feat: sensical user invitation

Users can now be invited to an org by email.

"Email" for now is "print to stdout"

Resolves #12

src/user/service.py

@@ -6,10 +6,12 @@ Exports:
 """
 
 from typing import Any
+from datetime import datetime, timedelta, timezone
 
 from sqlalchemy.orm import Session
 
 from src.exceptions import UnprocessableContentException
+from src.utils import send_email, generate_jwt
 
 from src.user.schemas import OIDCUser
 from src.user.models import User
@@ -48,3 +50,24 @@ async def add_user_to_db(db: Session, user_claims: dict[str, Any]) -> int:
 			db.add(db_user)
 			db.commit()
 		return user_id
+
+
+async def send_invitation(user_email: str, org_name: str, org_id: int):
+	expiry_delta = timedelta(hours=24)
+	expiry = datetime.now(timezone.utc) + expiry_delta
+	claims = {
+		"email": user_email,
+		"org_id": org_id,
+		"exp": expiry,
+		"type": "org_invite",
+	}
+
+	token = await generate_jwt(claims)
+	subject = f"You have been invited to join {org_name}"
+	body = f"You have been invited to join {org_name}.\nClick the link to accept.\nfrontend.capture/send/to/endpoint/{token}"
+
+	await send_email(
+		recipient=user_email,
+		subject=subject,
+		body=body,
+	)