Make NcursesLogger only show last set of lines

You would think ncurses would already do this for the infobox,
but apparently this is not true. You would also think we wouldn't
have to write any more word-wrap code after 1980, but apparently
this too is not true.

trustify/client/logger.py

@@ -51,19 +51,49 @@ class FileLogger(Logger):
 import dialog
 class NcursesLogger(Logger):
 
-    def __init__(self, firstmessage="", height=18, width=70):
-        self.content = firstmessage
+    def __init__(self, firstmessage="", height=16, width=66):
+        self.lines = []
+        self.all_content = ""
         self.d = dialog.Dialog()
         self.height = height
         self.width = width
-        self.show()
+        self.add(firstmessage)        
 
+    '''
+    Only show the last (self.height) lines;
+    note that lines can wrap at self.width, so 
+    a single line could actually be multiple lines
+    '''
     def add(self, s):
-        self.content += s
+        self.all_content += s
+
+        for line in s.splitlines():
+            # check for lines that would wrap
+            cur_out = line
+            while len(cur_out) > self.width:
+
+                # find first space before self.width chars into cur_out
+                last_space_pos = cur_out.rfind(' ', 0, self.width)
+
+                if (last_space_pos == -1):
+                    # no spaces, just cut them off at whatever
+                    self.lines.append(cur_out[0:self.width])
+                    cur_out = cur_out[self.width:]
+                else:
+                    # cut off at last space
+                    self.lines.append(cur_out[0:last_space_pos])
+                    cur_out = cur_out[last_space_pos+1:]
+            if cur_out != '':
+                self.lines.append(cur_out)
+
+        
+        # show last 16 lines
+        self.content = '\n'.join(self.lines[-self.height:])
         self.show()
 
     def show(self):
-        self.d.infobox(self.content, self.height, self.width)
+        # add the padding around the box
+        self.d.infobox(self.content, self.height+2, self.width+4)
 
     def log(self, level, data):
         self.add(data + "\n")
@@ -117,9 +147,16 @@ if __name__ == "__main__":
     logger.setLogLevel(logger.TRACE)
 
     # Log a message:
-    logger.log(logger.INFO, "logger!")
+    #logger.log(logger.INFO, "logger!")
 
     time.sleep(0.01)
+    logger.info("This is a long line, it's pretty long, butitalso hasbig wordsthat areprobably hardtobreak oninan easywayforthe ncurseslib, sowhatdoes itdo then?")
+    logger.info("aa " + "a"*70 + "B")
+
+    for i in range(20):
+        logger.info("iteration #%d/20" % i)
+        time.sleep(0.3)
+
 
     # Alternatively, use 
     logger.error("errrrr")