/* Formula program for FICS.  Written by Dave Herscovici
                                         (dhersco@math.nps.navy.mil)
			      Edited by DAV to include wild,non-std and untimed
				 lightning flags

   Operators allowed, in order of precedence:
      ! (not), - (unary),
      *, /,
      +, -,
      <, <=, =<, >, >=, =>, (<= and =< are equivalent, as are >= and =>)
      =, ==, !=, <>, (two ways of saying both equals and not equals)
      &, &&, (both "and")
      |, ||, (both "or").

   Parentheses () are also allowed, as is a pound sign '#' for comments.
   The program will divide by a fudge factor of .001 instead of 0.

   Variables allowed:
      time, inc, rating, myrating, rated, blitz, standard, lightning, registered,
      assesswin, assessdraw, assessloss, timeseal,
      ratingdiff = rating - myrating, private, wild, untimed, nonstandard,
      maxtime(n) = maximum time n moves will take (in seconds),
      mymaxtime(n) = same, but just count my time.
      f1, f2, f3, f4, f5, f6, f7, f8, f9.

   The code for translating blitz and standard variables may have to be
   redone.  F1 through f9 are user-defined formula variables.  They can
   be used to avoid having to retype your entire formula when you want
   to change one part of it, or to compensate for the lack of a 'mood'
   variable.

   For example:
      set f1 rated & time=5 & inc=0   # rated 5 minute games
      set f2 rating - myrating
      set f3 # this line is a random comment.
      set f4 f2>400   # I want a REAL fight

   Then you can type:
      set formula f1   # rated 5 min. games only
      set formula etime >= 10 & f2 > -100 # long games, decent competition
      set formula f1 & !f4
   or set formula f2 >= 0 | blitz
   depending on your mood.

   Further modifications could account for starting positions, time
   odds games, provisional or established opponents, etc.  Maybe f0
   should be reserved for your formula upon logging in; i.e. if f0
   is set, your formula is automatically set to f0 when you log in.
*/

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

#include <ctype.h>

#include "command.h"
#include "config.h"
#include "formula.h"
#include "gamedb.h"
#include "lists.h"
#include "network.h"
#include "playerdb.h"
#include "ratings.h"
#include "rmalloc.h"
#include "utils.h"

extern player parray[];

PRIVATE char *GetPlayersFormula (player *pWho, int clause)
{
  if (clause==MAX_FORMULA) return (pWho->formula);
  else return (pWho->formulaLines[clause]);
}

/* In MoveIndexPastString, *i is treated as the index into string[];
   this function returns 1 if the character string beginning with
   string[*i] match *text, and 0 otherwise.  In the former case, *i
   is incremented to move the index past *text.
*/
int MoveIndexPastString (char *string, int *i, char *text)
{
  int n = strlen(text);
  if (strncasecmp(text, string + *i, n)) return (0);
  *i += n;
  return (n);
}    /* end of function MoveIndexPastString. */

/* GetRating simply chooses between blitz, standard and ratings. */
int GetRating(player *p, int gametype)
{
    if (gametype == TYPE_BLITZ) return (p->b_stats.rating);
    else if (gametype == TYPE_STAND) return (p->s_stats.rating);
    else if (gametype == TYPE_WILD) return (p->w_stats.rating);
    else if (gametype == TYPE_LIGHT) return (p->l_stats.rating);
    else if (gametype == TYPE_BUGHOUSE) return (p->bug_stats.rating);
    else return 0;
}    /* end of function GetRating. */

int GetNumberInsideParens (game *g, int clause, int *i, int *token,
                           int eval)
{
  char *string = GetPlayersFormula(&parray[g->black], clause);
  int ret;

  while (string[*i] != '\0' && isspace(string[*i])) (*i)++;
  if (!MoveIndexPastString(string, i, "(")) return (ERR_BADCHAR);

  ret = CheckFormula(g, clause, i, OPTYPE_PAREN, token, eval);
  if (ret != ERR_NONE)
    return (ret);
  if (MoveIndexPastString(string, i, ")")) return (ERR_NONE);
  else return (ERR_PAREN);
}

int
Maxtime(game *g, int numMoves, int numPlayers)
{
	int max;

	if (g->bInitTime == g->wInitTime && g->bIncrement == g->wIncrement) {
		max = numPlayers * (60 * g->wInitTime + numMoves *
		    g->wIncrement);

		if (g->type != TYPE_UNTIMED && g->wInitTime == 0)
			max += (10 * numPlayers);
	} else if (numPlayers == 2) {
		max = 60 * (g->wInitTime + g->bInitTime) + numMoves *
		    (g->wIncrement + g->bIncrement);

		if (g->type != TYPE_UNTIMED && g->wInitTime == 0)
			max += 10;
		if (g->type != TYPE_UNTIMED && g->bInitTime == 0)
			max += 10;
	} else {
		max = (60 * g->bInitTime + numMoves * g->bIncrement);

		if (g->type != TYPE_UNTIMED && g->bInitTime == 0)
			max += 10;
	}
	return max;
}

/*
 * The black player in game 'g' has been challenged. S/he has a list
 * of formulas and we're checking the one given by the index
 * clause. 'MAX_FORMULA' denotes the actual formula. If clause is
 * smaller, we're looking at one of the user-defined formulas. We're
 * at position 'i' in the formula. If we find a legitimate variable
 * there and 'eval' is 1 VarToToken() puts its value in 'tok'. This
 * function returns 1 or 0 depending on whether a legitimate variable
 * was found.
 */
int
VarToToken(game *g, int clause, char *string, int *i, int *tok, int eval)
{
	double	 dummy_sterr;
	int	 index = 0, c;
	player	*me = &parray[g->black];
	player	*you = &parray[g->white];

	/*
	 * We list possible variables with the longest names first.
	 */
	if (MoveIndexPastString(string, i, "registered")) {
		*tok = you->registered;
	} else if (MoveIndexPastString(string, i, "ratingdiff")) {
		*tok = (GetRating(you, g->type) - GetRating(me, g->type));
	} else if (MoveIndexPastString(string, i, "assessloss")) {
		if (g->rated) {
			rating_sterr_delta(g->black, g->white, g->type,
			    time(NULL), RESULT_LOSS, tok, &dummy_sterr);
		} else {
			*tok = 0;
		}
	} else if (MoveIndexPastString(string, i, "assessdraw")) {
		if (g->rated) {
			rating_sterr_delta(g->black, g->white, g->type,
			    time(NULL), RESULT_DRAW, tok, &dummy_sterr);
		} else {
			*tok = 0;
		}
	} else if (MoveIndexPastString(string, i, "assesswin")) {
		if (g->rated) {
			rating_sterr_delta(g->black, g->white, g->type,
			    time(NULL), RESULT_WIN, tok, &dummy_sterr);
		} else {
			*tok = 0;
		}
	} else if (MoveIndexPastString(string, i, "mymaxtime")) {
		if (GetNumberInsideParens(g, clause, i, tok, eval) != ERR_NONE)
			return 0;
		*tok = Maxtime (g, *tok, 1);
	}
#ifdef TIMESEAL
	else if (MoveIndexPastString(string, i, "timeseal"))
		*tok = con[you->socket].timeseal;
#endif
	else if (MoveIndexPastString(string, i, "myrating"))
		*tok = GetRating(me, g->type);
	else if (MoveIndexPastString(string, i, "computer"))
		*tok = in_list(-1, L_COMPUTER, you->name);
	else if (MoveIndexPastString(string, i, "standard"))
		*tok = (g->type == TYPE_STAND);
	else if (MoveIndexPastString(string, i, "private"))
		*tok = you->private;
	else if (MoveIndexPastString(string, i, "maxtime")) {
		if (GetNumberInsideParens(g, clause, i, tok, eval) != ERR_NONE)
			return 0;
		*tok = Maxtime (g, *tok, 2);
	} else if (MoveIndexPastString(string, i, "abuser"))
		*tok = in_list(-1, L_ABUSER, you->name);
	else if (MoveIndexPastString(string, i, "rating"))
		*tok = GetRating(you, g->type);
	else if (MoveIndexPastString(string, i, "rated"))
		*tok = g->rated;
	else if (MoveIndexPastString(string, i, "blitz"))
		*tok = (g->type == TYPE_BLITZ);
	else if (MoveIndexPastString(string, i, "wild"))
		*tok = (g->type == TYPE_WILD);
	else if (MoveIndexPastString(string, i, "lightning"))
		*tok = (g->type == TYPE_LIGHT);
	else if (MoveIndexPastString(string, i, "nonstandard"))
		*tok = (g->type == TYPE_NONSTANDARD);
	else if (MoveIndexPastString(string, i, "untimed"))
		*tok = (g->type == TYPE_UNTIMED);
	else if (MoveIndexPastString(string, i, "time"))
		*tok = g->wInitTime;
	else if (MoveIndexPastString(string, i, "inc"))
		*tok = g->wIncrement;
	else if (tolower(string[*i]) == 'f' &&
	    isdigit(string[*i + 1]) &&
	    (c = (string[*i + 1] - '1')) >= 0 &&
	    clause > c) {
		*i += 2;
		return (!CheckFormula(g, c, &index, OPTYPE_NONE, tok, eval));
	} else
		return 0;
	return 1;
}

/*
 * ScanForOp() checks for an operator at position 'i' in 'string'.
 */
int
ScanForOp(char *string, int *i)
{
	while (string[*i] != '\0' && isspace(string[*i]))
		(*i)++;

	if (string[*i] == '\0')
		return OP_NONE;
	if (string[*i] == '#')
		return OP_NONE;
	if (string[*i] == ')')
		return OP_RTPAREN;

	/*
	 * Two char operators and longer first.
	 */
	if (MoveIndexPastString(string, i, "and"))
		return OP_AND;
	if (MoveIndexPastString(string, i, "or"))
		return OP_OR;
	if (MoveIndexPastString(string, i, "||"))
		return OP_OR;
	if (MoveIndexPastString(string, i, "&&"))
		return OP_AND;
	if (MoveIndexPastString(string, i, "=="))
		return OP_EQ;
	if (MoveIndexPastString(string, i, "!="))
		return OP_NEQ;
	if (MoveIndexPastString(string, i, "<>"))
		return OP_NEQ;
	if (MoveIndexPastString(string, i, ">="))
		return OP_GE;
	if (MoveIndexPastString(string, i, "=>"))
		return OP_GE;
	if (MoveIndexPastString(string, i, "<="))
		return OP_LE;
	if (MoveIndexPastString(string, i, "=<"))
		return OP_LE;

	/*
	 * One char operators now.
	 */
	if (MoveIndexPastString(string, i, "|"))
		return OP_OR;
	if (MoveIndexPastString(string, i, "&"))
		return OP_AND;
	if (MoveIndexPastString(string, i, ">"))
		return OP_GT;
	if (MoveIndexPastString(string, i, "<"))
		return OP_LT;
	if (MoveIndexPastString(string, i, "="))
		return OP_EQ;
	if (MoveIndexPastString(string, i, "+"))
		return OP_PLUS;
	if (MoveIndexPastString(string, i, "-"))
		return OP_MINUS;
	if (MoveIndexPastString(string, i, "*"))
		return OP_MULT;
	if (MoveIndexPastString(string, i, "/"))
		return OP_DIV;

	return OP_BAD;
}

/*
 * OpType() returns the precedence of the operator 'op'.
 */
int
OpType(int op)
{
	switch (op) {
	case OP_BAD:
		return OPTYPE_BAD;
	case OP_NONE:
		return OPTYPE_NONE;
	case OP_RTPAREN:
		return OPTYPE_RPAREN;
	case OP_OR:
		return OPTYPE_OR;
	case OP_AND:
		return OPTYPE_AND;
	case OP_EQ:
	case OP_NEQ:
		return OPTYPE_COMPEQ;
	case OP_GT:
	case OP_GE:
	case OP_LT:
	case OP_LE:
		return OPTYPE_COMPGL;
	case OP_PLUS:
	case OP_MINUS:
		return OPTYPE_ADD;
	case OP_MULT:
	case OP_DIV:
		return OPTYPE_MULT;
	case OP_NEGATE:
	case OP_NOT:
		return OPTYPE_UNARY;
	default:
		return OPTYPE_BAD;
	}
}

/*
 * In EvalBinaryOp() 'left' is the left operand, and 'op' is the
 * current operator. 'g' and 'clause' specify which formula string to
 * look at, and 'i' tells us where we are in the string. We look for a
 * right operand from position 'i' in the string. And place the
 * expression in 'left'. This function returns 0 if no error.
 * Otherwise an error code is returned.
 */
int
EvalBinaryOp(int *left, int op, game *g, int clause, int *i)
{
	int right, ret;

	if (op == OP_OR && *left != 0) { /* Nothing to decide. */
		*left = 1;
		return CheckFormula(g, clause, i, OpType(op), &right, 0);
	} else if (op == OP_AND && *left == 0) { /* Nothing to decide. */
		return CheckFormula(g, clause, i, OpType(op), &right, 0);
	} else {
		ret = CheckFormula(g, clause, i, OpType(op), &right, 1);

		if (ret != ERR_NONE)
			return ret;
	}

	switch (op) {
	default:
	case OP_BAD:
		return ERR_BADOP;
	case OP_NONE:
	case OP_RTPAREN:
		return ERR_NONE;
	case OP_OR:
		*left = (*left || right);
		return ERR_NONE;
	case OP_AND:
		*left = (*left && right);
		return ERR_NONE;
	case OP_EQ:
		*left = (*left == right);
		return ERR_NONE;
	case OP_NEQ:
		*left = (*left != right);
		return ERR_NONE;
	case OP_GT:
		*left = (*left > right);
		return ERR_NONE;
	case OP_GE:
		*left = (*left >= right);
		return ERR_NONE;
	case OP_LT:
		*left = (*left < right);
		return ERR_NONE;
	case OP_LE:
		*left = (*left <= right);
		return ERR_NONE;
	case OP_PLUS:
		*left += right;
		return ERR_NONE;
	case OP_MINUS:
		*left -= right;
		return ERR_NONE;
	case OP_MULT:
		*left *= right;
		return ERR_NONE;
	case OP_DIV:
		if (right != 0) {
			*left /= right;
			return ERR_NONE;
		} else {
			pprintf(g->black, "Dividing by %lf instead or zero in "
			    "formula.\n", FUDGE_FACTOR);
			*left /= FUDGE_FACTOR;
			return ERR_NONE;
		}
	} /* switch */
}

/*
 * If 'eval' is 1, ScanForNumber() evaluates the number at position
 * 'i' in the formula given by 'g' and 'clause', and places this value
 * in 'token'. 'op_type' is the precedence of the operator preceding
 * the i'th position. If we come to an operator of higher precedence
 * we must keep going before we can leave this function. If 'eval' is
 * 0, just move past the number we would evaluate. This function
 * returns 0 if no error. Otherwise an error code is returned.
 */
int
ScanForNumber(game *g, int clause, int *i, int op_type, int *token, int eval)
{
	char	*string = GetPlayersFormula(&parray[g->black], clause);
	char	 c;
	int	 ret;

	while (string[*i] != '\0' && isspace(string[*i]))
		(*i)++;

	switch (c = string[*i]) {
	case '\0':
	case '#':
		if (op_type != OPTYPE_NONE)
			return ERR_EOF;
		else
			*token = 1;
		return ERR_NONE;
	case ')':
		if (op_type != OPTYPE_PAREN)
			return ERR_PAREN;
		else
			*token = 1;
		return ERR_NONE;
	case '(':
		return GetNumberInsideParens(g, clause, i, token, eval);
	case '-':
	case '!':
		++(*i);

		if (c == string[*i])
			return ERR_UNARY;

		ret = ScanForNumber(g, clause, i, OPTYPE_UNARY, token, eval);

		if (ret != ERR_NONE)
			return ret;
		if (c == '-')
			*token = -(*token);
		else if (c == '!')
			*token = !(*token);
		return ERR_NONE;
	default:
		if (isdigit(string[*i])) {
			*token = 0;

			do {
				*token = (10 * (*token) + string[(*i)++] - '0');
			} while (isdigit(string[*i]));

			while (string[*i] != '\0' && isspace(string[*i]))
				(*i)++;

			if (MoveIndexPastString(string, i, "minutes"))
				*token *= 60;
			return ERR_NONE;
		} else if (isalpha(string[*i])) {
			if (!VarToToken(g, clause, string, i, token, eval))
				return ERR_BADVAR;
			return ERR_NONE;
		} else
			return ERR_NONESENSE;
	} /* switch */
}

/*
 * If 'eval' is 1, CheckFormula() looks for the next token in the
 * formula given by 'g', 'clause' and 'i'. Usually this is the right
 * side of an expression whose operator has precedence OpType(). If
 * 'eval' is 0, just go to the end of an expression.
 */
int
CheckFormula(game *g, int clause, int *i, int op_type, int *result, int eval)
{
	char	*string = GetPlayersFormula(&parray[g->black], clause);
	int	 token, ret, nextOp, lastPos;

	if (string == NULL) {
		*result = 1;
		return ERR_NONE;
	}

	ret = ScanForNumber(g, clause, i, op_type, &token, eval);

	if (ret != ERR_NONE)
		return ret;

	lastPos	= *i;
	nextOp	= ScanForOp(string, i);

	while (OpType(nextOp) > op_type) { /* Higher precedence. */
			if (nextOp == OP_RTPAREN)
				return ERR_PAREN;
			if (!eval) {
				ret = CheckFormula(g, clause, i, OpType(nextOp),
				    &token, 0);
			} else {
				ret = EvalBinaryOp(&token, nextOp, g, clause,
				    i);
			}

			if (ret != ERR_NONE)
				return ret;
			lastPos	= *i;
			nextOp	= ScanForOp(string, i);
	}

	if (nextOp == OP_BAD)
		return ERR_BADOP;
	*result = token;
	/*
	 * Move back unless we're at the end or at a right paren, in
	 * which case we never went forward.
	 */
	if (nextOp != OP_NONE && nextOp != OP_RTPAREN)
		*i = lastPos;
	return ERR_NONE;
}

/*
 * Which clauses are relevant for a player's formula.
 */
PRIVATE int
ChooseClauses(player *who, char *formula)
{
	int i, which, ret = 0;

	if (formula == NULL)
		return ret;

	for (i = 0; formula[i] != '\0' && formula[i] != '#'; i++) {
		if (formula[i] != 'f' || (i > 0 && isalnum(formula[i - 1])) ||
		    !isdigit(formula[i + 1]))
			continue;
		sscanf(&formula[i], "f%d", &which);
		ret |= (1 << (which - 1));
	}

	/* Now scan clauses found as part of the formula. */
	for (i = MAX_FORMULA - 1; i >= 0; i--) {
		if (ret & (1 << i))
			ret |= ChooseClauses(who, who->formulaLines[i]);
	}

	return ret;
}

void
ExplainFormula(game *g, textlist **clauses)
{
	char txt[20];
	int i, which, dummy_index, value;
	player *challenged = &parray[g->black];
	textlist **Cur = clauses;

	which = ChooseClauses(challenged, challenged->formula);

	for (i = 0; i < MAX_FORMULA; i++) {
		if ((which & (1 << i)) == 0)
			continue;
		dummy_index = 0;
		CheckFormula(g, i, &dummy_index, OPTYPE_NONE, &value, 1);
		sprintf(txt, "%d", value);
		SaveTextListEntry(Cur, txt, i);
		Cur = &(*Cur)->next;
	}
}

/*
 * GameMatchesFormula() converts parameters to a game structure and
 * passes a pointer to this game to CheckFormula() for evaluation. It
 * returns the evaluated formula.
 */
PUBLIC int
GameMatchesFormula(int w, int b, int wTime, int wInc, int bTime, int bInc,
    int rated, int gametype, textlist **clauseList)
{
	game	g;
	int	index = 0, ret;

	g.white		= w;
	g.black		= b;
	g.wInitTime	= wTime;
	g.bInitTime	= bTime;
	g.wIncrement	= wInc;
	g.bIncrement	= bInc;
	g.rated		= rated;
	g.type		= gametype;

	if (CheckFormula(&g, MAX_FORMULA, &index, OPTYPE_NONE, &ret, 1) !=
	    ERR_NONE)
		return 0;
	if (ret == 0)
		ExplainFormula (&g, clauseList);
	return ret;
}

/*
 * SetValidFormula() sets a clause of player 'p' and creates a game
 * structure to check whether that new formula is legitimate. If so,
 * return 1. Otherwise reset the formula and return 0.
 */
int
SetValidFormula(int p, int clause, char *string)
{
	char	*Old = NULL, **Cur;
	game	 g;
	int	 index = 0, ret, err = ERR_NONE;
	player	*me = &parray[p];

	if (clause == MAX_FORMULA)
		Cur = &me->formula;
	else
		Cur = &me->formulaLines[clause];

	Old = *Cur;

	if (string != NULL) {
		string = eatwhite(string);
		*Cur = (*string != '\0' ? xstrdup(string) : NULL);
	} else
		*Cur = NULL;

	if (*Cur == NULL) {
		if (Old != NULL)
			rfree(Old);
		return 1;
	}

	g.white = g.black = p;
	g.wInitTime = g.bInitTime = me->d_time;
	g.wIncrement = g.bIncrement = me->d_inc;
	g.rated = me->rated;
	g.type = TYPE_BLITZ;

	err = CheckFormula(&g, clause, &index, OPTYPE_NONE, &ret, 0);

	if (err != ERR_NONE) {
		/* Bad formula  --  reset it. */
		rfree(*Cur);
		*Cur = Old;
	} else {
		if (Old != NULL)
			rfree(Old);
	}

	return (err == ERR_NONE);
}

PUBLIC void
ShowClauses(int p, int p1, textlist *clauses)
{
	if (clauses != NULL)
		pprintf(p, "\n");
	for (textlist *Cur = clauses; Cur != NULL; Cur = Cur->next) {
		pprintf(p, "f%d=%s: %s\n", (Cur->index + 1), Cur->text,
		    parray[p1].formulaLines[Cur->index]);
	}
}