from flask import Blueprint, render_template, request, redirect, url_for, flash, jsonify
from flask_login import login_required, current_user
from app import db
from app.models.reservation import Reservation, ReservationStatus
from app.models.classroom import Classroom
from app.models.subject import Subject, Commission
from app.forms.reservation import ReservationForm
from datetime import datetime, timedelta, date
from sqlalchemy import func, or_
from sqlalchemy.orm import joinedload

schedule_bp = Blueprint('schedule', __name__, url_prefix='/schedule')

@schedule_bp.route('/today')
@login_required
def today_schedule():
    """Show today's schedule"""
    today = datetime.utcnow().date()
    today_start = datetime.combine(today, datetime.min.time())
    today_end = datetime.combine(today, datetime.max.time())
    
    # Get reservations with eager loading
    reservations = Reservation.query.options(
        joinedload(Reservation.classroom),
        joinedload(Reservation.commission),
        joinedload(Reservation.user)
    ).filter(
        Reservation.start_time >= today_start,
        Reservation.start_time <= today_end,
        Reservation.status.in_([ReservationStatus.CONFIRMED, ReservationStatus.PENDING])
    ).order_by(Reservation.start_time).all()
    
    # Create time blocks for timeline view
    time_blocks = {}
    for reservation in reservations:
        start_hour = reservation.start_time.hour
        end_hour = reservation.end_time.hour
        
        for hour in range(max(7, start_hour), min(22, end_hour + 1)):
            if hour not in time_blocks:
                time_blocks[hour] = []
            if reservation not in time_blocks[hour]:
                time_blocks[hour].append({
                    'reservation': reservation,
                    'classroom': reservation.classroom,
                    'commission': reservation.commission,
                    'user': reservation.user
                })
    
    # Calculate stats
    total_reservations = len(reservations)
    confirmed = len([r for r in reservations if r.status == ReservationStatus.CONFIRMED])
    pending = len([r for r in reservations if r.status == ReservationStatus.PENDING])
    
    # Get total classrooms and calculate occupied ones
    from app.models.classroom import Classroom
    total_classrooms = Classroom.query.count()
    occupied_classrooms = len(set(r.classroom_id for r in reservations if r.classroom_id))
    
    stats = {
        'total_reservations': total_reservations,
        'confirmed': confirmed,
        'pending': pending,
        'occupied_classrooms': occupied_classrooms,
        'total_classrooms': total_classrooms
    }
    
    return render_template('schedule/today.html', 
                         reservations=reservations,
                         time_blocks=time_blocks,
                         stats=stats,
                         today=today)

@schedule_bp.route('/cancel/<int:id>', methods=['POST'])
@login_required
def cancel_reservation(id):
    """Cancel a reservation"""
    try:
        reservation = Reservation.query.get_or_404(id)
        
        if not reservation.can_be_cancelled():
            flash('Reservations can only be cancelled at least 24 hours before start time.', 'error')
            return redirect(request.referrer)
        
        reservation.status = ReservationStatus.CANCELLED
        db.session.commit()
        
        flash('Reservation cancelled successfully!', 'success')
        
    except Exception as e:
        db.session.rollback()
        flash(f'Error cancelling reservation: {str(e)}', 'error')
    
    return redirect(request.referrer)

@schedule_bp.route('/reservation/<int:id>/view')
@login_required
def view_reservation(id):
    """View reservation details"""
    try:
        reservation = Reservation.query.options(
            joinedload(Reservation.classroom),
            joinedload(Reservation.commission),
            joinedload(Reservation.user)
        ).get_or_404(id)
        
        return render_template('schedule/view.html', 
                             reservation=reservation,
                             title='Reservation Details')
        
    except Exception as e:
        flash(f'Error loading reservation details: {str(e)}', 'error')
        return redirect(url_for('schedule.today_schedule'))

@schedule_bp.route('/calendar')
@login_required
def calendar_view():
    """Show calendar view"""
    return render_template('schedule/calendar.html', title='Calendar View')

@schedule_bp.route('/add')
@login_required
def add_reservation():
    """Add new reservation"""
    form = ReservationForm()
    return render_template('schedule/create.html', form=form, title='New Reservation')

@schedule_bp.route('/list')
@login_required
def list_reservations():
    """List all reservations"""
    return redirect(url_for('schedule.today_schedule'))

@schedule_bp.route('/reservation/<int:id>/confirm', methods=['POST'])
@login_required
def confirm_reservation(id):
    """Confirm a reservation"""
    try:
        reservation = Reservation.query.get_or_404(id)
        
        if reservation.status != ReservationStatus.PENDING:
            flash('Only pending reservations can be confirmed.', 'error')
            return redirect(request.referrer)
            
        reservation.status = ReservationStatus.CONFIRMED
        db.session.commit()
        
        flash('Reservation confirmed successfully!', 'success')
        
    except Exception as e:
        db.session.rollback()
        flash(f'Error confirming reservation: {str(e)}', 'error')
        
    return redirect(request.referrer)

# API endpoints
@schedule_bp.route('/calendar-data')
@login_required
def calendar_data():
    """Get calendar events data for FullCalendar"""
    try:
        # Get date range from query parameters
        start = request.args.get('start')
        end = request.args.get('end')
        
        if start and end:
            from datetime import datetime
            start_date = datetime.fromisoformat(start)
            end_date = datetime.fromisoformat(end)
        else:
            # Default to current month
            today = date.today()
            start_date = datetime.combine(today.replace(day=1), datetime.min.time())
            next_month = today.replace(day=28) + timedelta(days=4)  # Next month
            end_date = datetime.combine(next_month.replace(day=1), datetime.max.time())
        
        # Get reservations in the date range
        reservations = Reservation.query.options(
            joinedload(Reservation.classroom),
            joinedload(Reservation.commission)
        ).filter(
            Reservation.start_time >= start_date,
            Reservation.start_time <= end_date,
            Reservation.status.in_([ReservationStatus.CONFIRMED, ReservationStatus.PENDING])
        ).order_by(Reservation.start_time).all()
        
        events = []
        for reservation in reservations:
            events.append({
                'id': reservation.id,
                'title': f"{reservation.commission.get_full_code() if reservation.commission else 'No Commission'} - {reservation.classroom.code_display}",
                'start': reservation.start_time.isoformat(),
                'end': reservation.end_time.isoformat(),
                'url': url_for('schedule.view_reservation', id=reservation.id) if reservation.id else None,
                'className': f'fc-event-{reservation.status.value.lower()}',
                'extendedProps': {
                    'classroom': reservation.classroom.code_display if reservation.classroom else 'Unknown',
                    'commission': reservation.commission.get_full_code() if reservation.commission else 'No Commission',
                    'purpose': reservation.purpose or 'No purpose',
                    'attendees': reservation.expected_attendees,
                    'status': reservation.status.value,
                    'notes': reservation.notes or ''
                }
            })
        
        return jsonify(events)
        
    except Exception as e:
        return jsonify({'error': str(e)}), 500

@schedule_bp.route('/api/today-events')
@login_required
def api_today_events():
    """Get today's events as JSON"""
    try:
        today_start = datetime.combine(date.today(), datetime.min.time())
        today_end = datetime.combine(date.today(), datetime.max.time())
        
        reservations = Reservation.query.options(
            joinedload(Reservation.classroom),
            joinedload(Reservation.commission)
        ).filter(
            Reservation.start_time >= today_start,
            Reservation.start_time <= today_end,
            Reservation.status == ReservationStatus.CONFIRMED
        ).order_by(Reservation.start_time).all()
        
        events = []
        for reservation in reservations:
            events.append({
                'id': reservation.id,
                'title': f"{reservation.commission.get_full_code() if reservation.commission else 'No Commission'} - {reservation.classroom.code_display}",
                'start': reservation.start_time.isoformat(),
                'end': reservation.end_time.isoformat(),
                'url': url_for('schedule.view_reservation', id=reservation.id) if reservation.id else None,
                'extendedProps': {
                    'classroom': reservation.classroom.code_display if reservation.classroom else 'Unknown',
                    'purpose': reservation.purpose or 'No purpose',
                    'attendees': reservation.expected_attendees,
                    'status': reservation.status.value
                }
            })
        
        return jsonify({'events': events})
        
    except Exception as e:
        return jsonify({'error': str(e)}), 500