from django.core.management.base import BaseCommand
from django.db.models import Q
from apps.quiz.models import Quiz
from apps.course.models import CourseLesson


class Command(BaseCommand):
    help = "Sync lesson_number for all quizzes connected to a lesson."

    def add_arguments(self, parser):
        parser.add_argument(
            '--dry-run',
            action='store_true',
            help='Preview updates without saving changes.',
        )

    def handle(self, *args, **options):
        dry_run = options['dry_run']
        updated_quizzes = 0

        # We filter quizzes that have a lesson assigned
        quizzes = Quiz.objects.filter(lesson__isnull=False)

        for quiz in quizzes:
            lesson = quiz.lesson
            course = quiz.course or lesson.course

            if not course:
                self.stdout.write(
                    self.style.WARNING(f"Quiz {quiz.id} has lesson {lesson.id} but no associated course found.")
                )
                continue

            # Find all active lessons for this course to calculate position
            lessons_list = list(CourseLesson.objects.filter(
                course=course,
                is_active=True
            ).filter(
                Q(chapter__isnull=True) | Q(chapter__is_active=True)
            ).order_by('chapter__priority', 'priority'))

            try:
                pos = lessons_list.index(lesson) + 1
            except ValueError:
                # Lesson might not be active, or not in the course's active list
                self.stdout.write(
                    self.style.WARNING(
                        f"Quiz {quiz.id}: Lesson {lesson.id} is not active or not in course active list. Skipping."
                    )
                )
                continue

            needs_update = False
            update_fields = []

            if quiz.lesson_number != pos:
                self.stdout.write(
                    f"Quiz {quiz.id}: lesson_number {quiz.lesson_number} -> {pos}"
                )
                quiz.lesson_number = pos
                needs_update = True
                update_fields.append('lesson_number')

            if not quiz.course:
                self.stdout.write(f"Quiz {quiz.id}: setting course to {course.id}")
                quiz.course = course
                needs_update = True
                update_fields.append('course')

            if needs_update:
                updated_quizzes += 1
                if not dry_run:
                    quiz.save(update_fields=update_fields)

        if dry_run:
            self.stdout.write(
                self.style.WARNING(
                    f"Dry run complete. {updated_quizzes} quiz(zes) would be updated."
                )
            )
        else:
            self.stdout.write(
                self.style.SUCCESS(
                    f"Sync complete. {updated_quizzes} quiz(zes) updated."
                )
            )