from flask import Blueprint, render_template, abort
from flask_login import login_required, current_user
from app import db
from app.models.subject import Commission
from app.models.enrollment import StudentEnrollment
from app.models.classroom import Classroom

my_subjects_bp = Blueprint('my_subjects', __name__, url_prefix='/mis-materias')


@my_subjects_bp.route('/')
@login_required
def my_subjects_list():
    """Show the commissions assigned to the current user (teacher or student)."""
    role = current_user.get_institutional_role()

    commissions = []

    if role in ['admin', 'bedelia']:
        # Admin/Bedelia: see all active commissions
        commissions = (
            Commission.query
            .filter_by(active=True)
            .order_by(Commission.year.desc(), Commission.semester.asc(), Commission.code.asc())
            .all()
        )
        view_mode = 'all'

    elif role == 'docente':
        # Teacher: only commissions where they are assigned as teacher
        commissions = (
            Commission.query
            .filter_by(teacher_id=current_user.id, active=True)
            .order_by(Commission.year.desc(), Commission.semester.asc(), Commission.code.asc())
            .all()
        )
        view_mode = 'teacher'

    elif role == 'alumno':
        # Student: only commissions where they are enrolled
        enrollments = (
            StudentEnrollment.query
            .filter_by(student_id=current_user.id, status='activo')
            .all()
        )
        commission_ids = [e.commission_id for e in enrollments]
        commissions = (
            Commission.query
            .filter(Commission.id.in_(commission_ids), Commission.active == True)
            .order_by(Commission.year.desc(), Commission.semester.asc(), Commission.code.asc())
            .all()
        )
        view_mode = 'student'
    else:
        commissions = []
        view_mode = 'none'

    return render_template(
        'my_subjects/list.html',
        commissions=commissions,
        view_mode=view_mode,
        role=role
    )


@my_subjects_bp.route('/<int:commission_id>')
@login_required
def my_subject_detail(commission_id):
    """Detail view of a single commission for the current user."""
    role = current_user.get_institutional_role()
    commission = Commission.query.get_or_404(commission_id)

    # Access control: make sure the user is allowed to see this commission
    if role in ['admin', 'bedelia']:
        pass  # full access
    elif role == 'docente':
        if commission.teacher_id != current_user.id:
            abort(403)
    elif role == 'alumno':
        enrollment = StudentEnrollment.query.filter_by(
            student_id=current_user.id,
            commission_id=commission_id
        ).first()
        if not enrollment:
            abort(403)
    else:
        abort(403)

    # Get enrolled students (visible to teachers and admin/bedelia)
    enrollments = []
    if role in ['admin', 'bedelia', 'docente']:
        enrollments = (
            StudentEnrollment.query
            .filter_by(commission_id=commission_id)
            .order_by(StudentEnrollment.enrolled_at.asc())
            .all()
        )

    # Try to get classroom info from reservations linked to this commission
    from app.models.reservation import Reservation
    from sqlalchemy import func
    from datetime import datetime

    # Recent or upcoming reservation linked to this commission
    recent_reservation = (
        Reservation.query
        .filter(
            Reservation.commission_id == commission_id,
            Reservation.start_time >= datetime.utcnow()
        )
        .order_by(Reservation.start_time.asc())
        .first()
    )

    classroom = None
    if recent_reservation and recent_reservation.classroom_id:
        classroom = Classroom.query.get(recent_reservation.classroom_id)

    return render_template(
        'my_subjects/detail.html',
        commission=commission,
        enrollments=enrollments,
        classroom=classroom,
        recent_reservation=recent_reservation,
        role=role
    )