implement join() for freecell

[solVItaire.git] / sol.c

#define _DEFAULT_SOURCE /* for getopt, sigaction, usleep */
#include <poll.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/ioctl.h>
#include <time.h>
#include <termios.h>
#include <unistd.h>

#include "sol.h"
#include "schemes.h"

struct playfield f;
struct opts op;

// action table {{{
/* stores a function pointer for every takeable action; called by game loop */
int (*action[NUM_PLACES][10])(int,int,int) = {
#ifdef KLONDIKE
        /* 1    2    3    4    5    6    7   stk  wst  fnd*/
/* 1 */ { t2f, t2t, t2t, t2t, t2t, t2t, t2t, nop, nop, t2f },
/* 2 */ { t2t, t2f, t2t, t2t, t2t, t2t, t2t, nop, nop, t2f },
/* 3 */ { t2t, t2t, t2f, t2t, t2t, t2t, t2t, nop, nop, t2f },
/* 4 */ { t2t, t2t, t2t, t2f, t2t, t2t, t2t, nop, nop, t2f },
/* 5 */ { t2t, t2t, t2t, t2t, t2f, t2t, t2t, nop, nop, t2f },
/* 6 */ { t2t, t2t, t2t, t2t, t2t, t2f, t2t, nop, nop, t2f },
/* 7 */ { t2t, t2t, t2t, t2t, t2t, t2t, t2f, nop, nop, t2f },
/*stk*/ { nop, nop, nop, nop, nop, nop, nop, nop, s2w, nop },
/*wst*/ { w2t, w2t, w2t, w2t, w2t, w2t, w2t, w2s, w2f, w2f },
/*fnd*/ { f2t, f2t, f2t, f2t, f2t, f2t, f2t, nop, nop, nop },
#elif defined SPIDER
        /* 1    2    3    4    5    6    7    8    9    10*/
/* 1 */ { t2f, t2t, t2t, t2t, t2t, t2t, t2t, t2t, t2t, t2t },
/* 2 */ { t2t, t2f, t2t, t2t, t2t, t2t, t2t, t2t, t2t, t2t },
/* 3 */ { t2t, t2t, t2f, t2t, t2t, t2t, t2t, t2t, t2t, t2t },
/* 4 */ { t2t, t2t, t2t, t2f, t2t, t2t, t2t, t2t, t2t, t2t },
/* 5 */ { t2t, t2t, t2t, t2t, t2f, t2t, t2t, t2t, t2t, t2t },
/* 6 */ { t2t, t2t, t2t, t2t, t2t, t2f, t2t, t2t, t2t, t2t },
/* 7 */ { t2t, t2t, t2t, t2t, t2t, t2t, t2f, t2t, t2t, t2t },
/* 8 */ { t2t, t2t, t2t, t2t, t2t, t2t, t2t, t2f, t2t, t2t },
/* 9 */ { t2t, t2t, t2t, t2t, t2t, t2t, t2t, t2t, t2f, t2t },
/*10 */ { t2t, t2t, t2t, t2t, t2t, t2t, t2t, t2t, t2t, t2f },
/*stk*/ { s2t, s2t, s2t, s2t, s2t, s2t, s2t, s2t, s2t, s2t },
#elif defined FREECELL
        /* 1    2    3    4    5    6    7    8   cll  fnd*/
/* 1 */ { t2f, t2t, t2t, t2t, t2t, t2t, t2t, t2t, t2c, t2f },
/* 2 */ { t2t, t2f, t2t, t2t, t2t, t2t, t2t, t2t, t2c, t2f },
/* 3 */ { t2t, t2t, t2f, t2t, t2t, t2t, t2t, t2t, t2c, t2f },
/* 4 */ { t2t, t2t, t2t, t2f, t2t, t2t, t2t, t2t, t2c, t2f },
/* 5 */ { t2t, t2t, t2t, t2t, t2f, t2t, t2t, t2t, t2c, t2f },
/* 6 */ { t2t, t2t, t2t, t2t, t2t, t2f, t2t, t2t, t2c, t2f },
/* 7 */ { t2t, t2t, t2t, t2t, t2t, t2t, t2f, t2t, t2c, t2f },
/* 8 */ { t2t, t2t, t2t, t2t, t2t, t2t, t2t, t2f, t2c, t2f },
/*cll*/ { c2t, c2t, c2t, c2t, c2t, c2t, c2t, c2t, c2f, c2f },
/*fnd*/ { f2t, f2t, f2t, f2t, f2t, f2t, f2t, f2t, f2c, nop },
#endif
};
// }}}

// argv parsing, game loops, cleanup {{{
int main(int argc, char** argv) {
        /* opinionated defaults: */
        op.s = &unicode_large_color;
        op.v = 1; /* enable fake visbell by default */
#ifdef SPIDER
        op.m = MEDIUM;
#endif

        int optget;
        opterr = 0; /* don't print message on unrecognized option */
        while ((optget = getopt (argc, argv, "+:hs:vbcmMV")) != -1) {
                switch (optget) {
#ifdef SPIDER
                case 's': /* number of suits */
                        switch (optarg[0]) {
                        case '1': op.m = EASY; break;
                        case '2': op.m = MEDIUM; break;
                        case '4': op.m = NORMAL; break;
                        default: goto error;
                        } break;
#endif
                case 'b': op.s = &unicode_large_mono; break;
                case 'c': op.s = &unicode_large_color; break;
                case 'm': op.s = &unicode_small_mono; break; /* "mini, monochrome" */
                case 'M': op.s = &unicode_small_color; break; /* "mini, colorful" */
                case 'V': op.v = 0; break; /* WARN: experimental; might change */
                case 'h': default: goto error;
                error:
                        fprintf (stderr, SHORTHELP LONGHELP KEYHELP, argv[0]);
                        return optget != 'h';
                }
        }

        signal_setup();
        atexit (*quit);

        signal_handler(SIGWINCH); /* initialize window size */

newgame:
        screen_setup(1);

        switch(sol()) {
        case GAME_NEW: goto newgame;
        case GAME_WON:
                print_table(NO_HI, NO_HI);
                win_anim();
                if (getch(NULL)=='q') return 0;
                goto newgame;
        case GAME_QUIT: return 0;
        }
}

#define is_tableu(where) (where <= TAB_MAX) // "card games helper functions"

int sol(void) {
        int ret;
        long seed = time(NULL);
restart:
        free_undo(f.u);
        deal(seed);

        int from, to, opt;
        for(;;) {
                switch (get_cmd(&from, &to, &opt)) {
                case CMD_MOVE:
                        ret = action[from][to](from,to,opt);
#ifdef FREECELL
                        if (ret == ERR && is_tableu(from) && to == from) /*i.e. failed foundation move*/
                                ret = t2c(from, STOCK, 0);
                        else
#endif
                        if (ret == ERR && is_tableu(from) && is_tableu(to))
                                /* try again with from/to swapped: */
                                ret = action[to][from](to,from,opt);
                        switch (ret) {
                        case OK:  break;
                        case ERR: visbell(); break;
                        case WON: return GAME_WON;
                        }
                        break;
                case CMD_JOIN:
                        switch (join(to)) {
                        case OK:  break;
                        case ERR: visbell(); break;
                        case WON: return GAME_WON;
                        }
                        break;
                case CMD_HINT:  break;//TODO: show a possible (and sensible) move. if possible, involve active cursor
                case CMD_UNDO:  undo_pop(f.u); break;
                case CMD_INVAL: visbell(); break;
                case CMD_NEW:   return GAME_NEW;
                case CMD_AGAIN: goto restart;
                case CMD_QUIT:  return GAME_QUIT;
                case CMD_HELP:
                        printf (KEYHELP "\nPress any key to continue.");
                        getch(NULL);
                        break;
                }
        }
}

void quit(void) {
        screen_setup(0);
        free_undo(f.u);
}
//}}}

// card games helper functions {{{
#define get_suit(card) \
        ((card-1) % NUM_SUITS)
#define get_rank(card) \
        ((card-1) / NUM_SUITS)
#define get_color(card) \
        ((get_suit(card) ^ get_suit(card)>>1) & 1)

int find_top(card_t* pile) {
        int i;
        for(i=PILE_SIZE-1; i>=0 && !pile[i]; i--);
        return i;
}
int first_movable(card_t* pile) {
        /* NOTE: in FREECELL this does not take max_move into account! */
        int i = 0;
        for (;pile[i] && !is_movable(pile, i); i++);
        return i;
}
int turn_over(card_t* pile) {
        int top = find_top(pile);
        if (pile[top] < 0) {
                pile[top] *= -1;
                return 1;
        } else return 0;
}
int check_won(void) {
        for (int pile = 0; pile < NUM_DECKS*NUM_SUITS; pile++)
                if (f.f[pile][NUM_RANKS-1] == NO_CARD) return 0;

        return 1;
}
int rank_next (card_t a, card_t b) {
        return get_rank(a) == get_rank(b)-1;
}
int is_consecutive (card_t* pile, int pos) {
        if (pos+1 >= PILE_SIZE) return 1; /* card is last */
        if (pile[pos+1] == NO_CARD) return 1; /* card is first */

#if defined KLONDIKE || defined FREECELL
        /* ranks consecutive? */
        if (!rank_next(pile[pos+1], pile[pos])) return 0;
        /* color opposite? */
        if (get_color(pile[pos+1]) == get_color(pile[pos])) return 0;
#elif defined SPIDER
        /* ranks consecutive? */
        if (!rank_next(pile[pos+1], pile[pos])) return 0;
        /* same suit? */
        if (get_suit(pile[pos+1]) != get_suit(pile[pos])) return 0;
#endif

        return 1;
}

int is_movable(card_t* pile, int n) {
#ifdef KLONDIKE
        return(pile[n] > NO_CARD); /*non-movable cards don't exist in klondike*/
#elif defined SPIDER || defined FREECELL
        int top = find_top(pile);
        for (int i = top; i >= 0; i--) {
                if (pile[i] <= NO_CARD) return 0; /*no card or card face down?*/
                if (!is_consecutive(pile, i)) return 0;
                if (i == n) return 1; /* card reached, must be movable */
        }
        return 0;
#endif
}
//}}}

// takeable actions {{{
#ifdef KLONDIKE
card_t stack_take(void) { /*NOTE: assert(f.w >= 0) */
        card_t card = f.s[f.w];
        /* move stack one over, so there are no gaps in it: */
        for (int i = f.w; i < f.z-1; i++)
                f.s[i] = f.s[i+1];
        f.z--;
        f.w--; /* make previous card visible again */
        return card;
}
int t2f(int from, int to, int opt) { /* tableu to foundation */
        (void) to; (void) opt; /* don't need */
        int top_from = find_top(f.t[from]);
        to = get_suit(f.t[from][top_from]);
        int top_to   = find_top(f.f[to]);
        if ((top_to < 0 && get_rank(f.t[from][top_from]) == RANK_A)
        || (top_to >= 0 && rank_next(f.f[to][top_to],f.t[from][top_from]))) {
                f.f[to][top_to+1] = f.t[from][top_from];
                f.t[from][top_from] = NO_CARD;
                undo_push(from, FOUNDATION, to,
                turn_over(f.t[from]));
                if (check_won()) return WON;
                return OK;
        } else return ERR;
}
int w2f(int from, int to, int opt) { /* waste to foundation */
        (void) from; (void) to; (void) opt; /* don't need */
        if (f.w < 0) return ERR;
        to = get_suit(f.s[f.w]);
        int top_to = find_top(f.f[to]);
        if ((top_to < 0 && get_rank(f.s[f.w]) == RANK_A)
        || (top_to >= 0 && rank_next(f.f[to][top_to], f.s[f.w]))) {
                undo_push(WASTE, FOUNDATION, f.w | to<<16, 0);//ugly encoding :|
                f.f[to][top_to+1] = stack_take();
                if (check_won()) return WON;
                return OK;
        } else return ERR;
        
}
int s2w(int from, int to, int opt) { /* stock to waste */
        (void) from; (void) to; (void) opt; /* don't need */
        if (f.z == 0) return ERR;
        f.w++;
        if (f.w == f.z) f.w = -1;
        return OK;
}
int w2s(int from, int to, int opt) { /* waste to stock (undo stock to waste) */
        (void) from; (void) to; (void) opt; /* don't need */
        if (f.z == 0) return ERR;
        f.w--;
        if (f.w < -1) f.w = f.z-1;
        return OK;
}
int f2t(int from, int to, int opt) { /* foundation to tableu */
        (void) from; /* don't need */
        int top_to = find_top(f.t[to]);
        from = opt;
        int top_from = find_top(f.f[from]);
        
        if ((get_color(f.t[to][top_to]) != get_color(f.f[from][top_from]))
        && (rank_next(f.f[from][top_from], f.t[to][top_to]))) {
                f.t[to][top_to+1] = f.f[from][top_from];
                f.f[from][top_from] = NO_CARD;
                undo_push(FOUNDATION, to, from, 0);
                return OK;
        } else return ERR;
}
int w2t(int from, int to, int opt) { /* waste to tableu */
        (void) from; (void) opt; /* don't need */
        if (f.w < 0) return ERR;
        int top_to = find_top(f.t[to]);
        if (((get_color(f.t[to][top_to]) != get_color(f.s[f.w]))
           && (rank_next(f.s[f.w], f.t[to][top_to])))
        || (top_to < 0 && get_rank(f.s[f.w]) == RANK_K)) {
                undo_push(WASTE, to, f.w, 0);
                f.t[to][top_to+1] = stack_take();
                return OK;
        } else return ERR;
}
int t2t(int from, int to, int opt) { /* tableu to tableu */
        (void) opt; /* don't need */
        int top_to = find_top(f.t[to]);
        int top_from = find_top(f.t[from]);
        int count = 0; //NOTE: could probably be factored out
        for (int i = top_from; i >=0; i--) {
                if (((get_color(f.t[to][top_to]) != get_color(f.t[from][i]))
                   && (rank_next(f.t[from][i], f.t[to][top_to]))
                   && f.t[from][i] > NO_CARD) /* card face up? */
                || (top_to < 0 && get_rank(f.t[from][i]) == RANK_K)) {
                        /* move cards [i..top_from] to their destination */
                        for (;i <= top_from; i++) {
                                top_to++;
                                f.t[to][top_to] = f.t[from][i];
                                f.t[from][i] = NO_CARD;
                                count++;
                        }
                        undo_push(from, to, count,
                        turn_over(f.t[from]));
                        return OK;
                }
        }
        return ERR; /* no such move possible */
}
#elif defined SPIDER
int remove_if_complete (int pileno) { //cleanup!
        card_t* pile = f.t[pileno];
        /* test if K...A complete; move to foundation if so */
        int top_from = find_top(pile);
        if (get_rank(pile[top_from]) != RANK_A) return 0;
        for (int i = top_from; i>=0; i--) {
                if (!is_consecutive (pile, i)) return 0;
                if (i+RANK_K == top_from /* if ace to king: remove it */
                    && get_rank(pile[top_from-RANK_K]) == RANK_K) {
                        for(int i=top_from, j=0; i>top_from-NUM_RANKS; i--,j++){
                                f.f[f.w][j] = pile[i];
                                pile[i] = NO_CARD;
                        }
                        undo_push(pileno, FOUNDATION, f.w,
                        turn_over(pile));
                        f.w++;
                        return 1;
                }
        }

        return 0;
}
int t2t(int from, int to, int opt) { //in dire need of cleanup
        int top_from = find_top(f.t[from]);
        int top_to = find_top(f.t[to]);
        int empty_to = (top_to < 0)? opt: -1; /* empty pile? */
        int count = 0; //NOTE: could probably be factored out

        for (int i = top_from; i >= 0; i--) {
                if (!is_consecutive(f.t[from], i)) break;

                /* is consecutive OR to empty pile and rank ok? */
                if (rank_next(f.t[from][i], f.t[to][top_to])
                || (empty_to >= RANK_A && get_rank(f.t[from][i]) == empty_to)) {
                        for (;i <= top_from; i++) {
                                top_to++;
                                f.t[to][top_to] = f.t[from][i];
                                f.t[from][i] = NO_CARD;
                                count++;
                        }
                        undo_push(from, to, count,
                        turn_over(f.t[from]));
                        remove_if_complete(to);
                        if (check_won()) return WON;
                        return OK;
                }
        }

        return ERR; /* no such move possible */
}
int s2t(int from, int to, int opt) {
        (void) from; (void) to; (void) opt; /* don't need */
        if (f.z <= 0) return ERR; /* stack out of cards */
        for (int pile = 0; pile < NUM_PILES; pile++)
                if (f.t[pile][0]==NO_CARD) return ERR; /*no piles may be empty*/
        for (int pile = 0; pile < NUM_PILES; pile++) {
                f.t[pile][find_top(f.t[pile])+1] = f.s[--f.z];
                remove_if_complete(pile);
                if (check_won()) return WON;
        }
        undo_push(STOCK, TABLEU, 1, 0);/*NOTE: puts 1 card on each tableu pile*/
        return OK;
}
int t2f(int from, int to, int opt) {
        (void) to; (void) opt; /* don't need */
        /* manually retrigger remove_if_complete() (e.g. after undo_pop) */
        return remove_if_complete(from)?OK:ERR;
}
#elif defined FREECELL
int max_move(int from, int to) {
        /* returns the maximum number of cards that can be moved */
        /* see also: https://boardgames.stackexchange.com/a/45157/26498 */
        int free_tabs = 0, free_cells = 0;
        for (int i = 0; i < NUM_PILES; i++) free_tabs  += f.t[i][0] == NO_CARD;
        for (int i = 0; i < NUM_CELLS; i++) free_cells += f.s[i]    == NO_CARD;

        /* don't count the tableau we are moving to: */
        if (to >= 0 && f.t[to][0] == NO_CARD) free_tabs--;

        /* theoretic maximum is limited by the number of cards on the pile */
        int max_theory = (1<<free_tabs) * (free_cells + 1);
        int max_effective = 1 + find_top(f.t[from]) - first_movable(f.t[from]);
        return max_effective < max_theory? max_effective : max_theory;
}
//TODO FREECELL: auto move to tableu after each move (not all cards possible, only when it is the smallest rank still on the board)
int t2t(int from, int to, int opt) {
        int top_to = find_top(f.t[to]);
        int top_from = find_top(f.t[from]);
        int count = 0; //NOTE: could probably be factored out
        int cards = max_move(from, to);
        if (top_to < 0) { /* moving to empty pile? */
                if (opt > cards)
                        return ERR; /* cannot execute move */
                cards = opt; /* user wants to move n cards*/
        }

        for (int i = top_from; i >=0; i--) {
                if (cards-->0/*enough space and not more attempted than wanted*/
                && ((top_to >= 0 /* if destn. not empty: check rank/color */
                   && ((get_color(f.t[to][top_to]) != get_color(f.t[from][i]))
                   && (rank_next(f.t[from][i], f.t[to][top_to]))))
                || (top_to < 0 && !cards))) {/*if dest empty and right # cards*/
                        /* move cards [i..top_from] to their destination */
                        for (;i <= top_from; i++) {
                                top_to++;
                                f.t[to][top_to] = f.t[from][i];
                                f.t[from][i] = NO_CARD;
                                count++;
                        }
                        undo_push(from, to, count, 0);
                        return OK;
                }
        }
        return ERR; /* no such move possible */
}
int t2f(int from, int to, int opt) { /* 1:1 copy from KLONDIKE */
        (void) to; (void) opt; /* don't need */
        int top_from = find_top(f.t[from]);
        to = get_suit(f.t[from][top_from]);
        int top_to   = find_top(f.f[to]);
        if ((top_to < 0 && get_rank(f.t[from][top_from]) == RANK_A)
        || (top_to >= 0 && rank_next(f.f[to][top_to],f.t[from][top_from]))) {
                f.f[to][top_to+1] = f.t[from][top_from];
                f.t[from][top_from] = NO_CARD;
                undo_push(from, FOUNDATION, to, 0);
                if (check_won()) return WON;
                return OK;
        } else return ERR;
}
int f2t(int from, int to, int opt) {
        (void) from; /* don't need */
        int top_to = find_top(f.t[to]);
        from = opt;
        int top_from = find_top(f.f[from]);

        if (top_to < 0 /* empty tableu? */
        ||((get_color(f.t[to][top_to]) != get_color(f.f[from][top_from]))
        && (rank_next(f.f[from][top_from], f.t[to][top_to])))) {
                f.t[to][top_to+1] = f.f[from][top_from];
                f.f[from][top_from] = NO_CARD;
                undo_push(FOUNDATION, to, from, 0);
                return OK;
        } else return ERR;
}
int t2c(int from, int to, int opt) {
        (void) to; (void) opt; /* don't need */
        /* is a cell free? */
        if (f.w == (1<<NUM_CELLS)-1)
                return ERR;
        for (to = 0; to < NUM_CELLS; to++)
                if (!(f.w>>to&1)) break;
        /* move 1 card */
        int top_from = find_top(f.t[from]);
        f.s[to] = f.t[from][top_from];
        f.t[from][top_from] = NO_CARD;
        f.w |= 1<<to; /* mark cell as occupied */
        undo_push(from, STOCK, to, 0);

        return OK;
}
int c2t(int from, int to, int opt) {
        (void) from; /* don't need */
        int top_to = find_top(f.t[to]);
        from = opt;

        if (top_to < 0 /* empty tableu? */
        ||((get_color(f.t[to][top_to]) != get_color(f.s[from]))
        && (rank_next(f.s[from], f.t[to][top_to])))) {
                f.t[to][top_to+1] = f.s[from];
                f.s[from] = NO_CARD;
                f.w &= ~(1<<from); /* mark cell as free */
                undo_push(STOCK, to, from, 0);
                return OK;
        } else return ERR;
        return ERR;
}
int c2f(int from, int to, int opt) {
        (void) from; (void) to; /* don't need */
        from = opt;
        to = get_suit(f.s[from]);
        int top_to = find_top(f.f[to]);
        if ((top_to < 0 && get_rank(f.s[from]) == RANK_A)
        || (top_to >= 0 && rank_next(f.f[to][top_to],f.s[from]))) {
                f.f[to][top_to+1] = f.s[from];
                f.s[from] = NO_CARD;
                f.w &= ~(1<<from); /* mark cell as free */
                undo_push(STOCK, FOUNDATION, from | to<<16, 0);
                if (check_won()) return WON;
                return OK;
        } else return ERR;
}
int f2c(int from, int to, int opt) {
        (void) from; (void) to; /* don't need */
        /* is a cell free? */
        if (f.w == (1<<NUM_CELLS)-1)
                return ERR;
        for (to = 0; to < NUM_CELLS; to++)
                if (!(f.w>>to&1)) break;
        /* move 1 card */
        from = opt;
        int top_from = find_top(f.f[from]);
        f.s[to] = f.f[from][top_from];
        f.f[from][top_from] = NO_CARD;
        f.w |= 1<<to; /* mark cell as occupied */
        undo_push(FOUNDATION, STOCK, from | to<<16, 0);

        return OK;
}
#endif

//TODO: generalize prediction engine for CMD_HINT
#ifdef KLONDIKE
#define would_complete(pile) 0
#elif defined SPIDER
#define would_complete(pile) \
        (get_rank(f.t[pile][r[pile].top]) == RANK_A \
        && get_rank(f.t[to][bottom_to]) == RANK_K)
#elif defined FREECELL
#define would_complete(pile) 0
#endif
#define would_turn(pile) \
        (f.t[pile][r[pile].pos-1] < 0)
#define would_empty(pile) \
        (r[pile].pos == 0)

int join(int to) {
//TODO FREECELL: join to empty tableu (longest cascade?)
        int top_to = find_top(f.t[to]);
#ifdef SPIDER
        int bottom_to = first_movable(f.t[to]);
#endif

#ifdef KLONDIKE
        if (to == WASTE || to == STOCK) return ERR; /*why would you do that!?*/

        if (to == FOUNDATION) {
                int status = ERR;
                for (int i = 0; i <= TAB_MAX; i++)
                        switch ((i?t2f:w2f)(i-1, FOUNDATION, 0)) {
                        case WON: return WON;
                        case OK:  status = OK;
                        case ERR: /* nop */;
                        }
                return status;
        }

        if (top_to < 0) { /* move a king to empty pile: */
                for (int i = 0; i < TAB_MAX; i++) {
                        if (f.t[i][0] < 0) /* i.e. would turn? */
                                if (t2t(i, to, 0) == OK) return OK;
                }
                return w2t(WASTE, to, 0);
        }
#endif

        struct rating {
                int ok:1;    /* card to move in pile? */
                int above;   /* number of movable cards above */
                int below;   /* number of cards below ours */
                int pos;     /* where the card to move is in the pile */
                int top;     /* find_top() */
        } r[NUM_PILES] = {{0}};
        int complete = 0;/* SPIDER: true if any pile would complete a stack */
        int turn =  0; /* SPIDER: true if any pile would turn_over */
        int empty = 0; /* true if any pile would become empty */

        /* 1. rate each pile: */
#ifdef SPIDER
        if (top_to < 0) {
                for (int pile = 0; pile < NUM_PILES; pile++) {
                        if (pile == to) continue;
                        int top = find_top(f.t[pile]);
                        int bottom = first_movable(f.t[pile]);
                        r[pile].pos = bottom; /* need for would_empty */

                        if (top < 0) continue; /* no cards to move */
                        if (would_empty(pile)) continue; /* doesn't help */

                        r[pile].ok++;
                        r[pile].above = 0; /* always take as many as possible */
                        r[pile].below = top - bottom;
                        r[pile].top = top;
                        complete |= would_complete(pile); /* never happens */
                        turn     |= would_turn(pile);
                        empty    |= would_empty(pile);
                }
        } else
#endif
        for (int pile = 0; pile < NUM_PILES; pile++) {
                r[pile].top = r[pile].pos = find_top(f.t[pile]);
                /* backtrack until we find a compatible-to-'to'-pile card: */
#ifdef FREECELL
                int maxmove = max_move(pile, -1);
#endif
                while (r[pile].pos >= 0 && is_movable(f.t[pile], r[pile].pos)) {
                        int rankdiff = get_rank(f.t[pile][r[pile].pos])
                                       - get_rank(f.t[to][top_to]);
                        if (rankdiff >= 0) break; /* past our card */
#ifdef FREECELL
                        if (!maxmove--) break; /* can't move this many cards */
#endif
                        if (rankdiff == -1 /* rank matches */
#if defined KLONDIKE || defined FREECELL
                        && get_color(f.t[pile][r[pile].pos]) /* color OK */
                           != get_color(f.t[to][top_to])
#elif defined SPIDER
                        && get_suit(f.t[pile][r[pile].pos]) /* color OK */
                           == get_suit(f.t[to][top_to])
#endif
                        ) {
                                r[pile].ok++;
                                complete |= would_complete(pile);
                                turn     |= would_turn(pile);
                                empty    |= would_empty(pile);
                                for (int i = r[pile].pos; i >= 0; i--)
                                        if (is_movable(f.t[pile], i-1))
                                                r[pile].above++;
                                        else break;
                                break;
                        }
                        r[pile].pos--;
                        r[pile].below++;
                }
        }

        /* 2. find optimal pile: (optimized for spider) */
        //todo: in spider, prefer longest piles if above==0 (faster completions)
        int from = -1;
        for (int pile = 0, above = 99, below = 99; pile < NUM_PILES; pile++) {
                if (!r[pile].ok) continue;
                /* don't bother if another pile would be better: prefer ... */
                /* ... to complete a stack: */
                if (!would_complete(pile) && complete) continue;
                /* ... emptying piles: */
                if (!would_empty(pile) && empty && !complete) continue;
                /* ... to turn_over: */
                if (!would_turn(pile) && turn && !complete && !empty) continue;
                /* ... not to rip apart too many cards: */
                if (r[pile].above > above) continue;
                /* if tied, prefer ... */
                if (r[pile].above == above
                   /* ... larger pile if destination is empty */
                   && (top_to < 0? r[pile].below < below
                   /* ... shorter pile otherwise */
                                 : r[pile].below > below))
                        continue;

                from = pile;
                above = r[pile].above;
                below = r[pile].below;
        }

        /* 3. move cards over and return: */
#ifdef KLONDIKE
        /* prefer waste if it wouldn't turn_over: */
        /* NOTE: does not attempt to take from froundation */
        if (!empty && !turn && w2t(WASTE, to, 0) == OK)
                return OK;
        if (from < 0) /* nothing found */
                return ERR;
        return t2t(from, to, 0);
#elif defined SPIDER
        if (from < 0) /* nothing found */
                return ERR;
        int bottom = first_movable(f.t[from]);
        return t2t(from, to, get_rank(f.t[from][bottom]));
#elif defined FREECELL
        if (from < 0) /* no tableu move found */ {
                /* try all free cells before giving up: */
                for (int i = 0; i < NUM_CELLS; i++)
                        if (c2t(STOCK, to, i) == OK) return OK;
                return ERR;
        }
        return t2t(from, to, 0);
#endif
}
#undef would_empty
#undef would_turn
#undef would_complete
int nop(int from, int to, int opt) { (void)from;(void)to;(void)opt;return ERR; }
// }}}

// keyboard input handling {{{
// cursor functions{{{
#ifdef KLONDIKE
void cursor_left (struct cursor* cursor) {
        op.h = 1;
        if (is_tableu(cursor->pile)) {
                if (cursor->pile > 0) cursor->pile--;
                cursor->opt = 0;
        } else { /* stock/waste/foundation*/
                switch (cursor->pile) {
                case WASTE: cursor->pile = STOCK; cursor->opt = 0; break;
                case FOUNDATION:
                        if (cursor->opt <= 0)
                                cursor->pile = WASTE;
                        else
                                cursor->opt--;
                }
        }
}
void cursor_down (struct cursor* cursor) {
        op.h = 1;
        if (!is_tableu(cursor->pile)) {
                switch (cursor->pile) {
                case STOCK: cursor->pile = TAB_1; break;
                case WASTE: cursor->pile = TAB_2; break;
                case FOUNDATION:
                        cursor->pile = TAB_4 + cursor->opt;
                }
                cursor->opt = 0;
        }
}
void cursor_up (struct cursor* cursor) {
        op.h = 1;
        if (is_tableu(cursor->pile)) {
                switch (cursor->pile) { //ugly :|
                case TAB_1: cursor->pile = STOCK; break;
                case TAB_2: cursor->pile = WASTE; break;
                case TAB_3: cursor->pile = WASTE; break;
                case TAB_4: case TAB_5: case TAB_6: case TAB_7:
                        cursor->opt=cursor->pile-TAB_4;
                        cursor->pile = FOUNDATION;
                        break;
                }
        }
}
void cursor_right (struct cursor* cursor) {
        op.h = 1;
        if (is_tableu(cursor->pile)) {
                if (cursor->pile < TAB_MAX) cursor->pile++;
                cursor->opt = 0;
        } else {
                switch (cursor->pile) {
                case STOCK: cursor->pile = WASTE; break;
                case WASTE: cursor->pile = FOUNDATION;cursor->opt = 0; break;
                case FOUNDATION:
                        if (cursor->opt < NUM_SUITS-1)
                                cursor->opt++;
                }
        }
}
#elif defined SPIDER
/*NOTE: one can't highlight the stock due to me being too lazy to implement it*/
void cursor_left (struct cursor* cursor) {
        op.h = 1;
        if (cursor->pile > 0) cursor->pile--;
        cursor->opt = 0;
}
void cursor_down (struct cursor* cursor) {
        op.h = 1;
        int first = first_movable(f.t[cursor->pile]);
        int top = find_top(f.t[cursor->pile]);
        if (first + cursor->opt < top)
                cursor->opt++;
}
void cursor_up (struct cursor* cursor) {
        op.h = 1;
        if (cursor->opt > 0) cursor->opt--;
}
void cursor_right (struct cursor* cursor) {
        op.h = 1;
        if (cursor->pile < TAB_MAX) cursor->pile++;
        cursor->opt = 0;
}
#elif defined FREECELL
void cursor_left (struct cursor* cursor) {
        op.h = 1;
        if (is_tableu(cursor->pile)) {
                if (cursor->pile > 0) cursor->pile--;
                cursor->opt = 0;
        } else { /* cells/foundation*/
                switch (cursor->pile) {
                case STOCK:
                        if (cursor->opt > 0)
                                cursor->opt--;
                        break;
                case FOUNDATION:
                        if (cursor->opt <= 0) {
                                cursor->pile = STOCK;
                                cursor->opt = 3;
                        } else {
                                cursor->opt--;
                        }
                }
        }
}
void cursor_down (struct cursor* cursor) {
        op.h = 1;
        if (is_tableu(cursor->pile)) {
                if (cursor->opt < max_move(cursor->pile, -1)-1)
                        cursor->opt++;
        } else {
                cursor->pile = cursor->opt+NUM_CELLS*(cursor->pile==FOUNDATION);
                cursor->opt = 0;
        }
}
void cursor_up (struct cursor* cursor) {
        op.h = 1;
        if (is_tableu(cursor->pile)) {
                if (cursor->opt > 0) {
                        cursor->opt--;
                } else {
                        switch (cursor->pile) {
                        case TAB_1: case TAB_2: case TAB_3: case TAB_4:
                                cursor->opt = cursor->pile; /*assumes TAB_1==0*/
                                cursor->pile = STOCK;
                                break;
                        case TAB_5: case TAB_6: case TAB_7: case TAB_8:
                                cursor->opt = cursor->pile - NUM_CELLS;
                                cursor->pile = FOUNDATION;
                        }
                }
        }
}
void cursor_right (struct cursor* cursor) {
        op.h = 1;
        if (is_tableu(cursor->pile)) {
                if (cursor->pile < TAB_MAX) cursor->pile++;
                cursor->opt = 0;
        } else {
                switch (cursor->pile) {
                case STOCK:
                        if (cursor->opt < NUM_SUITS-1) {
                                cursor->opt++;
                        } else {
                                cursor->pile = FOUNDATION;
                                cursor->opt = 0;
                        } break;
                case FOUNDATION:
                        if (cursor->opt < NUM_SUITS-1)
                                cursor->opt++;
                }
        }
}
#endif
void cursor_to (struct cursor* cursor, int pile) {
        op.h = 1;
        cursor->pile = pile;
        cursor->opt = 0;
}
int set_mouse(int pile, int* main, int* opt) {
//TODO: this should set cursor.opt, so card selector choice dialog does not trigger!
        op.h = 0;
        if (pile < 0) return 1;
        *main = pile;
#ifdef KLONDIKE
        if (pile >= FOUNDATION)//TODO: check upper bound!
                *main = FOUNDATION,
                *opt  = pile - FOUNDATION;
#elif defined SPIDER
        (void)opt;
#elif defined FREECELL
        if (pile > TAB_MAX) {
                *main = pile-STOCK < NUM_CELLS? STOCK : FOUNDATION;
                *opt = (pile-STOCK) % 4;
        }
#endif
        return 0;
}
//}}}
int get_cmd (int* from, int* to, int* opt) {
        int _f, t;
        unsigned char mouse[6] = {0}; /* must clear [3]! */
        struct cursor inactive = {-1,-1};
        static struct cursor active = {0,0};
        if (is_tableu(active.pile))
                active.opt = 0;

        /***/
from_l: print_table(&active, &inactive);
        _f = getch(mouse);

        switch (_f) {
        /* direct addressing: */
        case '1': *from = TAB_1; break;
        case '2': *from = TAB_2; break;
        case '3': *from = TAB_3; break;
        case '4': *from = TAB_4; break;
        case '5': *from = TAB_5; break;
        case '6': *from = TAB_6; break;
        case '7': *from = TAB_7; break;
#ifdef SPIDER
        case '8': *from = TAB_8; break;
        case '9': *from = TAB_9; break;
        case '0': *from = TAB_10;break;
#elif defined FREECELL
        case '8': *from = TAB_8; break;
        case '9': *from = STOCK; break;
        case '0': *from = FOUNDATION; break;
#elif defined KLONDIKE
        case '9': *from = WASTE; break;
        case '0': *from = FOUNDATION; break;
        case '8': /* fallthrough */
#endif
#ifndef FREECELL
        case '\n': *from = STOCK; break;
#endif
        /* cursor keys addressing: */
        case KEY_LEFT:
        case 'h': cursor_left (&active); goto from_l;
        case KEY_DOWN:
        case 'j': cursor_down (&active); goto from_l;
        case KEY_UP:
        case 'k': cursor_up   (&active); goto from_l;
        case KEY_RIGHT:
        case 'l': cursor_right(&active); goto from_l;
        case KEY_HOME:
        case 'H': cursor_to(&active,TAB_1);  goto from_l; /* leftmost  tableu */
        case KEY_END:
        case 'L': cursor_to(&active,TAB_MAX);goto from_l; /* rigthmost tableu */
        case KEY_INS:
        case 'M': cursor_to(&active,TAB_MAX/2); goto from_l; /* center tableu */
        case ' ': /* continue with second cursor */
                *from = active.pile;
#ifdef KLONDIKE
                *opt = active.opt; /* when FOUNDATION */
#endif
                inactive = active;
                break;
        /* mouse addressing: */
        case MOUSE_MIDDLE: return CMD_NONE;
        case MOUSE_RIGHT:
                if (set_mouse(term2pile(mouse), to, opt))
                        return CMD_INVAL;
                goto join_l;
        case MOUSE_LEFT:
                if (set_mouse(term2pile(mouse), from, opt))
                        return CMD_INVAL;
                if (!is_tableu(*from))
                        inactive.opt = *opt; /* prevents card selector dialog */
                break;
        /* misc keys: */
        case ':':
                {char buf[256];
                fprintf (stderr, ":");
                raw_mode(0); /* turn on echo */
                fgets (buf, 256, stdin);
                raw_mode(1);
                switch(buf[0]) {
                case 'q': return CMD_QUIT;
                case 'n': return CMD_NEW;
                case 'r': return CMD_AGAIN;
                case 'h': return CMD_HELP;
                default:  return CMD_INVAL;
                }}
        case 'J':
                *to = active.pile;
join_l:
#ifdef KLONDIKE
                if (*to == FOUNDATION) return CMD_JOIN;
#endif
                if (*to > TAB_MAX) return CMD_INVAL;
                return CMD_JOIN;
        case 'K': /* fallthrough */
        case '?': return CMD_HINT;
        case 'u': return CMD_UNDO;
        case 002: return CMD_NONE; /* sent by SIGWINCH */
        case EOF: return CMD_NONE; /* sent by SIGCONT */
        default: return CMD_INVAL;
        }
        inactive.pile = *from; /* for direct addressing highlighting */
        if (is_tableu(*from) && f.t[*from][0] == NO_CARD) return CMD_INVAL;

#ifndef FREECELL
        if (*from == STOCK) {
                *to = WASTE;
                return CMD_MOVE;
        }
#endif

        /***/
to_l:   print_table(&active, &inactive);
        t = getch(mouse);

        switch (t) {
        case KEY_LEFT:
        case 'h': cursor_left (&active); goto to_l;
        case KEY_DOWN:
        case 'j': cursor_down (&active); goto to_l;
        case KEY_UP:
        case 'k': cursor_up   (&active); goto to_l;
        case KEY_RIGHT:
        case 'l': cursor_right(&active); goto to_l; 
        case KEY_HOME:
        case 'H': cursor_to(&active,TAB_1);     goto to_l;
        case KEY_END:
        case 'L': cursor_to(&active,TAB_MAX);   goto to_l;
        case KEY_INS:
        case 'M': cursor_to(&active,TAB_MAX/2); goto to_l;
        case 'J': /* fallthrough; just join selected pile */
        case ' ':
                *to = active.pile;
                break; /* continues with the foundation/empty tableu check */
        case MOUSE_MIDDLE:
        case MOUSE_RIGHT: return CMD_NONE;
        case MOUSE_LEFT:
                if (set_mouse(term2pile(mouse), to, opt))
                        return CMD_INVAL;
/*#ifdef SPIDER
                //TODO: set opt if to field is empty; suppress "up do" dialog from below
                if (is_tableu(*to) && f.t[*to][0] == NO_CARD) {
                        int top = find_top(f.t[*from]);
                        if (top < 0) return CMD_INVAL;
                        if (top >= 0 && !is_movable(f.t[*from], top-1)) {
                                *opt = get_rank(f.t[*from][top]);
                        } else {
                        // ask user
                        }
                }
#endif*/
                break;
        case 'K': /* fallthrough */
        case '?': return CMD_HINT;
        case 'u': return CMD_NONE; /* cancel selection */
        case EOF: return CMD_NONE; /* sent by SIGCONT */
        default:
                if (t < '0' || t > '9') return CMD_INVAL;
                if (t == '0')
#ifdef KLONDIKE
                        *to = FOUNDATION;
#elif defined SPIDER
                        *to = TAB_10;
#elif defined FREECELL
                        *to = FOUNDATION;
                else if (t == '9')
                        *to = STOCK;
#endif
                else
                        *to = t-'1';
        }

        /***/
#ifdef KLONDIKE
        if (*from == FOUNDATION) {
                if (inactive.opt >= 0) {
                        *opt = inactive.opt;
                        return CMD_MOVE;
                }
                int top = find_top(f.t[*to]);
                if (top < 0) return CMD_INVAL;
                int color = get_color(f.t[*to][top]);
                int choice_1 = 1-color; /* selects piles of   */
                int choice_2 = 2+color; /* the opposite color */
                int top_c1 = find_top(f.f[choice_1]);
                int top_c2 = find_top(f.f[choice_2]);

                switch ((rank_next(f.f[choice_1][top_c1], f.t[*to][top])
                         && top_c1 >= 0 ) << 0
                       |(rank_next(f.f[choice_2][top_c2], f.t[*to][top])
                         && top_c2 >= 0 ) << 1) {
                case (       1<<0): *opt = choice_1; break; /* choice_1 only */
                case (1<<1       ): *opt = choice_2; break; /* choice_2 only */
                case (1<<1 | 1<<0): /* both, ask user which to pick from */
                        printf ("take from (1-4): "); fflush (stdout);
                        *opt = getch(NULL) - '1';
                        if (*opt < 0 || *opt > 3) return CMD_INVAL;
                        break;
                default: return CMD_INVAL; /* none matched */
                }
                /* `opt` is the foundation index (0..3) */
        }
#elif defined SPIDER
        /* moving to empty tableu? */
        if (is_tableu(*to) && f.t[*to][0] == NO_CARD) {
                int bottom = first_movable(f.t[*from]);
                if (inactive.opt >= 0) { /*if from was cursor addressed: */
                        *opt = get_rank(f.t[*from][bottom + inactive.opt]);
                        return CMD_MOVE;
                }
                int top = find_top(f.t[*from]);
                if (top < 0) return CMD_INVAL;
                if (top >= 0 && !is_movable(f.t[*from], top-1)) {
                        *opt = get_rank(f.t[*from][top]);
                } else { /* only ask the user if it's unclear: */
                        printf ("\rup to ([a23456789xjqk] or space/return): ");
                        *opt = getch(NULL);
                        switch (*opt) {
                        case ' ': *opt = get_rank(f.t[*from][top]); break;
                        case'\n': *opt = get_rank(f.t[*from][bottom]); break;
                        case 'a': case 'A': *opt = RANK_A; break;
                        case '0': /* fallthrough */
                        case 'x': case 'X': *opt = RANK_X; break;
                        case 'j': case 'J': *opt = RANK_J; break;
                        case 'q': case 'Q': *opt = RANK_Q; break;
                        case 'k': case 'K': *opt = RANK_K; break;
                        default: *opt -= '1';
                        }
                        if (*opt < RANK_A || *opt > RANK_K) return ERR;
                }
                /* `opt` is the rank of the highest card to move */
        }
#elif defined FREECELL
        //TODO FREECELL: card selector choice dialog

        /* if it was selected with a cursor, it's obvious: */
        if (inactive.opt >= 0) {
                if (is_tableu(*from)) {
                        /* NOTE: max_move same as in cursor_down() */
                        *opt = max_move(*from, -1) - inactive.opt;
                } else {
                        *opt = inactive.opt;
                }
        /* moving from tableu to empty tableu? */
        } else if (is_tableu(*from) && is_tableu(*to) && f.t[*to][0] == NO_CARD) {
                // how many cards? (NOTE: spider asks "up to rank?"; do this then convert to number of cards?
printf ("take how many (1-9): "); fflush (stdout);
*opt = getch(NULL) - '0';
if (*opt < 1 || *opt > 9) return CMD_INVAL;
        /* moving between stock/foundation? */
        } else if (*from == FOUNDATION && *to == STOCK) {
                //can take from all non-empty foundations
printf ("take from (1-4): "); fflush (stdout);
*opt = getch(NULL) - '1';
if (*opt < 0 || *opt > 3) return CMD_INVAL;
        } else if (*from == STOCK && *to == FOUNDATION) {
                //check all non-empty cells
printf ("take from (1-4): "); fflush (stdout);
*opt = getch(NULL) - '1';
if (*opt < 0 || *opt > 3) return CMD_INVAL;
        } else if (*from == FOUNDATION || *from == STOCK) { /* -> tableu */
                //foundation: 2 choices
                //stock: 4 choices
printf ("take from (1-4): "); fflush (stdout);
*opt = getch(NULL) - '1';
if (*opt < 0 || *opt > 3) return CMD_INVAL;
        }
#endif
        return CMD_MOVE;
}

int getctrlseq(unsigned char* buf) {
        int c;
        enum esc_states {
                START,
                ESC_SENT,
                CSI_SENT,
                MOUSE_EVENT,
        } state = START;
        int offset = 0x20; /* never sends control chars as data */
        while ((c = getchar()) != EOF) {
                switch (state) {
                case START:
                        switch (c) {
                        case '\033': state=ESC_SENT; break;
                        default: return c;
                        }
                        break;
                case ESC_SENT:
                        switch (c) {
                        case '[': state=CSI_SENT; break;
                        default: return KEY_INVAL;
                        }
                        break;
                case CSI_SENT:
                        switch (c) {
                        case 'A': return KEY_UP;
                        case 'B': return KEY_DOWN;
                        case 'C': return KEY_RIGHT;
                        case 'D': return KEY_LEFT;
                        /*NOTE: home/end send ^[[x~ . no support for modifiers*/
                        case 'H': return KEY_HOME;
                        case 'F': return KEY_END;
                        case '2': getchar(); return KEY_INS;
                        case '5': getchar(); return KEY_PGUP;
                        case '6': getchar(); return KEY_PGDN;
                        case 'M': state=MOUSE_EVENT; break;
                        default: return KEY_INVAL;
                        }
                        break;
                case MOUSE_EVENT:
                        if (buf == NULL) return KEY_INVAL;
                        buf[0] = c - offset;
                        buf[1] = getchar() - offset;
                        buf[2] = getchar() - offset;
                        return MOUSE_ANY;
                default:
                        return KEY_INVAL;
                }
        }
        return 2;
}
int term2pile(unsigned char *mouse) {
        int line   = (mouse[2]-1);
        int column = (mouse[1]-1) / op.s->width;

        if (line < op.s->height) { /* first line */
#ifdef KLONDIKE
                switch (column) {
                case 0: return STOCK;
                case 1: return WASTE;
                case 2: return -1; /* spacer */
                case 3: return FOUNDATION+0;
                case 4: return FOUNDATION+1;
                case 5: return FOUNDATION+2;
                case 6: return FOUNDATION+3;
                }
#elif defined SPIDER
                if (column < 3) return STOCK;
                return -1;
#elif defined FREECELL
                if (column < NUM_SUITS + NUM_CELLS) return STOCK+column;
                return -1;
#endif
        } else if (line > op.s->height) { /* tableu */
                if (column <= TAB_MAX) return column;
        }
        return -1;
}
int wait_mouse_up(unsigned char* mouse) {
        //TODO: mouse drag: start gets inactive, hovering gets active cursors
        struct cursor cur = {-1,-1};
        int level = 1;
        /* note: if dragged [3]==1 and second position is in mouse[0,4,5] */

        /* display a cursor while mouse button is pushed: */
        int pile = term2pile(mouse);
        cur.pile = pile;
#ifdef KLONDIKE
        if (pile >= FOUNDATION) {
                cur.pile = FOUNDATION;
                cur.opt = pile-FOUNDATION;
        }
#elif defined FREECELL
        if (pile > TAB_MAX) {
                cur.pile = pile-STOCK < NUM_CELLS? STOCK : FOUNDATION;
                cur.opt = (pile-STOCK) % 4;
        }
#endif
        /* need to temporarily show the cursor, then revert to last state: */
        int old_show_cursor_hi = op.h; //TODO: ARGH! that's awful!
        op.h = 1;
        print_table(&cur, NO_HI); //TODO: should not overwrite inactive cursor!
        op.h = old_show_cursor_hi;

        while (level > 0) {
                if (getctrlseq (mouse+3) == MOUSE_ANY) {
                        /* ignore mouse wheel events: */
                        if (mouse[3] & 0x40) continue;

                        else if((mouse[3]&3) == 3) level--; /* release event */
                        else level++; /* another button pressed */
                }
        }

        int success = mouse[1] == mouse[4] && mouse[2] == mouse[5];
        if (success) {
                mouse[3] = 0;
        }
        return success;
}

int getch(unsigned char* buf) {
/* returns a character, EOF, or constant for an escape/control sequence - NOT
compatible with the ncurses implementation of same name */
        int action;
        if (buf && buf[3]) {
                /* mouse was dragged; return 'ungetted' previous destination */
                action = MOUSE_DRAG;
                /* keep original [0], as [3] only contains release event */
                buf[1] = buf[4];
                buf[2] = buf[5];
                buf[3] = 0;
        } else {
                action = getctrlseq(buf);
        }

        switch (action) {
        case MOUSE_ANY:
                if (buf[0] > 3) break; /* ignore wheel events */
                wait_mouse_up(buf);
                /* fallthrough */
        case MOUSE_DRAG:
                switch (buf[0]) {
                case 0: return MOUSE_LEFT;
                case 1: return MOUSE_MIDDLE;
                case 2: return MOUSE_RIGHT;
                }
        }

        return action;
}
// }}}

// shuffling and dealing {{{
void deal(long seed) {
        f = (const struct playfield){0}; /* clear playfield */
        card_t deck[DECK_SIZE*NUM_DECKS];
        int avail = DECK_SIZE*NUM_DECKS;
        for (int i = 0; i < DECK_SIZE*NUM_DECKS; i++) deck[i] = (i%DECK_SIZE)+1;
#ifdef SPIDER
        if (op.m != NORMAL) for (int i = 0; i < DECK_SIZE*NUM_DECKS; i++) {
                if (op.m == MEDIUM) deck[i] = 1+((deck[i]-1) | 2);
                if (op.m == EASY)   deck[i] = 1+((deck[i]-1) | 2 | 1);
                /* the 1+ -1 dance gets rid of the offset created by NO_CARD */
        }
#endif
        srand (seed);
        for (int i = DECK_SIZE*NUM_DECKS-1; i > 0; i--) { /* fisher-yates */
                int j = rand() % (i+1);
                if (j-i) deck[i]^=deck[j],deck[j]^=deck[i],deck[i]^=deck[j];
        }

        /* deal cards: */
        for (int i = 0; i < NUM_PILES; i++) {
#ifdef KLONDIKE
#define SIGN -
                int count = i; /* pile n has n closed cards, then 1 open */
#elif defined SPIDER
#define SIGN -
                int count = i<4?5:4; /* pile 1-4 have 5, 5-10 have 4 closed */
#elif defined FREECELL
#define SIGN +
                int count = i<4?6:5;/*like spider, but cards are dealt face-up*/
#endif
                /* "SIGN": face down cards are negated */
                for (int j = 0; j < count; j++) f.t[i][j] = SIGN deck[--avail];
                f.t[i][count] = deck[--avail]; /* the face-up card */
#undef SIGN
        }
        /* rest of the cards to the stock: */
        /* NOTE: assert(avail==50) for spider, assert(avail==0) for freecell */
        for (f.z = 0; avail; f.z++) f.s[f.z] = deck[--avail];
#ifdef KLONDIKE
        f.w = -1; /* @start: nothing on waste */
#elif defined SPIDER
        f.w = 0; /* number of used foundations */
#elif defined FREECELL
        f.w = 0; /* bitmask of used free cells */
#endif

        f.u = &undo_sentinel;
}
//}}}

// screen drawing routines {{{
void print_hi(int invert, int grey_bg, int bold, char* str) {
        if (!op.h) invert = 0; /* don't show invert if we used the mouse last */
        if (bold && op.s == &unicode_large_color){ //awful hack for bold + faint
                int offset = str[3]==017?16:str[4]==017?17:0;
                printf ("%s%s%s""%.*s%s%s""%s%s%s",
                        "\033[1m", invert?"\033[7m":"", grey_bg?"\033[100m":"",
                        offset, str, bold?"\033[1m":"", str+offset,
                        grey_bg?"\033[49m":"", invert?"\033[27m":"","\033[22m");
                return;
        }
        printf ("%s%s%s%s%s%s%s",
                bold?"\033[1m":"", invert?"\033[7m":"", grey_bg?"\033[100m":"",
                str,
                grey_bg?"\033[49m":"", invert?"\033[27m":"",bold?"\033[22m":"");
}
void print_table(const struct cursor* active, const struct cursor* inactive) {
        printf("\033[2J\033[H"); /* clear screen, reset cursor */
#ifdef KLONDIKE
        /* print stock, waste and foundation: */
        for (int line = 0; line < op.s->height; line++) {
                /* stock: */
                print_hi (active->pile == STOCK, inactive->pile == STOCK, 1, (
                        (f.w < f.z-1)?op.s->facedown
                        :op.s->placeholder)[line]);
                /* waste: */
                print_hi (active->pile == WASTE, inactive->pile == WASTE, 1, (
                        /* NOTE: cast, because f.w sometimes is (short)-1 !? */
                        ((short)f.w >= 0)?op.s->card[f.s[f.w]]
                        :op.s->placeholder)[line]);
                printf ("%s", op.s->card[NO_CARD][line]); /* spacer */
                /* foundation: */
                for (int pile = 0; pile < NUM_SUITS; pile++) {
                        int card = find_top(f.f[pile]);
                        print_hi (active->pile==FOUNDATION && active->opt==pile,
                                inactive->pile==FOUNDATION && (
                                        /* cursor addr.     || direct addr.   */
                                        inactive->opt==pile || inactive->opt < 0
                                ), 1,
                                (card < 0)?op.s->foundation[line]
                                :op.s->card[f.f[pile][card]][line]);
                }
                printf("\n");
        }
        printf("\n");
#elif defined SPIDER
        int fdone; for (fdone = NUM_DECKS*NUM_SUITS; fdone; fdone--)
                if (f.f[fdone-1][RANK_K]) break;  /*number of completed stacks*/
        int spacer_from = f.z?(f.z/10-1) * op.s->halfwidth[0] + op.s->width:0;
        int spacer_to   = NUM_PILES*op.s->width -
                ((fdone?(fdone-1) * op.s->halfwidth[1]:0)+op.s->width);
        for (int line = 0; line < op.s->height; line++) {
                /* available stock: */
                for (int i = f.z/10; i; i--) {
                        if (i==1) printf ("%s", op.s->facedown[line]);
                        else      printf ("%s", op.s->halfstack[line]);
                }
                /* spacer: */
                for (int i = spacer_from; i < spacer_to; i++) printf (" ");
                /* foundation (overlapping): */
                for (int i = NUM_DECKS*NUM_SUITS-1, half = 0; i >= 0; i--) {
                        int overlap = half? op.s->halfcard[line]: 0;
                        if (f.f[i][RANK_K]) printf ("%.*s", op.s->halfwidth[2],
                                op.s->card[f.f[i][RANK_K]][line]+overlap),
                                half++;
                }
                printf("\n");
        }
        printf("\n");
#elif defined FREECELL
        /* print open cells, foundation: */
        for (int line = 0; line < op.s->height; line++) {
                for (int pile = 0; pile < NUM_CELLS; pile++)
                        print_hi (active->pile==STOCK && active->opt==pile,
                                inactive->pile==STOCK && (
                                        /* cursor addr.     || direct addr.   */
                                        inactive->opt==pile || inactive->opt < 0
                                ), 1,
                                ((f.s[pile])?op.s->card[f.s[pile]]
                                :op.s->placeholder)[line]);
                for (int pile = 0; pile < NUM_SUITS; pile++) {
                        int card = find_top(f.f[pile]);
                        print_hi (active->pile==FOUNDATION && active->opt==pile,
                                inactive->pile==FOUNDATION && (
                                        /* cursor addr.     || direct addr.   */
                                        inactive->opt==pile || inactive->opt < 0
                                ), 1,
                                (card < 0)?op.s->foundation[line]
                                :op.s->card[f.f[pile][card]][line]);
                }
                printf("\n");
        }
        printf("\n");
#endif
#ifdef KLONDIKE
#define DO_HI(cursor) (cursor->pile == pile && (movable || empty))
#define TOP_HI(c) 1 /* can't select partial stacks in KLONDIKE */
#elif defined SPIDER || defined FREECELL
        int offset[NUM_PILES]={0}; /* first card to highlight */
#  ifdef FREECELL
        int bottom[NUM_PILES]; /* first movable card */
        for (int i=0; i<NUM_PILES; i++)
                bottom[i] = find_top(f.t[i]) - max_move(i,-1);
#  endif
#define DO_HI(cursor) (cursor->pile == pile && (movable || empty) \
        && offset[pile] >= cursor->opt)
#define TOP_HI(cursor) (cursor->pile == pile && movable \
        && offset[pile] == cursor->opt)
#endif
        /* print tableu piles: */
        int row[NUM_PILES] = {0};
        int line[NUM_PILES]= {0};
        int label[NUM_PILES]={0};
        int line_had_card;
        int did_placeholders = 0;
        do {
                line_had_card = 0;
                for (int pile = 0; pile < NUM_PILES; pile++) {
                        card_t card = f.t[pile][row[pile]];
                        card_t next = f.t[pile][row[pile]+1];
                        int movable = is_movable(f.t[pile], row[pile]);
#ifdef FREECELL
                        if(row[pile] <= bottom[pile]) movable = 0;
#endif
                        int empty   = !card && row[pile] == 0;

                        print_hi (DO_HI(active), DO_HI(inactive), movable, (
                                (!card && row[pile] == 0)?op.s->placeholder
                                :(card<0)?op.s->facedown
                                :op.s->card[card]
                                )[line[pile]]);

                        int extreme_overlap = ( 3  /* spacer, labels, status */
                                + 2 * op.s->height /* stock, top tableu card */
                                + find_top(f.t[pile]) * op.s->overlap) >op.w[0];
                        /* normal overlap: */
                        if (++line[pile] >= (next?op.s->overlap:op.s->height)
                        /* extreme overlap on closed cards: */
                        || (extreme_overlap &&
                            line[pile] >= 1 &&
                            f.t[pile][row[pile]] < 0 &&
                            f.t[pile][row[pile]+1] <0)
                        /* extreme overlap on sequences: */
                        || (extreme_overlap &&
                            !TOP_HI(active) && /*always show top selected card*/
                            line[pile] >= 1 && row[pile] > 0 &&
                            f.t[pile][row[pile]-1] > NO_CARD &&
                            is_consecutive (f.t[pile], row[pile]) &&
                            is_consecutive (f.t[pile], row[pile]-1) &&
                            f.t[pile][row[pile]+1] != NO_CARD)
                        ) {
                                line[pile]=0;
                                row[pile]++;
#if defined SPIDER || defined FREECELL
                                if (movable) offset[pile]++;
#endif
                        }
                        /* tableu labels: */
                        if(!card && !label[pile] && row[pile]>0&&line[pile]>0) {
                                label[pile] = 1;
                                printf ("\b\b%d ", (pile+1) % 10); //XXX: hack
                        }
                        line_had_card |= !!card;
                        did_placeholders |= row[pile] > 0;
                }
                printf ("\n");
        } while (line_had_card || !did_placeholders);
}

void visbell (void) {
        if (!op.v) return;
        printf ("\033[?5h"); fflush (stdout);
        usleep (100000);
        printf ("\033[?5l"); fflush (stdout);
}
void win_anim(void) {
        printf ("\033[?25l"); /* hide cursor */
        for (;;) {
                /* set cursor to random location */
                int row = 1+rand()%(1+op.w[0]-op.s->height);
                int col = 1+rand()%(1+op.w[1]-op.s->width);

                /* draw random card */
                int face = 1 + rand() % 52;
                for (int l = 0; l < op.s->height; l++) {
                        printf ("\033[%d;%dH", row+l, col);
                        printf ("%s", op.s->card[face][l]);
                }
                fflush (stdout);

                /* exit on keypress */
                struct pollfd p = {STDIN_FILENO, POLLIN, 0};
                if (poll (&p, 1, 80)) goto fin;
        }
fin:
        printf ("\033[?25h"); /* show cursor */
        return;
}
//}}}

// undo logic {{{
void undo_push (int _f, int t, int n, int o) {
        struct undo* new = malloc(sizeof(struct undo));
        new->f = _f;
        new->t = t;
        new->n = n;
        new->o = o;
        new->prev = f.u;
        new->next = NULL;
        f.u->next = new;
        f.u = f.u->next;
}
void undo_pop (struct undo* u) {
        if (u == &undo_sentinel) return;

#ifdef KLONDIKE
        if (u->f == FOUNDATION) {
                /* foundation -> tableu */
                int top_f = find_top(f.f[u->n]);
                int top_t = find_top(f.t[u->t]);
                f.f[u->n][top_f+1] = f.t[u->t][top_t];
                f.t[u->t][top_t] = NO_CARD;
        } else if (u->f == WASTE && u->t == FOUNDATION) {
                /* waste -> foundation */
                /* split u->n into wst and fnd: */
                int wst = u->n & 0xffff;
                int fnd = u->n >> 16;
                /* move stock cards one position up to make room: */
                for (int i = f.z; i >= wst; i--) f.s[i+1] = f.s[i];
                /* move one card from foundation to waste: */
                int top = find_top(f.f[fnd]);
                f.s[wst] = f.f[fnd][top];
                f.f[fnd][top] = NO_CARD;
                f.z++;
                f.w++;
        } else if (u->f == WASTE) {
                /* waste -> tableu */
                /* move stock cards one position up to make room: */
                for (int i = f.z-1; i >= u->n; i--) f.s[i+1] = f.s[i];
                /* move one card from tableu to waste: */
                int top = find_top(f.t[u->t]);
                f.s[u->n] = f.t[u->t][top];
                f.t[u->t][top] = NO_CARD;
                f.z++;
                f.w++;
        } else if (u->t == FOUNDATION) {
                /* tableu -> foundation */
                int top_f = find_top(f.t[u->f]);
                int top_t = find_top(f.f[u->n]);
                /* close topcard if previous action caused turn_over(): */
                if (u->o) f.t[u->f][top_f] *= -1;
                /* move one card from foundation to tableu: */
                f.t[u->f][top_f+1] = f.f[u->n][top_t];
                f.f[u->n][top_t] = NO_CARD;
        } else {
                /* tableu -> tableu */
                int top_f = find_top(f.t[u->f]);
                int top_t = find_top(f.t[u->t]);
                /* close topcard if previous action caused turn_over(): */
                if (u->o) f.t[u->f][top_f] *= -1;
                /* move n cards from tableu[f] to tableu[t]: */
                for (int i = 0; i < u->n; i++) {
                        f.t[u->f][top_f+u->n-i] = f.t[u->t][top_t-i];
                        f.t[u->t][top_t-i] = NO_CARD;
                }
        }
#elif defined SPIDER
        if (u->f == STOCK) {
                /* stock -> tableu */
                /*remove a card from each pile and put it back onto the stock:*/
                for (int pile = NUM_PILES-1; pile >= 0; pile--) {
                        int top = find_top(f.t[pile]);
                        f.s[f.z++] = f.t[pile][top];
                        f.t[pile][top] = NO_CARD;
                }
        } else if (u->t == FOUNDATION) {
                /* tableu -> foundation */
                int top = find_top(f.t[u->f]);
                /* close topcard if previous action caused turn_over(): */
                if (u->o) f.t[u->f][top] *= -1;
                /* append cards from foundation to tableu */
                for (int i = RANK_K; i >= RANK_A; i--) {
                        f.t[u->f][++top] = f.f[u->n][i];
                        f.f[u->n][i] = NO_CARD;
                }
                f.w--; /* decrement complete-foundation-counter */

        } else {
                /* tableu -> tableu */
                int top_f = find_top(f.t[u->f]);
                int top_t = find_top(f.t[u->t]);
                /* close topcard if previous action caused turn_over(): */
                if (u->o) f.t[u->f][top_f] *= -1;
                /* move n cards from tableu[f] to tableu[t]: */
                for (int i = 0; i < u->n; i++) {
                        f.t[u->f][top_f+u->n-i] = f.t[u->t][top_t-i];
                        f.t[u->t][top_t-i] = NO_CARD;
                }
        }
#elif defined FREECELL
        /*NOTE: if from and to are both stock/foundation, opt = from | to<<16 */
        if (u->f == STOCK && u->t == FOUNDATION) {
                /* free cells -> foundation */
                /* split u->n into cll and fnd: */
                int cll = u->n & 0xffff;
                int fnd = u->n >> 16;
                /* move one card from foundation to free cell: */
                int top = find_top(f.f[fnd]);
                f.s[cll] = f.f[fnd][top];
                f.f[fnd][top] = NO_CARD;
                f.w |= 1<<cll; /* mark cell as occupied */
        } else if (u->f == STOCK) {
                /* free cells -> cascade */
                int top_t = find_top(f.t[u->t]);
                f.s[u->n] = f.t[u->t][top_t];
                f.t[u->t][top_t] = NO_CARD;
                f.w |= 1<<u->n; /* mark cell as occupied */
        } else if (u->f == FOUNDATION && u->t == STOCK) {
                /* foundation -> free cells */
                /* split u->n into cll and fnd: */
                int cll = u->n >> 16;
                int fnd = u->n & 0xffff;
                /* move 1 card from free cell to foundation: */
                int top_f = find_top(f.f[fnd]);
                f.f[fnd][top_f+1] = f.s[cll];
                f.s[cll] = NO_CARD;
                f.w &= ~(1<<cll); /* mark cell as free */
        } else if (u->f == FOUNDATION) {
                /* foundation -> cascade */
                int top_f = find_top(f.f[u->n]);
                int top_t = find_top(f.t[u->t]);
                f.f[u->n][top_f+1] = f.t[u->t][top_t];
                f.t[u->t][top_t] = NO_CARD;
        } else if (u->t == STOCK) {
                /* cascade -> free cells */
                int top_f = find_top(f.t[u->f]);
                f.t[u->f][top_f+1] = f.s[u->n];
                f.s[u->n] = NO_CARD;
                f.w &= ~(1<<u->n); /* mark cell as free */
        } else if (u->t == FOUNDATION) {
                /* cascade -> foundation */
                int top_f = find_top(f.t[u->f]);
                int top_t = find_top(f.f[u->n]);
                /* move one card from foundation to cascade: */
                f.t[u->f][top_f+1] = f.f[u->n][top_t];
                f.f[u->n][top_t] = NO_CARD;
        } else {
                /* cascade -> cascade */
                int top_f = find_top(f.t[u->f]);
                int top_t = find_top(f.t[u->t]);
                /* move n cards from tableu[f] to tableu[t]: */
                for (int i = 0; i < u->n; i++) {
                        f.t[u->f][top_f+u->n-i] = f.t[u->t][top_t-i];
                        f.t[u->t][top_t-i] = NO_CARD;
                }
        }
#endif

        void* old = f.u;
        f.u = f.u->prev;
        free(old);
}
void free_undo (struct undo* u) {
        while (u && u != &undo_sentinel) {
                void* old = u;
                u = u->prev;
                free (old);
        }
}
//}}}

// initialization stuff {{{
void screen_setup (int enable) {
        if (enable) {
                raw_mode(1);
                printf ("\033[s\033[?47h"); /* save cursor, alternate screen */
                printf ("\033[H\033[J"); /* reset cursor, clear screen */
                printf ("\033[?1000h"); /* enable mouse */
        } else {
                printf ("\033[?1000l"); /* disable mouse */
                printf ("\033[?47l\033[u"); /* primary screen, restore cursor */
                raw_mode(0);
        }
}

void raw_mode(int enable) {
        static struct termios saved_term_mode;
        struct termios raw_term_mode;

        if (enable) {
                if (saved_term_mode.c_lflag == 0)/*don't overwrite stored mode*/
                        tcgetattr(STDIN_FILENO, &saved_term_mode);
                raw_term_mode = saved_term_mode;
                raw_term_mode.c_lflag &= ~(ICANON | ECHO);
                raw_term_mode.c_cc[VMIN] = 1 ;
                raw_term_mode.c_cc[VTIME] = 0;
                tcsetattr(STDIN_FILENO, TCSAFLUSH, &raw_term_mode);
        } else {
                tcsetattr(STDIN_FILENO, TCSAFLUSH, &saved_term_mode);
        }
}

void signal_handler (int signum) {
        struct winsize w;
        switch (signum) {
        case SIGTSTP:
                screen_setup(0);
                signal(SIGTSTP, SIG_DFL); /* NOTE: assumes SysV semantics! */
                raise(SIGTSTP);
                break;
        case SIGCONT:
                screen_setup(1);
                print_table(NO_HI, NO_HI);
                break;
        case SIGINT: //TODO: don't exit; just warn like vim does
                exit(128+SIGINT);
        case SIGWINCH:
                ioctl(STDOUT_FILENO, TIOCGWINSZ, &w);
                op.w[0] = w.ws_row;
                op.w[1] = w.ws_col;
                break;
        }
}
void signal_setup(void) {
        struct sigaction saction;

        saction.sa_handler = signal_handler;
        sigemptyset(&saction.sa_mask);
        saction.sa_flags = 0;
        if (sigaction(SIGTSTP, &saction, NULL) < 0) {
                perror ("SIGTSTP");
                exit (1);
        }
        if (sigaction(SIGCONT, &saction, NULL) < 0) {
                perror ("SIGCONT");
                exit (1);
        }
        if (sigaction(SIGINT, &saction, NULL) < 0) {
                perror ("SIGINT");
                exit (1);
        }
        if (sigaction(SIGWINCH, &saction, NULL) < 0) {
                perror ("SIGWINCH");
                exit (1);
        }
}
//}}}

//vim: foldmethod=marker