factors/email(minor): start rebuilding email integration as factor

passbook/factors/email/utils.py

@@ -0,0 +1,28 @@
+"""email utils"""
+from django.core.mail import EmailMultiAlternatives
+from django.template.loader import render_to_string
+from django.utils.html import strip_tags
+
+
+class TemplateEmailMessage(EmailMultiAlternatives):
+    """Wrapper around EmailMultiAlternatives with integrated template rendering"""
+
+    # pylint: disable=too-many-arguments
+    def __init__(self, subject='', body=None, from_email=None, to=None, bcc=None,
+                 connection=None, attachments=None, headers=None, cc=None,
+                 reply_to=None, template_name=None, template_context=None):
+        html_content = render_to_string(template_name, template_context)
+        if not body:
+            body = strip_tags(html_content)
+        super().__init__(
+            subject=subject,
+            body=body,
+            from_email=from_email,
+            to=to,
+            bcc=bcc,
+            connection=connection,
+            attachments=attachments,
+            headers=headers,
+            cc=cc,
+            reply_to=reply_to)
+        self.attach_alternative(html_content, "text/html")