from rest_framework import serializers
from drf_spectacular.utils import extend_schema_field, OpenApiTypes
from apps.lms.models import (
    Course,
    CourseModule,
    Lesson,
    QuizQuestion,
    CourseEnrollment,
    LessonProgress,
    DigitalCertificate,
)


class QuizQuestionStudentSerializer(serializers.ModelSerializer):
    class Meta:
        model = QuizQuestion
        fields = ['id', 'question_text', 'options', 'order']


class QuizQuestionAdminSerializer(serializers.ModelSerializer):
    class Meta:
        model = QuizQuestion
        fields = ['id', 'question_text', 'options', 'correct_option_index', 'explanation', 'order']


class LessonListSerializer(serializers.ModelSerializer):
    is_completed = serializers.SerializerMethodField()

    class Meta:
        model = Lesson
        fields = [
            'id', 'title', 'slug', 'lesson_type',
            'duration_minutes', 'order', 'is_preview',
            'is_completed',
        ]

    @extend_schema_field(OpenApiTypes.BOOL)
    def get_is_completed(self, obj) -> bool:
        request = self.context.get('request')
        if request and request.user and request.user.is_authenticated:
            return LessonProgress.objects.filter(
                user=request.user,
                lesson=obj,
                is_completed=True
            ).exists()
        return False


class LessonDetailSerializer(serializers.ModelSerializer):
    quiz_questions = serializers.SerializerMethodField()
    is_completed = serializers.SerializerMethodField()
    quiz_score = serializers.SerializerMethodField()

    class Meta:
        model = Lesson
        fields = [
            'id', 'title', 'slug', 'lesson_type',
            'duration_minutes', 'video_url', 'content',
            'slides_attachment', 'order', 'is_preview',
            'quiz_questions', 'is_completed', 'quiz_score',
        ]

    @extend_schema_field(QuizQuestionStudentSerializer(many=True))
    def get_quiz_questions(self, obj):
        questions = obj.quiz_questions.all().order_by('order', 'id')
        request = self.context.get('request')
        if request and request.user and request.user.is_authenticated and (request.user.is_staff or getattr(request.user, 'is_super_admin', False)):
            return QuizQuestionAdminSerializer(questions, many=True).data
        return QuizQuestionStudentSerializer(questions, many=True).data

    @extend_schema_field(OpenApiTypes.BOOL)
    def get_is_completed(self, obj) -> bool:
        request = self.context.get('request')
        if request and request.user and request.user.is_authenticated:
            progress = LessonProgress.objects.filter(user=request.user, lesson=obj).first()
            return progress.is_completed if progress else False
        return False

    @extend_schema_field(OpenApiTypes.FLOAT)
    def get_quiz_score(self, obj):
        request = self.context.get('request')
        if request and request.user and request.user.is_authenticated:
            progress = LessonProgress.objects.filter(user=request.user, lesson=obj).first()
            return progress.quiz_score if progress else None
        return None


class CourseModuleSerializer(serializers.ModelSerializer):
    lessons = LessonListSerializer(many=True, read_only=True)

    class Meta:
        model = CourseModule
        fields = ['id', 'title', 'description', 'order', 'lessons']


class CourseListSerializer(serializers.ModelSerializer):
    total_lessons = serializers.IntegerField(source='total_lessons_count', read_only=True)
    total_students = serializers.IntegerField(source='total_students_count', read_only=True)
    is_enrolled = serializers.SerializerMethodField()
    progress_percentage = serializers.SerializerMethodField()

    class Meta:
        model = Course
        fields = [
            'id', 'title', 'slug', 'category', 'language',
            'level', 'cover_image', 'instructor_name',
            'instructor_title', 'instructor_avatar',
            'organization_name', 'duration_hours', 'rating',
            'reviews_count', 'is_featured', 'total_lessons',
            'total_students', 'is_enrolled', 'progress_percentage',
            'created_at',
        ]

    @extend_schema_field(OpenApiTypes.BOOL)
    def get_is_enrolled(self, obj) -> bool:
        request = self.context.get('request')
        if request and request.user and request.user.is_authenticated:
            return CourseEnrollment.objects.filter(user=request.user, course=obj).exists()
        return False

    @extend_schema_field(OpenApiTypes.INT)
    def get_progress_percentage(self, obj) -> int:
        request = self.context.get('request')
        if request and request.user and request.user.is_authenticated:
            enrollment = CourseEnrollment.objects.filter(user=request.user, course=obj).first()
            return enrollment.progress_percentage if enrollment else 0
        return 0


class CourseDetailSerializer(serializers.ModelSerializer):
    modules = CourseModuleSerializer(many=True, read_only=True)
    total_lessons = serializers.IntegerField(source='total_lessons_count', read_only=True)
    total_students = serializers.IntegerField(source='total_students_count', read_only=True)
    is_enrolled = serializers.SerializerMethodField()
    progress_percentage = serializers.SerializerMethodField()
    certificate_code = serializers.SerializerMethodField()

    class Meta:
        model = Course
        fields = [
            'id', 'title', 'slug', 'category', 'language',
            'level', 'cover_image', 'instructor_name',
            'instructor_title', 'instructor_avatar',
            'institution', 'organization_name', 'description',
            'duration_hours', 'rating', 'reviews_count',
            'is_published', 'is_featured', 'modules',
            'total_lessons', 'total_students',
            'is_enrolled', 'progress_percentage', 'certificate_code',
            'created_at', 'updated_at',
        ]

    @extend_schema_field(OpenApiTypes.BOOL)
    def get_is_enrolled(self, obj) -> bool:
        request = self.context.get('request')
        if request and request.user and request.user.is_authenticated:
            return CourseEnrollment.objects.filter(user=request.user, course=obj).exists()
        return False

    @extend_schema_field(OpenApiTypes.INT)
    def get_progress_percentage(self, obj) -> int:
        request = self.context.get('request')
        if request and request.user and request.user.is_authenticated:
            enrollment = CourseEnrollment.objects.filter(user=request.user, course=obj).first()
            return enrollment.progress_percentage if enrollment else 0
        return 0

    @extend_schema_field(OpenApiTypes.STR)
    def get_certificate_code(self, obj):
        request = self.context.get('request')
        if request and request.user and request.user.is_authenticated:
            cert = DigitalCertificate.objects.filter(user=request.user, course=obj).first()
            return cert.certificate_code if cert else None
        return None


class CourseCreateUpdateSerializer(serializers.ModelSerializer):
    class Meta:
        model = Course
        fields = [
            'id', 'title', 'category', 'language', 'level',
            'cover_image', 'instructor_name', 'instructor_title',
            'instructor_avatar', 'institution', 'organization_name',
            'description', 'duration_hours', 'is_published', 'is_featured',
        ]


class SingleQuizAnswerSerializer(serializers.Serializer):
    question_id = serializers.IntegerField()
    selected_option = serializers.IntegerField()


class QuizSubmitRequestSerializer(serializers.Serializer):
    answers = SingleQuizAnswerSerializer(many=True)


class QuizQuestionResultItemSerializer(serializers.Serializer):
    question_id = serializers.IntegerField()
    is_correct = serializers.BooleanField()
    selected_option = serializers.IntegerField()
    correct_option = serializers.IntegerField()
    explanation = serializers.CharField(allow_blank=True, allow_null=True)


class QuizResultSerializer(serializers.Serializer):
    score = serializers.FloatField(help_text="Percentage score achieved (0-100)")
    passed = serializers.BooleanField(help_text="True if score >= 70%")
    total_questions = serializers.IntegerField()
    correct_count = serializers.IntegerField()
    question_results = QuizQuestionResultItemSerializer(many=True)
    is_lesson_completed = serializers.BooleanField()
    course_progress_percentage = serializers.IntegerField()
    certificate_code = serializers.CharField(allow_null=True, required=False)


class LessonCompleteResponseSerializer(serializers.Serializer):
    message = serializers.CharField()
    lesson_id = serializers.IntegerField()
    is_completed = serializers.BooleanField()
    course_progress_percentage = serializers.IntegerField()
    certificate_code = serializers.CharField(allow_null=True, required=False)


class CourseProgressSerializer(serializers.Serializer):
    course_id = serializers.IntegerField()
    course_title = serializers.CharField()
    progress_percentage = serializers.IntegerField()
    completed_lessons_count = serializers.IntegerField()
    total_lessons_count = serializers.IntegerField()
    is_completed = serializers.BooleanField()
    certificate_code = serializers.CharField(allow_null=True)


class DigitalCertificateSerializer(serializers.ModelSerializer):
    course_title = serializers.CharField(source='course.title', read_only=True)
    course_slug = serializers.CharField(source='course.slug', read_only=True)
    recipient_name = serializers.CharField(source='user.get_full_name', read_only=True)
    organization = serializers.CharField(source='course.organization_name', read_only=True)

    class Meta:
        model = DigitalCertificate
        fields = [
            'id', 'certificate_code', 'uuid',
            'recipient_name', 'course_title', 'course_slug',
            'organization', 'issue_date', 'final_score',
            'certificate_file', 'is_revoked', 'created_at',
        ]


class PublicCertificateVerifySerializer(serializers.Serializer):
    certificate_code = serializers.CharField()
    uuid = serializers.UUIDField()
    recipient_name = serializers.CharField()
    course_title = serializers.CharField()
    organization = serializers.CharField(allow_null=True)
    issue_date = serializers.DateField()
    final_score = serializers.FloatField()
    is_valid = serializers.BooleanField()