Implement theme command.

alot/commands/globals.py

@@ -16,6 +16,8 @@
 
 import urwid
 
+from alot.settings.theme import get_theme
+
 from . import Command, registerCommand
 from . import CommandCanceled, SequenceCanceled
 from .utils import update_keys
@@ -1217,3 +1219,39 @@ async def apply(self, ui):
         if (await ui.choice(self.msg, select='yes', cancel='no',
                             msg_position='left')) == 'no':
             raise SequenceCanceled()
+
+@registerCommand(
+    MODE, "theme",
+    arguments=[
+        (["theme_name"], {"help": "Name of the theme"})
+    ],
+    help="change theme")
+class ThemeCommand(Command):
+    """Change theme."""
+
+    def __init__(self, theme_name, **kwargs):
+        """
+        :param theme_name: Name of theme.
+        :type theme_name: str
+        """
+        super(ThemeCommand, self).__init__(**kwargs)
+        self.theme_name = theme_name
+
+    def apply(self, ui):
+        try:
+            themes_dir = settings.get("themes_dir")
+            theme = get_theme(themes_dir, self.theme_name)
+            if theme == settings.theme:
+                # Skip the update and don't rebuild buffers
+                # unnecessarily.
+                return
+            settings.theme = theme
+            for buffer in ui.buffers:
+                buffer.rebuild()
+            ui.update()
+            logging.info(f"Applied theme {self.theme_name}")
+        except ConfigError as e:
+            ui.notify(
+                f"Error when loading theme:\n {e}",
+                priority="error"
+            )

alot/settings/manager.py

@@ -2,7 +2,6 @@
 # This file is released under the GNU GPL, version 3 or a later revision.
 # For further details see the COPYING file
 import importlib.util
-import itertools
 import logging
 import mailcap
 import os
@@ -19,20 +18,18 @@
 from .errors import ConfigError, NoMatchingAccount
 from .utils import read_config, read_notmuch_config
 from .utils import resolve_att
-from .theme import Theme
+from .theme import get_theme
 
 
 DEFAULTSPATH = os.path.join(os.path.dirname(__file__), '..', 'defaults')
-DATA_DIRS = get_xdg_env('XDG_DATA_DIRS',
-                        '/usr/local/share:/usr/share').split(':')
 
 
 class SettingsManager:
     """Organizes user settings"""
     def __init__(self):
         self.hooks = None
         self._mailcaps = mailcap.getcaps()
-        self._theme = None
+        self.theme = None
         self._accounts = None
         self._accountmap = None
         self._notmuchconfig = None
@@ -99,38 +96,15 @@ def read_config(self, path):
         logging.debug('template directory: `%s`' % tempdir)
 
         # themes
-        themestring = newconfig['theme']
+        theme_name = newconfig['theme']
         themes_dir = self._config.get('themes_dir')
         logging.debug('themes directory: `%s`' % themes_dir)
 
-        # if config contains theme string use that
-        data_dirs = [os.path.join(d, 'alot/themes') for d in DATA_DIRS]
-        if themestring:
-            # This is a python for/else loop
-            # https://docs.python.org/3/reference/compound_stmts.html#for
-            #
-            # tl/dr; If the loop loads a theme it breaks. If it doesn't break,
-            # then it raises a ConfigError.
-            for dir_ in itertools.chain([themes_dir], data_dirs):
-                theme_path = os.path.join(dir_, themestring)
-                if not os.path.exists(os.path.expanduser(theme_path)):
-                    logging.warning('Theme `%s` does not exist.', theme_path)
-                else:
-                    try:
-                        self._theme = Theme(theme_path)
-                    except ConfigError as e:
-                        raise ConfigError('Theme file `%s` failed '
-                                          'validation:\n%s' % (theme_path, e))
-                    else:
-                        break
-            else:
-                raise ConfigError('Could not find theme {}, see log for more '
-                                  'information'.format(themestring))
-
-        # if still no theme is set, resort to default
-        if self._theme is None:
-            theme_path = os.path.join(DEFAULTSPATH, 'default.theme')
-            self._theme = Theme(theme_path)
+        self.theme = (
+            get_theme(themes_dir, theme_name)
+            if theme_name else
+            get_theme(DEFAULTSPATH, 'default.theme')
+        )
 
         self._accounts = self._parse_accounts(self._config)
         self._accountmap = self._account_table(self._accounts)
@@ -306,7 +280,7 @@ def get_theming_attribute(self, mode, name, part=None):
         :rtype: urwid.AttrSpec
         """
         colours = int(self._config.get('colourmode'))
-        return self._theme.get_attribute(colours, mode, name, part)
+        return self.theme.get_attribute(colours, mode, name, part)
 
     def get_threadline_theming(self, thread):
         """
@@ -318,7 +292,7 @@ def get_threadline_theming(self, thread):
         :type thread: alot.db.thread.Thread
         """
         colours = int(self._config.get('colourmode'))
-        return self._theme.get_threadline_theming(thread, colours)
+        return self.theme.get_threadline_theming(thread, colours)
 
     def get_tagstring_representation(self, tag, onebelow_normal=None,
                                      onebelow_focus=None):
@@ -341,7 +315,7 @@ def get_tagstring_representation(self, tag, onebelow_normal=None,
             :translated: to an alternative string representation
         """
         colourmode = int(self._config.get('colourmode'))
-        theme = self._theme
+        theme = self.theme
         cfg = self._config
         colours = [1, 16, 256]
 

alot/settings/theme.py

@@ -1,14 +1,18 @@
 # Copyright (C) 2011-2012  Patrick Totzke <patricktotzke@gmail.com>
 # This file is released under the GNU GPL, version 3 or a later revision.
 # For further details see the COPYING file
+import logging
 import os
 
+from ..helper import get_xdg_env
 from ..utils import configobj as checks
 from .utils import read_config
 from .errors import ConfigError
 
 DEFAULTSPATH = os.path.join(os.path.dirname(__file__), '..', 'defaults')
 DUMMYDEFAULT = ('default',) * 6
+DATA_DIRS = get_xdg_env('XDG_DATA_DIRS',
+                        '/usr/local/share:/usr/share').split(':')
 
 
 class Theme:
@@ -40,6 +44,9 @@ def __init__(self, path):
                         msg = 'missing threadline parts: %s' % ', '.join(diff)
                         raise ConfigError(msg)
 
+    def __eq__(self, other):
+        return self._config == other._config
+
     def get_attribute(self, colourmode, mode, name, part=None):
         """
         returns requested attribute
@@ -128,3 +135,28 @@ def fill(key, fallback=None):
             res[part]['normal'] = pickcolour(fill('normal'))
             res[part]['focus'] = pickcolour(fill('focus'))
         return res
+
+
+def get_theme(themes_dir, theme_name) -> Theme:
+    theme_dirs = [
+        themes_dir,
+        *(os.path.join(d, "alot/themes") for d in DATA_DIRS),
+        DEFAULTSPATH
+    ]
+    theme_paths = [os.path.join(d, theme_name) for d in theme_dirs]
+    theme_path = next(
+        (theme_path
+         for theme_path in theme_paths
+         if os.path.exists(os.path.expanduser(theme_path))),
+        None
+    )
+    if theme_path is None:
+        raise ConfigError(
+            f"Could not find theme {theme_name}."
+        )
+    try:
+        return Theme(theme_path)
+    except ConfigError as e:
+        msg = f"Theme file `{theme_path}` failed validation: {e}"
+        logging.error(msg)
+        raise ConfigError(msg) from e

docs/source/usage/modes/global.rst

@@ -230,3 +230,13 @@ The following commands are available globally:
     optional arguments
         :---tags: tags to display
 
+.. _cmd.global.theme:
+
+.. describe:: theme
+
+    change theme
+
+    argument
+        Name of the theme
+
+

tests/settings/test_theme.py

@@ -2,9 +2,10 @@
 # This file is released under the GNU GPL, version 3 or a later revision.
 # For further details see the COPYING file
 
-import unittest
+import os
+from unittest import TestCase, mock
 
-from alot.settings import theme
+from alot.settings import theme as module
 
 
 DUMMY_THEME = """\
@@ -60,15 +61,15 @@
 """
 
 
-class TestThemeGetAttribute(unittest.TestCase):
+class TestThemeGetAttribute(TestCase):
 
     @classmethod
     def setUpClass(cls):
         # We use a list of strings instead of a file path to pass in the config
         # file.  This is possible because the argument is handed to
         # configobj.ConfigObj directly and that accepts eigher:
         # https://configobj.rtfd.io/en/latest/configobj.html#reading-a-config-file
-        cls.theme = theme.Theme(DUMMY_THEME.splitlines())
+        cls.theme = module.Theme(DUMMY_THEME.splitlines())
 
     def test_invalid_mode_raises_key_error(self):
         with self.assertRaises(KeyError) as cm:
@@ -86,3 +87,34 @@ def test_invalid_name_raises_key_error(self):
     def test_invalid_colorindex_raises_value_error(self):
         with self.assertRaises(ValueError):
             self.theme.get_attribute(0, 'global', 'body')
+
+class GetThemeTest(TestCase):
+    def setUp(self):
+        self.mock_os_path = mock.patch(
+            "os.path", wraps=os.path
+        ).start()
+        self.mock_theme = mock.patch.object(
+            module, 'Theme', spec_set=module.Theme
+        ).start()
+        self.addCleanup(mock.patch.stopall)
+
+    def test_returns_theme_when_theme_found(self):
+        self.mock_os_path.exists.return_value = True
+        expected_theme = mock.sentinel
+        self.mock_theme.return_value = expected_theme
+        actual_theme = module.get_theme("test", "test.theme")
+        self.assertEqual(expected_theme, actual_theme)
+
+    def test_raises_config_error_when_theme_not_found(self):
+        self.mock_os_path.exists.return_value = False
+        with self.assertRaisesRegex(module.ConfigError, "Could not find theme test.theme"):
+            module.get_theme("test", "test.theme")
+
+    def test_raises_config_error_when_theme_fails_validation(self):
+        self.mock_os_path.exists.return_value = True
+        self.mock_theme.side_effect = module.ConfigError("test error")
+        with self.assertRaisesRegex(
+            module.ConfigError, 
+            "Theme file `test/test.theme` failed validation: test error"
+        ):
+            module.get_theme("test", "test.theme")