import io
import smtplib
from contextlib import redirect_stderr
from typing import Any

from django.conf import settings
from django.core.mail import mail_admins, mail_managers, send_mail
from django.core.management import CommandError
from django.core.management.commands import sendtestemail

from zerver.lib.send_email import FromAddress, log_email_config_errors


class Command(sendtestemail.Command):
    def handle(self, *args: Any, **kwargs: str) -> None:
        if settings.WARN_NO_EMAIL:
            raise CommandError(
                "Outgoing email not yet configured, see\n  "
                "https://zulip.readthedocs.io/en/latest/production/email.html"
            )

        log_email_config_errors()

        if len(kwargs["email"]) == 0:
            raise CommandError(
                "Usage: /home/zulip/deployments/current/manage.py "
                "send_test_email username@example.com"
            )

        print("If you run into any trouble, read:")
        print()
        print("  https://zulip.readthedocs.io/en/latest/production/email.html#troubleshooting")
        print()
        print("The most common error is not setting `ADD_TOKENS_TO_NOREPLY_ADDRESS=False` when")
        print("using an email provider that doesn't support that feature.")
        print()
        print("Sending 2 test emails from:")

        message = (
            "Success!  If you receive this message (and a second with a different subject), "
            "you've successfully configured sending emails from your Zulip server.  "
            "Remember that you need to restart "
            "the Zulip server with /home/zulip/deployments/current/scripts/restart-server "
            "after changing the settings in /etc/zulip before your changes will take effect."
        )
        with redirect_stderr(io.StringIO()) as f:
            smtplib.SMTP.debuglevel = 1
            try:
                sender = FromAddress.SUPPORT
                print(f"  * {sender}")
                send_mail("Zulip email test", message, sender, kwargs["email"])

                noreply_sender = FromAddress.tokenized_no_reply_address()
                print(f"  * {noreply_sender}")
                send_mail("Zulip noreply email test", message, noreply_sender, kwargs["email"])
            except smtplib.SMTPException as e:
                print(f"Failed to send mails: {e}")
                print()
                print("Full SMTP log follows:")
                print(f.getvalue())
                raise CommandError("Email sending failed!")
        print()
        print("Successfully sent 2 emails to {}!".format(", ".join(kwargs["email"])))

        if kwargs["managers"]:
            mail_managers("Zulip manager email test", "This email was sent to the site managers.")

        if kwargs["admins"]:
            mail_admins("Zulip admins email test", "This email was sent to the site admins.")
