Dovodi_Backend/apps/chat/models.py

from django.db import models
from django.utils import timezone

from apps.account.models import User, User
from apps.course.models import Course


def chat_upload_path(instance, filename):
    """
    Generate upload path for chat attachments
    Format: chat/room_{room_id}/YYYY/MM/DD/filename
    """
    date = timezone.now()
    return f'chat/room_{instance.room_id}/{date.year}/{date.month:02d}/{date.day:02d}/{filename}'



class RoomMessage(models.Model):
    class RoomTypeChoices(models.TextChoices):
        GROUP = 'group', 'Group'
        PRIVATE = 'private', 'Private'

    name = models.CharField(
        max_length=255,
        verbose_name="Room Name"
    )
    description = models.TextField(
        verbose_name="Description",
        blank=True,
        null=True
    )
    course = models.ForeignKey(Course,on_delete=models.CASCADE, null=True, blank=True ,related_name="room_messages", verbose_name="Course")    
    initiator = models.ForeignKey(
        User,
        on_delete=models.CASCADE,
        related_name="initiated_rooms",
        verbose_name="Initiator"
    )
    recipient = models.ForeignKey(
        User,
        on_delete=models.CASCADE,
        related_name="messages_received",
        verbose_name="Recipient",
        null=True,  
        blank=True
    )    
    created_at = models.DateTimeField(auto_now_add=True, verbose_name="Created At")
    updated_at = models.DateTimeField(
        auto_now=True,
        verbose_name="Updated At"
    )
    room_type = models.CharField(
        max_length=10,
        choices=RoomTypeChoices.choices,
        default=RoomTypeChoices.GROUP,
        verbose_name="Room Type"
    )
    unread_messages_count = models.IntegerField(default=0)

    def __str__(self):
        if self.room_type == self.RoomTypeChoices.GROUP:
            return f"Group Room: {self.course.title if self.course else 'N/A'}"
        return f"Private Room with {self.recipient}"
    
    

class ChatMessage(models.Model):
    class ChatTypeChoices(models.TextChoices):
        TEXT = 'text', 'Text'
        FILE = 'file', 'File'
        AUDIO = 'audio', 'Audio'
        IMAGE = 'image', 'Image'  
    
    room = models.ForeignKey(
        RoomMessage,  
        on_delete=models.CASCADE,
        related_name="messages",
        verbose_name="Room",
    )
    sender = models.ForeignKey(
        User,
        on_delete=models.CASCADE,
        related_name="messages_sent",
        verbose_name="Sender"
    )
    content = models.TextField(verbose_name="Message Content")
    content_type = models.CharField(
        max_length=10,
        choices=ChatTypeChoices.choices,
        default=ChatTypeChoices.TEXT,
        verbose_name="Chat Type"
    )
    content_size = models.PositiveIntegerField(
        verbose_name="Content Size (bytes)",
        blank=True,
        null=True
    )
    file_attachment = models.FileField(
        upload_to=chat_upload_path,
        blank=True,
        null=True,
        max_length=500,
        verbose_name="File Attachment",
        help_text="For file and audio messages"
    )
    image_attachment = models.ImageField(
        upload_to=chat_upload_path,
        blank=True,
        null=True,
        max_length=500,
        verbose_name="Image Attachment",
        help_text="For image messages"
    )
    is_read = models.BooleanField(default=False, verbose_name="Is Read")
    message_metadata = models.JSONField(blank=True, null=True)
    sent_at = models.DateTimeField(auto_now_add=True, verbose_name="Sent At")        
    updated_at = models.DateTimeField(auto_now=True, verbose_name="Updated At")
    deleted_at = models.DateTimeField(null=True, blank=True, verbose_name="Deleted At")
    is_deleted = models.BooleanField(default=False, verbose_name="Is deleted")    
    
    @property
    def file_url(self):
        """
        Get file URL - works for both old and new messages
        For backward compatibility with messages using content field
        """
        if self.image_attachment:
            return self.image_attachment.url
        elif self.file_attachment:
            return self.file_attachment.url
        elif self.content and self.content_type != 'text':
            # Legacy messages with URL in content field
            return self.content
        return None
    
    def delete(self, *args, **kwargs):
        """Override delete to remove uploaded files"""
        if self.file_attachment:
            self.file_attachment.delete(save=False)
        if self.image_attachment:
            self.image_attachment.delete(save=False)
        super().delete(*args, **kwargs)
    
    def __str__(self):
        return f"Message from {self.sender} in {self.room}"
    
            
class MessageReadStatus(models.Model):
    user = models.ForeignKey(
        User,
        on_delete=models.CASCADE,
        related_name="read_statuses",
        verbose_name="User"
    )
    message = models.ForeignKey(
        ChatMessage,
        on_delete=models.CASCADE,
        related_name="read_statuses",
        verbose_name="Message"
    )
    is_read = models.BooleanField(default=False, verbose_name="Is Read")
    read_at = models.DateTimeField(null=True, blank=True, verbose_name="Read At")

    class Meta:
        unique_together = ("user", "message")  # جلوگیری از ثبت تکراری

    def __str__(self):
        return f"User {self.user.fullname} read Message {self.message.id}: {self.is_read}"