from typing import List
from fastapi import APIRouter, Depends, HTTPException, Query
from sqlmodel import Session, select, desc
from database import get_session
from models import Notification, User
from schemas import NotificationRead, NotificationCreate
from auth import get_current_user

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

@router.get("/", response_model=List[NotificationRead])
def read_notifications(
    session: Session = Depends(get_session),
    current_user: User = Depends(get_current_user),
    limit: int = 20,
    offset: int = 0
):
    notifications = session.exec(
        select(Notification)
        .where(Notification.user_id == current_user.id)
        .order_by(desc(Notification.created_at))
        .offset(offset)
        .limit(limit)
    ).all()
    return notifications

@router.get("/unread-count")
def get_unread_count(
    session: Session = Depends(get_session),
    current_user: User = Depends(get_current_user)
):
    from sqlmodel import func
    count = session.exec(
        select(func.count(Notification.id))
        .where(Notification.user_id == current_user.id)
        .where(Notification.is_read == False)
    ).one()
    return {"count": count}

@router.post("/{notification_id}/read")
def mark_as_read(
    notification_id: int,
    session: Session = Depends(get_session),
    current_user: User = Depends(get_current_user)
):
    notification = session.get(Notification, notification_id)
    if not notification:
        raise HTTPException(status_code=404, detail="Notification not found")
    
    if notification.user_id != current_user.id:
        raise HTTPException(status_code=403, detail="Not authorized")
        
    notification.is_read = True
    session.add(notification)
    session.commit()
    return {"ok": True}

@router.post("/mark-all-read")
def mark_all_read(
    session: Session = Depends(get_session),
    current_user: User = Depends(get_current_user)
):
    notifications = session.exec(
        select(Notification)
        .where(Notification.user_id == current_user.id)
        .where(Notification.is_read == False)
    ).all()
    
    for n in notifications:
        n.is_read = True
        session.add(n)
        
    session.commit()
    return {"ok": True}

# Helper function to create notifications (not an endpoint)
def create_notification(session: Session, user_id: int, type: str, title: str, message: str, link: str = None):
    notification = Notification(
        user_id=user_id,
        type=type,
        title=title,
        message=message,
        link=link
    )
    session.add(notification)
    session.commit()
    session.refresh(notification)
    return notification