Dovodi_Backend/apps/course/models/course.py

import os
from decimal import Decimal
import math
from django.db import models
from django.db.models import TextChoices
from django.utils.translation import gettext_lazy as _

from apps.account.models import ProfessorUser
from utils.schema import default_timing
from utils import generate_slug_for_model



def course_file_upload_to(instance, filename):
    return os.path.join(f"courses/{instance.slug}/videos/{filename}")



def attachment_file_upload_to(instance, filename):
    return os.path.join(f"courses/{instance.course.slug}/attachments/{filename}")




class CourseCategory(models.Model):
    name = models.CharField(max_length=255, verbose_name='Category Name')
    slug = models.SlugField(unique=True, max_length=255)

    def __str__(self):
        return self.name

    def save(self, *args, **kwargs):
        if not self.slug:
            self.slug = generate_slug_for_model(CourseCategory, self.name)
        super().save(*args, **kwargs)

    @property
    def course_count(self):
        return self.courses.exclude(status="inactive").count()

class Course(models.Model):
    
    class LevelChoices(TextChoices):
        BEGINNER = 'beginner', 'Beginner'
        MID = 'mid', 'Mid Level'
        ADVANCED = 'advanced', 'Advanced'
        
    class StatusChoices(TextChoices):
        INACTIVE = 'inactive', 'Inactive'  # Not Active (does not show)
        UPCOMING = 'upcoming', 'Upcoming'  # Upcoming (visible but registration not allowed)-Предстоящие
        REGISTERING = 'registering', 'Registering'  # Registering (registration is open)-регистрация
        ONGOING = 'ongoing', 'Ongoing'  # Ongoing (course has started, registration closed)-В процессе
        FINISHED = 'finished', 'Finished'  # Finished (course has ended)-закончился

    class VedioTypeChoices(models.TextChoices):
        YOUTUBE_LINK = 'youtube_link', 'Youtube Link'
        VIDEO_FILE = 'video_file', 'Video File'


    title = models.CharField(max_length=255, verbose_name='Course Title')
    slug = models.SlugField(allow_unicode=True, unique=True)
    category = models.ForeignKey(CourseCategory, on_delete=models.CASCADE, related_name='courses', verbose_name='Category')
    professor = models.ForeignKey(
        ProfessorUser,
        on_delete=models.CASCADE,
        related_name="courses"
    )
    
    thumbnail = models.ImageField(upload_to="courses/thumbnails/", null=True, blank=True, verbose_name=_('Thumbnail'))
    video_type = models.CharField(
        max_length=20, 
        choices=VedioTypeChoices.choices, 
        verbose_name='Preview Video Type (YouTube Link or File Upload)'
    )
    video_file = models.FileField(
        upload_to=course_file_upload_to,
        null=True,
        blank=True
    )
    video_link = models.CharField(max_length=500, null=True, blank=True)

    is_online = models.BooleanField(default=False, verbose_name='Is Online Course')
    online_link = models.CharField(max_length=500, null=True, blank=True, verbose_name='Online Class Link')
    level = models.CharField(max_length=10, choices=LevelChoices.choices, verbose_name='Course Level')
    duration = models.PositiveIntegerField(verbose_name='Duration (in hours)')
    lessons_count = models.PositiveIntegerField(verbose_name='Number of Lessons')
    
    description = models.TextField(verbose_name='Course Description')
    short_description = models.CharField(max_length=500, blank=True, null=True, verbose_name="Short Description")
    status = models.CharField(max_length=15, choices=StatusChoices.choices, default=StatusChoices.INACTIVE, verbose_name='Course Status')
    is_free = models.BooleanField(default=True, verbose_name='Is Free')
    price = models.DecimalField(max_digits=10, decimal_places=2, default=0.00, verbose_name='Course Price')
    discount_percentage = models.PositiveIntegerField(default=0, verbose_name='Discount Percentage')
    final_price = models.DecimalField(
        verbose_name=_('Course Final Price'), decimal_places=2, max_digits=10, default=0.00, blank=True,
        help_text=_('This field is automatically calculated based on the discount percentage.')
    )
    
    timing = models.JSONField(blank=True, null=True, default=default_timing, verbose_name=_("Timing"))
    features  = models.JSONField(verbose_name=_('Course features'), default=dict, blank=True, null=True)
    created_at = models.DateTimeField(auto_now_add=True, verbose_name=_("Created at"))
    updated_at = models.DateTimeField(auto_now=True, verbose_name=_("Updated At"))


    def __str__(self):
        return self.title

    def get_completed_lessons_count(self, student):
        return self.lessons.filter(completions__student=student).count()

    def is_student_participant(self, student):
        return self.participants.filter(student=student).exists()


    def save(self, *args, **kwargs):
        if not self.slug:
            self.slug = generate_slug_for_model(Course, self.title)

        if self.discount_percentage > 0:
            discount_amount = (self.price * self.discount_percentage) / 100
            final_price = self.price - discount_amount
            self.final_price = Decimal(math.ceil(final_price)).quantize(Decimal('0.00'))
        else:
            self.final_price = Decimal(math.ceil(self.price)).quantize(Decimal('0.00'))

        super().save(*args, **kwargs)


    class Meta:
        verbose_name = "Course"
        verbose_name_plural = "Courses"



class Glossary(models.Model):
    course = models.ForeignKey(Course, on_delete=models.CASCADE, related_name='glossaries', verbose_name='Course')
    title = models.CharField(max_length=555, verbose_name='Glossary Title')
    description = models.TextField(verbose_name='Description')

    def __str__(self):
        return f"{self.course.title} - {self.title}"


    class Meta:
        ordering = ("-id",)
        verbose_name = "Glossary"
        verbose_name_plural = "Glossary"



class Attachment(models.Model):
    course = models.ForeignKey(Course, on_delete=models.CASCADE, related_name='attachments', verbose_name='Course')
    title = models.CharField(max_length=255, verbose_name='Attachment Title')
    file = models.FileField(
        upload_to=attachment_file_upload_to,
        verbose_name='Attachment File'
    )

    file_size = models.PositiveIntegerField(verbose_name='File Size (in bytes)', null=True, blank=True)

    def save(self, *args, **kwargs):
        # Calculate the file size before saving
        if self.file and not self.file_size:
            self.file_size = self.file.size
        super().save(*args, **kwargs)
        
        
    def __str__(self):
        return f"{self.course.title} - {self.title}"
    
    class Meta:
        ordering = ("-id",)
        verbose_name = "Attachment"
        verbose_name_plural = "Attachments"