Fix deletion of hashtag albums after rescanning images

- also improve performance by adding a new field

api/directory_watcher.py

@@ -12,7 +12,6 @@
 from django.db.models import Q, QuerySet
 from django_q.tasks import AsyncTask
 
-import api.models.album_thing
 import api.util as util
 from api.batch_jobs import create_batch_job
 from api.face_classify import cluster_all_faces
@@ -377,7 +376,7 @@ def scan_photos(user, full_scan, job_id, scan_directory="", scan_files=[]):
 
         place365_instance.unload()
         util.logger.info("Scanned {} files in : {}".format(files_found, scan_directory))
-        api.models.album_thing.update()
+
         util.logger.info("Finished updating album things")
         exisisting_photos = Photo.objects.filter(owner=user.id).order_by("image_hash")
         paginator = Paginator(exisisting_photos, 5000)

api/migrations/0062_albumthing_cover_photos.py

@@ -0,0 +1,19 @@
+# Generated by Django 4.2.11 on 2024-03-29 17:33
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("api", "0061_alter_person_name"),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name="albumthing",
+            name="cover_photos",
+            field=models.ManyToManyField(
+                related_name="album_thing_cover_photos", to="api.photo"
+            ),
+        ),
+    ]

api/migrations/0063_apply_default_album_things_cover.py

@@ -0,0 +1,22 @@
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+    def apply_default(apps, schema_editor):
+        AlbumThing = apps.get_model("api", "AlbumThing")
+
+        for thing in AlbumThing.objects.all():
+            if not thing.cover_photos and thing.photos.count() > 0:
+                thing.cover_photos.add(*thing.photos.all()[:4])
+                thing.save()
+
+    def remove_default(apps, schema_editor):
+        AlbumThing = apps.get_model("api", "AlbumThing")
+        for thing in AlbumThing.objects.all():
+            thing.cover_photos = None
+
+    dependencies = [
+        ("api", "0062_albumthing_cover_photos"),
+    ]
+
+    operations = [migrations.RunPython(apply_default, remove_default)]

api/models/album_thing.py

@@ -1,4 +1,6 @@
-from django.db import connection, models
+from django.db import models
+from django.db.models.signals import m2m_changed
+from django.dispatch import receiver
 
 from api.models.photo import Photo
 from api.models.user import User, get_deleted_user
@@ -14,6 +16,9 @@ class AlbumThing(models.Model):
     )
 
     shared_to = models.ManyToManyField(User, related_name="album_thing_shared_to")
+    cover_photos = models.ManyToManyField(
+        Photo, related_name="album_thing_cover_photos"
+    )
 
     class Meta:
         constraints = [
@@ -22,106 +27,22 @@ class Meta:
             )
         ]
 
+    def _set_default_cover_photo(self):
+        if self.cover_photos.count() < 4:
+            self.cover_photos.add(*self.photos.all()[:4])
+
     def __str__(self):
         return "%d: %s" % (self.id, self.title)
 
 
-def get_album_thing(title, owner):
-    return AlbumThing.objects.get_or_create(title=title, owner=owner)[0]
-
-
-# List all existing (thing / thing type / user)
-view_api_album_thing_sql = """
-    api_albumthing_sql as (
-       select title, 'places365_attribute' thing_type, false favorited, owner_id
-       from (select owner_id, jsonb_array_elements_text(jsonb_extract_path(captions_json,  'places365', 'attributes')) title from api_photo ) photo_attribut
-       group by title, thing_type, favorited, owner_id
-       union all
-       select title, 'places365_category' thing_type, false favorited, owner_id
-       from (select owner_id, jsonb_array_elements_text(jsonb_extract_path(captions_json,  'places365', 'categories')) title from api_photo ) photo_attribut
-       group by title, thing_type, favorited, owner_id
-    )"""
-
-# List all photos per albumThing
-view_api_album_thing_photos_sql = """
-    api_albumthing_photos_sql as (
-       select api_albumthing.id albumthing_id, photo_id
-       from (select owner_id, jsonb_array_elements_text(jsonb_extract_path(captions_json,  'places365', 'attributes')) title, image_hash photo_id, 'places365_attribute' thing_type from api_photo ) photo_attribut
-       join api_albumthing using (title,thing_type, owner_id )
-       group by api_albumthing.id, photo_id
-       union all
-       select api_albumthing.id albumthing_id, photo_id
-       from (select owner_id, jsonb_array_elements_text(jsonb_extract_path(captions_json,  'places365', 'categories')) title, image_hash photo_id, 'places365_category' thing_type from api_photo ) photo_attribut
-       join api_albumthing using (title,thing_type, owner_id )
-       group by api_albumthing.id, photo_id
-    )
-"""
-
-
-def create_new_album_thing(cursor):
-    """This function create albums from all detected thing on photos"""
-    SQL = """
-        with {}
-        insert into api_albumthing (title, thing_type,favorited, owner_id)
-        select api_albumthing_sql.*
-        from api_albumthing_sql
-        left join api_albumthing using (title, thing_type, owner_id)
-        where  api_albumthing is null;
-    """.replace(
-        "{}", view_api_album_thing_sql
-    )
-    cursor.execute(SQL)
-
-
-def create_new_album_thing_photo(cursor):
-    """This function create link between albums thing and photo from all detected thing on photos"""
-    SQL = """
-        with {}
-        insert into api_albumthing_photos (albumthing_id, photo_id)
-        select api_albumthing_photos_sql.*
-        from api_albumthing_photos_sql
-        left join api_albumthing_photos using (albumthing_id, photo_id)
-        where  api_albumthing_photos is null;
-    """.replace(
-        "{}", view_api_album_thing_photos_sql
-    )
-    cursor.execute(SQL)
-
-
-def delete_album_thing_photo(cursor):
-    """This function delete photos form albums thing where thing disappears"""
-    SQL = """
-        with {}
-        delete
-        from api_albumthing_photos as p
-        where not exists (
-            select 1
-            from api_albumthing_photos_sql
-            where albumthing_id = p.albumthing_id
-                and photo_id = p.photo_id
-            limit 1
-        )
-    """.replace(
-        "{}", view_api_album_thing_photos_sql
-    )
-    cursor.execute(SQL)
-
-
-def delete_album_thing(cursor):
-    """This function delete albums thing without photos"""
-    SQL = """
-        with {}
-        delete from api_albumthing
-        where (title, thing_type, owner_id) not in ( select title, thing_type, owner_id from api_albumthing_sql );
-    """.replace(
-        "{}", view_api_album_thing_sql
-    )
-    cursor.execute(SQL)
+@receiver(m2m_changed, sender=AlbumThing.photos.through)
+def update_default_cover_photo(sender, instance, action, **kwargs):
+    if action == "post_add":
+        instance._set_default_cover_photo()
+        instance.save()
 
 
-def update():
-    with connection.cursor() as cursor:
-        create_new_album_thing(cursor)
-        create_new_album_thing_photo(cursor)
-        delete_album_thing_photo(cursor)
-        delete_album_thing(cursor)
+def get_album_thing(title, owner, thing_type=None):
+    return AlbumThing.objects.get_or_create(
+        title=title, owner=owner, thing_type=thing_type
+    )[0]

api/models/photo.py

@@ -244,11 +244,10 @@ def _save_captions(self, commit=True, caption=None):
 
             for hashtag in hashtags:
                 album_thing = api.models.album_thing.get_album_thing(
-                    title=hashtag, owner=self.owner
+                    title=hashtag, owner=self.owner, thing_type="hashtag_attribute"
                 )
                 if album_thing.photos.filter(image_hash=self.image_hash).count() == 0:
                     album_thing.photos.add(self)
-                    album_thing.thing_type = "hashtag_attribute"
                     album_thing.save()
 
             for album_thing in api.models.album_thing.AlbumThing.objects.filter(
@@ -286,6 +285,36 @@ def _generate_captions(self, commit):
                 self.search_captions = " , ".join(
                     res_places365["categories"] + [res_places365["environment"]]
                 )
+
+            # Add to album things, when photo is not yet in any album thing with type places365_attribute or places365_category
+            if api.models.album_thing.AlbumThing.objects.filter(
+                Q(photos__in=[self.image_hash])
+                & (
+                    Q(thing_type="places365_attribute")
+                    or Q(thing_type="places365_category")
+                )
+                & Q(owner=self.owner)
+            ).exists():
+                return
+
+            for attribute in res_places365["attributes"]:
+                album_thing = api.models.album_thing.get_album_thing(
+                    title=attribute,
+                    owner=self.owner,
+                    thing_type="places365_attribute",
+                )
+                album_thing.photos.add(self)
+                album_thing.save()
+
+            for category in res_places365["categories"]:
+                album_thing = api.models.album_thing.get_album_thing(
+                    title=category,
+                    owner=self.owner,
+                    thing_type="places365_category",
+                )
+                album_thing.photos.add(self)
+                album_thing.save()
+
             if commit:
                 self.save()
             util.logger.info(

api/serializers/album_thing.py

@@ -41,7 +41,14 @@ class AlbumThingListSerializer(serializers.ModelSerializer):
 
     class Meta:
         model = AlbumThing
-        fields = ("id", "cover_photos", "title", "photo_count", "thing_type")
+        fields = (
+            "id",
+            "cover_photos",
+            "title",
+            "photo_count",
+            "thing_type",
+            "cover_photos",
+        )
 
     def get_photo_count(self, obj) -> int:
         return obj.photo_count

api/views/albums.py

@@ -171,7 +171,6 @@ def list(self, *args, **kwargs):
         return Response({"results": serializer.data})
 
 
-# To-Do: Make album_cover an actual database field to improve performance
 # To-Do: Could be literally the list command in AlbumThingViewSet
 class AlbumThingListViewSet(ListViewSet):
     serializer_class = AlbumThingListSerializer
@@ -183,17 +182,9 @@ def get_queryset(self):
         if self.request.user.is_anonymous:
             return AlbumThing.objects.none()
 
-        cover_photos_query = Photo.objects.filter(hidden=False).only(
-            "image_hash", "video"
-        )
-
         queryset = (
             AlbumThing.objects.filter(owner=self.request.user)
-            .prefetch_related(
-                Prefetch(
-                    "photos", queryset=cover_photos_query[:4], to_attr="cover_photos"
-                )
-            )
+            .prefetch_related("cover_photos")
             .annotate(
                 photo_count=Count(
                     Case(