"""SMTP2GO email via Django's SMTP backend (mail.smtp2go.com)."""

from django.conf import settings
from django.core.mail import EmailMultiAlternatives

from contacts.models import Channel
from messaging.services import one_click_unsubscribe_url, preferences_url

# Reported back on SMTP2GO webhooks when this header is selected in webhook settings.
MONICA_MESSAGE_HEADER = "X-Monica-Message-Id"


def send_email(message) -> str:
    contact = message.contact
    if not contact.email:
        raise ValueError("Contact has no email address")

    campaign = message.campaign
    subject = campaign.subject_override or (
        campaign.template.subject if campaign.template else "Message from Monica"
    )
    body = message.body_snapshot or campaign.body_override or (
        campaign.template.body if campaign.template else ""
    )

    site = (settings.PUBLIC_SITE_URL or "").rstrip("/")
    prefs_path = preferences_url(str(contact.pk), Channel.EMAIL)
    one_click_path = one_click_unsubscribe_url(str(contact.pk), Channel.EMAIL)
    prefs_url = f"{site}{prefs_path}" if site else prefs_path
    one_click_url = f"{site}{one_click_path}" if site else one_click_path
    body_with_unsub = (
        f"{body}\n\n---\n"
        f"Manage preferences: {prefs_url}\n"
        f"Unsubscribe from email: {one_click_url}"
    )

    email = EmailMultiAlternatives(
        subject=subject,
        body=body_with_unsub,
        from_email=settings.DEFAULT_FROM_EMAIL,
        to=[contact.email],
        headers={
            "List-Unsubscribe": f"<{one_click_url}>",
            "List-Unsubscribe-Post": "List-Unsubscribe=One-Click",
            MONICA_MESSAGE_HEADER: str(message.pk),
        },
    )
    email.send(fail_silently=False)
    # Placeholder until SMTP2GO webhook supplies the real email_id.
    return f"smtp-{message.pk}"