from rest_framework.generics import ListAPIView, RetrieveAPIView
from django.db.models import Count, Q, F
from drf_yasg.utils import swagger_auto_schema
from drf_yasg import openapi
from rest_framework.exceptions import NotFound
from rest_framework.permissions import IsAuthenticated
from rest_framework.filters import SearchFilter


from apps.course.serializers import (
    CourseListSerializer, CourseCategorySerializer, CourseDetailSerializer,
    CourseAttachmentSerializer, CourseGlossarySerializer, MyCourseListSerializer
)
from apps.course.models import Course, CourseCategory, CourseAttachment, CourseGlossary, Participant
from apps.course.doc import *


class CourseCategoryAPIView(ListAPIView):
    queryset = CourseCategory.objects.all()
    serializer_class = CourseCategorySerializer
    
    @swagger_auto_schema(
        operation_description=doc_course_category(),
    )
    def get(self, request, *args, **kwargs):
        return super().get(request, *args, **kwargs)        
    
        
    

class CourseListAPIView(ListAPIView):
    serializer_class = CourseListSerializer
    filter_backends = [SearchFilter]
    search_fields = ['title', 'category__name', 'professor__fullname']

    def get_queryset(self):
        """
        Optimized queryset with select_related for ForeignKey relationships
        """
        return Course.objects.select_related(
            'category',
            'professor'
        ).exclude(status=Course.StatusChoices.INACTIVE)

    @swagger_auto_schema(
    operation_description=doc_course_list(),
    manual_parameters=[
        openapi.Parameter(
            'search', openapi.IN_QUERY,
            description="Search by course title, category name, or professor's full name",
            type=openapi.TYPE_STRING,
        ),
        openapi.Parameter(
            'category_slug', openapi.IN_QUERY,
            description="Category of the Course",
            type=openapi.TYPE_STRING,
            # enum=[category.slug for category in CourseCategory.objects.all()]
        ),
        openapi.Parameter(
            'status', openapi.IN_QUERY,
            type=openapi.TYPE_STRING,
            description="""Status => 
            Upcoming (visible but registration not allowed)---Предстоящие
            Registering (registration is open)---регистрация
            Ongoing (course has started, registration closed)---Впроцессе
            Finished (course has ended)---закончился
            """,
            enum=[status for status in ['upcoming', 'registering', 'ongoing', 'finished']]
        ),
        openapi.Parameter(
            'is_free', openapi.IN_QUERY,
            description="Ценообразование is_free <bool>",
            type=openapi.TYPE_BOOLEAN,
        ),
        openapi.Parameter(
            'is_online', openapi.IN_QUERY,
            description="Статус участия is_online <bool>",
            type=openapi.TYPE_BOOLEAN,
        ),
    ])
    def get(self, request, *args, **kwargs):
        return super().get(request, *args, **kwargs)        
        
    def get_queryset(self):
        queryset = super().get_queryset()
        request = self.request
        filters = request.query_params
            
        # Handle category_slug with multiple values separated by commas
        if category_slugs := filters.get('category_slug'):
            category_slugs_list = category_slugs.split(',')
            queryset = queryset.filter(category__slug__in=category_slugs_list)

        # Handle status with multiple values separated by commas
        if statuses := filters.get('status'):
            statuses_list = statuses.split(',')
            queryset = queryset.filter(status__in=statuses_list)
        
        if is_free := filters.get('is_free'):
            is_free = is_free.lower() == 'true'
            queryset = queryset.filter(
                Q(is_free=is_free) | Q(price=0) if is_free else Q(is_free=False, price__gt=0)
            )
        if is_online := filters.get('is_online'):
            is_online = is_online.lower() == 'true'
            queryset = queryset.filter(is_online=is_online)
            
        return queryset
    
    
    
    
    
class CourseDetailAPIView(RetrieveAPIView):
    serializer_class = CourseDetailSerializer
    lookup_field = "slug"

    def get_queryset(self):
        """
        Optimized queryset with select_related and prefetch_related for all relationships
        """
        return Course.objects.select_related(
            'category',
            'professor'
        ).prefetch_related(
            'lessons__lesson',
            'lessons__completions',
            'attachments__attachment',
            'glossaries__glossary',
            'participants__student',
            'room_messages'
        )

    @swagger_auto_schema(
        operation_description=doc_course_detail(),
    )
    def get(self, request, *args, **kwargs):
        return super().get(request, *args, **kwargs)        
        

class MyCourseListAPIView(ListAPIView):
    serializer_class = MyCourseListSerializer
    permission_classes = [IsAuthenticated]  

    @swagger_auto_schema(manual_parameters=[
        openapi.Parameter(
            'completed', openapi.IN_QUERY,
            description="мои курсы completed <bool> true",
            type=openapi.TYPE_BOOLEAN,
        ),
        openapi.Parameter(
            'certificate', openapi.IN_QUERY,
            type=openapi.TYPE_BOOLEAN,
        ),
    ],
    operation_description=doc_courses_my_courses(),
    operation_summary="Home",

    )
    def get(self, request, *args, **kwargs):
        print(f'--> my-course-> {request}/ {kwargs}')
        return super().get(request, *args, **kwargs)        
        
    def get_queryset(self):
        """
        Optimized queryset for user's courses with select_related and prefetch_related
        """
        queryset = Course.objects.select_related(
            'category',
            'professor'
        ).prefetch_related(
            'lessons__lesson',
            'lessons__completions',
            'participants__student'
        ).exclude(status=Course.StatusChoices.INACTIVE)

        request = self.request
        filters = request.query_params
        student = self.request.user
        qs = queryset.filter(participants__student=student)
        completed_only = filters.get('completed', '').lower() == 'true'
        if completed_only == True:
            # نمایش دوره‌هایی که همه درس‌هایشان توسط کاربر تکمیل شده‌اند
            qs = qs.annotate(
                total_lessons=Count('lessons', distinct=True),
                completed_lessons=Count(
                    'lessons__completions',
                    filter=Q(lessons__completions__student=student),
                    distinct=True
                )
            ).filter(total_lessons=F('completed_lessons'))
        elif completed_only == False:
            # نمایش دوره‌هایی که همه درس‌هایشان تکمیل نشده‌اند
            qs = qs.annotate(
                total_lessons=Count('lessons', distinct=True),
                completed_lessons=Count(
                    'lessons__completions',
                    filter=Q(lessons__completions__student=student),
                    distinct=True
                )
            ).filter(total_lessons__gt=F('completed_lessons'))

        if 'completed' not in filters:
            certificate = filters.get('certificate', '').lower() == 'true'
            if certificate:
                qs = qs.exclude(
                    course_certificates__student=student,
                    course_certificates__status__in=['pending', 'approved']
                )
            
        return qs

    


class AttachmentListAPIView(ListAPIView):
    serializer_class = CourseAttachmentSerializer
    
    @swagger_auto_schema(
        manual_parameters=[
            openapi.Parameter(
                'slug', openapi.IN_PATH,
                description="Slug of the Course",
                type=openapi.TYPE_STRING,
                required=True  
            )
        ],
        operation_description="Retrieve a list of attachments for a given course by its slug."
    )
    def get(self, request, *args, **kwargs):
        return super().get(request, *args, **kwargs)

    def get_queryset(self):
        """
        Optimized queryset with select_related for attachment relationship
        """
        course_slug = self.kwargs.get('slug')
        try:
            course = Course.objects.get(slug=course_slug)
        except Course.DoesNotExist:
            raise NotFound("Course not found")
        return CourseAttachment.objects.select_related(
            'course',
            'attachment'
        ).filter(course=course)
    
    


class GlossaryListAPIView(ListAPIView):
    serializer_class = CourseGlossarySerializer
    filter_backends = [SearchFilter] 
    search_fields = ['glossary__title', 'glossary__description']
    
    def get_queryset(self):
        """
        Optimized queryset with select_related for glossary relationship
        """
        course_slug = self.kwargs.get('slug')
        try:
            course = Course.objects.get(slug=course_slug)
        except Course.DoesNotExist:
            raise NotFound("Course not found")

        return CourseGlossary.objects.select_related(
            'course',
            'glossary'
        ).filter(course=course)