(bugfix) HomePage: if current year was not found in DB containing data the app would crash.

This would happen at in January after user hasn't touched the app since the previous year and he did not create any records in the next (now current) year

app/ui/HomePage.tsx

@@ -2,8 +2,9 @@ import { fetchAllLocations } from '@/app/lib/actions/locationActions';
 import { fetchAvailableYears } from '@/app/lib/actions/monthActions';
 import { getUserSettings } from '@/app/lib/actions/userSettingsActions';
 import { BillingLocation, YearMonth } from '@/app/lib/db-types';
-import { FC } from 'react';
+import { FC, useEffect } from 'react';
 import { MonthLocationList } from '@/app/ui/MonthLocationList';
+import { redirect } from 'next/navigation';
 
 export interface HomePageProps {
   searchParams?: {
@@ -12,13 +13,29 @@ export interface HomePageProps {
   };
 }
 
+const ParamsYearInvalidMessage:FC<{ firstAvailableYear?: number }> = ({ firstAvailableYear }) => {
+
+  // Redirect to the first available year after showing the message
+  useEffect(() => {
+    if(firstAvailableYear) {
+      redirect(`/?year=${firstAvailableYear}`);
+    } else {
+      redirect(`/`);
+    }
+  });
+
+  return(
+    <main className="flex min-h-screen flex-col p-6 bg-base-300">
+      <p className="text-center text-2xl text-red-500">The year specified in the URL is invalid ... redirecting</p>
+    </main>
+    );
+};
+
 export const HomePage:FC<HomePageProps> = async ({ searchParams }) => {
 
+  /** years found in the DB sorted descending */
   let availableYears: number[];
 
-  // const asyncTimout = (ms:number) => new Promise(resolve => setTimeout(resolve, ms));
-  // await asyncTimout(5000);
-
   try {
     availableYears = await fetchAvailableYears();
   } catch (error:any) {
@@ -28,14 +45,34 @@ export const HomePage:FC<HomePageProps> = async ({ searchParams }) => {
       </main>);
   }
 
-  // if the database is in it's initial state, show the add location button for the current month
+  const paramsYear = searchParams?.year ? Number(searchParams.year) : null;
+  let selectedYear:number;
+
+  // IF year is set via params, check if it's valid
+  if(paramsYear) {
+
+    // IF the database is in it's initial state
+    //  THEN show message param being invalid AND redirect to root page
     if(availableYears.length === 0) {
-    return (<MonthLocationList />);
+      return (<ParamsYearInvalidMessage />);
     }
 
-  const currentYear = Number(searchParams?.year) || new Date().getFullYear();
+    // IF the year specified in the params is not found in the DB
+    //  THEN show message param being invalid AND redirect to page showing first available year
+    if(!availableYears.includes(paramsYear))  {
+      return (<ParamsYearInvalidMessage firstAvailableYear={availableYears[0]} />);
+    }
 
-  const locations = await fetchAllLocations(currentYear);
+    selectedYear = paramsYear;
+  } else {
+    const currYear = new Date().getFullYear();
+
+    // IF current year is available in DB THEN use it
+    // ELSE use the latest year found in the DB
+    selectedYear = availableYears.includes(currYear) ? currYear : availableYears[0];
+  }
+
+  const locations = await fetchAllLocations(selectedYear);
   const userSettings = await getUserSettings();
 
   // group locations by month