feat: reminder email opt-in 1 hour before registration opens

packages/api/src/routers/index.ts

@@ -1,6 +1,6 @@
 import { randomUUID } from "node:crypto";
 import { db } from "@kk/db";
-import { adminRequest, registration } from "@kk/db/schema";
+import { adminRequest, registration, reminder } from "@kk/db/schema";
 import { user } from "@kk/db/schema/auth";
 import { drinkkaart, drinkkaartTopup } from "@kk/db/schema/drinkkaart";
 import { env } from "@kk/env/server";
@@ -10,12 +10,19 @@ import { z } from "zod";
 import {
 	sendCancellationEmail,
 	sendConfirmationEmail,
+	sendReminderEmail,
 	sendUpdateEmail,
 } from "../email";
 import { adminProcedure, protectedProcedure, publicProcedure } from "../index";
 import { generateQrSecret } from "../lib/drinkkaart-utils";
 import { drinkkaartRouter } from "./drinkkaart";
 
+// Registration opens at this date — reminders fire 1 hour before
+const REGISTRATION_OPENS_AT = new Date("2026-03-10T17:00:00+01:00");
+const REMINDER_WINDOW_START = new Date(
+	REGISTRATION_OPENS_AT.getTime() - 60 * 60 * 1000,
+);
+
 // ---------------------------------------------------------------------------
 // Shared helpers
 // ---------------------------------------------------------------------------
@@ -729,6 +736,97 @@ export const appRouter = {
 			return { success: true, message: "Admin toegang geweigerd" };
 		}),
 
+	// ---------------------------------------------------------------------------
+	// Reminder opt-in
+	// ---------------------------------------------------------------------------
+
+	/**
+	 * Subscribe an email address to receive a reminder 1 hour before registration
+	 * opens. Silently deduplicates — if the email is already subscribed, returns
+	 * ok:true without error. Returns ok:false if registration is already open.
+	 */
+	subscribeReminder: publicProcedure
+		.input(z.object({ email: z.string().email() }))
+		.handler(async ({ input }) => {
+			const now = Date.now();
+
+			// Registration is already open — no point subscribing
+			if (now >= REGISTRATION_OPENS_AT.getTime()) {
+				return { ok: false, reason: "already_open" as const };
+			}
+
+			// Check for an existing subscription (silent dedup)
+			const existing = await db
+				.select({ id: reminder.id })
+				.from(reminder)
+				.where(eq(reminder.email, input.email))
+				.limit(1)
+				.then((rows) => rows[0]);
+
+			if (existing) {
+				return { ok: true };
+			}
+
+			await db.insert(reminder).values({
+				id: randomUUID(),
+				email: input.email,
+			});
+
+			return { ok: true };
+		}),
+
+	/**
+	 * Send pending reminder emails to all opted-in addresses.
+	 * Protected by a shared secret (`CRON_SECRET`) passed as an Authorization
+	 * header. Should be called by a Cloudflare Cron Trigger at the top of
+	 * every hour, or directly via `POST /api/cron/reminders`.
+	 *
+	 * Only sends when the current time is within the 1-hour reminder window
+	 * (between REGISTRATION_OPENS_AT - 1h and REGISTRATION_OPENS_AT).
+	 */
+	sendReminders: publicProcedure
+		.input(z.object({ secret: z.string() }))
+		.handler(async ({ input }) => {
+			// Validate the shared secret
+			if (!env.CRON_SECRET || input.secret !== env.CRON_SECRET) {
+				throw new Error("Unauthorized");
+			}
+
+			const now = Date.now();
+			const windowStart = REMINDER_WINDOW_START.getTime();
+			const windowEnd = REGISTRATION_OPENS_AT.getTime();
+
+			// Only send during the reminder window
+			if (now < windowStart || now >= windowEnd) {
+				return { sent: 0, skipped: true, reason: "outside_window" as const };
+			}
+
+			// Fetch all unsent reminders
+			const pending = await db
+				.select()
+				.from(reminder)
+				.where(isNull(reminder.sentAt));
+
+			let sent = 0;
+			const errors: string[] = [];
+
+			for (const row of pending) {
+				try {
+					await sendReminderEmail({ to: row.email });
+					await db
+						.update(reminder)
+						.set({ sentAt: new Date() })
+						.where(eq(reminder.id, row.id));
+					sent++;
+				} catch (err) {
+					errors.push(`${row.email}: ${String(err)}`);
+					console.error(`Failed to send reminder to ${row.email}:`, err);
+				}
+			}
+
+			return { sent, skipped: false, errors };
+		}),
+
 	// ---------------------------------------------------------------------------
 	// Checkout
 	// ---------------------------------------------------------------------------
@@ -835,3 +933,47 @@ export const appRouter = {
 
 export type AppRouter = typeof appRouter;
 export type AppRouterClient = RouterClient<typeof appRouter>;
+
+/**
+ * Standalone function that sends pending reminder emails.
+ * Exported so that the Cloudflare Cron HTTP handler can call it directly
+ * without needing drizzle-orm as a direct dependency of apps/web.
+ */
+export async function runSendReminders(): Promise<{
+	sent: number;
+	skipped: boolean;
+	reason?: string;
+	errors: string[];
+}> {
+	const now = Date.now();
+	const windowStart = REMINDER_WINDOW_START.getTime();
+	const windowEnd = REGISTRATION_OPENS_AT.getTime();
+
+	if (now < windowStart || now >= windowEnd) {
+		return { sent: 0, skipped: true, reason: "outside_window", errors: [] };
+	}
+
+	const pending = await db
+		.select()
+		.from(reminder)
+		.where(isNull(reminder.sentAt));
+
+	let sent = 0;
+	const errors: string[] = [];
+
+	for (const row of pending) {
+		try {
+			await sendReminderEmail({ to: row.email });
+			await db
+				.update(reminder)
+				.set({ sentAt: new Date() })
+				.where(eq(reminder.id, row.id));
+			sent++;
+		} catch (err) {
+			errors.push(`${row.email}: ${String(err)}`);
+			console.error(`Failed to send reminder to ${row.email}:`, err);
+		}
+	}
+
+	return { sent, skipped: false, errors };
+}