hrms/base/backends.py

"""
email_backend.py

This module is used to write email backends
"""

import importlib
import logging

from django.core.cache import cache
from django.core.mail import EmailMessage
from django.core.mail.backends.smtp import EmailBackend

from base.models import DynamicEmailConfiguration, EmailLog
from horilla import settings
from horilla.horilla_middlewares import _thread_locals

logger = logging.getLogger(__name__)


class DefaultHorillaMailBackend(EmailBackend):
    def __init__(
        self,
        host=None,
        port=None,
        username=None,
        password=None,
        use_tls=None,
        fail_silently=None,
        use_ssl=None,
        timeout=None,
        ssl_keyfile=None,
        ssl_certfile=None,
        **kwargs,
    ):
        self.configuration = self.get_dynamic_email_config()
        ssl_keyfile = (
            getattr(self.configuration, "ssl_keyfile", None)
            if self.configuration
            else ssl_keyfile or getattr(settings, "ssl_keyfile", None)
        )
        ssl_certfile = (
            getattr(self.configuration, "ssl_certfile", None)
            if self.configuration
            else ssl_certfile or getattr(settings, "ssl_certfile", None)
        )

        super().__init__(
            host=self.dynamic_host,
            port=self.dynamic_port,
            username=self.dynamic_username,
            password=self.dynamic_password,
            use_tls=self.dynamic_use_tls,
            fail_silently=self.dynamic_fail_silently,
            use_ssl=self.dynamic_use_ssl,
            timeout=self.dynamic_timeout,
            ssl_keyfile=ssl_keyfile,
            ssl_certfile=ssl_certfile,
            **kwargs,
        )

    @staticmethod
    def get_dynamic_email_config():
        request = getattr(_thread_locals, "request", None)
        company = None
        if request and not request.user.is_anonymous:
            company = request.user.employee_get.get_company()
        configuration = DynamicEmailConfiguration.objects.filter(
            company_id=company
        ).first()
        if configuration is None:
            configuration = DynamicEmailConfiguration.objects.filter(
                is_primary=True
            ).first()
        if configuration:
            display_email_name = (
                f"{configuration.display_name} <{configuration.from_email}>"
            )

            user_id = ""
            if request:
                if (
                    configuration.use_dynamic_display_name
                    and request.user.is_authenticated
                ):
                    display_email_name = f"{request.user.employee_get.get_full_name()} <{request.user.employee_get.get_email()}>"
                if request.user.is_authenticated:
                    user_id = request.user.pk
                    reply_to = [
                        f"{request.user.employee_get.get_full_name()} <{request.user.employee_get.get_email()}>",
                    ]
                    cache.set(f"reply_to{request.user.pk}", reply_to)

            cache.set(f"dynamic_display_name{user_id}", display_email_name)

        return configuration

    @property
    def dynamic_host(self):
        return (
            self.configuration.host
            if self.configuration
            else getattr(settings, "EMAIL_HOST", None)
        )

    @property
    def dynamic_port(self):
        return (
            self.configuration.port
            if self.configuration
            else getattr(settings, "EMAIL_PORT", None)
        )

    @property
    def dynamic_username(self):
        return (
            self.configuration.username
            if self.configuration
            else getattr(settings, "EMAIL_HOST_USER", None)
        )

    @property
    def dynamic_mail_sent_from(self):
        return (
            self.configuration.from_email
            if self.configuration
            else getattr(settings, "DEFAULT_FROM_EMAIL", None)
        )

    @property
    def dynamic_display_name(self):
        return self.configuration.display_name if self.configuration else None

    @property
    def dynamic_from_email_with_display_name(self):
        return (
            f"{self.dynamic_display_name} <{self.dynamic_mail_sent_from}>"
            if self.dynamic_display_name
            else self.dynamic_mail_sent_from
        )

    @property
    def dynamic_password(self):
        return (
            self.configuration.password
            if self.configuration
            else getattr(settings, "EMAIL_HOST_PASSWORD", None)
        )

    @property
    def dynamic_use_tls(self):
        return (
            self.configuration.use_tls
            if self.configuration
            else getattr(settings, "EMAIL_USE_TLS", None)
        )

    @property
    def dynamic_fail_silently(self):
        return (
            self.configuration.fail_silently
            if self.configuration
            else getattr(settings, "EMAIL_FAIL_SILENTLY", True)
        )

    @property
    def dynamic_use_ssl(self):
        return (
            self.configuration.use_ssl
            if self.configuration
            else getattr(settings, "EMAIL_USE_SSL", None)
        )

    @property
    def dynamic_timeout(self):
        return (
            self.configuration.timeout
            if self.configuration
            else getattr(settings, "EMAIL_TIMEOUT", None)
        )


EMAIL_BACKEND = getattr(settings, "EMAIL_BACKEND", "")


BACKEND_CLASS: EmailBackend = DefaultHorillaMailBackend
default = "base.backends.ConfiguredEmailBackend"

setattr(BACKEND_CLASS, "send_messages", DefaultHorillaMailBackend.send_messages)

if EMAIL_BACKEND and EMAIL_BACKEND != default:
    module_path, class_name = EMAIL_BACKEND.rsplit(".", 1)
    module = importlib.import_module(module_path)
    BACKEND_CLASS = getattr(module, class_name)


class ConfiguredEmailBackend(BACKEND_CLASS):

    def send_messages(self, email_messages):
        response = super(BACKEND_CLASS, self).send_messages(email_messages)
        for message in email_messages:
            email_log = EmailLog(
                subject=message.subject,
                from_email=self.dynamic_from_email_with_display_name,
                to=message.to,
                body=message.body,
                status="sent" if response else "failed",
            )
            email_log.save()
        return response


if EMAIL_BACKEND != default:
    from_mail = getattr(settings, "DEFAULT_FROM_EMAIL", "example@gmail.com")
    username = getattr(settings, "EMAIL_HOST_USER", "example@gmail.com")
    ConfiguredEmailBackend.dynamic_username = from_mail
    ConfiguredEmailBackend.dynamic_from_email_with_display_name = from_mail


__all__ = ["ConfiguredEmailBackend"]


message_init = EmailMessage.__init__


def new_init(
    self,
    subject="",
    body="",
    from_email=None,
    to=None,
    bcc=None,
    connection=None,
    attachments=None,
    headers=None,
    cc=None,
    reply_to=None,
):
    """
    custom __init_method to override
    """
    request = getattr(_thread_locals, "request", None)
    DefaultHorillaMailBackend()
    user_id = ""
    if request and request.user and request.user.is_authenticated:
        user_id = request.user.pk
        reply_to = cache.get(f"reply_to{user_id}") if not reply_to else reply_to

    if not from_email:
        from_email = cache.get(f"dynamic_display_name{user_id}")

    message_init(
        self,
        subject=subject,
        body=body,
        from_email=from_email,
        to=to,
        bcc=bcc,
        connection=connection,
        attachments=attachments,
        headers=headers,
        cc=cc,
        reply_to=reply_to,
    )


EmailMessage.__init__ = new_init