From 31a76c7c6cd2d1bdbc46c9396cf3fd94d65d7166 Mon Sep 17 00:00:00 2001
From: Dennis Chen <dchen@mathadvance.org>
Date: Wed, 5 Jun 2024 11:56:36 -0700
Subject: [PATCH] email_utils -> utils/email

---
 store/app/api/utils/email.py | 101 +++++++++++++++++++++++++++++++++++
 1 file changed, 101 insertions(+)
 create mode 100644 store/app/api/utils/email.py

diff --git a/store/app/api/utils/email.py b/store/app/api/utils/email.py
new file mode 100644
index 00000000..47853ce9
--- /dev/null
+++ b/store/app/api/utils/email.py
@@ -0,0 +1,101 @@
+"""Utility functions for sending emails to users."""
+
+import argparse
+import asyncio
+import datetime
+import logging
+import textwrap
+from dataclasses import dataclass
+from email.mime.multipart import MIMEMultipart
+from email.mime.text import MIMEText
+
+import aiosmtplib
+
+from store.app.api.crypto import decode_jwt, encode_jwt
+from store.settings import settings
+
+logger = logging.getLogger(__name__)
+
+
+async def send_email(subject: str, body: str, to: str) -> None:
+    msg = MIMEMultipart("alternative")
+    msg["Subject"] = subject
+    msg["From"] = f"{settings.email.sender_name} <{settings.email.sender_email}>"
+    msg["To"] = to
+
+    msg.attach(MIMEText(body, "html"))
+
+    smtp_client = aiosmtplib.SMTP(hostname=settings.email.host, port=settings.email.port)
+
+    await smtp_client.connect()
+    await smtp_client.login(settings.email.username, settings.email.password)
+    await smtp_client.sendmail(settings.email.sender_email, to, msg.as_string())
+    await smtp_client.quit()
+
+
+@dataclass
+class OneTimePassPayload:
+    email: str
+    lifetime: str
+
+    def encode(self) -> str:
+        expire_minutes = settings.crypto.expire_otp_minutes
+        expire_after = datetime.timedelta(minutes=expire_minutes)
+        return encode_jwt({"email": self.email, "lifetime": self.lifetime}, expire_after=expire_after)
+
+    @classmethod
+    def decode(cls, payload: str) -> "OneTimePassPayload":
+        data = decode_jwt(payload)
+        return cls(email=data["email"], lifetime=data["lifetime"])
+
+
+async def send_otp_email(payload: OneTimePassPayload, login_url: str) -> None:
+    url = f"{login_url}?otp={payload.encode()}"
+
+    body = textwrap.dedent(
+        f"""
+            <h1><code>K-Scale Labs</code></h1>
+            <h2><code><a href="{url}">log in</a></code></h2>
+            <p>Or copy-paste this link: {url}</p>
+        """
+    )
+
+    await send_email(subject="One-Time Password", body=body, to=payload.email)
+
+
+async def send_delete_email(email: str) -> None:
+    body = textwrap.dedent(
+        """
+            <h1><code>K-Scale Labs</code></h1>
+            <h2><code>your account has been deleted</code></h2>
+        """
+    )
+
+    await send_email(subject="Account Deleted", body=body, to=email)
+
+
+async def send_waitlist_email(email: str) -> None:
+    body = textwrap.dedent(
+        """
+            <h1><code>K-Scale Labs</code></h1>
+            <h2><code>you're on the waitlist!</code></h2>
+            <p>Thanks for signing up! We'll let you know when you can log in.</p>
+        """
+    )
+
+    await send_email(subject="Waitlist", body=body, to=email)
+
+
+def test_email_adhoc() -> None:
+    parser = argparse.ArgumentParser(description="Test sending an email.")
+    parser.add_argument("subject", help="The subject of the email.")
+    parser.add_argument("body", help="The body of the email.")
+    parser.add_argument("to", help="The recipient of the email.")
+    args = parser.parse_args()
+
+    asyncio.run(send_email(args.subject, args.body, args.to))
+
+
+if __name__ == "__main__":
+    # python -m bot.api.email
+    test_email_adhoc()