from datetime import UTC, datetime, timedelta

import httpx
from sqlalchemy import select
from sqlalchemy.ext.asyncio import AsyncSession

from app.core.config import settings
from app.models.car import ServiceNotification
from app.models.user import User

MODERATOR_ROLES = {"admin", "verifier", "moderator"}


async def notify_user(user: User, text: str) -> bool:
    if not settings.bot_token or settings.app_env == "test":
        return False
    try:
        async with httpx.AsyncClient(timeout=5) as client:
            response = await client.post(
                f"https://api.telegram.org/bot{settings.bot_token}/sendMessage",
                data={"chat_id": str(user.telegram_id), "text": text},
            )
            return response.status_code < 400
    except Exception:
        return False


async def notify_platform_moderators(session: AsyncSession, text: str) -> None:
    result = await session.execute(select(User).where(User.platform_role.in_(MODERATOR_ROLES)))
    for user in result.scalars():
        await notify_user(user, text)


async def retry_failed_notifications(session: AsyncSession, *, limit: int = 50) -> int:
    return await process_notification_queue(session, limit=limit)


async def process_notification_queue(session: AsyncSession, *, limit: int = 50) -> int:
    now = datetime.now(UTC)
    result = await session.execute(
        select(ServiceNotification)
        .where(
            ServiceNotification.status.in_(["pending", "failed", "retrying"]),
            ServiceNotification.retry_count < 5,
        )
        .order_by(ServiceNotification.created_at.asc())
        .limit(limit)
    )
    delivered = 0
    for notification in result.scalars():
        if notification.status == "retrying" and notification.created_at > now - timedelta(seconds=30):
            continue
        notification.status = "processing"
        user = await session.get(User, notification.recipient_user_id)
        if user is None:
            notification.status = "abandoned"
            notification.last_error = "recipient_not_found"
            continue
        ok = await notify_user(user, f"{notification.title}\n{notification.body}" if notification.body else notification.title)
        notification.retry_count += 1
        if ok:
            notification.status = "sent"
            notification.sent_at = datetime.now(UTC)
            notification.last_error = None
            delivered += 1
        else:
            notification.status = "abandoned" if notification.retry_count >= 5 else "retrying"
            notification.last_error = "telegram_delivery_failed"
    await session.commit()
    return delivered