From 8221224255e8c918777423053fadf9ad5055e6e4 Mon Sep 17 00:00:00 2001
From: Josh Creek <8179928+jcreek@users.noreply.github.com>
Date: Tue, 15 Oct 2024 19:31:37 +0100
Subject: [PATCH] feat(#6): Add proper pagination support

---
 package.json                     |   3 +-
 pnpm-lock.yaml                   |   8 ++
 src/routes/products/+page.svelte | 180 +++++++++++++++++++++++++++----
 3 files changed, 169 insertions(+), 22 deletions(-)

diff --git a/package.json b/package.json
index 51e89f3..6dd387c 100644
--- a/package.json
+++ b/package.json
@@ -49,7 +49,8 @@
 	"dependencies": {
 		"@supabase/ssr": "^0.4.0",
 		"@supabase/supabase-js": "^2.44.2",
-		"stripe": "^15.4.0"
+		"stripe": "^15.4.0",
+		"ts-debounce": "^4.0.0"
 	},
 	"engines": {
 		"node": ">=18.13.0"
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 93412db..437f249 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -17,6 +17,9 @@ importers:
       stripe:
         specifier: ^15.4.0
         version: 15.12.0
+      ts-debounce:
+        specifier: ^4.0.0
+        version: 4.0.0
     devDependencies:
       '@sveltejs/adapter-auto':
         specifier: ^3.0.0
@@ -3051,6 +3054,9 @@ packages:
     peerDependencies:
       typescript: '>=4.2.0'
 
+  ts-debounce@4.0.0:
+    resolution: {integrity: sha512-+1iDGY6NmOGidq7i7xZGA4cm8DAa6fqdYcvO5Z6yBevH++Bdo9Qt/mN0TzHUgcCcKv1gmh9+W5dHqz8pMWbCbg==}
+
   ts-interface-checker@0.1.13:
     resolution: {integrity: sha512-Y/arvbn+rrz3JCKl9C4kVNfTfSm2/mEp5FSz5EsZSANGPSlQrpRI5M4PKF+mJnE52jOO90PnPSc3Ur3bTQw0gA==}
 
@@ -6580,6 +6586,8 @@ snapshots:
     dependencies:
       typescript: 5.6.2
 
+  ts-debounce@4.0.0: {}
+
   ts-interface-checker@0.1.13: {}
 
   tslib@2.7.0: {}
diff --git a/src/routes/products/+page.svelte b/src/routes/products/+page.svelte
index 18feb8c..f7112f2 100644
--- a/src/routes/products/+page.svelte
+++ b/src/routes/products/+page.svelte
@@ -1,17 +1,108 @@
 <script lang="ts">
-	import ProductsListItem from '$lib/components/products/ProductsListItem.svelte';
 	import { onMount } from 'svelte';
-	let products = [] as any;
+	import { debounce } from 'ts-debounce';
+	import ProductsListItem from '$lib/components/products/ProductsListItem.svelte';
 
+	let products = [] as any[];
 	let enablePagination = false;
+	let totalPages = 1;
+	let currentPage = 1;
+	const limit = 20;
+	let isLoading = false;
+	let errorMessage = '';
 
-	onMount(async () => {
-		const response = await fetch('/products?limit=20&offset=0');
-		const responseJson = await response.json();
-		products = responseJson.products;
-		var count = responseJson.count;
-		// enablePagination needs to be set to true if there are more than 20 products
+	// Debounced fetchProducts function to prevent rapid requests
+	const fetchProducts = debounce(async (page: number) => {
+		isLoading = true;
+		errorMessage = '';
+
+		// Ensure page number is within valid range
+		if (page < 1) {
+			page = 1;
+		} else if (page > totalPages) {
+			page = totalPages;
+		}
+
+		const offset = (page - 1) * limit;
+
+		try {
+			const response = await fetch(`/products?limit=${limit}&offset=${offset}`);
+			const responseJson = await response.json();
+
+			if (response.ok) {
+				products = responseJson.products;
+				const count = responseJson.count;
+
+				totalPages = Math.ceil(count / limit);
+				enablePagination = totalPages > 1;
+				currentPage = page;
+			} else {
+				throw new Error(responseJson.error || 'Failed to load products.');
+			}
+		} catch (error) {
+			console.error(error);
+			errorMessage = error.message || 'Failed to load products.';
+		} finally {
+			isLoading = false;
+		}
+	}, 300); // 300ms debounce delay
+
+	onMount(() => {
+		fetchProducts(currentPage);
 	});
+
+	// Generate pagination buttons with ellipsis for large numbers of pages
+	function getPageNumbers() {
+		const maxButtons = 5;
+		const pageNumbers = [];
+
+		if (totalPages <= maxButtons) {
+			// Show all pages as there aren't many
+			for (let i = 1; i <= totalPages; i++) {
+				pageNumbers.push(i);
+			}
+		} else {
+			let startPage = Math.max(currentPage - 2, 1);
+			let endPage = Math.min(currentPage + 2, totalPages);
+
+			if (currentPage <= 3) {
+				startPage = 1;
+				endPage = maxButtons;
+			} else if (currentPage >= totalPages - 2) {
+				startPage = totalPages - (maxButtons - 1);
+				endPage = totalPages;
+			}
+
+			// Add first page and ellipsis if needed
+			if (startPage > 1) {
+				pageNumbers.push(1);
+				if (startPage > 2) {
+					pageNumbers.push('...');
+				}
+			}
+
+			// Add page numbers
+			for (let i = startPage; i <= endPage; i++) {
+				pageNumbers.push(i);
+			}
+
+			// Add ellipsis and last page if needed
+			if (endPage < totalPages) {
+				if (endPage < totalPages - 1) {
+					pageNumbers.push('...');
+				}
+				pageNumbers.push(totalPages);
+			}
+		}
+
+		return pageNumbers;
+	}
+
+	function handlePageClick(pageNumber: number | string) {
+		if (typeof pageNumber === 'number' && pageNumber !== currentPage) {
+			fetchProducts(pageNumber);
+		}
+	}
 </script>
 
 <section class="py-24">
@@ -21,20 +112,67 @@
 		>
 			Available Products
 		</h2>
-		<div class="grid grid-cols-1 lg:grid-cols-3 gap-8">
-			{#each products as product (product.id)}
-				<ProductsListItem {product} />
-			{/each}
-		</div>
-		{#if enablePagination}
-			<div class="flex justify-center mt-12">
-				<div class="join">
-					<button class="join-item btn">1</button>
-					<button class="join-item btn btn-active">2</button>
-					<button class="join-item btn">3</button>
-					<button class="join-item btn">4</button>
-				</div>
+
+		{#if isLoading}
+			<p class="loading">Loading products...</p>
+		{:else if errorMessage}
+			<p class="error">{errorMessage}</p>
+		{:else}
+			<div class="grid grid-cols-1 lg:grid-cols-3 gap-8">
+				{#each products as product (product.id)}
+					<ProductsListItem {product} />
+				{/each}
 			</div>
+
+			{#if enablePagination}
+				<div class="flex justify-center mt-12">
+					<div class="join">
+						<!-- Previous Button -->
+						<button
+							class="join-item btn"
+							on:click={() => fetchProducts(currentPage - 1)}
+							disabled={currentPage === 1}
+						>
+							Previous
+						</button>
+
+						<!-- Page Number Buttons -->
+						{#each getPageNumbers() as pageNumber}
+							{#if pageNumber === '...'}
+								<span class="join-item btn">...</span>
+							{:else}
+								<button
+									class="join-item btn {currentPage === pageNumber ? 'btn-active' : ''}"
+									on:click={() => handlePageClick(pageNumber)}
+								>
+									{pageNumber}
+								</button>
+							{/if}
+						{/each}
+
+						<!-- Next Button -->
+						<button
+							class="join-item btn"
+							on:click={() => fetchProducts(currentPage + 1)}
+							disabled={currentPage === totalPages}
+						>
+							Next
+						</button>
+					</div>
+				</div>
+			{/if}
 		{/if}
 	</div>
 </section>
+
+<style>
+	.loading {
+		text-align: center;
+		margin: 20px 0;
+	}
+	.error {
+		color: red;
+		text-align: center;
+		margin: 20px 0;
+	}
+</style>