Fix/58 roll issues (#67)

* fix/58-roll-issues: handle edge cases

server/src/classes/classUtils.js

@@ -1,3 +1,14 @@
+export const DAYMS = 86400000;
+
+/**
+ * @description handle events that span over midnight
+ * @param {num} start - When does the event start
+ * @param {num} end  - When does the event end
+ * @returns {num} normalised time
+ */
+export const normaliseEndTime = (start, end) => (end < start ? end + DAYMS : end);
+
+
 /**
  * @description Sorts an array of objects by given property
  * @param {array} arr - array to be sorted
@@ -41,8 +52,9 @@ export const getSelectionByRoll = (arr, now) => {
   let nowFound = false;
 
   // exit early if we are past the events
-  const lastEventEnd = orderedEvents[orderedEvents.length - 1].timeEnd;
-  if (now > lastEventEnd) {
+  const lastEvent = orderedEvents[orderedEvents.length - 1];
+  const lastNormalEnd = normaliseEndTime(lastEvent.timeStart, lastEvent.timeEnd);
+  if (now > lastNormalEnd) {
     return {
       nowIndex,
       nowId,
@@ -57,8 +69,7 @@ export const getSelectionByRoll = (arr, now) => {
   // loop through events, look for where we should be
   for (const e of orderedEvents) {
     // When does the event end (handle midnight)
-    const normalEnd =
-      e.timeEnd < e.timeStart ? (e.timeEnd += this.DAYMS) : e.timeEnd;
+    const normalEnd = normaliseEndTime(e.timeStart, e.timeEnd);
 
     if (normalEnd <= now) {
       // event ran already
@@ -83,7 +94,7 @@ export const getSelectionByRoll = (arr, now) => {
       // set timers
       timers = {
         _startedAt: e.timeStart,
-        _finishAt: normalEnd,
+        _finishAt: e.timeEnd,
         duration: normalEnd - e.timeStart,
         current: normalEnd - now,
       };
@@ -118,3 +129,4 @@ export const getSelectionByRoll = (arr, now) => {
     timeToNext,
   };
 };
+