"""
User-level notification dispatcher.

Channels:
- 'ui'       → no-op (dashboard shows the events anyway)
- 'telegram' → per-user bot token + chat id
"""
import logging
from typing import Optional
from urllib.parse import quote

import requests

import db
from settings import PUBLIC_URL

logger = logging.getLogger("web.notifications")

EventType = str  # 'match' | 'apply_ok' | 'apply_fail'


def telegram_send(token: str, chat_id: str, text: str) -> tuple[bool, str]:
    """Send a Telegram message. Returns (ok, detail) — detail is the Telegram
    API's `description` on failure, or a short error string, or "ok"."""
    try:
        r = requests.post(
            f"https://api.telegram.org/bot{token}/sendMessage",
            json={"chat_id": chat_id, "text": text, "parse_mode": "Markdown",
                  "disable_web_page_preview": True},
            timeout=10,
        )
        if r.ok:
            return True, "ok"
        try:
            detail = r.json().get("description") or f"HTTP {r.status_code}"
        except ValueError:
            detail = f"HTTP {r.status_code}"
        logger.warning("telegram send failed: %s %s", r.status_code, r.text[:200])
        return False, detail
    except requests.RequestException as e:
        logger.warning("telegram unreachable: %s", e)
        return False, str(e)


def _should_notify(notif, event: EventType) -> bool:
    if event == "match":
        return bool(notif["notify_on_match"])
    if event == "apply_ok":
        return bool(notif["notify_on_apply_success"])
    if event == "apply_fail":
        return bool(notif["notify_on_apply_fail"])
    return False


def notify_user(user_id: int, event: EventType, *,
                subject: str, body_plain: str, body_markdown: Optional[str] = None) -> None:
    """Fire a notification for one user on one event. Best-effort, non-raising."""
    try:
        notif = db.get_notifications(user_id)
        if not notif or not _should_notify(notif, event):
            return
        channel = notif["channel"] or "ui"
        if channel == "telegram":
            token = notif["telegram_bot_token"]
            chat = notif["telegram_chat_id"]
            if token and chat:
                telegram_send(token, chat, body_markdown or body_plain)
    except Exception:
        logger.exception("notify_user failed for user=%s event=%s", user_id, event)


# -- Convenience builders -----------------------------------------------------

def _address_lines(address: str) -> tuple[str, str]:
    """Split "Street Nr, PLZ, District" into (line1, line2) for the two-line
    layout in notifications. Falls back gracefully for unexpected shapes."""
    parts = [p.strip() for p in (address or "").split(",") if p.strip()]
    if len(parts) >= 3:
        return parts[0], f"{parts[1]} {', '.join(parts[2:])}"
    if len(parts) == 2:
        return parts[0], parts[1]
    return (address or "").strip(), ""


def _gmaps_url(address: str, lat, lng) -> str:
    if lat is not None and lng is not None:
        return f"https://www.google.com/maps/search/?api=1&query={lat},{lng}"
    return f"https://www.google.com/maps/search/?api=1&query={quote(address or '')}"


def _wbs_label(wbs: str) -> str:
    w = (wbs or "").strip().lower()
    if w == "erforderlich":
        return "erforderlich"
    if w in ("nicht erforderlich", "kein", "nein", "no", "ohne", "-", ""):
        return "nicht erforderlich"
    return wbs  # pass through unrecognised literals


def _fmt_num(v) -> str:
    return "—" if v is None else f"{v}"


def on_match(user_id: int, flat: dict) -> None:
    address = (flat.get("address") or "").strip()
    line1, line2 = _address_lines(address)
    link = flat.get("link", "")
    rent = flat.get("total_rent")
    sqm_price = flat.get("sqm_price")
    rooms = flat.get("rooms")
    size = flat.get("size")
    wbs_txt = _wbs_label(flat.get("wbs", ""))
    gmaps = flat.get("address_link_gmaps") or _gmaps_url(
        address, flat.get("lat"), flat.get("lng"),
    )
    flat_id = str(flat.get("id", ""))
    deep_link = f"{PUBLIC_URL}/?flat={quote(flat_id, safe='')}"

    rent_str = _fmt_num(rent)
    if sqm_price:
        rent_str += f" ({sqm_price} €/m²)"

    body = (
        f"{line1}\n{line2}\n"
        f"Miete: {rent_str}\n"
        f"Fläche: {_fmt_num(size)}\n"
        f"Zimmer: {_fmt_num(rooms)}\n"
        f"WBS: {wbs_txt}\n\n"
        f"Original: {link}\n"
        f"lazyflat: {deep_link}"
    )
    md = (
        f"[{line1}]({gmaps})\n{line2}\n"
        f"Miete: {rent_str}\n"
        f"Fläche: {_fmt_num(size)}\n"
        f"Zimmer: {_fmt_num(rooms)}\n"
        f"WBS: {wbs_txt}\n\n"
        f"[Zur original Anzeige]({link})\n"
        f"[Zur lazyflat Seite]({deep_link})"
    )
    notify_user(user_id, "match", subject="[lazyflat] passende Wohnung",
                body_plain=body, body_markdown=md)


def on_apply_ok(user_id: int, flat: dict, message: str) -> None:
    addr = flat.get("address") or flat.get("link")
    body = f"Bewerbung erfolgreich: {addr}\n{message}"
    md = f"*Bewerbung erfolgreich*\n{addr}\n{message}"
    notify_user(user_id, "apply_ok", subject="[lazyflat] Bewerbung OK", body_plain=body, body_markdown=md)


def on_apply_fail(user_id: int, flat: dict, message: str) -> None:
    addr = flat.get("address") or flat.get("link")
    body = f"Bewerbung fehlgeschlagen: {addr}\n{message}\n{PUBLIC_URL}/bewerbungen"
    md = (f"*Bewerbung fehlgeschlagen*\n{addr}\n{message}\n"
          f"[Bewerbungen ansehen]({PUBLIC_URL}/bewerbungen)")
    notify_user(user_id, "apply_fail", subject="[lazyflat] Bewerbung fehlgeschlagen",
                body_plain=body, body_markdown=md)