feat(reminders): validate frequency and time range

components/modals/reminderValidation.ts

@@ -0,0 +1,54 @@
+export const MIN_REMINDER_FREQUENCY_MINUTES = 5;
+export const MAX_REMINDER_FREQUENCY_MINUTES = 720;
+
+export const parseTimeToMinutes = (time: string): number | null => {
+  const [hours, minutes] = time.split(':').map(Number);
+  if (
+    Number.isNaN(hours) ||
+    Number.isNaN(minutes) ||
+    hours < 0 ||
+    hours > 23 ||
+    minutes < 0 ||
+    minutes > 59
+  ) {
+    return null;
+  }
+
+  return hours * 60 + minutes;
+};
+
+export interface ReminderValidationParams {
+  frequencyMinutes: number;
+  startTime: string;
+  endTime: string;
+}
+
+export const validateReminderInputs = ({
+  frequencyMinutes,
+  startTime,
+  endTime,
+}: ReminderValidationParams): { frequency?: string; timeRange?: string } => {
+  const errors: { frequency?: string; timeRange?: string } = {};
+  const frequency = Number(frequencyMinutes);
+
+  if (
+    !Number.isInteger(frequency) ||
+    frequency < MIN_REMINDER_FREQUENCY_MINUTES ||
+    frequency > MAX_REMINDER_FREQUENCY_MINUTES
+  ) {
+    errors.frequency = `Choose a value between ${MIN_REMINDER_FREQUENCY_MINUTES} and ${MAX_REMINDER_FREQUENCY_MINUTES} minutes.`;
+  }
+
+  const startMinutes = parseTimeToMinutes(startTime);
+  const endMinutes = parseTimeToMinutes(endTime);
+
+  if (
+    startMinutes === null ||
+    endMinutes === null ||
+    endMinutes <= startMinutes
+  ) {
+    errors.timeRange = 'End time must be later than start time.';
+  }
+
+  return errors;
+};