/*
 * CHEST, chess analyst.  For Copyright notice read file "COPYRIGHT".
 *
 * $Source: /home/heiner/ca/chest/RCS/asw.c,v $
 * $Id: asw.c,v 3.5 1999/07/20 20:59:41 heiner Exp $
 *
 *	answer switch
 */

#include "types.h"
#include "board.h"
#include "answer.h"
#include "asw.h"


/*
 * Sort a list of (all) legal moves for the purpose of defending
 * against an attack (already executed) of the specified depth.
 * Here decide for and call the appropriate specialized procedure.
 * Return the approximate cost as needed by "analyse()".
 */

#define MIN_SORT_DEPTH	2       /* else sorting is too expensive */

typedef int     (*FuncPtr) (int, Xconst Board *, Movelist *);
 /* pointer to answer function */

static const FuncPtr answer_func[] = {  /* answer function by depth */
     /* 0 */ 0,
     /* 1 */ 0,
     /* 2 */ sort_2_weighted,
};

static const FuncPtr default_func = sort_weighted;

Eximpl int      sort_answer(
                                            int depth,
                                            Xconst Board * bp,
                                            Movelist * lp)
{
    register FuncPtr fp;

    if (depth < MIN_SORT_DEPTH) {
        return (0);             /* nothing done, no cost */
    }
#if 1
    if (lp->l_free < &(lp->l_m[2])) {
        return 0;               /* not at least 2 moves => leave alone */
    }
#endif
    if (depth >= NELEMS(answer_func)) {
        fp = default_func;
    } else {
        fp = answer_func[depth];
        if (fp == (FuncPtr) 0) {
            fp = default_func;
        }
    }
    return (*fp) (depth, bp, lp);
}