;
	execute_move(&fakeMove, mt, 0);
	fakeMove.onMove = CToggle(fakeMove.onMove);

	if (in_check(&fakeMove))
		strcat(mStr, "+");

	return mStr;
}