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

from filer.fields.image import FilerImageField
from filer.fields.file import FilerFileField

from apps.account.models import StudentUser


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




class Lesson(models.Model):
    class ContentTypeChoices(models.TextChoices):
        LINK = 'link', 'Link'
        FILE = 'file', 'File'

    course = models.ForeignKey("course.Course", on_delete=models.CASCADE, related_name='lessons', verbose_name='Course')
    title = models.CharField(max_length=255, verbose_name='Lesson Title')
    priority = models.IntegerField(null=True, blank=True, verbose_name='Priority')
    is_active = models.BooleanField(default=True, verbose_name=_('Is Active'))
    duration = models.PositiveIntegerField(verbose_name='Duration (in minutes)')
    content_type = models.CharField(max_length=10, choices=ContentTypeChoices.choices, verbose_name='Content Type')
    content_file = models.FileField(
        null=True,
        blank=True,
        upload_to=lesson_file_upload_to,
    )
    video_link = models.CharField(max_length=500, null=True, blank=True, verbose_name='Video Link')

    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 f"{self.course.title} - {self.title}"

    def is_completed_by(self, student):
        return self.completions.filter(student=student).exists()
    
    

class LessonCompletion(models.Model):
    student = models.ForeignKey(
        StudentUser,
        on_delete=models.CASCADE,
        related_name='lesson_completions'
    )
    lesson = models.ForeignKey(
        Lesson,
        on_delete=models.CASCADE,
        related_name='completions'
    )
    completed_at = models.DateTimeField(auto_now_add=True)
    created_at = models.DateTimeField(auto_now_add=True, verbose_name=_("Created at"))

    class Meta:
        unique_together = ('student', 'lesson') 
        
    def __str__(self):
        return f"{self.student.fullname} - {self.lesson.title} - Completed"