src/gnudebbugs/ui/__init__.py

   1 # Copyright (C) 2021 Free Software Foundation, Inc.
   2 #
   3 # This program is free software: you can redistribute it and/or modify it under
   4 # the terms of the GNU Lesser General Public License as published by the Free
   5 # Software Foundation, either version 3 of the License, or at your option) any
   6 # later version.
   7 #
   8 # This program is distributed in the hope that it will be useful, but WITHOUT
   9 # ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  10 # FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more
  11 # details.
  12 #
  13 # You should have received a copy of the GNU Lesser General Public License
  14 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
  15
  16 """Common UI settings."""
  17
  18 import abc
  19
  20 from .. import BaseError
  21
  22
  23 class Error(BaseError):
  24     """Base UI error class."""
  25
  26
  27 class MissingUrwidError(Error):
  28     """The urwid module is unavailable."""
  29
  30
  31 class UIBase(abc.ABC):
  32     """Base class for all UI implementations."""
  33
  34     def __init__(self):
  35         pass
  36
  37     def start(self) -> None:
  38         pass
  39
  40     def stop(self) -> None:
  41         pass
  42
  43     def status(self, text: str) -> None:
  44         """Print status information."""
  45
  46     def interface_query(self, client, statuses, bug_width, summary_tags, tags_width, summary_states, states_width) -> None:
  47         """Run the query interface."""
  48
  49
  50 def get_backend(backend: str) -> UIBase:
  51     """Helper to dynamically load the right backend."""
  52     if backend == "cli":
  53         from . import cli
  54
  55         return cli.UI
  56     elif backend == "urwid":
  57         try:
  58             from . import urwid
  59         except ImportError as e:
  60             raise MissingUrwidError(f'Unable to import urwid: {e}')
  61
  62         return urwid.UI