feat(06-02): create dashboard-queries.ts with getDashboardStats()

- KPI queries: clienti attivi, revenue totale, pagamenti in sospeso, progetti in corso
- Activity feed: last 10 events across clients, projects, deliverables, time entries
- Uses isNotNull for nullable timestamp filters, Promise.all for parallel fetch

src/lib/dashboard-queries.ts

@@ -0,0 +1,138 @@
+import { db } from "@/db";
+import { clients, projects, payments, deliverables, time_entries } from "@/db/schema";
+import { eq, and, isNotNull, isNull, desc, sum, count } from "drizzle-orm";
+
+export type KpiStats = {
+  clientiAttivi: number;
+  revenueTotale: string;       // sum of projects.accepted_total (non-archived)
+  pagamentiInSospeso: string;  // sum of payments.amount where status = 'da_saldare' or 'inviata'
+  progettiInCorso: number;     // projects not archived
+};
+
+export type ActivityItem = {
+  type: "nuovo_cliente" | "nuovo_progetto" | "deliverable_approvato" | "timer_stoppato";
+  label: string;
+  detail: string;
+  timestamp: Date;
+};
+
+export type DashboardStats = {
+  kpi: KpiStats;
+  activity: ActivityItem[];
+};
+
+export async function getDashboardStats(): Promise<DashboardStats> {
+  // ── KPIs ─────────────────────────────────────────────────────────────────────
+  const [clientiAttiviRow] = await db
+    .select({ count: count() })
+    .from(clients)
+    .where(eq(clients.archived, false));
+
+  const [revenueRow] = await db
+    .select({ total: sum(projects.accepted_total) })
+    .from(projects)
+    .where(eq(projects.archived, false));
+
+  const [pagamentiDaSaldareRow] = await db
+    .select({ total: sum(payments.amount) })
+    .from(payments)
+    .where(eq(payments.status, "da_saldare"));
+
+  const [pagamentiInviataRow] = await db
+    .select({ total: sum(payments.amount) })
+    .from(payments)
+    .where(eq(payments.status, "inviata"));
+
+  const [progettiRow] = await db
+    .select({ count: count() })
+    .from(projects)
+    .where(eq(projects.archived, false));
+
+  const pagamentiSospeso =
+    (parseFloat(pagamentiDaSaldareRow?.total ?? "0") || 0) +
+    (parseFloat(pagamentiInviataRow?.total ?? "0") || 0);
+
+  const kpi: KpiStats = {
+    clientiAttivi: clientiAttiviRow?.count ?? 0,
+    revenueTotale: revenueRow?.total ?? "0",
+    pagamentiInSospeso: pagamentiSospeso.toFixed(2),
+    progettiInCorso: progettiRow?.count ?? 0,
+  };
+
+  // ── Activity feed ─────────────────────────────────────────────────────────────
+  // Fetch recent events from multiple tables, merge and sort
+  const [recentClients, recentProjects, recentApprovals, recentTimers] = await Promise.all([
+    db
+      .select({ id: clients.id, name: clients.name, created_at: clients.created_at })
+      .from(clients)
+      .orderBy(desc(clients.created_at))
+      .limit(5),
+
+    db
+      .select({ id: projects.id, name: projects.name, created_at: projects.created_at })
+      .from(projects)
+      .orderBy(desc(projects.created_at))
+      .limit(5),
+
+    db
+      .select({ id: deliverables.id, title: deliverables.title, approved_at: deliverables.approved_at })
+      .from(deliverables)
+      .where(isNotNull(deliverables.approved_at))
+      .orderBy(desc(deliverables.approved_at))
+      .limit(5),
+
+    db
+      .select({
+        id: time_entries.id,
+        ended_at: time_entries.ended_at,
+        duration_seconds: time_entries.duration_seconds,
+      })
+      .from(time_entries)
+      .where(
+        and(
+          isNotNull(time_entries.ended_at),
+          isNotNull(time_entries.duration_seconds)
+        )
+      )
+      .orderBy(desc(time_entries.ended_at))
+      .limit(5),
+  ]);
+
+  const activity: ActivityItem[] = [
+    ...recentClients.map((c) => ({
+      type: "nuovo_cliente" as const,
+      label: "Nuovo cliente",
+      detail: c.name,
+      timestamp: c.created_at,
+    })),
+    ...recentProjects.map((p) => ({
+      type: "nuovo_progetto" as const,
+      label: "Nuovo progetto",
+      detail: p.name,
+      timestamp: p.created_at,
+    })),
+    ...recentApprovals
+      .filter((d): d is typeof d & { approved_at: Date } => d.approved_at !== null)
+      .map((d) => ({
+        type: "deliverable_approvato" as const,
+        label: "Deliverable approvato",
+        detail: d.title,
+        timestamp: d.approved_at,
+      })),
+    ...recentTimers
+      .filter(
+        (t): t is typeof t & { ended_at: Date; duration_seconds: number } =>
+          t.ended_at !== null && t.duration_seconds !== null
+      )
+      .map((t) => ({
+        type: "timer_stoppato" as const,
+        label: "Timer stoppato",
+        detail: `${Math.round(t.duration_seconds / 60)} min`,
+        timestamp: t.ended_at,
+      })),
+  ]
+    .sort((a, b) => b.timestamp.getTime() - a.timestamp.getTime())
+    .slice(0, 10);
+
+  return { kpi, activity };
+}