Completed backend intern assignment including conversation summaries,PostgreSQL migration, scheduled cleanup, and file upload/list/delete APIs with duplicate prevention –jayaramknss@gmail.com

backend/backend/__init__.py

@@ -0,0 +1,3 @@
+from .celery import app as celery_app
+
+__all__ = ('celery_app',)

backend/backend/celery.py

@@ -0,0 +1,27 @@
+import os
+from celery import Celery
+from celery.schedules import crontab
+
+os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'backend.settings')
+
+
+app = Celery('backend')
+app.config_from_object('django.conf:settings', namespace='CELERY')
+app.autodiscover_tasks()
+
+# Celery Beat Schedule
+app.conf.beat_schedule = {
+    'cleanup-old-conversations': {
+        'task': 'chat.tasks.cleanup_old_conversations',
+        'schedule': crontab(hour=2, minute=0),  # Daily at 2 AM
+        'args': (30,)  # Delete conversations older than 30 days
+    },
+    'generate-missing-summaries': {
+        'task': 'chat.tasks.generate_missing_summaries',
+        'schedule': crontab(hour=3, minute=0),  # Daily at 3 AM
+    },
+}
+
+@app.task(bind=True)
+def debug_task(self):
+    print(f'Request: {self.request!r}')

backend/backend/settings.py

@@ -15,17 +15,19 @@
 
 from dotenv import load_dotenv
 
-load_dotenv()
+
 
 # Build paths inside the project like this: BASE_DIR / 'subdir'.
 BASE_DIR = Path(__file__).resolve().parent.parent
+load_dotenv(os.path.join(BASE_DIR, ".env"))
 
 # Quick-start development settings - unsuitable for production
 # See https://docs.djangoproject.com/en/4.2/howto/deployment/checklist/
 
 # SECURITY WARNING: keep the secret key used in production secret!
-SECRET_KEY = os.environ["DJANGO_SECRET_KEY"]
-FRONTEND_URL = os.environ["FRONTEND_URL"]
+SECRET_KEY = os.environ.get("DJANGO_SECRET_KEY", "fallback-secret-key") 
+print("SECRET:", os.environ.get("DJANGO_SECRET_KEY"))   
+FRONTEND_URL = os.environ.get("FRONTEND_URL", "http://localhost:3000")
 
 # SECURITY WARNING: don't run with debug turned on in production!
 DEBUG = True
@@ -85,9 +87,13 @@
 # https://docs.djangoproject.com/en/4.2/ref/settings/#databases
 
 DATABASES = {
-    "default": {
-        "ENGINE": "django.db.backends.sqlite3",
-        "NAME": BASE_DIR / "db.sqlite3",
+    'default': {
+        'ENGINE': 'django.db.backends.postgresql',
+        'NAME': 'chatgpt_db',
+        'USER': 'chatgpt_user',
+        'PASSWORD': 'chatgpt_password',
+        'HOST': 'localhost',
+        'PORT': '5432',
     }
 }
 
@@ -149,3 +155,13 @@
 SESSION_COOKIE_SECURE = True
 CSRF_COOKIE_SECURE = True
 CSRF_COOKIE_SAMESITE = "None"
+
+# Celery Configuration
+CELERY_BROKER_URL = os.getenv('CELERY_BROKER_URL', 'redis://localhost:6379/0')
+CELERY_RESULT_BACKEND = os.getenv('CELERY_RESULT_BACKEND', 'redis://localhost:6379/0')
+CELERY_ACCEPT_CONTENT = ['json']
+CELERY_TASK_SERIALIZER = 'json'
+CELERY_RESULT_SERIALIZER = 'json'
+CELERY_TIMEZONE = 'UTC'
+CELERY_TASK_TRACK_STARTED = True
+CELERY_TASK_TIME_LIMIT = 30 * 60  # 30 minutes

backend/chat/admin.py

@@ -1,7 +1,7 @@
 from django.contrib import admin
 from django.utils import timezone
 from nested_admin.nested import NestedModelAdmin, NestedStackedInline, NestedTabularInline
-
+from django.utils.html import format_html
 from chat.models import Conversation, Message, Role, Version
 
 
@@ -51,8 +51,8 @@ def queryset(self, request, queryset):
 class ConversationAdmin(NestedModelAdmin):
     actions = ["undelete_selected", "soft_delete_selected"]
     inlines = [VersionInline]
-    list_display = ("title", "id", "created_at", "modified_at", "deleted_at", "version_count", "is_deleted", "user")
-    list_filter = (DeletedListFilter,)
+    list_display = ("title", "id", "created_at", "modified_at", "deleted_at", "version_count", "is_deleted",  "has_summary", "summary_status", "user")
+    list_filter = (DeletedListFilter,"is_summary_stale",)
     ordering = ("-modified_at",)
 
     def undelete_selected(self, request, queryset):
@@ -79,7 +79,27 @@ def is_deleted(self, obj):
 
     is_deleted.boolean = True
     is_deleted.short_description = "Deleted?"
-
+    def has_summary(self, obj):
+        """Display if conversation has summary"""
+        if obj.summary:
+            return format_html(
+                '<span style="color: green;">✓ Has Summary</span>'
+            )
+        return format_html(
+            '<span style="color: red;">✗ No Summary</span>'
+        )
+    has_summary.short_description = "Summary Status"
+
+    def summary_status(self, obj):
+        """Show if summary is stale"""
+        if obj.is_summary_stale:
+            return format_html(
+                '<span style="color: orange;">Stale</span>'
+            )
+        return format_html(
+            '<span style="color: green;">Current</span>'
+        )
+    summary_status.short_description = "Summary Freshness"
 
 class VersionAdmin(NestedModelAdmin):
     inlines = [MessageInline]

backend/chat/apps.py

@@ -4,3 +4,6 @@
 class ChatConfig(AppConfig):
     default_auto_field = "django.db.models.BigAutoField"
     name = "chat"
+
+    def ready(self):
+        import chat.signals

backend/chat/management/commands/cleanup_conversations.py

@@ -0,0 +1,68 @@
+from django.core.management.base import BaseCommand
+from django.utils.timezone import now
+from django.db.models import Count
+from datetime import timedelta
+from chat.models import Conversation
+import logging
+
+logger = logging.getLogger(__name__)
+
+class Command(BaseCommand):
+    help = 'Clean up old conversations based on age'
+
+    def add_arguments(self, parser):
+        parser.add_argument(
+            '--days',
+            type=int,
+            default=30,
+            help='Delete conversations older than specified days (default: 30)'
+        )
+        parser.add_argument(
+            '--dry-run',
+            action='store_true',
+            help='Show what would be deleted without actually deleting'
+        )
+        parser.add_argument(
+            '--user',
+            type=str,
+            help='Only delete conversations for specific user'
+        )
+
+    def handle(self, *args, **options):
+        days = options['days']
+        dry_run = options['dry_run']
+        user_filter = options.get('user')
+
+        cutoff_date = now() - timedelta(days=days)
+        queryset = Conversation.objects.filter(created_at__lt=cutoff_date)
+
+        if user_filter:
+            queryset = queryset.filter(user__username=user_filter)
+
+        count = queryset.count()
+
+        if count == 0:
+            self.stdout.write(
+                self.style.WARNING('No conversations found matching criteria')
+            )
+            return
+
+        self.stdout.write(f"Conversations to delete: {count}\n")
+
+        if dry_run:
+            self.stdout.write(self.style.WARNING('DRY RUN - No deletions made\n'))
+            for conv in queryset[:5]:
+                self.stdout.write(
+                    f"  - {conv.title} ({conv.messages.count()} messages)"
+                )
+            return
+
+        confirm = input(f"Delete {count} conversations? (yes/no): ")
+
+        if confirm.lower() == 'yes':
+            deleted_count = queryset.delete()[0]
+            self.stdout.write(
+                self.style.SUCCESS(f'✓ Deleted {deleted_count} conversations')
+            )
+        else:
+            self.stdout.write(self.style.WARNING('Deletion cancelled'))

backend/chat/migrations/0002_activitylog_filepermission_uploadedfile_userrole_and_more.py

@@ -0,0 +1,162 @@
+# Generated by Django 5.2.11 on 2026-02-28 06:51
+
+import django.db.models.deletion
+import uuid
+from django.conf import settings
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('chat', '0001_initial'),
+        migrations.swappable_dependency(settings.AUTH_USER_MODEL),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='ActivityLog',
+            fields=[
+                ('id', models.UUIDField(default=uuid.uuid4, editable=False, primary_key=True, serialize=False)),
+                ('action', models.CharField(choices=[('file_upload', 'File Upload'), ('file_delete', 'File Delete'), ('file_access', 'File Access'), ('conversation_create', 'Conversation Create'), ('conversation_delete', 'Conversation Delete'), ('conversation_edit', 'Conversation Edit'), ('message_send', 'Message Send'), ('summary_generate', 'Summary Generate'), ('summary_regenerate', 'Summary Regenerate')], max_length=50)),
+                ('resource_type', models.CharField(max_length=50)),
+                ('resource_id', models.CharField(blank=True, max_length=100, null=True)),
+                ('details', models.JSONField(blank=True, default=dict)),
+                ('ip_address', models.GenericIPAddressField(blank=True, null=True)),
+                ('user_agent', models.TextField(blank=True)),
+                ('status', models.CharField(choices=[('success', 'Success'), ('failed', 'Failed')], default='success', max_length=20)),
+                ('timestamp', models.DateTimeField(auto_now_add=True, db_index=True)),
+            ],
+            options={
+                'ordering': ['-timestamp'],
+            },
+        ),
+        migrations.CreateModel(
+            name='FilePermission',
+            fields=[
+                ('id', models.UUIDField(default=uuid.uuid4, editable=False, primary_key=True, serialize=False)),
+                ('permission', models.CharField(choices=[('view', 'View'), ('upload', 'Upload'), ('delete', 'Delete'), ('share', 'Share')], max_length=20)),
+                ('created_at', models.DateTimeField(auto_now_add=True)),
+            ],
+        ),
+        migrations.CreateModel(
+            name='UploadedFile',
+            fields=[
+                ('id', models.UUIDField(default=uuid.uuid4, editable=False, primary_key=True, serialize=False)),
+                ('file', models.FileField(upload_to='uploads/%Y/%m/%d/')),
+                ('filename', models.CharField(max_length=255)),
+                ('file_size', models.BigIntegerField()),
+                ('file_type', models.CharField(max_length=50)),
+                ('file_hash', models.CharField(max_length=64, unique=True)),
+                ('status', models.CharField(choices=[('pending', 'Pending'), ('processing', 'Processing'), ('completed', 'Completed'), ('failed', 'Failed')], default='pending', max_length=20)),
+                ('uploaded_at', models.DateTimeField(auto_now_add=True)),
+                ('processed_at', models.DateTimeField(blank=True, null=True)),
+                ('error_message', models.TextField(blank=True, null=True)),
+                ('mime_type', models.CharField(blank=True, max_length=100, null=True)),
+                ('page_count', models.IntegerField(blank=True, null=True)),
+                ('is_indexed', models.BooleanField(default=False)),
+            ],
+            options={
+                'ordering': ['-uploaded_at'],
+            },
+        ),
+        migrations.CreateModel(
+            name='UserRole',
+            fields=[
+                ('id', models.UUIDField(default=uuid.uuid4, editable=False, primary_key=True, serialize=False)),
+                ('role', models.CharField(choices=[('user', 'Regular User'), ('moderator', 'Moderator'), ('admin', 'Administrator')], default='user', max_length=20)),
+                ('created_at', models.DateTimeField(auto_now_add=True)),
+                ('updated_at', models.DateTimeField(auto_now=True)),
+            ],
+        ),
+        migrations.AlterModelOptions(
+            name='conversation',
+            options={'ordering': ['-created_at']},
+        ),
+        migrations.AddField(
+            model_name='conversation',
+            name='is_summary_stale',
+            field=models.BooleanField(default=False, help_text='Indicates if summary needs to be regenerated'),
+        ),
+        migrations.AddField(
+            model_name='conversation',
+            name='summary',
+            field=models.TextField(blank=True, help_text='Auto-generated summary of the conversation', null=True),
+        ),
+        migrations.AddField(
+            model_name='conversation',
+            name='summary_generated_at',
+            field=models.DateTimeField(blank=True, help_text='Timestamp when summary was generated', null=True),
+        ),
+        migrations.AddIndex(
+            model_name='conversation',
+            index=models.Index(fields=['user', '-created_at'], name='chat_conver_user_id_49b34c_idx'),
+        ),
+        migrations.AddIndex(
+            model_name='conversation',
+            index=models.Index(fields=['is_summary_stale'], name='chat_conver_is_summ_c1de9d_idx'),
+        ),
+        migrations.AddField(
+            model_name='activitylog',
+            name='user',
+            field=models.ForeignKey(null=True, on_delete=django.db.models.deletion.SET_NULL, related_name='activity_logs', to=settings.AUTH_USER_MODEL),
+        ),
+        migrations.AddField(
+            model_name='filepermission',
+            name='granted_by',
+            field=models.ForeignKey(null=True, on_delete=django.db.models.deletion.SET_NULL, related_name='granted_permissions', to=settings.AUTH_USER_MODEL),
+        ),
+        migrations.AddField(
+            model_name='filepermission',
+            name='user',
+            field=models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='file_permissions', to=settings.AUTH_USER_MODEL),
+        ),
+        migrations.AddField(
+            model_name='uploadedfile',
+            name='conversation',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.SET_NULL, related_name='files', to='chat.conversation'),
+        ),
+        migrations.AddField(
+            model_name='uploadedfile',
+            name='user',
+            field=models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='uploaded_files', to=settings.AUTH_USER_MODEL),
+        ),
+        migrations.AddField(
+            model_name='filepermission',
+            name='file',
+            field=models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='permissions', to='chat.uploadedfile'),
+        ),
+        migrations.AddField(
+            model_name='userrole',
+            name='user',
+            field=models.OneToOneField(on_delete=django.db.models.deletion.CASCADE, related_name='role_profile', to=settings.AUTH_USER_MODEL),
+        ),
+        migrations.AddIndex(
+            model_name='activitylog',
+            index=models.Index(fields=['user', '-timestamp'], name='chat_activi_user_id_a7ffef_idx'),
+        ),
+        migrations.AddIndex(
+            model_name='activitylog',
+            index=models.Index(fields=['action', '-timestamp'], name='chat_activi_action_c91d2c_idx'),
+        ),
+        migrations.AddIndex(
+            model_name='activitylog',
+            index=models.Index(fields=['resource_type', 'resource_id'], name='chat_activi_resourc_9d4685_idx'),
+        ),
+        migrations.AddIndex(
+            model_name='uploadedfile',
+            index=models.Index(fields=['user', '-uploaded_at'], name='chat_upload_user_id_618957_idx'),
+        ),
+        migrations.AddIndex(
+            model_name='uploadedfile',
+            index=models.Index(fields=['file_hash'], name='chat_upload_file_ha_43c6d5_idx'),
+        ),
+        migrations.AddIndex(
+            model_name='uploadedfile',
+            index=models.Index(fields=['status'], name='chat_upload_status_97172d_idx'),
+        ),
+        migrations.AlterUniqueTogether(
+            name='filepermission',
+            unique_together={('user', 'file', 'permission')},
+        ),
+    ]