Improve dates, times and schedule backup info

client/plugins/utils.js

@@ -136,6 +136,47 @@ Vue.prototype.$parseCronExpression = (expression) => {
   }
 }
 
+Vue.prototype.$getNextScheduledDate = (expression) => {
+  const cronFields = expression.split(' ');
+  const currentDate = new Date();
+  const nextDate = new Date();
+
+  // Calculate next minute
+  const minute = cronFields[0];
+  const currentMinute = currentDate.getMinutes();
+  const nextMinute = getNextValue(minute, currentMinute, 59);
+  nextDate.setMinutes(nextMinute);
+
+  // Calculate next hour
+  const hour = cronFields[1];
+  const currentHour = currentDate.getHours();
+  const nextHour = getNextValue(hour, currentHour, 23);
+  nextDate.setHours(nextHour);
+
+  // Calculate next day of month
+  const dayOfMonth = cronFields[2];
+  const currentDayOfMonth = currentDate.getDate();
+  const lastDayOfMonth = new Date(currentDate.getFullYear(), currentDate.getMonth() + 1, 0).getDate();
+  const nextDayOfMonth = getNextValue(dayOfMonth, currentDayOfMonth, lastDayOfMonth);
+  nextDate.setDate(nextDayOfMonth);
+
+  // Calculate next month
+  const month = cronFields[3];
+  const currentMonth = currentDate.getMonth() + 1;
+  const nextMonth = getNextValue(month, currentMonth, 12);
+  nextDate.setMonth(nextMonth - 1);
+
+  // Calculate next day of week
+  const dayOfWeek = cronFields[4];
+  const currentDayOfWeek = currentDate.getDay();
+  const nextDayOfWeek = getNextValue(dayOfWeek, currentDayOfWeek, 6);
+  const daysUntilNextDayOfWeek = getNextDaysUntilDayOfWeek(currentDate, nextDayOfWeek);
+  nextDate.setDate(currentDate.getDate() + daysUntilNextDayOfWeek);
+
+  // Return the next scheduled date
+  return nextDate;
+}
+
 export function supplant(str, subs) {
   // source: http://crockford.com/javascript/remedial.html
   return str.replace(/{([^{}]*)}/g,
@@ -144,4 +185,26 @@ export function supplant(str, subs) {
       return typeof r === 'string' || typeof r === 'number' ? r : a
     }
   )
-}
+}
+
+function getNextValue(cronField, currentValue, maxValue) {
+  if (cronField === '*') {
+    return currentValue + 1 <= maxValue ? currentValue + 1 : 0;
+  }
+  const values = cronField.split(',');
+  const len = values.length;
+  let nextValue = parseInt(values[0]);
+  for (let i = 0; i < len; i++) {
+    const value = parseInt(values[i]);
+    if (value > currentValue) {
+      nextValue = value;
+      break;
+    }
+  }
+  return nextValue <= maxValue ? nextValue : parseInt(values[0]);
+}
+
+function getNextDaysUntilDayOfWeek(currentDate, nextDayOfWeek) {
+  const daysUntilNextDayOfWeek = (nextDayOfWeek + 7 - currentDate.getDay()) % 7;
+  return daysUntilNextDayOfWeek === 0 ? 7 : daysUntilNextDayOfWeek;
+}