317 lines
11 KiB
Python
317 lines
11 KiB
Python
from io import BytesIO
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from typing import Optional, Sequence
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from uuid import uuid4
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from django.conf import settings
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from django.core.exceptions import ValidationError
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from django.core.files.base import ContentFile
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from django.db import models
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from django.utils import timezone
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from PIL import Image, ImageDraw, ImageFont
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from events.models import Registration
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from users.models import User
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from utils.models import BaseModel
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SHORT_CERTIFICATE_CODE_LENGTH = 10
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def _generate_certificate_code() -> str:
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return uuid4().hex[:SHORT_CERTIFICATE_CODE_LENGTH]
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class Skill(BaseModel):
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name = models.CharField(max_length=120, unique=True)
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description = models.TextField(blank=True)
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class Meta:
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ordering = ['name']
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def __str__(self):
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return self.name
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class CertificateTemplate(BaseModel):
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event = models.OneToOneField(
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'events.Event',
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on_delete=models.CASCADE,
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related_name='certificate_template',
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)
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image = models.ImageField(upload_to='certificates/templates/')
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skills = models.ManyToManyField(
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Skill,
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blank=True,
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related_name='certificate_templates',
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help_text='Skills covered by this event.',
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)
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class Meta:
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verbose_name = 'Certificate template'
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verbose_name_plural = 'Certificate templates'
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def __str__(self):
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return f'{self.event.title} template'
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def _validate_score(self, score: Optional[int]) -> int:
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"""Normalize score values and ensure they stay within 0-100."""
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if score is None:
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raise ValidationError("Score is required")
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try:
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normalized = int(score)
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except (TypeError, ValueError):
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raise ValidationError("Score must be an integer between 0 and 100")
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if normalized < 0 or normalized > 100:
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raise ValidationError("Score must be between 0 and 100")
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return normalized
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def _resolve_skill_ids(self, skill_ids: Optional[Sequence[int]]) -> list[int]:
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"""Return a cleaned list of skill IDs, defaulting to the template skills."""
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if skill_ids is None:
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return list(self.skills.values_list('id', flat=True))
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normalized = []
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seen = set()
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for skill_id in skill_ids:
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if skill_id is None:
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continue
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try:
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skill_int = int(skill_id)
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except (TypeError, ValueError):
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continue
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if skill_int not in seen:
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seen.add(skill_int)
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normalized.append(skill_int)
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if not normalized:
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return []
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existing = set(Skill.objects.filter(id__in=normalized).values_list('id', flat=True))
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missing = set(normalized) - existing
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if missing:
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raise ValidationError(f"Skills not found: {', '.join(str(mid) for mid in sorted(missing))}")
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return normalized
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def _ensure_user_registration(self, user: User) -> Registration:
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"""Require that the user has a confirmed or attended registration for the event."""
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registration = Registration.objects.filter(
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event=self.event,
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user=user,
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status__in=[
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Registration.StatusChoices.CONFIRMED,
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Registration.StatusChoices.ATTENDED,
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],
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is_deleted=False,
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).order_by('-registered_at').first()
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if not registration:
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raise ValidationError("User must have a confirmed or attended registration for this event.")
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return registration
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def _load_font(self, size: int = 48):
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try:
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return ImageFont.truetype("arial.ttf", size)
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except Exception:
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return ImageFont.load_default()
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def _render_certificate_image(self, certificate: 'UserCertificate') -> None:
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"""Overlay user-specific text on the template image and attach it to the certificate."""
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if not self.image:
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return
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try:
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template_path = self.image.path
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except (AttributeError, ValueError):
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return
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try:
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base_image = Image.open(template_path).convert("RGB")
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except FileNotFoundError:
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return
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draw = ImageDraw.Draw(base_image)
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font = self._load_font(size=48)
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width, height = base_image.size
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lines = [
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certificate.user.get_full_name() or certificate.user.email,
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self.event.title,
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f"Score: {certificate.score} ({certificate.score_label})",
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timezone.localtime(certificate.issued_at).strftime('%Y-%m-%d'),
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]
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margin = 40
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total_height = 0
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measurements = []
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for line in lines:
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bbox = draw.textbbox((0, 0), line, font=font)
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line_height = bbox[3] - bbox[1]
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line_width = bbox[2] - bbox[0]
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measurements.append((line, line_width, line_height))
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total_height += line_height + 10
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y = height - margin - total_height
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for line, line_width, line_height in measurements:
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x = (width - line_width) / 2
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draw.text((x, y), line, fill='black', font=font)
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y += line_height + 10
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buffer = BytesIO()
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base_image.save(buffer, format='PNG')
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buffer.seek(0)
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filename = f"{self.event.slug}_{certificate.user_id}_{uuid4().hex}.png"
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certificate.image.save(filename, ContentFile(buffer.read()), save=False)
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certificate.save(update_fields=['image'])
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def award_certificate(
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self,
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*,
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user: User,
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title: str,
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description: str = '',
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score: Optional[int] = None,
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skill_ids: Optional[Sequence[int]] = None,
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issued_at=None,
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expires_at=None,
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) -> 'UserCertificate':
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"""
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Create or update the certificate for a single user.
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"""
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self._ensure_user_registration(user)
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resolved_score = self._validate_score(score)
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resolved_skills = self._resolve_skill_ids(skill_ids)
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issued_at = issued_at or timezone.now()
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title = title or f"{self.event.title} Certificate"
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description = description or ''
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certificate, _ = UserCertificate.objects.update_or_create(
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user=user,
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event=self.event,
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defaults={
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'template': self,
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'title': title,
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'description': description,
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'score': resolved_score,
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'issued_at': issued_at,
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'expires_at': expires_at,
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},
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)
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certificate.skills.set(resolved_skills)
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self._render_certificate_image(certificate)
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return certificate
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def generate_certificates(
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self,
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entries: Sequence[dict],
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*,
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default_title: Optional[str] = None,
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default_description: Optional[str] = None,
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) -> list['UserCertificate']:
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"""
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Create certificates for a batch of users.
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Entries expect dicts with at least `user_id` and `score`.
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"""
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if not entries:
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raise ValidationError("Entries payload must contain at least one item.")
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user_ids = {entry.get('user_id') for entry in entries if entry.get('user_id') is not None}
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if not user_ids:
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raise ValidationError("No valid user IDs were provided.")
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users = {user.id: user for user in User.objects.filter(id__in=user_ids)}
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missing = user_ids - users.keys()
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if missing:
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raise ValidationError(f"Users not found: {', '.join(str(uid) for uid in sorted(missing))}")
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certificates = []
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for entry in entries:
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user = users.get(entry.get('user_id'))
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if not user:
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continue
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certificate = self.award_certificate(
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user=user,
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title=entry.get('title') or default_title or f"{self.event.title} Certificate",
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description=entry.get('description') or default_description or '',
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score=entry.get('score'),
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skill_ids=entry.get('skill_ids'),
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issued_at=entry.get('issued_at'),
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expires_at=entry.get('expires_at'),
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)
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certificates.append(certificate)
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return certificates
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class UserCertificate(BaseModel):
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SCORE_RANGES = [
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(0, 24, 'Fair'),
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(25, 49, 'Good'),
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(50, 74, 'Very Good'),
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(75, 100, 'Perfect'),
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]
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user = models.ForeignKey(
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settings.AUTH_USER_MODEL,
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on_delete=models.CASCADE,
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related_name='certificates',
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)
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event = models.ForeignKey(
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'events.Event',
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on_delete=models.CASCADE,
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related_name='user_certificates',
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)
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template = models.ForeignKey(
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CertificateTemplate,
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on_delete=models.PROTECT,
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related_name='awarded_certificates',
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)
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certificate_id = models.UUIDField(default=uuid4, unique=True, editable=False)
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code = models.CharField(
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max_length=SHORT_CERTIFICATE_CODE_LENGTH,
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unique=True,
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editable=False,
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default=_generate_certificate_code,
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)
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title = models.CharField(max_length=255)
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description = models.TextField(blank=True)
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score = models.PositiveSmallIntegerField(default=0)
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issued_at = models.DateTimeField(default=timezone.now)
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expires_at = models.DateTimeField(null=True, blank=True)
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image = models.ImageField(
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upload_to='certificates/generated/',
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null=True,
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blank=True,
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)
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skills = models.ManyToManyField(
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Skill,
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blank=True,
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related_name='user_certificates',
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help_text='Skills demonstrated on this certificate.',
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)
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class Meta:
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unique_together = ('user', 'event')
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ordering = ['-issued_at']
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indexes = [
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models.Index(fields=['user', 'event']),
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models.Index(fields=['event', 'score']),
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]
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def __str__(self):
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return f'{self.user} - {self.title} ({self.certificate_id})'
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@property
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def score_label(self) -> str:
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for lower, upper, label in self.SCORE_RANGES:
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if lower <= self.score <= upper:
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return label
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return 'Unknown'
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@staticmethod
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def _make_unique_code() -> str:
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"""Generate a short certificate code without collisions."""
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for _ in range(5):
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candidate = _generate_certificate_code()
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if not UserCertificate.objects.filter(code=candidate).exists():
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return candidate
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raise RuntimeError("Unable to generate a unique certificate code.")
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def save(self, *args, **kwargs):
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if not self.code or UserCertificate.objects.filter(code=self.code).exclude(pk=self.pk).exists():
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self.code = self._make_unique_code()
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super().save(*args, **kwargs)
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