server: add implies/suggests named filters

Add new named filters:
- suggests:     find tags that suggest the search criteria
- suggested-by: find tags that are suggested by the search criteria
- implies:      find tags that imply the search criteria
- implied-by:   find tags that are implied by the search criteria

server/szurubooru/search/configs/tag_search_config.py

@@ -96,6 +96,50 @@ class TagSearchConfig(BaseSearchConfig):
                     ["implication-count"],
                     search_util.create_num_filter(model.Tag.implication_count),
                 ),
+                (
+                    ["suggested-by"],
+                    search_util.create_nested_filter(
+                        model.Tag.tag_id,
+                        model.TagSuggestion.child_id,
+                        model.TagSuggestion.parent_id,
+                        model.TagName.tag_id,
+                        model.TagName.name,
+                        search_util.create_str_filter,
+                    ),
+                ),
+                (
+                    ["suggests"],
+                    search_util.create_nested_filter(
+                        model.Tag.tag_id,
+                        model.TagSuggestion.parent_id,
+                        model.TagSuggestion.child_id,
+                        model.TagName.tag_id,
+                        model.TagName.name,
+                        search_util.create_str_filter,
+                    ),
+                ),
+                (
+                    ["implied-by"],
+                    search_util.create_nested_filter(
+                        model.Tag.tag_id,
+                        model.TagImplication.child_id,
+                        model.TagImplication.parent_id,
+                        model.TagName.tag_id,
+                        model.TagName.name,
+                        search_util.create_str_filter,
+                    ),
+                ),
+                (
+                    ["implies"],
+                    search_util.create_nested_filter(
+                        model.Tag.tag_id,
+                        model.TagImplication.parent_id,
+                        model.TagImplication.child_id,
+                        model.TagName.tag_id,
+                        model.TagName.name,
+                        search_util.create_str_filter,
+                    ),
+                ),
             ]
         )
 

server/szurubooru/search/configs/util.py

@@ -226,3 +226,38 @@ def create_subquery_filter(
         return query.filter(expression)
 
     return wrapper
+
+
+def create_nested_filter(
+    left_id_column: SaColumn,
+    right_id_column: SaColumn,
+    filter_column: SaColumn,
+    nested_id_column: SaColumn,
+    nested_filter_column: SaColumn,
+    filter_factory: SaColumn,
+    subquery_decorator: Callable[[SaQuery], None] = None,
+) -> Filter:
+    filter_func = filter_factory(nested_filter_column)
+
+    def wrapper(
+        query: SaQuery,
+        criterion: Optional[criteria.BaseCriterion],
+        negated: bool,
+    ) -> SaQuery:
+        assert criterion
+        nested = db.session.query(nested_id_column.label("foreign_id"))
+        nested = nested.options(sa.orm.lazyload("*"))
+        nested = filter_func(nested, criterion, False)
+        nested = nested.subquery("t")
+        subquery = db.session.query(right_id_column.label("foreign_id"))
+        if subquery_decorator:
+            subquery = subquery_decorator(subquery)
+        subquery = subquery.options(sa.orm.lazyload("*"))
+        subquery = subquery.filter(filter_column.in_(nested))
+        subquery = subquery.subquery("t")
+        expression = left_id_column.in_(subquery)
+        if negated:
+            expression = ~expression
+        return query.filter(expression)
+
+    return wrapper