"""
Notifications router — CRUD for user notifications with WebSocket push support.
"""
from typing import Optional
from fastapi import APIRouter, Depends, HTTPException
from sqlalchemy.orm import Session
from sqlalchemy import desc

from app.database.database import get_db
from app.database.models import Notification, User, generate_uuid
from datetime import datetime

router = APIRouter(prefix="/api/notifications", tags=["Notifications"])

def _resolve_user(db: Session, user_id: Optional[str]) -> str:
    if user_id:
        return user_id
    user = db.query(User).first()
    if not user:
        raise HTTPException(status_code=404, detail="No users found.")
    return user.id

@router.get("/")
def get_notifications(user_id: Optional[str] = None, limit: int = 20, db: Session = Depends(get_db)):
    uid = _resolve_user(db, user_id)
    notifications = (
        db.query(Notification)
        .filter(Notification.user_id == uid)
        .order_by(desc(Notification.created_at))
        .limit(limit)
        .all()
    )
    return {
        "notifications": [
            {
                "id": n.id,
                "title": n.title,
                "message": n.message,
                "type": n.type,
                "read": n.read_status,
                "created_at": n.created_at.isoformat() if n.created_at else None,
            }
            for n in notifications
        ],
        "unread_count": sum(1 for n in notifications if not n.read_status),
    }

@router.patch("/{notification_id}/read")
def mark_notification_read(
    notification_id: str,
    user_id: Optional[str] = None,
    db: Session = Depends(get_db)
):
    uid = _resolve_user(db, user_id)
    notif = db.query(Notification).filter(
        Notification.id == notification_id,
        Notification.user_id == uid
    ).first()
    if not notif:
        raise HTTPException(status_code=404, detail="Notification not found")
    notif.read_status = True
    db.commit()
    return {"success": True}

@router.patch("/read-all")
def mark_all_read(user_id: Optional[str] = None, db: Session = Depends(get_db)):
    uid = _resolve_user(db, user_id)
    db.query(Notification).filter(
        Notification.user_id == uid,
        Notification.read_status == False
    ).update({"read_status": True})
    db.commit()
    return {"success": True}

@router.delete("/{notification_id}")
def delete_notification(
    notification_id: str,
    user_id: Optional[str] = None,
    db: Session = Depends(get_db)
):
    uid = _resolve_user(db, user_id)
    notif = db.query(Notification).filter(
        Notification.id == notification_id,
        Notification.user_id == uid
    ).first()
    if not notif:
        raise HTTPException(status_code=404, detail="Notification not found")
    db.delete(notif)
    db.commit()
    return {"success": True}