from django.db import models
from django.contrib.auth import get_user_model
from django.core.validators import MinValueValidator, MaxValueValidator
from django.db.models import Avg

User = get_user_model()

class Rate(models.Model):
    """
    Rate model for different services like library, podcast, hadith, and video.
    Users can rate content from 1 to 5.
    """
    
    class ServiceChoices(models.TextChoices):
        LIBRARY = 'library', 'Library'
        PODCAST = 'podcast', 'Podcast'
        HADITH = 'hadith', 'Hadith'
        VIDEO = 'video', 'Video'
        VIDEO_PLAYLIST = 'video_playlist', 'Video Playlist'
    
    user = models.ForeignKey(User, on_delete=models.CASCADE, related_name='rates', verbose_name='User')
    service = models.CharField(max_length=20, choices=ServiceChoices.choices, verbose_name='Service')
    content_id = models.PositiveIntegerField(verbose_name='Content ID')
    rate = models.PositiveSmallIntegerField(
        validators=[MinValueValidator(1), MaxValueValidator(5)],
        verbose_name='Rate'
    )
    status = models.BooleanField(default=True, verbose_name='Status')
    created_at = models.DateTimeField(auto_now_add=True, verbose_name='Created At')
    updated_at = models.DateTimeField(auto_now=True, verbose_name='Updated At')
    
    class Meta:
        verbose_name = 'Rate'
        verbose_name_plural = 'Rates'
        unique_together = ('user', 'service', 'content_id')
        
    def __str__(self):
        return f"{self.user.username} - {self.get_service_display()} - {self.content_id} - {self.rate}"
    
    @classmethod
    def get_user_rate(cls, user, service, content_id):
        """
        Get the rate information for a specific content by the user.
        
        Args:
            user: User instance
            service: Service name (library, podcast, hadith, video)
            content_id: ID of the content
            
        Returns:
            Dictionary containing:
            - is_rated: Boolean indicating if the content is rated by the user
            - rate: The rate value given by the user (1-5) or None if not rated
        """
        try:
            rate_obj = cls.objects.get(
                user=user,
                service=service,
                content_id=content_id,
                status=True
            )
            return {
                'is_rated': True,
                'rate': rate_obj.rate
            }
        except cls.DoesNotExist:
            return {
                'is_rated': False,
                'rate': None
            }
    
    @classmethod
    def validate_content_exists(cls, service, content_id):
        """
        Validate if content with the given ID exists in the specified service.
        
        Args:
            service: Service name (library, podcast, hadith, video)
            content_id: ID of the content to validate
            
        Returns:
            Boolean indicating if the content exists
        """
        if service == cls.ServiceChoices.LIBRARY:
            from apps.library.models import Book
            return Book.objects.filter(id=content_id).exists()
        elif service == cls.ServiceChoices.PODCAST:
            from apps.podcast.models import Podcast
            return Podcast.objects.filter(id=content_id).exists()
        elif service == cls.ServiceChoices.HADITH:
            from apps.hadith.models import Hadith
            return Hadith.objects.filter(id=content_id).exists()
        elif service == cls.ServiceChoices.VIDEO:
            from apps.video.models import Video
            return Video.objects.filter(id=content_id).exists()
        elif service == cls.ServiceChoices.VIDEO_PLAYLIST:
            from apps.video.models import VideoPlaylist
            return VideoPlaylist.objects.filter(id=content_id).exists()
        return False
    
    @classmethod
    def get_average_rate(cls, service, content_id):
        """
        Get the average rate for a specific content.
        
        Args:
            service: Service name (library, podcast, hadith, video)
            content_id: ID of the content
            
        Returns:
            Float representing the average rate (1-5) or None if no rates
        """
        result = cls.objects.filter(
            service=service,
            content_id=content_id,
            status=True
        ).aggregate(avg_rate=Avg('rate'))
        
        return result['avg_rate']