"""浏览器推送通知服务 — Web Push Protocol (RFC 8291)"""
from __future__ import annotations

import json
import logging
from typing import Optional

from app.core.database import SessionLocal
from app.models.push_subscription import PushSubscription

logger = logging.getLogger(__name__)


async def send_push_to_user(
    user_id: str,
    title: str,
    body: str = "",
    url: str = "/",
    require_interaction: bool = False,
) -> int:
    """向指定用户的所有设备发送推送通知。返回成功发送数。"""
    db = SessionLocal()
    sent = 0
    try:
        subs = (
            db.query(PushSubscription)
            .filter(PushSubscription.user_id == user_id)
            .all()
        )
        for sub in subs:
            ok = await _send_webpush(
                endpoint=sub.endpoint,
                p256dh=sub.p256dh,
                auth=sub.auth,
                title=title,
                body=body,
                url=url,
                require_interaction=require_interaction,
            )
            if ok:
                sent += 1
        return sent
    finally:
        db.close()


async def broadcast_push(
    title: str,
    body: str = "",
    url: str = "/",
) -> int:
    """向所有已订阅用户广播推送通知。"""
    db = SessionLocal()
    sent = 0
    try:
        subs = db.query(PushSubscription).all()
        for sub in subs:
            ok = await _send_webpush(
                endpoint=sub.endpoint,
                p256dh=sub.p256dh,
                auth=sub.auth,
                title=title,
                body=body,
                url=url,
                require_interaction=False,
            )
            if ok:
                sent += 1
        return sent
    finally:
        db.close()


async def _send_webpush(
    endpoint: str,
    p256dh: str,
    auth: str,
    title: str,
    body: str,
    url: str = "/",
    require_interaction: bool = False,
) -> bool:
    """发送单条 Web Push 消息。使用 pywebpush 或直接 HTTP POST。"""
    payload = json.dumps({
        "title": title,
        "body": body,
        "data": {"url": url},
        "requireInteraction": require_interaction,
        "icon": "/icons/icon-192.png",
        "badge": "/icons/icon-192.png",
    })

    try:
        # 尝试 pywebpush（如果已安装）
        try:
            from pywebpush import WebPusher, WebPushException
            wp = WebPusher({
                "endpoint": endpoint,
                "keys": {"p256dh": p256dh, "auth": auth},
            })
            wp.send(payload, timeout=10)
            return True
        except ImportError:
            pass

        # Fallback: 直接 HTTP POST（不加密，仅用于开发环境）
        import aiohttp
        async with aiohttp.ClientSession() as session:
            async with session.post(
                endpoint,
                data=payload,
                headers={
                    "Content-Type": "application/json",
                    "TTL": "86400",
                },
                timeout=aiohttp.ClientTimeout(total=10),
            ) as resp:
                ok = resp.status in (200, 201, 204)
                if not ok:
                    logger.warning("Push 发送失败: status=%d", resp.status)
                return ok
    except Exception as e:
        logger.error("Push 发送异常: %s", e)
        return False