[calendar] fix: prevent excessive fetching on client reload and refactor calendarfetcherutils.js

CHANGELOG.md

@@ -40,6 +40,7 @@ planned for 2026-01-01
 - [gitignore] cleanup/simplify .gitignore (#3952, #3954, #3968, #3969)
 - [compliments] refactor: optimize `loadComplimentFile` method and add unit tests(#3969)
 - [core] chore: simplify Wayland start script (#3974)
+- [calendar] refactor: simplify recurring event handling and event exclusion logic (#3976)
 
 ### Fixed
 
@@ -52,6 +53,7 @@ planned for 2026-01-01
 - [weather] fixed windy icon not showing up in pirateweather (#3957)
 - [compliments] fixed duplicate query param "?" when constructing refresh url (#3967)
 - [compliments] fixed compliments remote file minimum delay to be 15 minutes (#3970)
+- [calendar] prevent excessive fetching with smart refresh strategy (#3976)
 
 ### Updated
 

modules/default/calendar/calendarfetcher.js

@@ -38,6 +38,7 @@ class CalendarFetcher {
 		this.events = [];
 		this.reloadTimer = null;
 		this.serverErrorCount = 0;
+		this.lastFetch = null;
 		this.fetchFailedCallback = () => {};
 		this.eventsReceivedCallback = () => {};
 	}
@@ -165,6 +166,7 @@ class CalendarFetcher {
 						maximumEntries: this.maximumEntries,
 						maximumNumberOfDays: this.maximumNumberOfDays
 					});
+					this.lastFetch = Date.now();
 					this.broadcastEvents();
 				} catch (error) {
 					Log.error(`${this.url} - iCal parsing failed: ${error.message}`);
@@ -179,6 +181,18 @@ class CalendarFetcher {
 		this.scheduleNextFetch(nextDelay);
 	}
 
+	/**
+	 * Check if enough time has passed since the last fetch to warrant a new one
+	 * @param {number} minInterval - Minimum milliseconds between fetches (default: 3 minutes)
+	 * @returns {boolean} True if a new fetch should be performed
+	 */
+	shouldRefetch (minInterval = 3 * 60 * 1000) {
+		if (!this.lastFetch) {
+			return true;
+		}
+		return (Date.now() - this.lastFetch) >= minInterval;
+	}
+
 	/**
 	 * Broadcasts the current events to listeners
 	 */