server: search term similar posts applies sort automatically

2 files changed, 50 insertions, 14 deletions

diff --git a/server/szurubooru/search/configs/post_search_config.py b/server/szurubooru/search/configs/post_search_config.py
index c8eed18..4b2c8bb 100644
--- a/server/szurubooru/search/configs/post_search_config.py
+++ b/server/szurubooru/search/configs/post_search_config.py
@@ -122,29 +122,40 @@ def _pool_filter(
     )(query, criterion, negated)
 
 
-# includes the given post itself
+# includes the given post itself, also applies sort
 def _similar_filter(
     query: SaQuery, criterion: Optional[criteria.BaseCriterion], negated: bool
 ) -> SaQuery:
     assert criterion
-    # subquery for tags of the given post (post id in criterion)
     filter_func_tag = search_util.create_num_filter(model.PostTag.post_id)
+    pt_alias = sa.orm.aliased(model.PostTag)
+
+    # subquery for tags of the given post (post id in criterion)
     tag_query = db.session.query(model.PostTag.tag_id)
     tag_query = filter_func_tag(tag_query, criterion, False)
     tag_query = tag_query.subquery("source_tags")
 
-    # subquery for posts with matching tags
-    pt_alias = sa.orm.aliased(model.PostTag)
-    subquery = (
-        db.session.query(pt_alias.post_id)
-        .filter(pt_alias.tag_id.in_(tag_query))
-        .group_by(pt_alias.post_id)
-        .subquery("similar_posts")
-    )
-    expr = model.Post.post_id.in_(subquery)
     if negated:
-        expr = ~expr
-    return query.filter(expr)
+        # negated query runs normally, doesn't apply sort
+        subquery = (
+            db.session.query(pt_alias.post_id)
+            .filter(pt_alias.tag_id.in_(tag_query))
+            .group_by(pt_alias.post_id)
+            .subquery("similar_posts")
+        )
+        expr = model.Post.post_id.in_(subquery)
+        return query.filter(~expr)
+    else:
+        # direct query applies sort
+        subquery = query.subquery("main_query")
+        return (
+            db.session.query(model.Post)
+            .join(pt_alias, pt_alias.post_id == model.Post.post_id)
+            .filter(pt_alias.tag_id.in_(tag_query))
+            .group_by(model.Post.post_id)
+            .join(subquery, pt_alias.post_id == subquery.c.id)
+            .order_by(sa.func.count(pt_alias.tag_id).desc())
+        )
 
 
 def _create_metric_num_filter(name: str):
diff --git a/server/szurubooru/tests/search/configs/test_post_search_config.py b/server/szurubooru/tests/search/configs/test_post_search_config.py
index 3a347de..c9f2408 100644
--- a/server/szurubooru/tests/search/configs/test_post_search_config.py
+++ b/server/szurubooru/tests/search/configs/test_post_search_config.py
@@ -971,7 +971,7 @@ def test_around_query(
     ("similar:1", [6, 4, 1]),
     ("similar:2", [6, 5, 4, 2]),
     ("similar:3", [6, 5, 3]),
-    ("similar:4", [6, 5, 4, 2, 1]),
+    ("similar:4", [6, 4, 5, 2, 1]),
     ("similar:5", [6, 5, 4, 3, 2]),
     ("similar:6", [6, 5, 4, 3, 2, 1]),
     ("-similar:1", [5, 3, 2]),
@@ -980,6 +980,9 @@ def test_around_query(
     ("-similar:4", [3]),
     ("-similar:5", [1]),
     ("-similar:6", []),
+    ("similar:4 sort:id,asc", [4, 6, 1, 2, 5]),
+    ("similar:4 b", [6, 4, 5, 2]),
+    ("similar:4 c", [6, 5]),
 ])
 def test_filter_by_similar(
     post_factory, tag_factory, verify_unpaged, input, expected_post_ids
@@ -998,3 +1001,25 @@ def test_filter_by_similar(
     )
     db.session.flush()
     verify_unpaged(input, expected_post_ids, True)
+
+
+
+@pytest.mark.parametrize("input,expected_post_ids", [
+    ("similar:1", [3, 1, 2]),
+    ("similar:2", [3, 2, 1]),
+    ("similar:3", [3, 1, 2]),
+])
+def test_sort_by_similar(
+    post_factory, tag_factory, verify_unpaged, input, expected_post_ids
+):
+    tagA = tag_factory(names=["a"])
+    tagB = tag_factory(names=["b"])
+    tagC = tag_factory(names=["c"])
+    postAB = post_factory(id=1, tags=[tagA, tagB])
+    postA = post_factory(id=2, tags=[tagA])
+    postABC = post_factory(id=3, tags=[tagA, tagB, tagC])
+    db.session.add_all(
+        [tagA, tagB, tagC, postA,postAB, postABC]
+    )
+    db.session.flush()
+    verify_unpaged(input, expected_post_ids, True)