"""Celery task: send monthly reports to schools."""
import logging
from app.worker import celery_app

logger = logging.getLogger(__name__)

@celery_app.task(name="reports.send_monthly_reports")
def send_monthly_reports():
    """Send monthly attendance and SMS report email to each active school."""
    import os
    from datetime import date, timedelta
    from sqlalchemy import create_engine, select
    from sqlalchemy.orm import sessionmaker
    from app.models.school import School, SchoolStatus
    from app.services.email import send_email

    db_url = os.getenv("DATABASE_URL", "postgresql://postgres:postgres@db:5432/taptrack_hub")
    engine = create_engine(db_url.replace("postgresql+asyncpg://", "postgresql://"), pool_pre_ping=True)
    db = sessionmaker(bind=engine)()
    try:
        today = date.today()
        prev_month_end = date(today.year, today.month, 1) - timedelta(days=1)
        prev_month_start = date(prev_month_end.year, prev_month_end.month, 1)
        schools = db.execute(select(School).where(School.status == SchoolStatus.active)).scalars().all()
        for school in schools:
            if not school.billing_email:
                continue
            send_email(
                to=school.billing_email,
                subject=f"Monthly Report — {school.name} — {prev_month_start.strftime('%B %Y')}",
                body=f"Dear {school.contact_name or school.name},\n\nPlease find your monthly summary for {prev_month_start.strftime('%B %Y')} in your TapTrack Hub portal.\n\nSMS Credits Remaining: {float(school.sms_credits):.0f}\n\nLog in to view full details.\n\nThank you,\nTapTrack Hub Team",
            )
        logger.info(f"Sent monthly reports to {len(schools)} schools")
    finally:
        db.close()