support for color theme plugins

4 files changed, 24 insertions, 8 deletions

diff --git a/khal/khalendar/event.py b/khal/khalendar/event.py
index c3112fba..d300b17d 100644
--- a/khal/khalendar/event.py
+++ b/khal/khalendar/event.py
@@ -25,7 +25,7 @@ helper functions."""
 import datetime as dt
 import logging
 import os
-from typing import Dict, List, Optional, Tuple, Type, Union
+from typing import Callable, Dict, List, Optional, Tuple, Type, Union
 
 import icalendar
 import icalendar.cal
@@ -729,9 +729,9 @@ class Event:
 
         formatters = FORMATTERS.values()
         if len(formatters) == 1:
-            fmt = list(formatters)[0]
+            fmt: Callable[[str], str] = list(formatters)[0]
         else:
-            def fmt(s): return s.strip()
+            def fmt(s: str) -> str: return s.strip()
 
         attributes["description"] = fmt(self.description)
         attributes["description-separator"] = ""
diff --git a/khal/plugins.py b/khal/plugins.py
index 891eca99..fc3d5096 100644
--- a/khal/plugins.py
+++ b/khal/plugins.py
@@ -1,4 +1,5 @@
 from collections.abc import Callable, Mapping
+from typing import Dict, List, Tuple
 
 from khal._compat import importlib_metadata
 
@@ -18,6 +19,12 @@ def _load_formatters() -> dict[str, Callable[[str], str]]:
 
 FORMATTERS: Mapping[str, Callable[[str], str]] = _load_formatters()
 
+def _load_color_themes() -> Dict[str, List[Tuple[str, ...]]]:
+    color_theme_entrypoints = importlib_metadata.entry_points(group="khal.color_theme")
+    return {ep.name: ep.load() for ep in color_theme_entrypoints}
+
+THEMES: Dict[str, List[Tuple[str, ...]],] = _load_color_themes()
+
 # class ParserExtensionInterface(Protocol):
 #     """An interface for parser extension plugins."""
 
@@ -43,7 +50,6 @@ FORMATTERS: Mapping[str, Callable[[str], str]] = _load_formatters()
 #         """Add options to the khal CLI, to be stored in mdit.options["mdformat"]
 #         (optional)"""
 
-
 # def _load_parser_extensions() -> dict[str, ParserExtensionInterface]:
 #     parser_extension_entrypoints = importlib_metadata.entry_points(
 #         group="khal.parser_extension"
diff --git a/khal/settings/khal.spec b/khal/settings/khal.spec
index 676d5103..b5e758dd 100644
--- a/khal/settings/khal.spec
+++ b/khal/settings/khal.spec
@@ -269,7 +269,7 @@ blank_line_before_day = boolean(default=False)
 #
 # __ http://urwid.org/manual/displayattributes.html
 # .. _github: https://github.com/pimutils/khal/issues
-theme = option('dark', 'light', default='dark')
+theme = string(default='dark')
 
 # Whether to show a visible frame (with *box drawing* characters) around some
 # (groups of) elements or not. There are currently several different frame
diff --git a/khal/ui/__init__.py b/khal/ui/__init__.py
index 930b3023..f3ea06de 100644
--- a/khal/ui/__init__.py
+++ b/khal/ui/__init__.py
@@ -29,9 +29,9 @@ from typing import Dict, List, Literal, Optional, Tuple
 import click
 import urwid
 
-from .. import utils
+from .. import plugins, utils
 from ..khalendar import CalendarCollection
-from ..khalendar.exceptions import ReadOnlyCalendarError
+from ..khalendar.exceptions import FatalError, ReadOnlyCalendarError
 from ..parse_datetime import timedelta2str
 from . import colors
 from .base import Pane, Window
@@ -1367,6 +1367,17 @@ def start_pane(
         color_mode: Literal['rgb', '256colors']='rgb',
 ):
     """Open the user interface with the given initial pane."""
+    # We don't validate the themes in settings.spec but instead here
+    # first try to load built-in themes, then try to load themes from
+    # plugins
+    theme = colors.themes.get(pane._conf['view']['theme'])
+    if theme is None:
+        theme = plugins.THEMES.get(pane._conf['view']['theme'])
+    if theme is None:
+        logger.fatal(f'Invalid theme {pane._conf["view"]["theme"]} configured')
+        logger.fatal(f'Available themes are: {", ".join(colors.themes.keys())}')
+        raise FatalError
+
     quit_keys = quit_keys or ['q']
 
     frame = Window(
@@ -1417,7 +1428,6 @@ def start_pane(
     logger.addHandler(header_handler)
 
     frame.open(pane, callback)
-    theme = getattr(colors, pane._conf['view']['theme'])
     palette = _add_calendar_colors(
         theme, pane.collection, color_mode=color_mode,
         base='calendar', attr_template='calendar {}',