Added window resizing redraws to curses mode (#663)

* Added window resizing redraws to curses mode

* Cleanup

* Cleanup

* Notes from PR

* Simplified space calculation for messages

dftimewolf/cli/curses_display_manager.py

@@ -9,6 +9,8 @@
 from typing import Any, Callable, Dict, List, Optional, Union
 
 import curses
+import signal
+
 
 class Status(Enum):
   """Enum class for module states.
@@ -157,6 +159,7 @@ def StartCurses(self) -> None:
     curses.noecho()
     curses.cbreak()
     self._stdscr.keypad(True)
+    signal.signal(signal.SIGWINCH, self.SIGWINCH_Handler)
 
   def EndCurses(self) -> None:
     """Curses finalisation actions."""
@@ -210,23 +213,33 @@ def EnqueueMessage(self,
     if self._messages_longest_source_len < len(source):
       self._messages_longest_source_len = len(source)
 
-    _, x = self._stdscr.getmaxyx()
-
-    lines = []
-
-    # textwrap.wrap behaves strangely if there are newlines in the content
     for line in content.split('\n'):
-      lines += textwrap.wrap(line,
-                             width=x - self._messages_longest_source_len - 8,
-                             subsequent_indent='  ',
-                             replace_whitespace=False)
-
-    for line in lines:
       if line:
         self._messages.append(Message(source, line, is_error))
 
     self.Draw()
 
+  def PrepareMessagesForDisplay(self, available_lines: int) -> List[str]:
+    """Prepares the list of messages to be displayed.
+
+    Args:
+      available_lines: The number of lines available to print messages.
+
+    Returns:
+      A list of strings, formatted for display."""
+    _, x = self._stdscr.getmaxyx()
+
+    lines = []
+
+    for m in self._messages:
+      lines.extend(
+        textwrap.wrap(m.Stringify(self._messages_longest_source_len),
+                      width=x - self._messages_longest_source_len - 8,
+                      initial_indent='  ', subsequent_indent='    ',
+                      replace_whitespace=False))
+
+    return lines[-available_lines:]
+
   def EnqueuePreflight(self,
                        name: str,
                        dependencies: List[str],
@@ -336,13 +349,8 @@ def Draw(self) -> None:
         curr_line += 1
 
         message_space = y - 4 - curr_line
-        start = len(self._messages) - message_space
-        start = 0 if start < 0 else start
-
-        # Slice the aray, we may not be able to fit all messages on the screen
-        for m in self._messages[start:]:
-          self._stdscr.addstr(curr_line, 0,
-              f'  {m.Stringify(self._messages_longest_source_len)}'[:x])
+        for m in self.PrepareMessagesForDisplay(message_space):
+          self._stdscr.addstr(curr_line, 0, m[:x])
           curr_line += 1
 
         # Exceptions
@@ -383,6 +391,10 @@ def Pause(self) -> None:
       self._stdscr.getkey()
       self._stdscr.addstr(y - 1, 0, "                         ")
 
+  def SIGWINCH_Handler(self, *unused_argvs: Any) -> None:
+    """Redraw the window when SIGWINCH is raised."""
+    self.Draw()
+
 
 class CDMStringIOWrapper(io.StringIO):
   """Subclass of io.StringIO, adds a callback to write().

tests/cli/curses_display_manager.py

@@ -342,7 +342,6 @@ def testMessages(self):
       mock_getmaxyx.return_value = 30, 60
       self.cdm.EnqueueMessage('source 1', 'content 1')
       self.cdm.EnqueueMessage('a longer source name', 'error message', True)
-      self.cdm.EnqueueMessage('source 2', 'this message is longer than the screen width, 60 characters, and will need to be printed on multiple lines.')  # pylint: disable=line-too-long
       self.cdm.EnqueueMessage('source 3', 'this message\nhas a newline in it')
 
     try:
@@ -358,10 +357,6 @@ def testMessages(self):
           'Messages',
           '  [ source 1             ] content 1',
           '  [ a longer source name ] \u001b[31;1merror message\u001b[0m',
-          '  [ source 2             ] this message is longer than the',
-          '  [ source 2             ]   screen width, 60 characters,',
-          '  [ source 2             ]   and will need to be printed on',
-          '  [ source 2             ]   multiple lines.',
           '  [ source 3             ] this message',
           '  [ source 3             ] has a newline in it',
           '',
@@ -551,6 +546,69 @@ def testShortWindowDraw(self):
       self.assertEqual(mock_addstr.call_count, 12)
       # pylint: enable=line-too-long
 
+  def testWindowResizeDraw(self):
+    """Tests resizing the window."""
+    with mock.patch('curses.cbreak'), \
+        mock.patch('curses.noecho'), \
+        mock.patch('curses.initscr'):
+      self.cdm.StartCurses()
+
+    with mock.patch.object(self.cdm._stdscr, 'getmaxyx') as mock_getmaxyx, \
+        mock.patch.object(self.cdm, 'Draw'):
+      mock_getmaxyx.return_value = 30, 60
+
+      self.cdm.SetRecipe('Recipe name')
+      self.cdm.EnqueuePreflight('First Preflight', [], '1st Preflight')
+      self.cdm.EnqueueModule('First Module', [], '1st Module')
+      self.cdm.EnqueueMessage('source', 'A standard message')
+      self.cdm.EnqueueMessage('source', 'this message is longer than the screen width, 60 characters, and will need to be printed on multiple lines.')  # pylint: disable=line-too-long
+      self.cdm.EnqueueMessage('source', 'Another standard message')
+
+    with mock.patch.object(self.cdm._stdscr, 'getmaxyx') as mock_getmaxyx, \
+        mock.patch.object(self.cdm._stdscr, 'clear') as mock_clear, \
+        mock.patch.object(self.cdm._stdscr, 'addstr') as mock_addstr:
+      mock_getmaxyx.return_value = 30, 60
+
+      self.cdm.Draw()
+
+      mock_clear.assert_called_once_with()
+      # pylint: disable=line-too-long
+      mock_addstr.assert_has_calls([
+          mock.call(0, 0,  ' Recipe name'),
+          mock.call(1, 0,  '   Preflights:'),
+          mock.call(2, 0,  '     1st Preflight: Pending'),
+          mock.call(3, 0,  '   Modules:'),
+          mock.call(4, 0,  '     1st Module: Pending'),
+          mock.call(6, 0,  ' Messages:'),
+          mock.call(7, 0,  '  [ source ] A standard message'),
+          mock.call(8, 0,  '  [ source ] this message is longer than the'),
+          mock.call(9, 0,  '    screen width, 60 characters, and will need'),
+          mock.call(10, 0, '    to be printed on multiple lines.'),
+          mock.call(11, 0, '  [ source ] Another standard message')])
+      self.assertEqual(mock_addstr.call_count, 11)
+      # pylint: enable=line-too-long
+
+    with mock.patch.object(self.cdm._stdscr, 'getmaxyx') as mock_getmaxyx, \
+        mock.patch.object(self.cdm._stdscr, 'clear') as mock_clear, \
+        mock.patch.object(self.cdm._stdscr, 'addstr') as mock_addstr:
+      mock_getmaxyx.return_value = 30, 140
+
+      self.cdm.SIGWINCH_Handler(None, None)
+
+      mock_clear.assert_called_once_with()
+      # pylint: disable=line-too-long
+      mock_addstr.assert_has_calls([
+          mock.call(0, 0, ' Recipe name'),
+          mock.call(1, 0, '   Preflights:'),
+          mock.call(2, 0, '     1st Preflight: Pending'),
+          mock.call(3, 0, '   Modules:'),
+          mock.call(4, 0, '     1st Module: Pending'),
+          mock.call(6, 0, ' Messages:'),
+          mock.call(7, 0, '  [ source ] A standard message'),
+          mock.call(8, 0, '  [ source ] this message is longer than the screen width, 60 characters, and will need to be printed on multiple lines.'),  # pylint: disable=line-too-long
+          mock.call(9, 0, '  [ source ] Another standard message')])
+      self.assertEqual(mock_addstr.call_count, 9)
+
 
 class CDMStringIOWrapperTest(unittest.TestCase):
   """Tests for the CDMStringIOWrapper class."""