Add ICS calendar support

src/config.py

@@ -33,6 +33,8 @@ class Settings(BaseSettings):
     caldav_url: Optional[str] = Field(default=None, alias="CALDAV_URL")
     caldav_username: Optional[str] = Field(default=None, alias="CALDAV_USERNAME")
     caldav_password: Optional[SecretStr] = Field(default=None, alias="CALDAV_PASSWORD")
+    ics_calendars: Optional[str] = Field(default=None, alias="ICS_CALENDARS")
+    ics_calendar_timeout: int = Field(default=20, alias="ICS_CALENDAR_TIMEOUT")
 
     # CardDAV Configuration
     carddav_url: Optional[str] = Field(default=None, alias="CARDDAV_URL")
@@ -107,7 +109,7 @@ class Settings(BaseSettings):
             self.smtp_from_email,
         ])
 
-    def is_calendar_configured(self) -> bool:
+    def is_caldav_configured(self) -> bool:
         return all([
             self.enable_calendar,
             self.caldav_url,
@@ -115,6 +117,33 @@ class Settings(BaseSettings):
             self.caldav_password,
         ])
 
+    def is_calendar_configured(self) -> bool:
+        return all([
+            self.enable_calendar,
+            (self.is_caldav_configured() or self.get_ics_calendars()),
+        ])
+
+    def get_ics_calendars(self) -> list[tuple[Optional[str], str]]:
+        if not self.ics_calendars:
+            return []
+
+        calendars: list[tuple[Optional[str], str]] = []
+        for entry in self.ics_calendars.split(","):
+            item = entry.strip()
+            if not item:
+                continue
+            if "|" in item:
+                name, url = item.split("|", 1)
+                name = name.strip() or None
+                url = url.strip()
+            else:
+                name = None
+                url = item
+            if url:
+                calendars.append((name, url))
+
+        return calendars
+
     def is_contacts_configured(self) -> bool:
         return all([
             self.enable_contacts,