from sqlmodel import Session, select, func, desc
from models import Performance, Show, Song, Attendance, UserBadge, Badge
from datetime import datetime

def get_song_stats(session: Session, song_id: int):
    """Calculate times played and gap for a song."""
    # Times Played
    times_played = session.exec(
        select(func.count(Performance.id)).where(Performance.song_id == song_id)
    ).one()

    # Last Played
    last_performance = session.exec(
        select(Show)
        .join(Performance)
        .where(Performance.song_id == song_id)
        .order_by(desc(Show.date))
        .limit(1)
    ).first()

    gap = 0
    if last_performance:
        # Calculate gap: number of shows since last_performance
        # This is a bit heavy if we count all shows. 
        # For now, let's just return the date of last played.
        # To calculate true gap, we'd need: count(shows where date > last_performance.date)
        gap = session.exec(
            select(func.count(Show.id)).where(Show.date > last_performance.date)
        ).one()
    
    return {
        "times_played": times_played,
        "last_played": last_performance.date if last_performance else None,
        "gap": gap
    }

def check_and_award_badges(session: Session, user_id: int):
    """Check for badge milestones and award them."""
    # Example: 10 Shows Attended
    attendance_count = session.exec(
        select(func.count(Attendance.id)).where(Attendance.user_id == user_id)
    ).one()
    
    if attendance_count >= 10:
        award_badge(session, user_id, "10-shows", "10 Shows Club", "Awarded for attending 10 shows.", "ticket")

    # Example: First Review
    # (Need Review model import if implemented, assuming it is from previous steps)
    # ...

def award_badge(session: Session, user_id: int, slug: str, name: str, description: str, icon: str):
    """Award a badge if not already owned."""
    # Check if badge exists, create if not (for system badges)
    badge = session.exec(select(Badge).where(Badge.slug == slug)).first()
    if not badge:
        badge = Badge(name=name, description=description, icon=icon, slug=slug)
        session.add(badge)
        session.commit()
        session.refresh(badge)
    
    # Check if user has it
    user_badge = session.exec(
        select(UserBadge)
        .where(UserBadge.user_id == user_id)
        .where(UserBadge.badge_id == badge.id)
    ).first()
    
    if not user_badge:
        user_badge = UserBadge(user_id=user_id, badge_id=badge.id)
        session.add(user_badge)
        session.commit()