feat(admin): add analytics aggregator

src/Services/Analytics.php

@@ -0,0 +1,89 @@
+<?php
+
+namespace Bazaar\Services;
+
+use Bazaar\Core\Database;
+
+final class Analytics
+{
+    public function __construct(private readonly Database $db)
+    {
+    }
+
+    public function salesByDay(int $days = 14): array
+    {
+        $rows = $this->db->select(
+            "SELECT substr(COALESCE(paidAt, createdAt), 1, 10) AS day,
+                    COUNT(*) AS orderCount,
+                    COALESCE(SUM(totalCents), 0) AS revenueCents
+             FROM orders
+             WHERE status IN ('paid', 'fulfilled')
+             GROUP BY day
+             ORDER BY day ASC"
+        );
+
+        $byDay = [];
+        foreach ($rows as $row) {
+            $byDay[$row['day']] = [
+                'orderCount' => (int) $row['orderCount'],
+                'revenueCents' => (int) $row['revenueCents'],
+            ];
+        }
+
+        $series = [];
+        for ($offset = $days - 1; $offset >= 0; $offset--) {
+            $day = gmdate('Y-m-d', strtotime("-{$offset} days"));
+            $series[] = [
+                'day' => $day,
+                'orderCount' => $byDay[$day]['orderCount'] ?? 0,
+                'revenueCents' => $byDay[$day]['revenueCents'] ?? 0,
+            ];
+        }
+        return $series;
+    }
+
+    public function topProducts(int $limit = 5): array
+    {
+        return $this->db->select(
+            "SELECT oi.productId,
+                    oi.productName AS name,
+                    SUM(oi.quantity) AS unitsSold,
+                    SUM(oi.quantity * oi.unitPriceCents) AS revenueCents
+             FROM orderItems oi
+             JOIN orders o ON o.id = oi.orderId
+             WHERE o.status IN ('paid', 'fulfilled')
+             GROUP BY oi.productName
+             ORDER BY unitsSold DESC, revenueCents DESC
+             LIMIT ?",
+            [$limit]
+        );
+    }
+
+    public function averageOrderValueCents(): int
+    {
+        return (int) round((float) $this->db->scalar(
+            "SELECT COALESCE(AVG(totalCents), 0) FROM orders WHERE status IN ('paid', 'fulfilled')"
+        ));
+    }
+
+    public function unitsSold(): int
+    {
+        return (int) $this->db->scalar(
+            "SELECT COALESCE(SUM(oi.quantity), 0)
+             FROM orderItems oi
+             JOIN orders o ON o.id = oi.orderId
+             WHERE o.status IN ('paid', 'fulfilled')"
+        );
+    }
+
+    public function couponUsage(): array
+    {
+        return $this->db->select(
+            "SELECT couponCode, COUNT(*) AS orderCount, COALESCE(SUM(discountCents), 0) AS discountCents
+             FROM orders
+             WHERE couponCode IS NOT NULL AND couponCode != ''
+             GROUP BY couponCode
+             ORDER BY orderCount DESC"
+        );
+    }
+}