Preserve the guide until a complete EPG refresh can activate

Adapted from MikaelKW/nodecast-tv-plus commits c267d98d734753a09b08d267c8ec2c3fa11c33f5, b761690bac7626a3cc5ddf754d96b14a02f506fe, and 5524fdaffed5c6a44ae69474e7eaa2f18d428c75. Preserve every parser batch, decode gzip once, and retain live channel metadata.

Co-authored-by: Mikael <mikaelkwessel@gmail.com>

server/services/xmltvDate.js

@@ -0,0 +1,94 @@
+function createValidatedCalendarDate(year, month, day, hour, minute, second) {
+    if (
+        month < 1 || month > 12 ||
+        day < 1 || day > 31 ||
+        hour < 0 || hour > 23 ||
+        minute < 0 || minute > 59 ||
+        second < 0 || second > 59
+    ) {
+        return null;
+    }
+
+    // setUTCFullYear avoids Date.UTC's special handling of years 0-99.
+    const calendarDate = new Date(0);
+    calendarDate.setUTCFullYear(year, month - 1, day);
+    calendarDate.setUTCHours(hour, minute, second, 0);
+
+    // Date normalizes impossible calendar values (for example February 30),
+    // so compare every component before accepting it.
+    if (
+        calendarDate.getUTCFullYear() !== year ||
+        calendarDate.getUTCMonth() !== month - 1 ||
+        calendarDate.getUTCDate() !== day ||
+        calendarDate.getUTCHours() !== hour ||
+        calendarDate.getUTCMinutes() !== minute ||
+        calendarDate.getUTCSeconds() !== second
+    ) {
+        return null;
+    }
+
+    return calendarDate;
+}
+
+function parseTimezoneOffset(timezone) {
+    if (!timezone || timezone.toUpperCase() === 'Z') return 0;
+
+    const normalized = timezone.replace(':', '');
+    const offsetHours = Number(normalized.slice(1, 3));
+    const offsetRemainder = Number(normalized.slice(3, 5));
+    if (offsetHours > 23 || offsetRemainder > 59) return null;
+
+    const total = (offsetHours * 60) + offsetRemainder;
+    return normalized[0] === '-' ? -total : total;
+}
+
+/**
+ * Parse an XMLTV date/time. XMLTV permits YYYYMMDDHHmmss or a shorter
+ * initial precision (for example YYYYMMDDHHmm, YYYYMMDDHH, or YYYYMMDD).
+ * Missing components use the earliest value in that precision and UTC is
+ * assumed when no numeric offset is provided.
+ * @param {string} dateStr - XMLTV format date string
+ * @returns {Date|null}
+ */
+function parseXmltvDate(dateStr) {
+    if (!dateStr) return null;
+
+    const value = String(dateStr).trim();
+    const match = value.match(/^(\d{4}(?:\d{2}){0,5})\s*(Z|[+-]\d{4})?$/i);
+    if (!match) {
+        // Preserve the existing compatibility fallback for explicit ISO 8601
+        // timestamps without accepting arbitrary host-dependent date strings.
+        const isoMatch = value.match(/^(\d{4})-(\d{2})-(\d{2})T(\d{2}):(\d{2})(?::(\d{2})(?:\.\d{1,3})?)?(Z|[+-]\d{2}:?\d{2})$/i);
+        if (!isoMatch) return null;
+
+        const [, year, month, day, hour, minute, second = '0', timezone] = isoMatch;
+        if (!createValidatedCalendarDate(
+            Number(year),
+            Number(month),
+            Number(day),
+            Number(hour),
+            Number(minute),
+            Number(second)
+        ) || parseTimezoneOffset(timezone) === null) return null;
+
+        const isoDate = new Date(value);
+        return Number.isNaN(isoDate.getTime()) ? null : isoDate;
+    }
+
+    const digits = match[1];
+    const timezone = match[2]?.toUpperCase();
+    const year = Number(digits.slice(0, 4));
+    const month = digits.length >= 6 ? Number(digits.slice(4, 6)) : 1;
+    const day = digits.length >= 8 ? Number(digits.slice(6, 8)) : 1;
+    const hour = digits.length >= 10 ? Number(digits.slice(8, 10)) : 0;
+    const minute = digits.length >= 12 ? Number(digits.slice(10, 12)) : 0;
+    const second = digits.length >= 14 ? Number(digits.slice(12, 14)) : 0;
+
+    const calendarDate = createValidatedCalendarDate(year, month, day, hour, minute, second);
+    const offsetMinutes = parseTimezoneOffset(timezone);
+    if (!calendarDate || offsetMinutes === null) return null;
+
+    return new Date(calendarDate.getTime() - (offsetMinutes * 60 * 1000));
+}
+
+module.exports = { parseXmltvDate };