"""Owner Telegram notification webhook (#23): fires an internal webhook call
on booking create/cancel/reschedule, with the same {booking, business_name,
notify_channel} payload shape n8n/booking-sync.json's "Build booking row"
step used to hand the Telegram node -- plus an "event" field (that node
never needed, since it only ever fired for a new EA booking) so the message
text can say what actually happened instead of always "new booking".

Fire-and-forget over HTTP, mirroring mailer.py's background-thread queue: a
slow/unreachable webhook must never block or fail a booking mutation.
"""
import json
import os
import queue
import threading
import traceback
import urllib.request

# Left blank, sending is skipped (logged, not fatal) -- same convention as
# mailer.py's SMTP_HOST. Channel routing (only "telegram" does anything at
# launch) lives on the n8n side of this webhook, not here -- see #23.
NOTIFY_WEBHOOK_URL = os.environ.get("OWNER_NOTIFY_WEBHOOK_URL", "")

_queue = queue.Queue()


def _serialize_booking(booking):
    return {k: (v.isoformat() if hasattr(v, "isoformat") else v)
            for k, v in booking.items()}


def _send_now(payload):
    if not NOTIFY_WEBHOOK_URL:
        print(f"[owner_notify] OWNER_NOTIFY_WEBHOOK_URL not configured, "
              f"skipping notify for booking {payload['booking'].get('booking_id')}",
              flush=True)
        return
    req = urllib.request.Request(
        NOTIFY_WEBHOOK_URL,
        data=json.dumps(payload).encode("utf-8"),
        headers={"Content-Type": "application/json"},
        method="POST",
    )
    with urllib.request.urlopen(req, timeout=10):
        pass


def _worker():
    while True:
        payload = _queue.get()
        try:
            _send_now(payload)
        except Exception:  # noqa: BLE001
            print(f"[owner_notify] send for booking "
                  f"{payload['booking'].get('booking_id')} failed:", flush=True)
            traceback.print_exc()
        finally:
            _queue.task_done()


threading.Thread(target=_worker, daemon=True).start()


def notify(client, booking, event):
    """Queue a best-effort owner notification for a booking create/cancel/
    reschedule (#23). event is "created"/"cancelled"/"rescheduled" -- booking
    status alone can't distinguish a fresh booking from a rescheduled one
    (both land as "confirmed"), and the n8n message text needs to say which
    happened. Fires for every notify_channel value, including one that isn't
    "telegram" (or is unset) -- that's not an error, the n8n workflow this
    webhook feeds is what decides whether a given channel actually sends
    anything, which keeps this call site the same regardless of how many
    channels exist in the future."""
    payload = {
        "event": event,
        "booking": _serialize_booking(booking),
        "business_name": (client or {}).get("business_name") or "",
        "notify_channel": (client or {}).get("notify_channel"),
    }
    _queue.put(payload)