from __future__ import annotations

import re
from datetime import datetime, time
from typing import Any
from zoneinfo import ZoneInfo

import httpx

from .settings import get_settings


def ntfy_topic_for_user(user_id: str) -> str:
    clean = re.sub(r"[^a-zA-Z0-9_-]", "", user_id.strip())[:32]
    return f"nomadcna-{clean or 'guest'}"


def ntfy_subscribe_url(user_id: str) -> str:
    settings = get_settings()
    topic = ntfy_topic_for_user(user_id)
    return f"{settings.ntfy_url}/{topic}"


def _in_quiet_hours(preferences: dict[str, Any]) -> bool:
    start_raw = str(preferences.get("quietHoursStart") or "22:00")
    end_raw = str(preferences.get("quietHoursEnd") or "08:00")
    try:
        start = time.fromisoformat(start_raw[:5])
        end = time.fromisoformat(end_raw[:5])
    except ValueError:
        return False
    now = datetime.now(ZoneInfo("Asia/Shanghai")).time()
    if start <= end:
        return start <= now <= end
    return now >= start or now <= end


def _should_push(preferences: dict[str, Any], category: str, priority: str) -> bool:
    channels = preferences.get("channels") or {}
    categories = preferences.get("categories") or {}
    if not channels.get("push"):
        return False
    if not categories.get(category, True):
        return False
    if priority == "high":
        return True
    return not _in_quiet_hours(preferences)


async def push_ntfy_message(
    *,
    topic: str,
    title: str,
    message: str,
    click: str = "",
    priority: str = "default",
    tags: str = "",
) -> bool:
    settings = get_settings()
    if not settings.ntfy_enabled:
        return False
    url = f"{settings.ntfy_url.rstrip('/')}/{topic}"
    headers: dict[str, str] = {"Title": title[:250]}
    if click:
        headers["Click"] = click[:1000]
    if tags:
        headers["Tags"] = tags[:100]
    if priority in {"min", "low", "default", "high", "max", "urgent"}:
        headers["Priority"] = priority
    auth = settings.ntfy_auth_token.strip()
    if auth:
        headers["Authorization"] = f"Bearer {auth}"
    try:
        async with httpx.AsyncClient(timeout=12.0) as client:
            response = await client.post(url, content=message[:4000], headers=headers)
            return response.status_code < 400
    except httpx.HTTPError:
        return False


async def dispatch_ntfy_for_user(
    *,
    user_id: str,
    preferences: dict[str, Any],
    title: str,
    body: str,
    category: str = "system",
    priority: str = "normal",
    action_url: str = "",
    icon: str = "🔔",
) -> bool:
    if not user_id or not _should_push(preferences, category, priority):
        return False
    settings = get_settings()
    site = settings.site_public_url.rstrip("/")
    click = action_url if action_url.startswith("http") else f"{site}{action_url}" if action_url else site
    ntfy_priority = "high" if priority == "high" else "default"
    return await push_ntfy_message(
        topic=ntfy_topic_for_user(user_id),
        title=title,
        message=body or title,
        click=click,
        priority=ntfy_priority,
        tags=icon,
    )