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fix: make export use correct time zone #85

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Merged
condyl merged 1 commit into from
Mar 8, 2026
Merged

fix: make export use correct time zone #85

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74 changes: 66 additions & 8 deletions src/lib/generator/ExportCal.js
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Original file line number Diff line number Diff line change
@@ -1,6 +1,7 @@
import ReactGA from "react-ga4";

const isAnalyticsEnabled = import.meta.env.PROD;
const ICS_TIMEZONE = "America/Toronto";
let cachedTimetableData;
export function exportCal() {
if (isAnalyticsEnabled) {
Expand All @@ -25,7 +26,28 @@ export function exportCal() {

function generateICSFileData() {
let ICSData =
"BEGIN:VCALENDAR\nVERSION:2.0\nPRODID:-//Brock Timetable//Brock Timetable//EN\n";
"BEGIN:VCALENDAR\n" +
"VERSION:2.0\n" +
"PRODID:-//Brock Timetable//Brock Timetable//EN\n" +
"CALSCALE:GREGORIAN\n" +
"BEGIN:VTIMEZONE\n" +
"TZID:America/Toronto\n" +
"X-LIC-LOCATION:America/Toronto\n" +
"BEGIN:DAYLIGHT\n" +
"TZOFFSETFROM:-0500\n" +
"TZOFFSETTO:-0400\n" +
"TZNAME:EDT\n" +
"DTSTART:19700308T020000\n" +
"RRULE:FREQ=YEARLY;BYMONTH=3;BYDAY=2SU\n" +
"END:DAYLIGHT\n" +
"BEGIN:STANDARD\n" +
"TZOFFSETFROM:-0400\n" +
"TZOFFSETTO:-0500\n" +
"TZNAME:EST\n" +
"DTSTART:19701101T020000\n" +
"RRULE:FREQ=YEARLY;BYMONTH=11;BYDAY=1SU\n" +
"END:STANDARD\n" +
"END:VTIMEZONE\n";
const courses = cachedTimetableData.courses;
for (let i = 0; i < courses.length; i++) {
const courseCode = courses[i].courseCode;
Expand Down Expand Up @@ -128,22 +150,32 @@ function generateICSEvent(
let EventData = "BEGIN:VEVENT\n";
EventData = EventData + "UID:" + self.crypto.randomUUID() + "\n";
EventData =
EventData + "DTSTAMP:" + generateICSTimeStampFromDate(new Date()) + "\n";
EventData + "DTSTAMP:" + generateICSUtcTimestampFromDate(new Date()) + "\n";
EventData =
EventData +
"DTSTART:" +
generateICSTimeStampFromDate(new Date(startTimestamp * 1000)) +
"DTSTART;TZID=" +
ICS_TIMEZONE +
":" +
generateICSTimeStampFromDateInTimeZone(
new Date(startTimestamp * 1000),
ICS_TIMEZONE,
) +
"\n";
EventData =
EventData +
"DTEND:" +
generateICSTimeStampFromDate(new Date(endTimestamp * 1000)) +
"DTEND;TZID=" +
ICS_TIMEZONE +
":" +
generateICSTimeStampFromDateInTimeZone(
new Date(endTimestamp * 1000),
ICS_TIMEZONE,
) +
"\n";
EventData =
EventData +
"RRULE:FREQ=WEEKLY;" +
"UNTIL=" +
generateICSTimeStampFromDate(new Date(endReoccurTimestamp * 1000)) +
generateICSUtcTimestampFromDate(new Date(endReoccurTimestamp * 1000)) +
";BYDAY=";
const validDays = days
.filter((day) => dayICSMap[day])
Expand Down Expand Up @@ -190,7 +222,33 @@ function addComponent(component, courseCode) {
);
}

function generateICSTimeStampFromDate(date) {
function generateICSTimeStampFromDateInTimeZone(date, timeZone) {
const parts = new Intl.DateTimeFormat("en-CA", {
timeZone,
year: "numeric",
month: "2-digit",
day: "2-digit",
hour: "2-digit",
minute: "2-digit",
second: "2-digit",
hourCycle: "h23",
}).formatToParts(date);
const valueMap = Object.fromEntries(
parts.map((part) => [part.type, part.value]),
);

return (
valueMap.year +
valueMap.month +
valueMap.day +
"T" +
valueMap.hour +
valueMap.minute +
valueMap.second
);
}

function generateICSUtcTimestampFromDate(date) {
const pad = (n) => String(n).padStart(2, "0");

const year = date.getUTCFullYear();
Expand Down