[quadrapassel/lr/difficult-mode-fixes: 7/7] game: restore the preview in difficult mode

[Jeremy Bicha <jbicha src gnome org>]

commit 1c18243dcf6a4fdcb0d2d8a50c667b287c749c1e
Author: Lubomir Rintel <lkundrak v3 sk>
Date:   Tue Dec 18 22:47:08 2018 +0100

    game: restore the preview in difficult mode
    
    It was removed without a good reason. The point of the preview in the
    difficult mode is to frustrate the user even more with a preview of an
    useful piece that they're not going to get.
    
    Fixes: bd2180af6f3347a81a4c2378b8d112a4e258f79b

 src/game.vala         | 25 ++++++++++++++++++-------
 src/quadrapassel.vala | 15 +++------------
 2 files changed, 21 insertions(+), 19 deletions(-)
---
diff --git a/src/game.vala b/src/game.vala
index a1c6987..256d1fe 100644
--- a/src/game.vala
+++ b/src/game.vala
@@ -502,8 +502,11 @@ public class Game : Object
 
     private void add_shape ()
     {
-        if (pick_difficult_blocks)
-            shape = pick_difficult_shape ();
+        if (pick_difficult_blocks) {
+            var difficult_shapes = pick_difficult_shapes ();
+            shape = difficult_shapes[0];
+            next_shape = difficult_shapes[1];
+        }
         else
         {
             shape = (owned) next_shape;
@@ -538,7 +541,7 @@ public class Game : Object
         return make_shape (Random.int_range (0, NCOLORS), Random.int_range (0, 4));
     }
 
-    private Shape pick_difficult_shape ()
+    private Shape[] pick_difficult_shapes ()
     {
        /* The algorithm comes from Federico Poloni's "bastet" game */
         var metrics = new int[NCOLORS];
@@ -622,13 +625,21 @@ public class Game : Object
         /* Actually choose a piece */
         var rnd = Random.int_range (0, 99);
         if (rnd < 75)
-            return make_shape (possible_types[0], Random.int_range (0, 4));
+            shape = make_shape (possible_types[0], Random.int_range (0, 4));
         else if (rnd < 92)
-            return make_shape (possible_types[1], Random.int_range (0, 4));
+            shape = make_shape (possible_types[1], Random.int_range (0, 4));
         else if (rnd < 98)
-            return make_shape (possible_types[2], Random.int_range (0, 4));
+            shape = make_shape (possible_types[2], Random.int_range (0, 4));
         else
-            return make_shape (possible_types[3], Random.int_range (0, 4));
+            shape = make_shape (possible_types[3], Random.int_range (0, 4));
+
+       /* Look, this one is a great fit. It would be a shame if it wouldn't be given next */
+       next_shape = make_shape (possible_types[NCOLORS - 1], Random.int_range (0, 4));
+
+       var shapes = new Shape[2];
+       shapes[0] = shape;
+       shapes[1] = next_shape;
+       return shapes;
     }
 
     private Shape make_shape (int type, int rotation)
diff --git a/src/quadrapassel.vala b/src/quadrapassel.vala
index 77c5a4e..6ecb047 100644
--- a/src/quadrapassel.vala
+++ b/src/quadrapassel.vala
@@ -346,7 +346,6 @@ public class Quadrapassel : Gtk.Application
 
         do_preview_toggle = new Gtk.CheckButton.with_mnemonic (_("_Preview next block"));
         do_preview_toggle.set_active (settings.get_boolean ("do-preview"));
-        do_preview_toggle.set_sensitive (!settings.get_boolean ("pick-difficult-blocks"));
         do_preview_toggle.toggled.connect (do_preview_toggle_toggled_cb);
         grid.attach (do_preview_toggle, 0, 5, 2, 1);
 
@@ -456,22 +455,14 @@ public class Quadrapassel : Gtk.Application
 
     private void do_preview_toggle_toggled_cb ()
     {
-        settings.set_boolean ("do-preview", do_preview_toggle.get_active ());
-        update_preview_settings ();
+        var preview_enabled = do_preview_toggle.get_active ();
+        settings.set_boolean ("do-preview", preview_enabled);
+        preview.enabled = preview_enabled;
     }
 
     private void difficult_blocks_toggled_cb ()
     {
         settings.set_boolean ("pick-difficult-blocks", difficult_blocks_toggle.get_active ());
-        do_preview_toggle.set_sensitive (!settings.get_boolean ("pick-difficult-blocks"));
-        update_preview_settings ();
-    }
-
-    private void update_preview_settings ()
-    {
-        var do_preview = do_preview_toggle.get_active ();
-        var difficult_block_mode = difficult_blocks_toggle.get_active ();
-        preview.enabled = do_preview && !difficult_block_mode;
     }
 
     private void set_rotate_counter_clock_wise ()