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

from django.conf import settings
from django.core.mail import EmailMultiAlternatives
from django.template.loader import get_template

from contacts.models import Channel
from messaging.services import one_click_unsubscribe_url, preferences_url, render_merge_tags
from public.email_branding import (
    campaign_body_to_email_html,
    campaign_body_to_plain_text,
    email_brand_context,
)

# 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 ""
    )
    subject = render_merge_tags(subject, contact)
    body = render_merge_tags(body, contact)

    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

    ctx = email_brand_context(
        title=subject,
        content=campaign_body_to_plain_text(body),
        content_html=campaign_body_to_email_html(body),
        prefs_url=prefs_url,
        one_click_url=one_click_url,
    )
    text_content = get_template("emails/marketing_email.txt").render(ctx)
    html_content = get_template("emails/marketing_email.html").render(ctx)

    email = EmailMultiAlternatives(
        subject=subject,
        body=text_content,
        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.attach_alternative(html_content, "text/html")
    email.send(fail_silently=False)
    # Placeholder until SMTP2GO webhook supplies the real email_id.
    return f"smtp-{message.pk}"