feat: send customer confirmation of cancellation

src/routes/WebhookRouter.ts

@@ -9,6 +9,7 @@ import {
 import { getDatabase } from '../data_layer';
 import { StripeController } from '../controllers/StripeController/StripeController';
 import UsersRepository from '../data_layer/UsersRepository';
+import { useDefaultEmailService } from '../services/EmailService/EmailService';
 
 const WebhooksRouter = () => {
   const router = express.Router();
@@ -44,32 +45,66 @@ const WebhooksRouter = () => {
       switch (event.type) {
         case 'customer.subscription.updated':
           const customerSubscriptionUpdated = event.data.object;
-          // Then define and call a function to handle the event customer.subscription.updated
-          const customer = await stripe.customers.retrieve(
-            // @ts-ignore
-            getCustomerId(customerSubscriptionUpdated.customer)
+          const customerId = getCustomerId(
+            customerSubscriptionUpdated.customer as string
           );
+          if (!customerId) {
+            console.error('No customer ID found');
+            return;
+          }
+          const customer = await stripe.customers.retrieve(customerId);
 
           await updateStoreSubscription(
             getDatabase(),
             customer as Stripe.Customer,
             customerSubscriptionUpdated
           );
+
+          if (
+            customerSubscriptionUpdated.cancel_at_period_end === true &&
+            event.data.previous_attributes?.cancel_at_period_end === false
+          ) {
+            const cancelDate = new Date(
+              customerSubscriptionUpdated.current_period_end * 1000
+            );
+            const emailService = useDefaultEmailService();
+            if ('email' in customer) {
+              await emailService.sendSubscriptionScheduledCancellationEmail(
+                customer.email!,
+                customer.name || 'there',
+                cancelDate,
+                customerSubscriptionUpdated.id
+              );
+            }
+          }
           break;
         case 'customer.subscription.deleted':
           const customerSubscriptionDeleted = event.data.object;
           if (typeof customerSubscriptionDeleted.customer === 'string') {
-            // Then define and call a function to handle the event customer.subscription.deleted
-            const customerDeleted = await stripe.customers.retrieve(
-              // @ts-ignore
-              getCustomerId(customerSubscriptionDeleted.customer)
+            const deletedCustomerId = getCustomerId(
+              customerSubscriptionDeleted.customer
             );
+            if (!deletedCustomerId) {
+              console.error('No customer ID found');
+              return;
+            }
+            const customerDeleted =
+              await stripe.customers.retrieve(deletedCustomerId);
 
             await updateStoreSubscription(
               getDatabase(),
               customerDeleted as Stripe.Customer,
               customerSubscriptionDeleted
             );
+
+            if ('email' in customerDeleted) {
+              const emailService = useDefaultEmailService();
+              await emailService.sendSubscriptionCancelledEmail(
+                customerDeleted.email!,
+                customerDeleted.name || 'there',
+                customerSubscriptionDeleted.id
+              );
+            }
           }
           break;
         case 'checkout.session.completed':

src/services/EmailService/EmailService.ts

@@ -9,7 +9,10 @@ import {
   DEFAULT_SENDER,
   PASSWORD_RESET_TEMPLATE,
   VAT_NOTIFICATION_TEMPLATE,
+  SUBSCRIPTION_CANCELLED_TEMPLATE,
   VAT_NOTIFICATIONS_LOG_PATH,
+  SUBSCRIPTION_CANCELLATIONS_LOG_PATH,
+  SUBSCRIPTION_SCHEDULED_CANCELLATION_TEMPLATE,
 } from './constants';
 import { isValidDeckName, addDeckNameSuffix } from '../../lib/anki/format';
 import { ClientResponse } from '@sendgrid/mail';
@@ -32,6 +35,17 @@ export interface IEmailService {
     currency: string,
     name: string
   ): Promise<void>;
+  sendSubscriptionCancelledEmail(
+    email: string,
+    name: string,
+    subscriptionId: string
+  ): Promise<void>;
+  sendSubscriptionScheduledCancellationEmail(
+    email: string,
+    name: string,
+    cancelDate: Date,
+    subscriptionId: string
+  ): Promise<void>;
 }
 
 class EmailService implements IEmailService {
@@ -201,6 +215,126 @@ class EmailService implements IEmailService {
       throw error;
     }
   }
+
+  private loadCancellationsSent(): Set<string> {
+    try {
+      // Ensure .2anki directory exists
+      const dir = path.dirname(SUBSCRIPTION_CANCELLATIONS_LOG_PATH);
+      if (!fs.existsSync(dir)) {
+        fs.mkdirSync(dir, { recursive: true });
+      }
+
+      if (fs.existsSync(SUBSCRIPTION_CANCELLATIONS_LOG_PATH)) {
+        const data = fs.readFileSync(
+          SUBSCRIPTION_CANCELLATIONS_LOG_PATH,
+          'utf8'
+        );
+        return new Set(JSON.parse(data));
+      }
+    } catch (error) {
+      console.warn('Error loading cancellations log:', error);
+    }
+    return new Set();
+  }
+
+  private saveCancellationSent(subscriptionId: string): void {
+    try {
+      const cancellationsSent = this.loadCancellationsSent();
+      cancellationsSent.add(subscriptionId);
+      fs.writeFileSync(
+        SUBSCRIPTION_CANCELLATIONS_LOG_PATH,
+        JSON.stringify([...cancellationsSent])
+      );
+    } catch (error) {
+      console.error('Error saving cancellation log:', error);
+    }
+  }
+
+  async sendSubscriptionCancelledEmail(
+    email: string,
+    name: string,
+    subscriptionId: string
+  ): Promise<void> {
+    const cancellationsSent = this.loadCancellationsSent();
+    if (cancellationsSent.has(subscriptionId)) {
+      console.log(
+        `Skipping ${email} - Cancellation notification already sent for subscription ${subscriptionId}`
+      );
+      return;
+    }
+
+    const markup = SUBSCRIPTION_CANCELLED_TEMPLATE.replace(
+      '{{name}}',
+      name || 'there'
+    );
+
+    const $ = cheerio.load(markup);
+    const text = $('body').text().replace(/\s+/g, ' ').trim();
+
+    const msg = {
+      to: email,
+      from: this.defaultSender,
+      subject: '2anki.net - Subscription Cancelled',
+      text,
+      html: markup,
+      replyTo: 'support@2anki.net',
+    };
+
+    try {
+      await sgMail.send(msg);
+      this.saveCancellationSent(subscriptionId);
+      console.log(`Successfully sent cancellation confirmation to ${email}`);
+    } catch (error) {
+      console.error(
+        `Failed to send cancellation confirmation to ${email}:`,
+        error
+      );
+      throw error;
+    }
+  }
+
+  async sendSubscriptionScheduledCancellationEmail(
+    email: string,
+    name: string,
+    cancelDate: Date,
+    subscriptionId: string
+  ): Promise<void> {
+    const formattedDate = cancelDate.toLocaleDateString('en-US', {
+      year: 'numeric',
+      month: 'long',
+      day: 'numeric',
+    });
+
+    const markup = SUBSCRIPTION_SCHEDULED_CANCELLATION_TEMPLATE.replace(
+      '{{name}}',
+      name || 'there'
+    ).replace(/{{cancelDate}}/g, formattedDate);
+
+    const $ = cheerio.load(markup);
+    const text = $('body').text().replace(/\s+/g, ' ').trim();
+
+    const msg = {
+      to: email,
+      from: this.defaultSender,
+      subject: '2anki.net - Subscription Cancellation Scheduled',
+      text,
+      html: markup,
+      replyTo: 'support@2anki.net',
+    };
+
+    try {
+      await sgMail.send(msg);
+      console.log(
+        `Successfully sent scheduled cancellation notification to ${email}`
+      );
+    } catch (error) {
+      console.error(
+        `Failed to send scheduled cancellation notification to ${email}:`,
+        error
+      );
+      throw error;
+    }
+  }
 }
 
 export class UnimplementedEmailService implements IEmailService {
@@ -240,6 +374,36 @@ export class UnimplementedEmailService implements IEmailService {
     console.info('sendVatNotificationEmail not handled', email, currency, name);
     return Promise.resolve();
   }
+
+  sendSubscriptionCancelledEmail(
+    email: string,
+    name: string,
+    subscriptionId: string
+  ): Promise<void> {
+    console.info(
+      'sendSubscriptionCancelledEmail not handled',
+      email,
+      name,
+      subscriptionId
+    );
+    return Promise.resolve();
+  }
+
+  sendSubscriptionScheduledCancellationEmail(
+    email: string,
+    name: string,
+    cancelDate: Date,
+    subscriptionId: string
+  ): Promise<void> {
+    console.info(
+      'sendSubscriptionScheduledCancellationEmail not handled',
+      email,
+      name,
+      cancelDate,
+      subscriptionId
+    );
+    return Promise.resolve();
+  }
 }
 
 export const useDefaultEmailService = () => {

src/services/EmailService/constants.ts

@@ -31,3 +31,22 @@ export const VAT_NOTIFICATIONS_LOG_PATH = path.join(
   '.2anki',
   'vat-notifications-sent.json'
 );
+
+export const SUBSCRIPTION_CANCELLED_TEMPLATE = fs.readFileSync(
+  path.join(EMAIL_TEMPLATES_DIRECTORY, 'subscription-cancelled.html'),
+  'utf8'
+);
+
+export const SUBSCRIPTION_CANCELLATIONS_LOG_PATH = path.join(
+  os.homedir(),
+  '.2anki',
+  'subscriptions-cancelled-sent.json'
+);
+
+export const SUBSCRIPTION_SCHEDULED_CANCELLATION_TEMPLATE = fs.readFileSync(
+  path.join(
+    EMAIL_TEMPLATES_DIRECTORY,
+    'subscription-scheduled-cancellation.html'
+  ),
+  'utf8'
+);

src/services/EmailService/templates/subscription-cancelled.html

@@ -0,0 +1,30 @@
+<!DOCTYPE html>
+<html lang="en">
+
+<head>
+        <meta charset="utf-8" />
+        <meta name="viewport" content="width=device-width, initial-scale=1" />
+        <title>2anki.net - Subscription Cancelled</title>
+</head>
+
+<body>
+        <p>Hei {{name}},</p>
+
+        <p>This email confirms that your 2anki.net subscription has been cancelled successfully.</p>
+
+        <p>If you cancelled by mistake or would like to resubscribe in the future, you can do so at any time by visiting
+                <a href="https://2anki.net">2anki.net</a>.
+        </p>
+
+        <p>Thank you for being a subscriber. If you have any feedback about your experience, please let us know by
+                replying to this email.</p>
+
+        <p style="margin-top: 2em; color: #666;">
+                --<br>
+                Happy learning,<br>
+                The 2anki Team<br>
+                <a href="https://2anki.net/" style="color: #0066cc; text-decoration: none;">2anki.net</a>
+        </p>
+</body>
+
+</html>

src/services/EmailService/templates/subscription-scheduled-cancellation.html

@@ -0,0 +1,31 @@
+<!DOCTYPE html>
+<html lang="en">
+
+<head>
+        <meta charset="utf-8" />
+        <meta name="viewport" content="width=device-width, initial-scale=1" />
+        <title>2anki.net - Subscription Cancellation Scheduled</title>
+</head>
+
+<body>
+        <p>Hei {{name}},</p>
+
+        <p>We've received your request to cancel your 2anki.net subscription. Your subscription will remain active until
+                {{cancelDate}}, after which it will be cancelled automatically.</p>
+
+        <p>You'll continue to have full access to all premium features until then. If you change your mind, you can
+                reactivate your subscription at any time before {{cancelDate}} by visiting your <a
+                        href="https://billing.stripe.com/p/login/test">billing portal</a>.</p>
+
+        <p>Thank you for being a subscriber. If you have any feedback about your experience, please let us know by
+                replying to this email.</p>
+
+        <p style="margin-top: 2em; color: #666;">
+                --<br>
+                Happy learning,<br>
+                The 2anki Team<br>
+                <a href="https://2anki.net/" style="color: #0066cc; text-decoration: none;">2anki.net</a>
+        </p>
+</body>
+
+</html>