"""Booking confirmation email (#18): sender-address resolution, the
customer-facing manage-booking link, and the render/send call. Booking
creation must succeed even if this fails -- see mailer.py's fire-and-forget
send, which this relies on rather than talking to smtplib directly.
"""
import os
import re
from zoneinfo import ZoneInfo

from flask import render_template

import mailer

PUBLIC_BASE_URL = os.environ.get("PUBLIC_BASE_URL", "https://onboard.mivanchenko.de").rstrip("/")

# customer_contact is a single free-text "E-Mail oder Telefon" field (#16/#17)
# -- not guaranteed to be an email address. Only attempt to send when it
# looks like one.
_EMAIL_RE = re.compile(r"^[^@\s]+@[^@\s]+\.[^@\s]+$")


def looks_like_email(contact):
    return bool(_EMAIL_RE.match((contact or "").strip()))


def manage_url(token):
    return f"{PUBLIC_BASE_URL}/manage/{token}"


# clients.domain is free text from the onboarding form (e.g. "cafe-lichtblick.de",
# but nothing stops "https://cafe-lichtblick.de/" being entered) -- strip any
# scheme/path/whitespace so a malformed value can't end up in a From header.
_DOMAIN_RE = re.compile(r"^(?:[a-z][a-z0-9+.-]*://)?([^/\s]+)", re.IGNORECASE)


def _clean_domain(domain):
    m = _DOMAIN_RE.match((domain or "").strip())
    return m.group(1).lower() if m else None


def _sender_for(client):
    domain = _clean_domain((client or {}).get("domain"))
    return f"noreply@{domain}" if domain else mailer.MAIL_FALLBACK_FROM


def send_booking_confirmation(client, booking, token):
    """No-op if customer_contact doesn't look like an email address -- it's a
    free-text "E-Mail oder Telefon" field (#16/#17), so this is expected for
    phone-only customers, not an error."""
    if not looks_like_email(booking.get("customer_contact")):
        print(f"[booking_mail] customer_contact for booking "
              f"{booking.get('booking_id')} doesn't look like an email, "
              f"skipping confirmation send", flush=True)
        return
    tz = ZoneInfo((client or {}).get("timezone") or "Europe/Berlin")
    business_name = (client or {}).get("business_name") or "Ihr Termin"
    html = render_template(
        "emails/booking_confirmation.html",
        business_name=business_name,
        customer_name=booking["customer_name"],
        service=booking["service"],
        start_local=booking["start_time"].astimezone(tz),
        status=booking["status"],
        manage_url=manage_url(token),
    )
    mailer.send_email(
        booking["customer_contact"],
        f"Terminbestätigung – {business_name}",
        html,
        from_addr=_sender_for(client),
    )