feat: implement visual analytics and activity charts

shared/modules/dashboard/dashboard.service.ts

@@ -1,7 +1,8 @@
 import { DrizzleClient } from "@shared/db/DrizzleClient";
 import { users, transactions, moderationCases, inventory } from "@db/schema";
 import { desc, sql, and, gte } from "drizzle-orm";
-import type { RecentEvent } from "./dashboard.types";
+import type { RecentEvent, ActivityData } from "./dashboard.types";
+import { TransactionType } from "@shared/lib/constants";
 
 export const dashboardService = {
     /**
@@ -149,6 +150,57 @@ export const dashboardService = {
             console.error("Failed to emit system event:", e);
         }
     },
+
+    /**
+     * Get hourly activity aggregation for the last 24 hours
+     */
+    getActivityAggregation: async (): Promise<ActivityData[]> => {
+        const twentyFourHoursAgo = new Date(Date.now() - 24 * 60 * 60 * 1000);
+
+        // Postgres aggregation
+        // We treat everything as a transaction.
+        // We treat everything except TRANSFER_IN as a 'command' (to avoid double counting transfers)
+        const result = await DrizzleClient
+            .select({
+                hour: sql<string>`date_trunc('hour', ${transactions.createdAt})`,
+                transactions: sql<string>`COUNT(*)`,
+                commands: sql<string>`COUNT(*) FILTER (WHERE ${transactions.type} != ${TransactionType.TRANSFER_IN})`
+            })
+            .from(transactions)
+            .where(gte(transactions.createdAt, twentyFourHoursAgo))
+            .groupBy(sql`1`)
+            .orderBy(sql`1`);
+
+        // Map into a record for easy lookups
+        const dataMap = new Map<string, { commands: number, transactions: number }>();
+        result.forEach(row => {
+            if (!row.hour) return;
+            const dateStr = new Date(row.hour).toISOString();
+            dataMap.set(dateStr, {
+                commands: Number(row.commands),
+                transactions: Number(row.transactions)
+            });
+        });
+
+        // Generate the last 24 hours of data
+        const activity: ActivityData[] = [];
+        const current = new Date();
+        current.setHours(current.getHours(), 0, 0, 0);
+
+        for (let i = 23; i >= 0; i--) {
+            const h = new Date(current.getTime() - i * 60 * 60 * 1000);
+            const iso = h.toISOString();
+            const existing = dataMap.get(iso);
+
+            activity.push({
+                hour: iso,
+                commands: existing?.commands || 0,
+                transactions: existing?.transactions || 0
+            });
+        }
+
+        return activity;
+    },
 };
 
 /**