Implement mail signal webhook and IMAP mail fetching logic

lib/mail.ts

@@ -0,0 +1,66 @@
+import { ImapFlow } from 'imapflow';
+import { simpleParser } from 'mailparser';
+
+export interface EmailData {
+  from: string;
+  subject: string;
+  text: string;
+  html?: string;
+  date: Date;
+}
+
+export async function getLatestEmail(email: string, password: string): Promise<EmailData | null> {
+  const host = process.env.MAILCOW_HOSTNAME || email.split('@')[1];
+  
+  const client = new ImapFlow({
+    host: host,
+    port: 993,
+    secure: true,
+    auth: {
+      user: email,
+      pass: password
+    },
+    logger: false
+  });
+
+  try {
+    await client.connect();
+
+    // Select INBOX
+    let lock = await client.getMailboxLock('INBOX');
+    try {
+      // Find the last message
+      const messages = await client.fetch('1:*', {
+        envelope: true,
+        source: true,
+      });
+
+      // imapflow fetch returns an async generator or array?
+      // Actually fetch() returns an async iterator.
+      let lastMsg = null;
+      for await (const msg of messages) {
+        lastMsg = msg;
+      }
+
+      if (lastMsg && lastMsg.source) {
+        const parsed = await simpleParser(lastMsg.source);
+        return {
+          from: parsed.from?.text || '',
+          subject: parsed.subject || '',
+          text: parsed.text || '',
+          html: parsed.html || undefined,
+          date: parsed.date || new Date()
+        };
+      }
+    } finally {
+      lock.release();
+    }
+
+    await client.logout();
+  } catch (err) {
+    console.error(`[IMAP] Error fetching mail for ${email}:`, err);
+    return null;
+  }
+
+  return null;
+}