feat(email_sending): introduce multi-tenant delivery system

apps/notification/backend/infra/email_handler.py

@@ -2,7 +2,12 @@ from common.config.app_settings import app_settings
 from sendgrid import SendGridAPIClient
 from sendgrid.helpers.mail import Mail
 from common.log.module_logger import ModuleLogger
+from typing import List, Dict
+import uuid
+from datetime import datetime
 
+from backend.models.models import EmailSendStatusDoc
+from common.constants.email import EmailSendStatus
 
 class EmailHandler:
     def __init__(self) -> None:
@@ -38,3 +43,83 @@ class EmailHandler:
             )
         except Exception as e:
             await module_logger.log_exception(e)
+
+    async def send_tenant_email(
+        self,
+        tenant_id: str,
+        template_id: str,
+        recipient_email: str,
+        sender_emails: List[str],
+        subject_properties: Dict = {},
+        body_properties: Dict = {}
+    ):
+        """Send tenant email using specified senders"""
+        module_logger = ModuleLogger(sender_id="EmailHandler")
+        
+        try:
+            email_id = str(uuid.uuid4())
+            
+            from_email = sender_emails[0] if sender_emails else app_settings.EMAIL_FROM
+            
+            subject = subject_properties.get("subject", "No Subject")
+            html_content = body_properties.get("html_content", "")
+            text_content = body_properties.get("text_content", "")
+            
+            email_status_doc = EmailSendStatusDoc(
+                email_id=email_id,
+                tenant_id=tenant_id,
+                email_senders=sender_emails,
+                recipient_email=recipient_email,
+                template_id=template_id,
+                subject=subject,
+                body=html_content,
+                status=EmailSendStatus.SENDING
+            )
+            await email_status_doc.save()
+            
+            mail = Mail(
+                from_email=from_email,
+                to_emails=recipient_email,
+                subject=subject,
+                html_content=html_content,
+            )
+            
+            sg = SendGridAPIClient(app_settings.SENDGRID_API_KEY)
+            response = sg.send(mail)
+            
+            email_status_doc.status = EmailSendStatus.SENT
+            email_status_doc.sent_at = datetime.utcnow()
+            email_status_doc.message_id = str(response.headers.get('X-Message-Id', ''))
+            await email_status_doc.save()
+            
+            await module_logger.log_info(
+                f"Tenant email sent successfully",
+                properties={
+                    "tenant_id": tenant_id,
+                    "template_id": template_id,
+                    "email_id": email_id,
+                    "recipient_email": recipient_email,
+                    "sender_email": from_email,
+                    "status_code": response.status_code
+                }
+            )
+            
+            return email_id
+            
+        except Exception as e:
+            if 'email_status_doc' in locals():
+                email_status_doc.status = EmailSendStatus.FAILED
+                email_status_doc.failed_at = datetime.utcnow()
+                email_status_doc.error_message = str(e)
+                await email_status_doc.save()
+            
+            await module_logger.log_error(
+                f"Failed to send tenant email",
+                properties={
+                    "tenant_id": tenant_id,
+                    "template_id": template_id,
+                    "recipient_email": recipient_email,
+                    "error": str(e)
+                }
+            )
+            raise