Added an automatic `Solve' feature to most games. This is useful for

various things:
 - if you haven't fully understood what a game is about, it gives
   you an immediate example of a puzzle plus its solution so you can
   understand it
 - in some games it's useful to compare your solution with the real
   one and see where you made a mistake
 - in the rearrangement games (Fifteen, Sixteen, Twiddle) it's handy
   to be able to get your hands on a pristine grid quickly so you
   can practise or experiment with manoeuvres on it
 - it provides a good way of debugging the games if you think you've
   encountered an unsolvable grid!

[originally from svn r5731]

1 files changed, 32 insertions, 0 deletions

diff --git a/midend.c b/midend.c
index dbbaad4..084cd16 100644
--- a/midend.c
+++ b/midend.c
@@ -595,3 +595,35 @@ char *midend_text_format(midend_data *me)
     else
 	return NULL;
 }
+
+char *midend_solve(midend_data *me)
+{
+    game_state *s;
+    char *msg;
+
+    if (!me->ourgame->can_solve)
+	return "This game does not support the Solve operation";
+
+    if (me->statepos < 1)
+	return "No game set up to solve";   /* _shouldn't_ happen! */
+
+    msg = "Solve operation failed";    /* game _should_ overwrite on error */
+    s = me->ourgame->solve(me->states[0], me->aux_info, &msg);
+    if (!s)
+	return msg;
+
+    /*
+     * Now enter the solved state as the next move.~|~
+     */
+    midend_stop_anim(me);
+    while (me->nstates > me->statepos)
+	me->ourgame->free_game(me->states[--me->nstates]);
+    ensure(me);
+    me->states[me->nstates] = s;
+    me->statepos = ++me->nstates;
+    me->anim_time = 0.0;
+    midend_finish_move(me);
+    midend_redraw(me);
+    activate_timer(me->frontend);
+    return NULL;
+}