From 023f6d5c8cd47b1265fb1ea39df023ee8866d535 Mon Sep 17 00:00:00 2001
From: creme332 <65414576+creme332@users.noreply.github.com>
Date: Tue, 8 Oct 2024 16:48:06 +0400
Subject: [PATCH] implement GET `/products/stats/sales-per-category endpoint

---
 docs/API.md                      | 19 ++++++++++---------
 src/controllers/api/Products.php | 24 ++++++++++++++++++++++++
 2 files changed, 34 insertions(+), 9 deletions(-)

diff --git a/docs/API.md b/docs/API.md
index f7b294a..8153456 100644
--- a/docs/API.md
+++ b/docs/API.md
@@ -47,15 +47,16 @@ A user can be a client or an administrator.
 
 ### Product
 
-| Endpoint                           | Description                                            | Protected | Query string parameters |
-|------------------------------------|--------------------------------------------------------|-----------|-------------------------|
-| `GET /api/v1/products`             | Get the list of all products available in the store.   | No        | `sort`, `group-by`      |
-| `GET /api/v1/products/[id]`        | Get the details of a specific product by its ID.       | No        |
-| `GET /api/v1/products/[id]/stores` | Get the details of stores where a product is sold.     | No        |
-| `GET /api/v1/products/categories`  | Get the list of product categories.                    | No        |
-| `POST /api/v1/products`            | Create a new product entry in the database.            | No        |
-| `DELETE /api/v1/products/[id]`     | Delete a product with the specified ID.                | No        |
-| `PUT /api/v1/products/[id]`        | Update the details of a product with the specified ID. | No        |
+| Endpoint                                        | Description                                            | Protected | Query string parameters |
+|-------------------------------------------------|--------------------------------------------------------|-----------|-------------------------|
+| `GET /api/v1/products`                          | Get the list of all products available in the store.   | No        | `sort`, `group-by`      |
+| `GET /api/v1/products/[id]`                     | Get the details of a specific product by its ID.       | No        |
+| `GET /api/v1/products/[id]/stores`              | Get the details of stores where a product is sold.     | No        |
+| `GET /api/v1/products/categories`               | Get the list of product categories.                    | No        |
+| `POST /api/v1/products`                         | Create a new product entry in the database.            | No        |
+| `DELETE /api/v1/products/[id]`                  | Delete a product with the specified ID.                | No        |
+| `PUT /api/v1/products/[id]`                     | Update the details of a product with the specified ID. | No        |
+| `GET /api/v1/products/sales/sales-per-category` | Get the number of units sold per category.             | No        |                         |
 
 ### Order
 
diff --git a/src/controllers/api/Products.php b/src/controllers/api/Products.php
index 699493b..3b1190d 100644
--- a/src/controllers/api/Products.php
+++ b/src/controllers/api/Products.php
@@ -5,6 +5,7 @@
 namespace Steamy\Controller\API;
 
 use Opis\JsonSchema\{Errors\ErrorFormatter};
+use PDO;
 use Steamy\Core\Utility;
 use Steamy\Model\Product;
 use Steamy\Core\Model;
@@ -22,6 +23,8 @@ class Products
             '/products/{id}' => 'getProductById',
             '/products/{id}/reviews' => 'getAllReviewsForProduct',
             '/products/{id}/stores' => 'getAllStoresForProduct',
+
+            '/products/stats/sales-per-category' => 'getSalesPerCategory',
         ],
         'POST' => [
             '/products' => 'createProduct',
@@ -256,4 +259,25 @@ public function getAllStoresForProduct(): void
         // Return JSON response
         echo json_encode($result);
     }
+
+    /**
+     * Get units sold per product category
+     * @return void
+     */
+    public function getSalesPerCategory(): void
+    {
+        $query = <<< EOL
+        SELECT category, COUNT(*) as unitsSold
+        FROM product
+        INNER JOIN order_product
+        ON product.product_id = order_product.product_id
+        GROUP BY category
+        EOL;
+
+        $con = self::connect();
+        $stm = $con->prepare($query);
+        $stm->execute();
+
+        echo json_encode($stm->fetchAll(PDO::FETCH_ASSOC));
+    }
 }