[gnome-chess] Display a message if a human player is in check

[Michael Catanzaro <mcatanzaro src gnome org>]

commit a62746fe7510fb423d578ce8060059c9d8db18e9
Author: Michael Catanzaro <mcatanzaro gnome org>
Date:   Tue Jan 7 15:12:24 2014 -0600

    Display a message if a human player is in check
    
    https://bugzilla.gnome.org/show_bug.cgi?id=703183

 src/chess-game.vala  |    2 +-
 src/gnome-chess.vala |   13 ++++++++++++-
 2 files changed, 13 insertions(+), 2 deletions(-)
---
diff --git a/src/chess-game.vala b/src/chess-game.vala
index 423b244..ee72992 100644
--- a/src/chess-game.vala
+++ b/src/chess-game.vala
@@ -861,7 +861,7 @@ public class ChessState
         return CheckState.NONE;
     }
 
-    private bool is_in_check (ChessPlayer player)
+    public bool is_in_check (ChessPlayer player)
     {
         var opponent = player.color == Color.WHITE ? players[Color.BLACK] : players[Color.WHITE];
 
diff --git a/src/gnome-chess.vala b/src/gnome-chess.vala
index 61302d6..4cb42fc 100644
--- a/src/gnome-chess.vala
+++ b/src/gnome-chess.vala
@@ -1015,7 +1015,18 @@ public class Application : Gtk.Application
 
     private void update_headerbar_title ()
     {
-        if (game.current_player.color == Color.WHITE)
+        if ((human_player == null ||
+             human_player.color == game.current_player.color) &&
+            game.current_state.is_in_check (game.current_player))
+        {
+            if (game.current_player.color == Color.WHITE)
+                /* Window title on a White human's turn if he is in check */
+                headerbar.set_title (_("White is in Check"));
+            else
+                /* Window title on a Black human's turn if he is in check */
+                headerbar.set_title (_("Black is in Check"));
+        }
+        else if (game.current_player.color == Color.WHITE)
         {
             if (human_player == null || human_player.color == Color.WHITE)
                 /* Window title on White's turn if White is human */