from datetime import datetime, timezone

from fastapi import HTTPException, status
from sqlalchemy import select
from sqlalchemy.orm import Session, joinedload

from app.models.catalog import Event, EventMedia, TicketType, Venue
from app.models.enums import EventStatus, EventType
from app.schemas.catalog import EventDetail, EventSummary, TicketTypePublic, VenuePublic


def _ticket_type_public(ticket: TicketType) -> TicketTypePublic:
    return TicketTypePublic(
        id=ticket.id,
        name=ticket.name,
        description=ticket.description,
        price_paise=ticket.price_paise,
        status=ticket.status,
        sort_order=ticket.sort_order,
        remaining_quantity=max(ticket.quantity_total - ticket.quantity_sold, 0),
    )


def list_events(
    db: Session,
    *,
    category: EventType | None,
    status: EventStatus | None,
    upcoming: bool,
) -> list[Event]:
    query = (
        select(Event)
        .options(joinedload(Event.venue))
        .order_by(Event.starts_at.asc())
    )

    if status is not None:
        query = query.where(Event.status == status)
    if category is not None:
        query = query.where(Event.category == category)
    if upcoming:
        now = datetime.now(timezone.utc)
        query = query.where(Event.starts_at >= now)

    return list(db.scalars(query).unique().all())


def get_event_by_slug(db: Session, slug: str) -> Event:
    event = db.scalar(
        select(Event)
        .options(
            joinedload(Event.venue),
            joinedload(Event.media),
            joinedload(Event.ticket_types),
        )
        .where(Event.slug == slug)
    )
    if not event:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Event not found")
    return event


def event_to_summary(event: Event) -> EventSummary:
    return EventSummary.model_validate(event)


def event_to_detail(event: Event) -> EventDetail:
    return EventDetail(
        id=event.id,
        slug=event.slug,
        title=event.title,
        category=event.category,
        status=event.status,
        starts_at=event.starts_at,
        ends_at=event.ends_at,
        is_featured=event.is_featured,
        cover_image_url=event.cover_image_url,
        cover_image_alt=event.cover_image_alt,
        venue=VenuePublic.model_validate(event.venue),
        description=event.description,
        meta_description=event.meta_description,
        media=event.media,
        ticket_types=[_ticket_type_public(ticket) for ticket in event.ticket_types],
    )


def list_venues(db: Session) -> list[Venue]:
    return list(db.scalars(select(Venue).order_by(Venue.name.asc())).all())


def get_venue_by_id(db: Session, venue_id: int) -> Venue:
    venue = db.get(Venue, venue_id)
    if not venue:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Venue not found")
    return venue