from fastapi import APIRouter, Depends, HTTPException
from sqlalchemy.orm import Session
from typing import List
from app.db.base import get_db
from app.models.user import User
from app.models.event import Event, EventRegistration
from app.schemas.event import (
    EventCreate,
    EventUpdate,
    EventResponse,
    EventRegistrationResponse,
)
from app.api.auth import get_current_user

router = APIRouter()


@router.post("/", response_model=EventResponse)
def create_event(
    event: EventCreate,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    db_event = Event(**event.dict(), created_by=current_user.id)
    db.add(db_event)
    db.commit()
    db.refresh(db_event)
    return db_event


@router.get("/", response_model=List[EventResponse])
def get_events(
    skip: int = 0,
    limit: int = 100,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    events = db.query(Event).filter(Event.is_public).offset(skip).limit(limit).all()

    # Add additional info for each event
    for event in events:
        event.creator_name = f"{event.creator.first_name} {event.creator.last_name}"
        event.registered_count = (
            db.query(EventRegistration)
            .filter(EventRegistration.event_id == event.id)
            .count()
        )
        event.is_registered = (
            db.query(EventRegistration)
            .filter(
                EventRegistration.event_id == event.id,
                EventRegistration.user_id == current_user.id,
            )
            .first()
            is not None
        )

    return events


@router.get("/{event_id}", response_model=EventResponse)
def get_event(
    event_id: int,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    event = db.query(Event).filter(Event.id == event_id).first()
    if event is None:
        raise HTTPException(status_code=404, detail="Event not found")

    event.creator_name = f"{event.creator.first_name} {event.creator.last_name}"
    event.registered_count = (
        db.query(EventRegistration)
        .filter(EventRegistration.event_id == event.id)
        .count()
    )
    event.is_registered = (
        db.query(EventRegistration)
        .filter(
            EventRegistration.event_id == event.id,
            EventRegistration.user_id == current_user.id,
        )
        .first()
        is not None
    )

    return event


@router.put("/{event_id}", response_model=EventResponse)
def update_event(
    event_id: int,
    event_update: EventUpdate,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    event = db.query(Event).filter(Event.id == event_id).first()
    if event is None:
        raise HTTPException(status_code=404, detail="Event not found")

    if event.created_by != current_user.id and not current_user.is_admin:
        raise HTTPException(
            status_code=403, detail="Not authorized to update this event"
        )

    for field, value in event_update.dict(exclude_unset=True).items():
        setattr(event, field, value)

    db.commit()
    db.refresh(event)
    return event


@router.delete("/{event_id}")
def delete_event(
    event_id: int,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    event = db.query(Event).filter(Event.id == event_id).first()
    if event is None:
        raise HTTPException(status_code=404, detail="Event not found")

    if event.created_by != current_user.id and not current_user.is_admin:
        raise HTTPException(
            status_code=403, detail="Not authorized to delete this event"
        )

    db.delete(event)
    db.commit()
    return {"message": "Event deleted successfully"}


@router.post("/{event_id}/register", response_model=EventRegistrationResponse)
def register_for_event(
    event_id: int,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    event = db.query(Event).filter(Event.id == event_id).first()
    if event is None:
        raise HTTPException(status_code=404, detail="Event not found")

    # Check if already registered
    existing_registration = (
        db.query(EventRegistration)
        .filter(
            EventRegistration.event_id == event_id,
            EventRegistration.user_id == current_user.id,
        )
        .first()
    )

    if existing_registration:
        raise HTTPException(status_code=400, detail="Already registered for this event")

    # Check if event is full
    if event.max_attendees:
        current_count = (
            db.query(EventRegistration)
            .filter(EventRegistration.event_id == event_id)
            .count()
        )
        if current_count >= event.max_attendees:
            raise HTTPException(status_code=400, detail="Event is full")

    registration = EventRegistration(event_id=event_id, user_id=current_user.id)
    db.add(registration)
    db.commit()
    db.refresh(registration)

    registration.user_name = f"{current_user.first_name} {current_user.last_name}"
    return registration


@router.delete("/{event_id}/register")
def unregister_from_event(
    event_id: int,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    registration = (
        db.query(EventRegistration)
        .filter(
            EventRegistration.event_id == event_id,
            EventRegistration.user_id == current_user.id,
        )
        .first()
    )

    if registration is None:
        raise HTTPException(status_code=404, detail="Registration not found")

    db.delete(registration)
    db.commit()
    return {"message": "Unregistered successfully"}


@router.get("/{event_id}/registrations", response_model=List[EventRegistrationResponse])
def get_event_registrations(
    event_id: int,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    event = db.query(Event).filter(Event.id == event_id).first()
    if event is None:
        raise HTTPException(status_code=404, detail="Event not found")

    if event.created_by != current_user.id and not current_user.is_admin:
        raise HTTPException(
            status_code=403, detail="Not authorized to view registrations"
        )

    registrations = (
        db.query(EventRegistration).filter(EventRegistration.event_id == event_id).all()
    )

    for registration in registrations:
        registration.user_name = (
            f"{registration.user.first_name} {registration.user.last_name}"
        )

    return registrations