from django.db import models

class Document(models.Model):
    title = models.CharField(max_length=200)
    file = models.FileField(upload_to='documents/')
    uploaded_at = models.DateTimeField(auto_now_add=True)
    
    def __str__(self):
        return self.title

from django.db import models

class Profile(models.Model):
    user = models.OneToOneField('auth.User', on_delete=models.CASCADE)
    avatar = models.ImageField(
        upload_to='avatars/',
        default='avatars/default.jpg',
        help_text='Upload a profile picture'
    )
    bio = models.TextField(blank=True)

from PIL import Image
from django.core.exceptions import ValidationError

def validate_image_size(image):
    """Custom validator for image dimensions"""
    if image:
        with Image.open(image) as img:
            if img.width > 1920 or img.height > 1080:
                raise ValidationError('Image dimensions cannot exceed 1920x1080 pixels.')

class Photo(models.Model):
    title = models.CharField(max_length=100)
    image = models.ImageField(
        upload_to='photos/',
        validators=[validate_image_size]
    )

def user_directory_path(instance, filename):
    """File will be uploaded to MEDIA_ROOT/user_<id>/<filename>"""
    return f'user_{instance.user.id}/{filename}'

def date_directory_path(instance, filename):
    """Organize files by date"""
    from datetime import datetime
    return f'uploads/{datetime.now().strftime("%Y/%m/%d")}/{filename}'

class UserFile(models.Model):
    user = models.ForeignKey('auth.User', on_delete=models.CASCADE)
    file = models.FileField(upload_to=user_directory_path)
    
class DatedUpload(models.Model):
    name = models.CharField(max_length=100)
    file = models.FileField(upload_to=date_directory_path)

import os
from django.core.exceptions import ValidationError

def validate_file_extension(value):
    """Validate file extension"""
    ext = os.path.splitext(value.name)[1]
    valid_extensions = ['.pdf', '.doc', '.docx', '.txt']
    if not ext.lower() in valid_extensions:
        raise ValidationError('Unsupported file extension.')

def validate_file_size(value):
    """Validate file size (max 5MB)"""
    filesize = value.size
    if filesize > 5 * 1024 * 1024:  # 5MB
        raise ValidationError("File size cannot exceed 5MB.")

class Document(models.Model):
    title = models.CharField(max_length=200)
    file = models.FileField(
        upload_to='documents/',
        validators=[validate_file_extension, validate_file_size]
    )

# In views or templates
document = Document.objects.get(pk=1)

# File URL
file_url = document.file.url

# File path
file_path = document.file.path

# File name
filename = document.file.name

# File size
file_size = document.file.size

# Check if file exists
if document.file:
    print(f"File exists: {document.file.name}")

from django.core.files import File
from django.core.files.base import ContentFile

# Assign existing file
with open('/path/to/file.pdf', 'rb') as f:
    document = Document()
    document.title = "My Document"
    document.file.save('document.pdf', File(f))

# Create file from content
content = b"This is file content"
document = Document()
document.title = "Generated Document"
document.file.save('generated.txt', ContentFile(content))

class Article(models.Model):
    title = models.CharField(max_length=200)
    content = models.TextField()
    
    # Different file types
    featured_image = models.ImageField(
        upload_to='articles/images/',
        blank=True,
        null=True
    )
    pdf_version = models.FileField(
        upload_to='articles/pdfs/',
        blank=True,
        null=True,
        validators=[validate_pdf_extension]
    )
    attachments = models.ManyToManyField(
        'Attachment',
        blank=True
    )

class Attachment(models.Model):
    name = models.CharField(max_length=100)
    file = models.FileField(upload_to='attachments/')
    uploaded_at = models.DateTimeField(auto_now_add=True)

class MediaFile(models.Model):
    file = models.FileField(
        upload_to='media/',
        max_length=255,           # Max filename length
        blank=True,               # Allow empty in forms
        null=True,                # Allow NULL in database
        default='default.jpg',    # Default file
        help_text='Upload a file', # Form help text
        verbose_name='Media File' # Admin display name
    )

from django.core.files.storage import default_storage
from myapp.storage import CustomStorage

class Document(models.Model):
    # Use default storage
    file1 = models.FileField(upload_to='docs/')
    
    # Use custom storage
    file2 = models.FileField(
        upload_to='docs/',
        storage=CustomStorage()
    )