Rearranged the display class files, related to issue #56.

squirrelbattle/display/display.py

@@ -290,3 +290,29 @@ class Box(Display):
 
         self.refresh_pad(self.pad, 0, 0, self.y, self.x,
                          self.y + self.height - 1, self.x + self.width - 1)
+
+
+class MessageDisplay(Display):
+    """
+    A class to handle the display of popup messages.
+    """
+
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+
+        self.box = Box(fg_border_color=curses.COLOR_RED, *args, **kwargs)
+        self.message = ""
+        self.pad = self.newpad(1, 1)
+
+    def update(self, game: Game) -> None:
+        self.message = game.message
+
+    def display(self) -> None:
+        self.box.refresh(self.y - 1, self.x - 2,
+                         self.height + 2, self.width + 4)
+        self.box.display()
+        self.pad.erase()
+        self.addstr(self.pad, 0, 0, self.message, bold=True)
+        self.refresh_pad(self.pad, 0, 0, self.y, self.x,
+                         self.height + self.y - 1,
+                         self.width + self.x - 1)