X-Git-Url: https://git.distorted.org.uk/~mdw/sgt/puzzles/blobdiff_plain/cbb5549e12c8edfd8b38b642b7b25c1fb8912c9b..28d0118c5fbdbbbb656f0ea6fb3b2e48e6aa73f8:/midend.c

diff --git a/midend.c b/midend.c
index 4636fa0..0c91491 100644
--- a/midend.c
+++ b/midend.c
@@ -11,36 +11,48 @@
 
 #include "puzzles.h"
 
+enum { DEF_PARAMS, DEF_SEED, DEF_DESC };   /* for midend_game_id_int */
+
+struct midend_state_entry {
+    game_state *state;
+    int special;                       /* created by solve or restart */
+};
+
 struct midend_data {
     frontend *frontend;
     random_state *random;
+    const game *ourgame;
 
-    char *seed;
-    int fresh_seed;
+    char *desc, *seedstr;
+    game_aux_info *aux_info;
+    enum { GOT_SEED, GOT_DESC, GOT_NOTHING } genmode;
     int nstates, statesize, statepos;
 
     game_params **presets;
     char **preset_names;
     int npresets, presetsize;
 
-    game_params *params;
-    game_state **states;
+    game_params *params, *tmpparams;
+    struct midend_state_entry *states;
     game_drawstate *drawstate;
     game_state *oldstate;
     game_ui *ui;
     float anim_time, anim_pos;
     float flash_time, flash_pos;
     int dir;
+
+    int pressed_mouse_button;
 };
 
 #define ensure(me) do { \
     if ((me)->nstates >= (me)->statesize) { \
 	(me)->statesize = (me)->nstates + 128; \
-	(me)->states = sresize((me)->states, (me)->statesize, game_state *); \
+	(me)->states = sresize((me)->states, (me)->statesize, \
+                               struct midend_state_entry); \
     } \
 } while (0)
 
-midend_data *midend_new(frontend *fe)
+midend_data *midend_new(frontend *fe, const game *ourgame)
 {
     midend_data *me = snew(midend_data);
     void *randseed;
@@ -49,12 +61,16 @@ midend_data *midend_new(frontend *fe)
     get_random_seed(&randseed, &randseedsize);
 
     me->frontend = fe;
+    me->ourgame = ourgame;
     me->random = random_init(randseed, randseedsize);
     me->nstates = me->statesize = me->statepos = 0;
     me->states = NULL;
-    me->params = default_params();
-    me->seed = NULL;
-    me->fresh_seed = FALSE;
+    me->params = ourgame->default_params();
+    me->tmpparams = NULL;
+    me->desc = NULL;
+    me->seedstr = NULL;
+    me->aux_info = NULL;
+    me->genmode = GOT_NOTHING;
     me->drawstate = NULL;
     me->oldstate = NULL;
     me->presets = NULL;
@@ -64,6 +80,7 @@ midend_data *midend_new(frontend *fe)
     me->flash_time = me->flash_pos = 0.0F;
     me->dir = 0;
     me->ui = NULL;
+    me->pressed_mouse_button = 0;
 
     sfree(randseed);
 
@@ -73,54 +90,85 @@ midend_data *midend_new(frontend *fe)
 void midend_free(midend_data *me)
 {
     sfree(me->states);
-    sfree(me->seed);
-    free_params(me->params);
+    sfree(me->desc);
+    sfree(me->seedstr);
+    random_free(me->random);
+    if (me->aux_info)
+	me->ourgame->free_aux_info(me->aux_info);
+    me->ourgame->free_params(me->params);
+    if (me->tmpparams)
+        me->ourgame->free_params(me->tmpparams);
     sfree(me);
 }
 
 void midend_size(midend_data *me, int *x, int *y)
 {
-    game_size(me->params, x, y);
+    me->ourgame->size(me->params, x, y);
 }
 
 void midend_set_params(midend_data *me, game_params *params)
 {
-    free_params(me->params);
-    me->params = dup_params(params);
+    me->ourgame->free_params(me->params);
+    me->params = me->ourgame->dup_params(params);
 }
 
 void midend_new_game(midend_data *me)
 {
     while (me->nstates > 0)
-	free_game(me->states[--me->nstates]);
+	me->ourgame->free_game(me->states[--me->nstates].state);
 
     if (me->drawstate)
-        game_free_drawstate(me->drawstate);
+        me->ourgame->free_drawstate(me->drawstate);
 
     assert(me->nstates == 0);
 
-    if (!me->fresh_seed) {
-	sfree(me->seed);
-	me->seed = new_game_seed(me->params, me->random);
-    } else
-	me->fresh_seed = FALSE;
+    if (me->genmode == GOT_DESC) {
+	me->genmode = GOT_NOTHING;
+    } else {
+        random_state *rs;
+
+        if (me->genmode == GOT_SEED) {
+            me->genmode = GOT_NOTHING;
+        } else {
+            /*
+             * Generate a new random seed. 15 digits comes to about
+             * 48 bits, which should be more than enough.
+             */
+            char newseed[16];
+            int i;
+            newseed[15] = '\0';
+            for (i = 0; i < 15; i++)
+                newseed[i] = '0' + random_upto(me->random, 10);
+            sfree(me->seedstr);
+            me->seedstr = dupstr(newseed);
+        }
+
+	sfree(me->desc);
+	if (me->aux_info)
+	    me->ourgame->free_aux_info(me->aux_info);
+	me->aux_info = NULL;
+
+        rs = random_init(me->seedstr, strlen(me->seedstr));
+        me->desc = me->ourgame->new_desc
+            (me->tmpparams ? me->tmpparams : me->params, rs, &me->aux_info);
+        random_free(rs);
+
+        if (me->tmpparams) {
+            me->ourgame->free_params(me->tmpparams);
+            me->tmpparams = NULL;
+        }
+    }
 
     ensure(me);
-    me->states[me->nstates++] = new_game(me->params, me->seed);
+    me->states[me->nstates].state = me->ourgame->new_game(me->params, me->desc);
+    me->states[me->nstates].special = TRUE;
+    me->nstates++;
     me->statepos = 1;
-    me->drawstate = game_new_drawstate(me->states[0]);
+    me->drawstate = me->ourgame->new_drawstate(me->states[0].state);
     if (me->ui)
-        free_ui(me->ui);
-    me->ui = new_ui(me->states[0]);
-}
-
-void midend_restart_game(midend_data *me)
-{
-    while (me->nstates > 1)
-	free_game(me->states[--me->nstates]);
-    me->statepos = me->nstates;
-    free_ui(me->ui);
-    me->ui = new_ui(me->states[0]);
+        me->ourgame->free_ui(me->ui);
+    me->ui = me->ourgame->new_ui(me->states[0].state);
+    me->pressed_mouse_button = 0;
 }
 
 static int midend_undo(midend_data *me)
@@ -147,11 +195,19 @@ static void midend_finish_move(midend_data *me)
 {
     float flashtime;
 
-    if (me->oldstate || me->statepos > 1) {
-	flashtime = game_flash_length(me->oldstate ? me->oldstate :
-				      me->states[me->statepos-2],
-				      me->states[me->statepos-1],
-                                      me->oldstate ? me->dir : +1);
+    /*
+     * We do not flash if the later of the two states is special.
+     * This covers both forward Solve moves and backward (undone)
+     * Restart moves.
+     */
+    if ((me->oldstate || me->statepos > 1) &&
+        ((me->dir > 0 && !me->states[me->statepos-1].special) ||
+         (me->dir < 0 && me->statepos < me->nstates &&
+          !me->states[me->statepos].special))) {
+	flashtime = me->ourgame->flash_length(me->oldstate ? me->oldstate :
+					      me->states[me->statepos-2].state,
+					      me->states[me->statepos-1].state,
+					      me->oldstate ? me->dir : +1);
 	if (flashtime > 0) {
 	    me->flash_pos = 0.0F;
 	    me->flash_time = flashtime;
@@ -159,7 +215,7 @@ static void midend_finish_move(midend_data *me)
     }
 
     if (me->oldstate)
-	free_game(me->oldstate);
+	me->ourgame->free_game(me->oldstate);
     me->oldstate = NULL;
     me->anim_pos = me->anim_time = 0;
     me->dir = 0;
@@ -178,9 +234,37 @@ static void midend_stop_anim(midend_data *me)
     }
 }
 
-int midend_process_key(midend_data *me, int x, int y, int button)
+void midend_restart_game(midend_data *me)
+{
+    game_state *s;
+
+    assert(me->statepos >= 1);
+    if (me->statepos == 1)
+        return;                        /* no point doing anything at all! */
+
+    s = me->ourgame->dup_game(me->states[0].state);
+
+    /*
+     * Now enter the restarted state as the next move.
+     */
+    midend_stop_anim(me);
+    while (me->nstates > me->statepos)
+	me->ourgame->free_game(me->states[--me->nstates].state);
+    ensure(me);
+    me->states[me->nstates].state = s;
+    me->states[me->nstates].special = TRUE;   /* we just restarted */
+    me->statepos = ++me->nstates;
+    me->anim_time = 0.0;
+    midend_finish_move(me);
+    midend_redraw(me);
+    activate_timer(me->frontend);
+}
+
+static int midend_really_process_key(midend_data *me, int x, int y, int button)
 {
-    game_state *oldstate = dup_game(me->states[me->statepos - 1]);
+    game_state *oldstate =
+        me->ourgame->dup_game(me->states[me->statepos - 1].state);
+    int special = FALSE, gotspecial = FALSE;
     float anim_time;
 
     if (button == 'n' || button == 'N' || button == '\x0E') {
@@ -196,6 +280,8 @@ int midend_process_key(midend_data *me, int x, int y, int button)
     } else if (button == 'u' || button == 'u' ||
                button == '\x1A' || button == '\x1F') {
 	midend_stop_anim(me);
+        special = me->states[me->statepos-1].special;
+        gotspecial = TRUE;
 	if (!midend_undo(me))
             return 1;
     } else if (button == '\x12') {
@@ -203,13 +289,14 @@ int midend_process_key(midend_data *me, int x, int y, int button)
 	if (!midend_redo(me))
             return 1;
     } else if (button == 'q' || button == 'Q' || button == '\x11') {
-	free_game(oldstate);
+	me->ourgame->free_game(oldstate);
         return 0;
     } else {
-        game_state *s = make_move(me->states[me->statepos-1], me->ui,
-                                  x, y, button);
+        game_state *s =
+            me->ourgame->make_move(me->states[me->statepos-1].state,
+                                   me->ui, x, y, button);
 
-        if (s == me->states[me->statepos-1]) {
+        if (s == me->states[me->statepos-1].state) {
             /*
              * make_move() is allowed to return its input state to
              * indicate that although no move has been made, the UI
@@ -220,21 +307,31 @@ int midend_process_key(midend_data *me, int x, int y, int button)
         } else if (s) {
 	    midend_stop_anim(me);
             while (me->nstates > me->statepos)
-                free_game(me->states[--me->nstates]);
+                me->ourgame->free_game(me->states[--me->nstates].state);
             ensure(me);
-            me->states[me->nstates] = s;
+            me->states[me->nstates].state = s;
+            me->states[me->nstates].special = FALSE;   /* normal move */
             me->statepos = ++me->nstates;
             me->dir = +1;
         } else {
-            free_game(oldstate);
+            me->ourgame->free_game(oldstate);
             return 1;
         }
     }
 
+    if (!gotspecial)
+        special = me->states[me->statepos-1].special;
+
     /*
      * See if this move requires an animation.
      */
-    anim_time = game_anim_length(oldstate, me->states[me->statepos-1], me->dir);
+    if (special) {
+        anim_time = 0;
+    } else {
+        anim_time = me->ourgame->anim_length(oldstate,
+                                             me->states[me->statepos-1].state,
+                                             me->dir);
+    }
 
     me->oldstate = oldstate;
     if (anim_time > 0) {
@@ -252,6 +349,104 @@ int midend_process_key(midend_data *me, int x, int y, int button)
     return 1;
 }
 
+int midend_process_key(midend_data *me, int x, int y, int button)
+{
+    int ret = 1;
+
+    /*
+     * Harmonise mouse drag and release messages.
+     * 
+     * Some front ends might accidentally switch from sending, say,
+     * RIGHT_DRAG messages to sending LEFT_DRAG, half way through a
+     * drag. (This can happen on the Mac, for example, since
+     * RIGHT_DRAG is usually done using Command+drag, and if the
+     * user accidentally releases Command half way through the drag
+     * then there will be trouble.)
+     * 
+     * It would be an O(number of front ends) annoyance to fix this
+     * in the front ends, but an O(number of back ends) annoyance
+     * to have each game capable of dealing with it. Therefore, we
+     * fix it _here_ in the common midend code so that it only has
+     * to be done once.
+     * 
+     * The possible ways in which things can go screwy in the front
+     * end are:
+     * 
+     *  - in a system containing multiple physical buttons button
+     *    presses can inadvertently overlap. We can see ABab (caps
+     *    meaning button-down and lowercase meaning button-up) when
+     *    the user had semantically intended AaBb.
+     * 
+     *  - in a system where one button is simulated by means of a
+     *    modifier key and another button, buttons can mutate
+     *    between press and release (possibly during drag). So we
+     *    can see Ab instead of Aa.
+     * 
+     * Definite requirements are:
+     * 
+     *  - button _presses_ must never be invented or destroyed. If
+     *    the user presses two buttons in succession, the button
+     *    presses must be transferred to the backend unchanged. So
+     *    if we see AaBb , that's fine; if we see ABab (the button
+     *    presses inadvertently overlapped) we must somehow
+     *    `correct' it to AaBb.
+     * 
+     *  - every mouse action must end up looking like a press, zero
+     *    or more drags, then a release. This allows back ends to
+     *    make the _assumption_ that incoming mouse data will be
+     *    sane in this regard, and not worry about the details.
+     * 
+     * So my policy will be:
+     * 
+     *  - treat any button-up as a button-up for the currently
+     *    pressed button, or ignore it if there is no currently
+     *    pressed button.
+     * 
+     *  - treat any drag as a drag for the currently pressed
+     *    button, or ignore it if there is no currently pressed
+     *    button.
+     * 
+     *  - if we see a button-down while another button is currently
+     *    pressed, invent a button-up for the first one and then
+     *    pass the button-down through as before.
+     * 
+     */
+    if (IS_MOUSE_DRAG(button) || IS_MOUSE_RELEASE(button)) {
+        if (me->pressed_mouse_button) {
+            if (IS_MOUSE_DRAG(button)) {
+                button = me->pressed_mouse_button +
+                    (LEFT_DRAG - LEFT_BUTTON);
+            } else {
+                button = me->pressed_mouse_button +
+                    (LEFT_RELEASE - LEFT_BUTTON);
+            }
+        } else
+            return ret;                /* ignore it */
+    } else if (IS_MOUSE_DOWN(button) && me->pressed_mouse_button) {
+        /*
+         * Fabricate a button-up for the previously pressed button.
+         */
+        ret = ret && midend_really_process_key
+            (me, x, y, (me->pressed_mouse_button +
+                        (LEFT_RELEASE - LEFT_BUTTON)));
+    }
+
+    /*
+     * Now send on the event we originally received.
+     */
+    ret = ret && midend_really_process_key(me, x, y, button);
+
+    /*
+     * And update the currently pressed button.
+     */
+    if (IS_MOUSE_RELEASE(button))
+        me->pressed_mouse_button = 0;
+    else if (IS_MOUSE_DOWN(button))
+        me->pressed_mouse_button = button;
+
+    return ret;
+}
+
 void midend_redraw(midend_data *me)
 {
     if (me->statepos > 0 && me->drawstate) {
@@ -259,13 +454,13 @@ void midend_redraw(midend_data *me)
         if (me->oldstate && me->anim_time > 0 &&
             me->anim_pos < me->anim_time) {
             assert(me->dir != 0);
-            game_redraw(me->frontend, me->drawstate, me->oldstate,
-                        me->states[me->statepos-1], me->dir,
-                        me->ui, me->anim_pos, me->flash_pos);
+            me->ourgame->redraw(me->frontend, me->drawstate, me->oldstate,
+				me->states[me->statepos-1].state, me->dir,
+				me->ui, me->anim_pos, me->flash_pos);
         } else {
-            game_redraw(me->frontend, me->drawstate, NULL,
-                        me->states[me->statepos-1], +1 /*shrug*/,
-                        me->ui, 0.0, me->flash_pos);
+            me->ourgame->redraw(me->frontend, me->drawstate, NULL,
+				me->states[me->statepos-1].state, +1 /*shrug*/,
+				me->ui, 0.0, me->flash_pos);
         }
         end_draw(me->frontend);
     }
@@ -294,16 +489,19 @@ float *midend_colours(midend_data *me, int *ncolours)
     float *ret;
 
     if (me->nstates == 0) {
-        char *seed = new_game_seed(me->params, me->random);
-        state = new_game(me->params, seed);
-        sfree(seed);
+	game_aux_info *aux = NULL;
+        char *desc = me->ourgame->new_desc(me->params, me->random, &aux);
+        state = me->ourgame->new_game(me->params, desc);
+        sfree(desc);
+	if (aux)
+	    me->ourgame->free_aux_info(aux);
     } else
-        state = me->states[0];
+        state = me->states[0].state;
 
-    ret = game_colours(me->frontend, state, ncolours);
+    ret = me->ourgame->colours(me->frontend, state, ncolours);
 
     if (me->nstates == 0)
-        free_game(state);
+        me->ourgame->free_game(state);
 
     return ret;
 }
@@ -314,7 +512,7 @@ int midend_num_presets(midend_data *me)
         char *name;
         game_params *preset;
 
-        while (game_fetch_preset(me->npresets, &name, &preset)) {
+        while (me->ourgame->fetch_preset(me->npresets, &name, &preset)) {
             if (me->presetsize <= me->npresets) {
                 me->presetsize = me->npresets + 10;
                 me->presets = sresize(me->presets, me->presetsize,
@@ -342,7 +540,7 @@ void midend_fetch_preset(midend_data *me, int n,
 
 int midend_wants_statusbar(midend_data *me)
 {
-    return game_wants_statusbar();
+    return me->ourgame->wants_statusbar();
 }
 
 config_item *midend_get_config(midend_data *me, int which, char **wintitle)
@@ -350,30 +548,52 @@ config_item *midend_get_config(midend_data *me, int which, char **wintitle)
     char *titlebuf, *parstr;
     config_item *ret;
 
-    titlebuf = snewn(40 + strlen(game_name), char);
+    titlebuf = snewn(40 + strlen(me->ourgame->name), char);
 
     switch (which) {
       case CFG_SETTINGS:
-	sprintf(titlebuf, "%s configuration", game_name);
+	sprintf(titlebuf, "%s configuration", me->ourgame->name);
 	*wintitle = dupstr(titlebuf);
-	return game_configure(me->params);
+	return me->ourgame->configure(me->params);
       case CFG_SEED:
-	sprintf(titlebuf, "%s game selection", game_name);
+      case CFG_DESC:
+	sprintf(titlebuf, "%s %s selection", me->ourgame->name,
+                which == CFG_SEED ? "random" : "game");
 	*wintitle = dupstr(titlebuf);
 
 	ret = snewn(2, config_item);
 
 	ret[0].type = C_STRING;
-	ret[0].name = "Game ID";
+        if (which == CFG_SEED)
+            ret[0].name = "Game random seed";
+        else
+            ret[0].name = "Game ID";
 	ret[0].ival = 0;
         /*
-         * The text going in here will be a string encoding of the
-         * parameters, plus a colon, plus the game seed. This is a
-         * full game ID.
+         * For CFG_DESC the text going in here will be a string
+         * encoding of the restricted parameters, plus a colon,
+         * plus the game description. For CFG_SEED it will be the
+         * full parameters, plus a hash, plus the random seed data.
+         * Either of these is a valid full game ID (although only
+         * the former is likely to persist across many code
+         * changes).
          */
-        parstr = encode_params(me->params);
-        ret[0].sval = snewn(strlen(parstr) + strlen(me->seed) + 2, char);
-        sprintf(ret[0].sval, "%s:%s", parstr, me->seed);
+        parstr = me->ourgame->encode_params(me->params, which == CFG_SEED);
+        if (which == CFG_DESC) {
+            ret[0].sval = snewn(strlen(parstr) + strlen(me->desc) + 2, char);
+            sprintf(ret[0].sval, "%s:%s", parstr, me->desc);
+        } else if (me->seedstr) {
+            ret[0].sval = snewn(strlen(parstr) + strlen(me->seedstr) + 2, char);
+            sprintf(ret[0].sval, "%s#%s", parstr, me->seedstr);
+        } else {
+            /*
+             * If the current game was not randomly generated, the
+             * best we can do is to give a template for typing a
+             * new seed in.
+             */
+            ret[0].sval = snewn(strlen(parstr) + 2, char);
+            sprintf(ret[0].sval, "%s#", parstr);
+        }
         sfree(parstr);
 
 	ret[1].type = C_END;
@@ -387,59 +607,103 @@ config_item *midend_get_config(midend_data *me, int which, char **wintitle)
     return NULL;
 }
 
-char *midend_game_id(midend_data *me, char *id, int def_seed)
+static char *midend_game_id_int(midend_data *me, char *id, int defmode)
 {
-    char *error, *par, *seed;
-    game_params *params;
+    char *error, *par, *desc, *seed;
 
-    seed = strchr(id, ':');
+    seed = strchr(id, '#');
+    desc = strchr(id, ':');
 
-    if (seed) {
+    if (desc && (!seed || desc < seed)) {
+        /*
+         * We have a colon separating parameters from game
+         * description. So `par' now points to the parameters
+         * string, and `desc' to the description string.
+         */
+        *desc++ = '\0';
+        par = id;
+        seed = NULL;
+    } else if (seed && (!desc || seed < desc)) {
         /*
-         * We have a colon separating parameters from game seed. So
-         * `par' now points to the parameters string, and `seed' to
-         * the seed string.
+         * We have a hash separating parameters from random seed.
+         * So `par' now points to the parameters string, and `seed'
+         * to the seed string.
          */
         *seed++ = '\0';
         par = id;
+        desc = NULL;
     } else {
         /*
-         * We only have one string. Depending on `def_seed', we
-         * take it to be either parameters or seed.
+         * We only have one string. Depending on `defmode', we take
+         * it to be either parameters, seed or description.
          */
-        if (def_seed) {
+        if (defmode == DEF_SEED) {
             seed = id;
-            par = NULL;
+            par = desc = NULL;
+        } else if (defmode == DEF_DESC) {
+            desc = id;
+            par = seed = NULL;
         } else {
-            seed = NULL;
             par = id;
+            seed = desc = NULL;
         }
     }
 
     if (par) {
-        params = decode_params(par);
-        error = validate_params(params);
+        game_params *tmpparams;
+        tmpparams = me->ourgame->dup_params(me->params);
+        me->ourgame->decode_params(tmpparams, par);
+        error = me->ourgame->validate_params(tmpparams);
         if (error) {
-            free_params(params);
+            me->ourgame->free_params(tmpparams);
             return error;
         }
-        free_params(me->params);
-        me->params = params;
+        if (me->tmpparams)
+            me->ourgame->free_params(me->tmpparams);
+        me->tmpparams = tmpparams;
+
+        /*
+         * Now filter only the persistent parts of this state into
+         * the long-term params structure, unless we've _only_
+         * received a params string in which case the whole lot is
+         * persistent.
+         */
+        if (seed || desc) {
+            char *tmpstr = me->ourgame->encode_params(tmpparams, FALSE);
+            me->ourgame->decode_params(me->params, tmpstr);
+        } else {
+            me->ourgame->free_params(me->params);
+            me->params = me->ourgame->dup_params(tmpparams);
+        }
     }
 
-    if (seed) {
-        error = validate_seed(me->params, seed);
+    if (desc) {
+        error = me->ourgame->validate_desc(me->params, desc);
         if (error)
             return error;
 
-        sfree(me->seed);
-        me->seed = dupstr(seed);
-        me->fresh_seed = TRUE;
+        sfree(me->desc);
+        me->desc = dupstr(desc);
+        me->genmode = GOT_DESC;
+	if (me->aux_info)
+	    me->ourgame->free_aux_info(me->aux_info);
+	me->aux_info = NULL;
+    }
+
+    if (seed) {
+        sfree(me->seedstr);
+        me->seedstr = dupstr(seed);
+        me->genmode = GOT_SEED;
     }
 
     return NULL;
 }
 
+char *midend_game_id(midend_data *me, char *id)
+{
+    return midend_game_id_int(me, id, DEF_PARAMS);
+}
+
 char *midend_set_config(midend_data *me, int which, config_item *cfg)
 {
     char *error;
@@ -447,20 +711,22 @@ char *midend_set_config(midend_data *me, int which, config_item *cfg)
 
     switch (which) {
       case CFG_SETTINGS:
-	params = custom_params(cfg);
-	error = validate_params(params);
+	params = me->ourgame->custom_params(cfg);
+	error = me->ourgame->validate_params(params);
 
 	if (error) {
-	    free_params(params);
+	    me->ourgame->free_params(params);
 	    return error;
 	}
 
-	free_params(me->params);
+	me->ourgame->free_params(me->params);
 	me->params = params;
 	break;
 
       case CFG_SEED:
-        error = midend_game_id(me, cfg[0].sval, TRUE);
+      case CFG_DESC:
+        error = midend_game_id_int(me, cfg[0].sval,
+                                   (which == CFG_SEED ? DEF_SEED : DEF_DESC));
 	if (error)
 	    return error;
 	break;
@@ -468,3 +734,44 @@ char *midend_set_config(midend_data *me, int which, config_item *cfg)
 
     return NULL;
 }
+
+char *midend_text_format(midend_data *me)
+{
+    if (me->ourgame->can_format_as_text && me->statepos > 0)
+	return me->ourgame->text_format(me->states[me->statepos-1].state);
+    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].state, 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].state);
+    ensure(me);
+    me->states[me->nstates].state = s;
+    me->states[me->nstates].special = TRUE;   /* created using solve */
+    me->statepos = ++me->nstates;
+    me->anim_time = 0.0;
+    midend_finish_move(me);
+    midend_redraw(me);
+    activate_timer(me->frontend);
+    return NULL;
+}