feat: подписка на уведомление о поступлении товара

Co-authored-by: Cursor <cursoragent@cursor.com>

README.md

@@ -16,6 +16,7 @@
 - Личный кабинет: профиль, бронирования
 - Роли клиент / администратор, админ-панель
 - Согласие на cookies
+- Подписка «сообщить о поступлении», если товара нет в наличии
 
 ## Требования
 

postgres/init/05_stock_alerts.sql

@@ -0,0 +1,14 @@
+-- Подписка «сообщить о поступлении»
+CREATE TABLE IF NOT EXISTS product_stock_alerts (
+  id SERIAL PRIMARY KEY,
+  product_id INTEGER NOT NULL REFERENCES products(id) ON DELETE CASCADE,
+  email TEXT NOT NULL,
+  user_id INTEGER REFERENCES users(id) ON DELETE SET NULL,
+  created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+  notified_at TIMESTAMPTZ,
+  UNIQUE (product_id, email)
+);
+
+CREATE INDEX IF NOT EXISTS idx_stock_alerts_product_pending
+  ON product_stock_alerts (product_id)
+  WHERE notified_at IS NULL;

src/public/css/style.css

@@ -281,6 +281,39 @@ a:hover {
   color: var(--muted);
 }
 
+.stock-notify {
+  margin-top: 1.25rem;
+  padding: 1.25rem;
+}
+
+.stock-notify__title {
+  margin: 0 0 0.35rem;
+  font-size: 1.05rem;
+}
+
+.stock-notify__hint {
+  margin: 0 0 1rem;
+  font-size: 0.9rem;
+}
+
+.stock-notify__form {
+  max-width: 320px;
+}
+
+.stock-notify--done {
+  margin-top: 1rem;
+  padding: 0.75rem 1rem;
+  background: rgba(0, 184, 148, 0.12);
+  border-radius: 8px;
+  color: var(--success);
+}
+
+.admin-stock-form {
+  display: flex;
+  align-items: center;
+  gap: 0.35rem;
+}
+
 .product-detail__form {
   display: flex;
   flex-wrap: wrap;

src/routes/admin.js

@@ -3,6 +3,7 @@ const { query, formatPrice } = require('../db');
 const { requireAdmin } = require('../middleware/auth');
 const { asyncHandler } = require('../utils/asyncHandler');
 const { ROLE_LABELS } = require('../constants/roles');
+const { notifyIfBackInStock } = require('../services/stock-alerts');
 
 const router = express.Router();
 
@@ -91,7 +92,9 @@ router.get(
   '/products',
   asyncHandler(async (req, res) => {
     const { rows: products } = await query(
-      `SELECT p.*, c.name AS category_name
+      `SELECT p.*, c.name AS category_name,
+              (SELECT COUNT(*)::int FROM product_stock_alerts a
+               WHERE a.product_id = p.id AND a.notified_at IS NULL) AS alert_count
        FROM products p
        LEFT JOIN categories c ON c.id = p.category_id
        ORDER BY p.id`
@@ -100,10 +103,38 @@ router.get(
       title: 'Товары',
       products,
       formatPrice,
+      stockUpdated: req.query.stock_updated === '1',
+      notified: req.query.notified ? parseInt(req.query.notified, 10) : 0,
     });
   })
 );
 
+router.post(
+  '/products/:id/stock',
+  asyncHandler(async (req, res) => {
+    const productId = parseInt(req.params.id, 10);
+    const stock = parseInt(req.body.stock, 10);
+    if (!Number.isFinite(productId) || !Number.isFinite(stock) || stock < 0) {
+      return res.redirect('/admin/products');
+    }
+
+    const { rows } = await query('SELECT stock FROM products WHERE id = $1', [productId]);
+    const oldStock = rows[0]?.stock ?? 0;
+
+    await query('UPDATE products SET stock = $1 WHERE id = $2', [stock, productId]);
+
+    let notified = 0;
+    if (oldStock <= 0 && stock > 0) {
+      const result = await notifyIfBackInStock(productId);
+      notified = result.sent;
+    }
+
+    const qs = new URLSearchParams({ stock_updated: '1' });
+    if (notified > 0) qs.set('notified', String(notified));
+    res.redirect(`/admin/products?${qs}`);
+  })
+);
+
 router.get(
   '/reservations',
   asyncHandler(async (req, res) => {

src/routes/shop.js

@@ -89,6 +89,25 @@ router.get(
 
     const errorMsg = req.query.error ? decodeURIComponent(String(req.query.error)) : null;
     const reserved = req.query.reserved === '1';
+    const notifySuccess = req.query.notify_success
+      ? decodeURIComponent(String(req.query.notify_success))
+      : null;
+    const notifyError = req.query.notify_error
+      ? decodeURIComponent(String(req.query.notify_error))
+      : null;
+
+    let stockAlertSubscribed = false;
+    let notifyEmail = res.locals.user?.email || '';
+    if (product.stock <= 0) {
+      const stockAlerts = require('../services/stock-alerts');
+      if (notifyEmail) {
+        stockAlertSubscribed = await stockAlerts.isSubscribed(
+          product.id,
+          notifyEmail,
+          req.session.userId
+        );
+      }
+    }
 
     res.render('product', {
       title: product.name,
@@ -96,6 +115,10 @@ router.get(
       userReservation,
       error: errorMsg,
       reserved,
+      notifySuccess,
+      notifyError,
+      stockAlertSubscribed,
+      notifyEmail,
     });
   })
 );

src/routes/stock-alerts.js

@@ -0,0 +1,75 @@
+const express = require('express');
+const { query, formatPrice } = require('../db');
+const { getCart, cartCount } = require('../cart');
+const { requireCookieConsent } = require('../middleware/cookieConsent');
+const { asyncHandler } = require('../utils/asyncHandler');
+const stockAlerts = require('../services/stock-alerts');
+
+const router = express.Router();
+
+router.use((req, res, next) => {
+  const cart = getCart(req);
+  res.locals.cartCount = cartCount(cart);
+  res.locals.formatPrice = formatPrice;
+  next();
+});
+
+const emailRe = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;
+
+router.post(
+  '/product/:slug/notify-stock',
+  requireCookieConsent,
+  asyncHandler(async (req, res) => {
+    const slug = req.params.slug;
+    const { rows } = await query('SELECT id, name, stock FROM products WHERE slug = $1', [
+      slug,
+    ]);
+    const product = rows[0];
+
+    if (!product) {
+      return res.status(404).render('error', {
+        title: 'Не найдено',
+        message: 'Товар не найден',
+        code: 404,
+      });
+    }
+
+    if (product.stock > 0) {
+      return res.redirect(
+        `/product/${slug}?notify_error=${encodeURIComponent('Товар уже в наличии')}`
+      );
+    }
+
+    let email = (req.body.email || '').trim().toLowerCase();
+    if (req.session.userId) {
+      const { rows: users } = await query('SELECT email FROM users WHERE id = $1', [
+        req.session.userId,
+      ]);
+      if (users[0]) email = users[0].email;
+    }
+
+    if (!email || !emailRe.test(email)) {
+      return res.redirect(
+        `/product/${slug}?notify_error=${encodeURIComponent('Укажите корректный email')}`
+      );
+    }
+
+    if (await stockAlerts.isSubscribed(product.id, email, req.session.userId)) {
+      return res.redirect(
+        `/product/${slug}?notify_success=${encodeURIComponent('Вы уже подписаны — сообщим на почту')}`
+      );
+    }
+
+    await stockAlerts.subscribe({
+      productId: product.id,
+      email,
+      userId: req.session.userId || null,
+    });
+
+    res.redirect(
+      `/product/${slug}?notify_success=${encodeURIComponent('Когда товар появится, отправим письмо на ' + email)}`
+    );
+  })
+);
+
+module.exports = router;

src/server.js

@@ -18,6 +18,7 @@ const cookiesRoutes = require('./routes/cookies');
 const passwordResetRoutes = require('./routes/password-reset');
 const reservationsRoutes = require('./routes/reservations');
 const passkeyRoutes = require('./routes/passkey');
+const stockAlertsRoutes = require('./routes/stock-alerts');
 
 const PORT = process.env.PORT || 3000;
 const HOST = process.env.HOST || '0.0.0.0';
@@ -68,6 +69,7 @@ async function start() {
   app.use('/cookies', cookiesRoutes);
   app.use('/', passwordResetRoutes);
   app.use('/reservations', reservationsRoutes);
+  app.use('/', stockAlertsRoutes);
   app.use('/', shopRoutes);
   app.use('/', authRoutes);
   app.use('/webauthn', passkeyRoutes);

src/services/mail.js

@@ -68,10 +68,22 @@ async function sendReservationEmail(to, productName, quantity, expiresAt) {
   return sendMail({ to, subject, text, html });
 }
 
+async function sendStockAvailableEmail(to, productName, productUrl) {
+  const subject = `Снова в наличии: ${productName}`;
+  const text = `Товар «${productName}» снова в наличии.\n\nПерейти: ${productUrl}`;
+  const html = `
+    <p>Товар <strong>${productName}</strong> снова в наличии.</p>
+    <p><a href="${productUrl}">Открыть товар в магазине</a></p>
+    <p style="color:#666">Вы получили это письмо, потому что подписались на уведомление о поступлении.</p>
+  `;
+  return sendMail({ to, subject, text, html });
+}
+
 module.exports = {
   isConfigured,
   sendMail,
   sendPasswordResetEmail,
   sendReservationEmail,
+  sendStockAvailableEmail,
   siteUrl,
 };

src/services/stock-alerts.js

@@ -0,0 +1,74 @@
+const { query } = require('../db');
+const { sendStockAvailableEmail, siteUrl } = require('./mail');
+
+async function isSubscribed(productId, email, userId) {
+  const normalized = email.trim().toLowerCase();
+  const params = [productId, normalized];
+  let sql = `SELECT 1 FROM product_stock_alerts
+             WHERE product_id = $1 AND notified_at IS NULL
+             AND (email = $2`;
+  if (userId) {
+    sql += ' OR user_id = $3';
+    params.push(userId);
+  }
+  sql += ')';
+  const { rows } = await query(sql, params);
+  return rows.length > 0;
+}
+
+async function subscribe({ productId, email, userId }) {
+  const normalized = email.trim().toLowerCase();
+  await query(
+    `INSERT INTO product_stock_alerts (product_id, email, user_id)
+     VALUES ($1, $2, $3)
+     ON CONFLICT (product_id, email) DO UPDATE SET
+       user_id = COALESCE(EXCLUDED.user_id, product_stock_alerts.user_id),
+       notified_at = NULL,
+       created_at = CASE
+         WHEN product_stock_alerts.notified_at IS NOT NULL THEN NOW()
+         ELSE product_stock_alerts.created_at
+       END`,
+    [productId, normalized, userId || null]
+  );
+}
+
+async function notifyIfBackInStock(productId) {
+  const { rows: products } = await query(
+    'SELECT id, slug, name, stock FROM products WHERE id = $1',
+    [productId]
+  );
+  const product = products[0];
+  if (!product || product.stock <= 0) return { sent: 0 };
+
+  const { rows: alerts } = await query(
+    `SELECT id, email FROM product_stock_alerts
+     WHERE product_id = $1 AND notified_at IS NULL`,
+    [productId]
+  );
+
+  if (!alerts.length) return { sent: 0 };
+
+  const productUrl = `${siteUrl()}/product/${product.slug}`;
+  let sent = 0;
+
+  for (const alert of alerts) {
+    try {
+      await sendStockAvailableEmail(alert.email, product.name, productUrl);
+      await query(
+        'UPDATE product_stock_alerts SET notified_at = NOW() WHERE id = $1',
+        [alert.id]
+      );
+      sent++;
+    } catch (err) {
+      console.error('stock alert email failed:', alert.email, err.message);
+    }
+  }
+
+  return { sent };
+}
+
+module.exports = {
+  isSubscribed,
+  subscribe,
+  notifyIfBackInStock,
+};

src/views/admin/products.ejs

@@ -12,6 +12,12 @@
   </nav>
 </div>
 
+<% if (stockUpdated) { %>
+  <p class="alert alert--success">
+    Остаток обновлён.<% if (notified > 0) { %> Отправлено уведомлений подписчикам: <%= notified %>.<% } %>
+  </p>
+<% } %>
+
 <table class="cart-table">
   <thead>
     <tr>
@@ -20,6 +26,7 @@
       <th>Категория</th>
       <th>Цена</th>
       <th>Остаток</th>
+      <th>Подписки</th>
       <th></th>
     </tr>
   </thead>
@@ -30,7 +37,19 @@
         <td><%= p.name %></td>
         <td><%= p.category_name || '—' %></td>
         <td><%= formatPrice(p.price_cents) %></td>
-        <td><%= p.stock %></td>
+        <td>
+          <form action="/admin/products/<%= p.id %>/stock" method="post" class="inline-form admin-stock-form">
+            <input type="number" name="stock" class="input input--sm" min="0" value="<%= p.stock %>" aria-label="Остаток">
+            <button type="submit" class="btn btn--ghost btn--sm">OK</button>
+          </form>
+        </td>
+        <td>
+          <% if (p.alert_count > 0) { %>
+            <span class="badge" title="Ждут уведомления"><%= p.alert_count %></span>
+          <% } else { %>
+            —
+          <% } %>
+        </td>
         <td><a href="/product/<%= p.slug %>">На сайте</a></td>
       </tr>
     <% }) %>

src/views/product.ejs

@@ -18,6 +18,8 @@
     <p class="product-detail__stock">В наличии: <strong><%= product.stock %></strong> шт.</p>
 
     <% if (error) { %><p class="alert alert--error"><%= error %></p><% } %>
+    <% if (notifySuccess) { %><p class="alert alert--success"><%= notifySuccess %></p><% } %>
+    <% if (notifyError) { %><p class="alert alert--error"><%= notifyError %></p><% } %>
     <% if (reserved) { %><p class="alert alert--success">Товар успешно забронирован. Подробности на почте и в личном кабинете.</p><% } %>
     <% if (userReservation) { %>
       <p class="alert alert--success">
@@ -52,6 +54,31 @@
       <% } %>
     <% } else { %>
       <p class="alert alert--warn">Нет в наличии</p>
+
+      <% if (typeof cookieConsent !== 'undefined' && !cookieConsent) { %>
+        <p class="muted">Примите cookies, чтобы подписаться на уведомление о поступлении.</p>
+      <% } else if (stockAlertSubscribed) { %>
+        <p class="stock-notify stock-notify--done">
+          Вы подписаны на уведомление<% if (notifyEmail) { %> — письмо придёт на <strong><%= notifyEmail %></strong><% } %>.
+        </p>
+      <% } else { %>
+        <section class="stock-notify card">
+          <h2 class="stock-notify__title">Сообщить о поступлении</h2>
+          <p class="muted stock-notify__hint">Будьте среди первых, кто узнает, когда товар снова появится в наличии.</p>
+          <form action="/product/<%= product.slug %>/notify-stock" method="post" class="form stock-notify__form">
+            <% if (user && notifyEmail) { %>
+              <p class="muted">Уведомление отправим на <strong><%= notifyEmail %></strong></p>
+              <input type="hidden" name="email" value="<%= notifyEmail %>">
+            <% } else { %>
+              <label class="label">
+                Email
+                <input type="email" name="email" class="input" required autocomplete="email" placeholder="you@example.com" value="<%= notifyEmail || '' %>">
+              </label>
+            <% } %>
+            <button type="submit" class="btn btn--primary">Подписаться</button>
+          </form>
+        </section>
+      <% } %>
     <% } %>
     <a href="/" class="link-back">← Назад в каталог</a>
   </div>