Add Tickets domain for the voucher-based ticket shop (#8)

Reviewed-on: #8
Co-authored-by: Patrick Mueller <patrick@mueller-patrick.tech>
Co-committed-by: Patrick Mueller <patrick@mueller-patrick.tech>

src/common/common.mail.nodemailer.ts

@@ -13,26 +13,30 @@ export namespace MailService {
         tls: {rejectUnauthorized: false}
     });
 
-    const mailConfigurations = {
+    export interface MailAttachment {
+        filename: string;
+        content: string | Buffer;
+        contentType?: string;
+    }
 
-        // It should be a string of sender email
-        from: 'noreply@nachklang.art',
+    export interface SendMailOptions {
+        html?: string;
+        attachments?: MailAttachment[];
+    }
 
-        // Comma Separated list of mails
-        to: 'mail@pmueller.me',
-
-        // Subject of Email
-        subject: '',
-
-        // This would be the text of email body
-        text: ''
+    // Builds a fresh options object per call rather than mutating a shared
+    // module-level one - the transporter is pooled, so overlapping sendMail
+    // calls (e.g. two guests redeeming at once) previously risked one
+    // call's recipient/subject/body being overwritten by another's before
+    // transporter.sendMail() read it.
+    export const sendMail = async (recipientAddress: string, subject: string, body: string, options?: SendMailOptions) => {
+        await transporter.sendMail({
+            from: 'noreply@nachklang.art',
+            to: recipientAddress,
+            subject: subject,
+            text: body,
+            html: options?.html,
+            attachments: options?.attachments
+        });
     };
-
-    export const sendMail = async (recipientAddress: string, subject: string, body: string) => {
-        mailConfigurations.to = recipientAddress;
-        mailConfigurations.subject = subject;
-        mailConfigurations.text = body;
-
-        await transporter.sendMail(mailConfigurations);
-    };
-}
+}