from django.db import models
from django.utils import timezone
from django.utils.translation import gettext_lazy as _

from apps.account.models import 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")
    )

    is_locked = models.BooleanField(
        default=False, 
        verbose_name=_("Is Locked"),
        help_text=_("If True, only the professor and admins can send new messages.")
    )
    room_type = models.CharField(
        max_length=10,
        choices=RoomTypeChoices.choices,
        default=RoomTypeChoices.GROUP,
        verbose_name=_("Room Type")
    )
    unread_messages_count = models.IntegerField(default=0, verbose_name=_("Unread Messages Count"))

    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 Meta:
        verbose_name = _("Room Message")
        verbose_name_plural = _("Room Messages")


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, verbose_name=_("Message Metadata"))
    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 Meta:
        verbose_name = _("Chat Message")
        verbose_name_plural = _("Chat Messages")
    
            
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
        verbose_name = _("Message Read Status")
        verbose_name_plural = _("Message Read Statuses")

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