Create next_business_window.js

Author: franks883

Core ServiceNow APIs/GlideDateTime/Next Business Window Calculator/next_business_window.js

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+var NextBusinessWindow = Class.create();
+NextBusinessWindow.prototype = (function () {
+	// Configuration
+	var DEFAULT_SCHEDULE_SYS_ID = ''; // optional fallback schedule sys_id (cmn_schedule)
+	var DEFAULT_TZ = 'Europe/London';
+	var MAX_SEGMENTS = 1000; // safety guard
+
+	// Helpers
+	function _toGdt(input) {
+		if (input instanceof GlideDateTime) return input;
+		var g = new GlideDateTime();
+		if (input) g.setDisplayValue(input);
+		return g;
+	}
+	function _getSchedule(scheduleSysId) {
+		var sch = new GlideSchedule();
+		if (scheduleSysId) sch.load(scheduleSysId);
+		else if (DEFAULT_SCHEDULE_SYS_ID) sch.load(DEFAULT_SCHEDULE_SYS_ID);
+		else throw new Error('No schedule sys_id supplied and no default configured.');
+		return sch;
+	}
+	function _setTz(gdt, tz) { if (tz) gdt.setTZ(tz); return gdt; }
+
+	return {
+		initialize: function () {},
+
+		/**
+		 * Add working minutes across a GlideSchedule.
+		 * @param {String|GlideDateTime} start
+		 * @param {Number} minutes
+		 * @param {String} scheduleSysId
+		 * @param {String} [timeZone] IANA name, e.g. "Europe/London"
+		 * @returns {{endGdt: GlideDateTime, consumedMinutes: number, segments: Array}}
+		 */
+		addWorkingMinutes: function (start, minutes, scheduleSysId, timeZone) {
+			if (!minutes || minutes < 0) throw new Error('Minutes must be a positive integer.');
+			var tz = timeZone || DEFAULT_TZ;
+			var sch = _getSchedule(scheduleSysId);
+
+			var cursor = _toGdt(start);
+			_setTz(cursor, tz);
+
+			// If not in schedule, jump to the next working start
+			if (!sch.isInSchedule(cursor)) {
+				var nextStart = sch.getNextStartTime(cursor);
+				if (!nextStart) throw new Error('No next working period found from start time.');
+				cursor = nextStart;
+			}
+
+			var remaining = parseInt(minutes, 10);
+			var segments = [];
+			var guard = 0;
+
+			while (remaining > 0) {
+				if (guard++ > MAX_SEGMENTS) throw new Error('Exceeded max segments; check schedule/inputs.');
+
+				var segEnd = sch.getNextEndTime(cursor);
+				if (!segEnd) throw new Error('Schedule has no next end time; check configuration.');
+
+				var available = Math.ceil((segEnd.getNumericValue() - cursor.getNumericValue()) / (60 * 1000)); // minutes
+
+				if (remaining <= available) {
+					var end = new GlideDateTime(cursor);
+					end.addSeconds(remaining * 60);
+					segments.push({ segmentStart: new GlideDateTime(cursor), segmentEnd: new GlideDateTime(end), consumed: remaining });
+					return { endGdt: end, consumedMinutes: minutes, segments: segments };
+				}
+
+				// consume full segment
+				segments.push({ segmentStart: new GlideDateTime(cursor), segmentEnd: new GlideDateTime(segEnd), consumed: available });
+				remaining -= available;
+
+				var nextStart = sch.getNextStartTime(segEnd);
+				if (!nextStart) throw new Error('No subsequent working segment found.');
+				cursor = nextStart;
+			}
+
+			return { endGdt: new GlideDateTime(cursor), consumedMinutes: minutes, segments: segments };
+		}
+	};
+})();