from typing import List
from fastapi import APIRouter, Depends, HTTPException, Query
from sqlmodel import Session, select
from sqlalchemy import func
from database import get_session
from models import Show, Tag, EntityTag, Vertical, UserVerticalPreference
from schemas import ShowCreate, ShowRead, ShowUpdate, TagRead, PaginatedResponse, PaginationMeta, VerticalSimple, VenueRead, TourRead
from auth import get_current_user, get_current_user_optional

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

from services.notification_service import NotificationService

def get_notification_service(session: Session = Depends(get_session)) -> NotificationService:
    return NotificationService(session)

@router.post("/", response_model=ShowRead)
def create_show(
    show: ShowCreate, 
    session: Session = Depends(get_session), 
    current_user = Depends(get_current_user),
    notification_service: NotificationService = Depends(get_notification_service)
):
    db_show = Show.model_validate(show)
    session.add(db_show)
    session.commit()
    session.refresh(db_show)
    
    # Trigger notifications
    try:
        notification_service.check_show_alert(db_show)
    except Exception as e:
        print(f"Error sending notifications: {e}")
        
    return db_show

def serialize_show(show: Show) -> dict:
    """
    Robustly serialize a Show object to a dictionary.
    Returning a dict breaks the link to SQLAlchemy ORM objects completely,
    preventing Pydantic from triggering lazy loads or infinite recursion during validation.
    """
    try:
        # Base fields
        data = {
            "id": show.id,
            "date": show.date,
            "slug": show.slug,
            "vertical_id": show.vertical_id,
            "venue_id": show.venue_id,
            "tour_id": show.tour_id,
            "notes": show.notes,
            "bandcamp_link": show.bandcamp_link,
            "nugs_link": show.nugs_link,
            "youtube_link": show.youtube_link,
            "vertical": None,
            "venue": None,
            "tour": None,
            "tags": [],
            "performances": []
        }
        
        # Manually map relationships if present
        if show.vertical:
            try:
                data["vertical"] = {
                    "id": show.vertical.id,
                    "name": show.vertical.name,
                    "slug": show.vertical.slug,
                    "description": show.vertical.description,
                    "logo_url": show.vertical.logo_url,
                    "accent_color": show.vertical.accent_color
                }
            except Exception as e:
                print(f"Error serializing vertical for show {show.id}: {e}")

        if show.venue:
            try:
                data["venue"] = {
                    "id": show.venue.id,
                    "name": show.venue.name,
                    "slug": show.venue.slug,
                    "city": show.venue.city,
                    "state": show.venue.state,
                    "country": show.venue.country,
                    "capacity": show.venue.capacity,
                    "notes": show.venue.notes
                }
            except Exception as e:
                print(f"Error serializing venue for show {show.id}: {e}")

        if show.tour:
            try:
                data["tour"] = {
                    "id": show.tour.id,
                    "name": show.tour.name,
                    "slug": show.tour.slug,
                    "start_date": show.tour.start_date,
                    "end_date": show.tour.end_date,
                    "notes": show.tour.notes
                }
            except Exception as e:
                print(f"Error serializing tour for show {show.id}: {e}")
                
        return data
        
    except Exception as e:
        print(f"CRITICAL Error serializing show {show.id}: {e}")
        # Return minimal valid dict
        return {
            "id": show.id, 
            "date": show.date, 
            "vertical_id": show.vertical_id,
            "slug": show.slug or "",
            "tags": [],
            "performances": []
        }

@router.get("/", response_model=PaginatedResponse[ShowRead])
def read_shows(
    offset: int = 0, 
    limit: int = Query(default=2000, le=5000), 
    venue_id: int = None,
    tour_id: int = None,
    year: int = None,
    vertical: str = None,  # Single vertical slug filter
    vertical_id: int = None,  # Vertical ID filter
    vertical_slugs: List[str] = Query(None),
    status: str = Query(default=None, regex="^(past|upcoming)$"),
    tiers: List[str] = Query(None),
    current_user = Depends(get_current_user_optional),
    session: Session = Depends(get_session)
):
    from sqlalchemy.orm import joinedload
    from datetime import datetime
    
    query = select(Show).options(
        joinedload(Show.vertical),
        joinedload(Show.venue),
        joinedload(Show.tour)
    )
    
    if tiers and current_user:
        prefs = session.exec(
            select(UserVerticalPreference)
            .where(UserVerticalPreference.user_id == current_user.id)
            .where(UserVerticalPreference.tier.in_(tiers))
        ).all()
        allowed_ids = [p.vertical_id for p in prefs]
        # If user selected tiers but has no bands in them, return empty
        if not allowed_ids:
            return PaginatedResponse(data=[], meta=PaginationMeta(total=0, limit=limit, offset=offset))
        query = query.where(Show.vertical_id.in_(allowed_ids))
    elif tiers and not current_user:
        # Anonymous users can't filter by personal tiers
        return PaginatedResponse(data=[], meta=PaginationMeta(total=0, limit=limit, offset=offset))
        
    if venue_id:
        query = query.where(Show.venue_id == venue_id)
    if tour_id:
        query = query.where(Show.tour_id == tour_id)
    if year:
        from sqlalchemy import extract
        query = query.where(extract('year', Show.date) == year)
    
    if vertical_slugs:
        query = query.join(Vertical).where(Vertical.slug.in_(vertical_slugs))
    elif vertical:
        # Single vertical slug filter
        query = query.join(Vertical).where(Vertical.slug == vertical)
    
    if vertical_id:
        query = query.where(Show.vertical_id == vertical_id)
        
    if status:
        today = datetime.now()
        if status == "past":
            query = query.where(Show.date <= today)
        elif status == "upcoming":
            query = query.where(Show.date > today)

    # Calculate total count before pagination
    total = session.exec(select(func.count()).select_from(query.subquery())).one()

    # Apply sorting and pagination
    if status == "upcoming":
        query = query.order_by(Show.date.asc())
    else:
        # Default sort by date descending so we get recent shows first
        query = query.order_by(Show.date.desc())
    
    shows = session.exec(query.offset(offset).limit(limit)).all()
    
    # Serialize robustly
    serialized_shows = [serialize_show(s) for s in shows]
    
    return PaginatedResponse(
        data=serialized_shows,
        meta=PaginationMeta(total=total, limit=limit, offset=offset)
    )

@router.get("/recent", response_model=List[ShowRead])
def read_recent_shows(
    limit: int = Query(default=10, le=50),
    tiers: List[str] = Query(None),
    current_user = Depends(get_current_user_optional),
    session: Session = Depends(get_session)
):
    """Get the most recent shows ordered by date descending"""
    from datetime import datetime
    from sqlalchemy.orm import joinedload
    query = select(Show).options(
        joinedload(Show.vertical),
        joinedload(Show.venue),
        joinedload(Show.tour)
    ).where(Show.date <= datetime.now())
    
    if tiers and current_user:
        prefs = session.exec(
            select(UserVerticalPreference)
            .where(UserVerticalPreference.user_id == current_user.id)
            .where(UserVerticalPreference.tier.in_(tiers))
        ).all()
        allowed_ids = [p.vertical_id for p in prefs]
        if not allowed_ids:
            return []
        query = query.where(Show.vertical_id.in_(allowed_ids))
    
    query = query.order_by(Show.date.desc()).limit(limit)
    shows = session.exec(query).all()
    return shows

@router.get("/upcoming", response_model=List[ShowRead])
def read_upcoming_shows(
    limit: int = Query(default=50, le=100),
    tiers: List[str] = Query(None),
    current_user = Depends(get_current_user_optional),
    session: Session = Depends(get_session)
):
    """Get upcoming shows ordered by date ascending"""
    from datetime import datetime
    from sqlalchemy.orm import joinedload
    query = select(Show).options(
        joinedload(Show.vertical),
        joinedload(Show.venue),
        joinedload(Show.tour)
    ).where(Show.date > datetime.now())
    
    if tiers and current_user:
        prefs = session.exec(
            select(UserVerticalPreference)
            .where(UserVerticalPreference.user_id == current_user.id)
            .where(UserVerticalPreference.tier.in_(tiers))
        ).all()
        allowed_ids = [p.vertical_id for p in prefs]
        if not allowed_ids:
            return []
        query = query.where(Show.vertical_id.in_(allowed_ids))
        
    query = query.order_by(Show.date.asc()).limit(limit)
    shows = session.exec(query).all()
    return shows

@router.get("/{slug}", response_model=ShowRead)
def read_show(slug: str, session: Session = Depends(get_session)):
    from sqlalchemy.orm import selectinload, joinedload
    from models import Performance, VideoPerformance, Video, VideoPlatform
    
    # Eager load relationships clearly
    show = session.exec(
        select(Show)
        .options(
            selectinload(Show.performances).selectinload(Performance.video_links).joinedload(VideoPerformance.video)
        )
        .where(Show.slug == slug)
    ).first()
        
    if not show:
        raise HTTPException(status_code=404, detail="Show not found")
    
    tags = session.exec(
        select(Tag)
        .join(EntityTag, Tag.id == EntityTag.tag_id)
        .where(EntityTag.entity_type == "show")
        .where(EntityTag.entity_id == show.id)
    ).all()
    
    show_data = ShowRead.model_validate(show)
    show_data.tags = tags
    
    # Get vertical for band name
    vertical = session.get(Vertical, show.vertical_id)
    show_data.vertical = vertical
    
    # Sort performances by position
    sorted_perfs = sorted(show.performances, key=lambda p: p.position)
    
    # Process performances: Filter nicknames and populate video links
    for perf in sorted_perfs:
        perf.nicknames = [n for n in perf.nicknames if n.status == "approved"]
        
        # Backfill youtube_link from Video entity if not present
        if not perf.youtube_link and perf.video_links:
            for link in perf.video_links:
                if link.video and link.video.platform == VideoPlatform.YOUTUBE:
                    perf.youtube_link = link.video.url
                    break
        
    show_data.performances = sorted_perfs
    
    return show_data

@router.patch("/{show_id}", response_model=ShowRead)
def update_show(show_id: int, show: ShowUpdate, session: Session = Depends(get_session), current_user = Depends(get_current_user)):
    db_show = session.get(Show, show_id)
    if not db_show:
        raise HTTPException(status_code=404, detail="Show not found")
    show_data = show.model_dump(exclude_unset=True)
    db_show.sqlmodel_update(show_data)
    session.add(db_show)
    session.commit()
    session.refresh(db_show)
    return db_show