Implement modifying of kitty.conf

An include for the current theme is added and
all existing color related settings are commented out
so that the theme overlays on kitty's default settings.

kittens/themes/collection.py

@@ -26,6 +26,49 @@ MARK_BEFORE = '\033[33m'
 MARK_AFTER = '\033[39m'
 
 
+def patch_conf(raw: str) -> str:
+    addition = '# BEGIN_KITTY_THEME\ninclude current-theme.conf\n# END_KITTY_THEME'
+    nraw, num = re.subn(r'^# BEGIN_KITTY_THEME.+?# END_KITTY_THEME', addition, raw, flags=re.MULTILINE | re.DOTALL)
+    if not num:
+        if raw:
+            raw += '\n\n'
+        nraw = raw + addition
+    # comment out all existing color definitions
+    color_conf_items = [f'color{i}' for i in range(256)] + list(filter(None, '''
+foreground
+background
+selection_foreground
+selection_background
+
+cursor
+cursor_text_color
+
+url_color
+
+active_border_color
+inactive_border_color
+bell_border_color
+
+wayland_titlebar_color
+macos_titlebar_color
+
+active_tab_foreground
+active_tab_background
+inactive_tab_foreground
+inactive_tab_background
+tab_bar_background
+
+mark1_foreground
+mark1_background
+mark2_foreground
+mark2_background
+mark3_foreground
+mark3_background
+'''.splitlines()))
+    pat = f'^({"|".join(color_conf_items)})'
+    return re.sub(pat, r'# \1', nraw, flags=re.MULTILINE)
+
+
 def set_comment_in_zip_file(path: str, data: str) -> None:
     with zipfile.ZipFile(path, 'a') as zf:
         zf.comment = data.encode('utf-8')
@@ -203,6 +246,17 @@ class Theme:
 
     def save_in_conf(self, confdir: str) -> None:
         atomic_save(self.raw.encode('utf-8'), os.path.join(confdir, 'current-theme.conf'))
+        confpath = os.path.join(confdir, 'kitty.conf')
+        try:
+            with open(confpath) as f:
+                raw = f.read()
+        except FileNotFoundError:
+            raw = ''
+        nraw = patch_conf(raw)
+        if raw:
+            with open(confpath + '.bak', 'w') as f:
+                f.write(raw)
+        atomic_save(nraw.encode('utf-8'), confpath)
 
 
 class Themes: