implemented pagination

app/lib/actions/locationActions.ts

@@ -89,22 +89,23 @@ export const updateOrAddLocation = withUser(async (user:AuthenticatedUser, locat
 });
 
 
-export const fetchAllLocations = withUser(async (user:AuthenticatedUser, pageIx:number=0, pageSize:number=2000) => {
+export const fetchAllLocations = withUser(async (user:AuthenticatedUser, year:number) => {
 
     const dbClient = await getDbClient();
 
     const { id: userId } = user;
 
-    // fetch `pageSize` locations for the given page index
+    // fetch all locations for the given year
     const locations = await dbClient.collection<BillingLocation>("lokacije")
-        .find({ userId })
+        .find({
+            userId,
+            "yearMonth.year": year,
+        })
         .sort({ 
             "yearMonth.year": -1,
             "yearMonth.month": -1,
             name: 1,
         })
-        .skip(pageIx * pageSize)
-        .limit(pageSize)
         .toArray();
 
     return(locations);

app/lib/actions/monthActions.ts

@@ -76,7 +76,13 @@ export const fetchAvailableYears = withUser(async (user:AuthenticatedUser) => {
     const dbClient = await getDbClient();
 
     // query mnogodb for all `yearMonth` values
-    const yearMonths = await dbClient.collection<BillingLocation>("lokacije").distinct("yearMonth.year", { userId });
+    const years = await dbClient.collection<BillingLocation>("lokacije")
+        .distinct("yearMonth.year", { userId })
 
-    return(yearMonths);
+    // sort the years in descending order
+    const sortedYears = years.sort((a, b) => b - a);
+
+    console.log("sortedYears", sortedYears);
+
+    return(sortedYears);
 })

app/page.tsx

@@ -3,12 +3,13 @@ import { MonthTitle } from './ui/MonthTitle';
 import { AddMonthButton } from './ui/AddMonthButton';
 import { AddLocationButton } from './ui/AddLocationButton';
 import { PageFooter } from './ui/PageFooter';
-import { isAuthErrorMessage } from '@/app/lib/auth';
 import { fetchAllLocations } from './lib/actions/locationActions';
 import { formatCurrency } from './lib/formatStrings';
 import { fetchAvailableYears } from './lib/actions/monthActions';
 import { YearMonth } from './lib/db-types';
 import { formatYearMonth } from './lib/format';
+import { FC } from 'react';
+import Pagination from './ui/Pagination';
 
 const getNextYearMonth = (yearMonth:YearMonth) => {
   const {year, month} = yearMonth;
@@ -18,20 +19,27 @@ const getNextYearMonth = (yearMonth:YearMonth) => {
   } as YearMonth);
 }
 
-const Page = async () => {
+export interface PageProps {
+  searchParams?: {
+    year?: string;
+  };
+}
 
- const locations = await fetchAllLocations();
- const availableYears = await fetchAvailableYears();
+const Page:FC<PageProps> = async ({ searchParams }) => {
 
- if(isAuthErrorMessage(locations)) {
-  return (
-    <main className="flex min-h-screen flex-col p-6 bg-base-300">
-      <p className="text-center text-2xl text-red-500">{locations.message}</p>
-    </main>);
+  let availableYears: number[];
+
+  try {
+    availableYears = await fetchAvailableYears();
+  } catch (error:any) {
+    return (
+      <main className="flex min-h-screen flex-col p-6 bg-base-300">
+        <p className="text-center text-2xl text-red-500">{error.message}</p>
+      </main>);
   }
 
   // if the database is in it's initial state, show the add location button for the current month
-  if(locations.length === 0) {
+  if(availableYears.length === 0) {
     
     const currentYearMonth:YearMonth = {
       year: new Date().getFullYear(),
@@ -47,11 +55,21 @@ const Page = async () => {
     );
   }
 
+  console.log("page.availableYears", availableYears)
+
+  const [ latestYear ] = availableYears;
+  const currentYear = Number(searchParams?.year) || availableYears[0];
+  const locations = await fetchAllLocations(currentYear);
+
   let monthlyExpense = 0;
 
  return (
     <main className="flex min-h-screen flex-col p-6 bg-base-300">
-        <AddMonthButton yearMonth={getNextYearMonth(locations[0].yearMonth)} />
+        {
+          // if this is the latest year, show the add month button
+          currentYear === latestYear &&
+            <AddMonthButton yearMonth={getNextYearMonth(locations[0].yearMonth)} />
+        }
         {
           locations.map((location, ix, array) => {
 
@@ -59,9 +77,10 @@ const Page = async () => {
             const { year: prevYear, month: prevMonth } = array[ix-1]?.yearMonth ?? { year: undefined, month: undefined };
             const { year: nextYear, month: nextMonth } = array[ix+1]?.yearMonth ?? { year: undefined, month: undefined };
 
+            const isLatestYear = year === latestYear;
             const isFirstLocationInMonth = ix === 0 || year !== prevYear || month !== prevMonth;
             const isLastLocationInMonth = year !== nextYear || month !== nextMonth;
-            const isLastLocationOfFirstMonth = isLastLocationInMonth && year === array[0].yearMonth.year && month === array[0].yearMonth.month
+            const isLastLocationOfLatestMonth = isLastLocationInMonth && year === array[0].yearMonth.year && month === array[0].yearMonth.month
 
             if(isFirstLocationInMonth) {
               monthlyExpense = 0;
@@ -78,8 +97,8 @@ const Page = async () => {
                 }
                 <LocationCard key={`${location._id}`} location={location} />
                 {
-                  // show AddLocationButton as a last item in the firts month
-                  isLastLocationOfFirstMonth ?
+                  // show AddLocationButton as a last item in the first month
+                  isLastLocationOfLatestMonth && isLatestYear ?
                     <AddLocationButton key={`add-loc-${formatYearMonth(location.yearMonth)}`} yearMonth={location.yearMonth} /> : null
                 }
                 {
@@ -96,8 +115,10 @@ const Page = async () => {
             )
           })
         }
+        <div className="mt-5 flex w-full justify-center">
+          <Pagination availableYears={availableYears} />
+        </div>
         <PageFooter />
-        { availableYears.map(ym => <p key={`year-month-${ym}`}>{ym}</p>) }
     </main>
   );
 }

app/ui/Pagination.tsx

@@ -0,0 +1,141 @@
+'use client';
+
+import Link from 'next/link';
+import { usePathname, useSearchParams } from 'next/navigation';
+
+export const generatePagination = (availableYears: number[], currentYear:number) => {
+
+  const [firstYear, secondYear, thirdYear] = availableYears;
+  const [lastYear, yearBeforeLast1, yearBeforeLast2] = [...availableYears].reverse();
+  const currentYearIndex = availableYears.indexOf(currentYear);
+
+  // If the current year is among the first 3 years,
+  // show the first 3 and ellipsis
+  if (currentYearIndex < 2) {
+    return [firstYear, secondYear, thirdYear, '...'];
+  }
+
+  // If the current year is among the last 2 years,
+  // ellipsis and last 3 years.
+  if (currentYearIndex > availableYears.length - 3) {
+    return ['...', yearBeforeLast2, yearBeforeLast1, lastYear];
+  }
+
+  // If the current year is somewhere in the middle,
+  // show the first year, an ellipsis, the current year and its neighbors,
+  // another ellipsis, and the last year.
+  return [
+    '...',
+    availableYears[currentYearIndex - 1],
+    currentYear,
+    availableYears[currentYearIndex + 1],
+    '...',
+  ];
+};
+
+export default function Pagination({ availableYears } : { availableYears: number[] }) {
+  const pathname = usePathname();
+  const searchParams = useSearchParams();
+
+  console.log("Pagination.availableYears", availableYears);
+
+  // don't show pagination if there's less than 2 years available
+  if(availableYears.length < 2) {
+    return null;
+  }
+
+  const showAllPages = availableYears.length < 5;
+
+  const createYearURL = (yearNumber: number | string | undefined) => {
+    if(!yearNumber) return "/";
+
+    const params = new URLSearchParams(searchParams);
+    params.set('year', yearNumber.toString());
+    return `${pathname}?${params.toString()}`;
+  }
+
+  const currentYear = Number(searchParams.get('year')) || 1;
+  
+  const selectedYears = showAllPages ? availableYears : generatePagination(availableYears, currentYear);
+
+  console.log("selectedYears", selectedYears);
+
+  const latestYear = availableYears[0];
+  const earliestYear = availableYears[availableYears.length-1];
+
+  return (
+    <>
+      <div className="join">
+        {
+          // If there are more than 3 years, show the left arrow.
+          !showAllPages &&
+            <YearArrow
+              direction="left"
+              href={createYearURL(latestYear)}
+              isDisabled={currentYear === latestYear}
+            />
+        }
+
+        <div className="flex -space-x-px">
+          {selectedYears.map((year, index) => {
+            let position: 'first' | 'last' | 'single' | 'middle' | undefined;
+
+            if (index === 0) position = 'first';
+            if (index === selectedYears.length - 1) position = 'last';
+            if (selectedYears.length === 1) position = 'single';
+            if (year === '...') position = 'middle';
+
+            return (
+              <YearNumber
+                key={`${year}-${index}`}
+                href={createYearURL(year)}
+                year={year}
+                position={position}
+                isActive={currentYear === year}
+              />
+            );
+          })}
+        </div>
+
+        {
+          // If there are more than 3 years, show the left arrow.
+          !showAllPages &&
+          <YearArrow
+            direction="right"
+            href={createYearURL(earliestYear)}
+            isDisabled={currentYear === earliestYear}
+            />
+        }
+
+      </div>
+    </>
+  );
+}
+
+function YearNumber({
+  year,
+  href,
+  isActive,
+  position,
+}: {
+  year: number | string;
+  href: string;
+  position?: 'first' | 'last' | 'middle' | 'single';
+  isActive: boolean;
+}) {
+  return(<Link href={href} className={`join-item btn ${ isActive ? 'btn-active' : '' } ${ position === 'middle' ? 'btn-disabled' : '' }`}>{year}</Link>);
+}
+
+function YearArrow({
+  href,
+  direction,
+  isDisabled,
+}: {
+  href: string;
+  direction: 'left' | 'right';
+  isDisabled?: boolean;
+}) {
+
+  const icon = direction === 'left' ? "⏴" : "⏵";
+  return (<Link className={`join-item btn ${isDisabled ? "btn-disabled" : ""}`} href={href}>{icon}</Link>);
+}