feat: extend operational investigation workflows

app/native/wndb/gis/network_views.py

@@ -1,4 +1,4 @@
-"""Read-only projections backed by the GIS materialized-view query layer."""
+"""Read-only GIS projections and authoritative network topology snapshots."""
 
 from typing import Any
 
@@ -69,6 +69,46 @@ def get_network_link_nodes(name: str) -> list[str]:
     ]
 
 
+def get_valve_isolation_topology(name: str) -> tuple[list[str], list[str], list[str]]:
+    """Read links, closed statuses and sources from one consistent SQL snapshot.
+
+    Isolation must include model links without published geometries, and use
+    initial statuses rather than treating every link as open. UNION ALL keeps
+    source nodes in the same statement snapshot without repeating them for
+    every link or relying on materialized view refresh timing.
+    """
+    rows = read_all(
+        name,
+        """
+        SELECT l.id, l.link_type::text AS element_type,
+               l.start_node_id, l.end_node_id,
+               COALESCE(s.status::text, p.status::text) AS status
+        FROM network.links AS l
+        LEFT JOIN network.pipes AS p ON p.link_id = l.id
+        LEFT JOIN network.link_initial_settings AS s ON s.link_id = l.id
+        UNION ALL
+        SELECT n.id, n.node_type::text AS element_type,
+               NULL, NULL, NULL
+        FROM network.nodes AS n
+        WHERE n.node_type::text IN ('reservoir', 'tank')
+        """,
+    )
+    link_entries: list[str] = []
+    source_nodes: list[str] = []
+    closed_links: list[str] = []
+    for row in rows:
+        element_id = str(row["id"])
+        if row["element_type"] in {"reservoir", "tank"}:
+            source_nodes.append(element_id)
+        else:
+            link_entries.append(
+                f"{element_id}:{row['element_type']}:{row['start_node_id']}:{row['end_node_id']}"
+            )
+            if row["status"] == "CLOSED":
+                closed_links.append(element_id)
+    return link_entries, source_nodes, closed_links
+
+
 def get_major_pipe_nodes(name: str, diameter: int) -> list[str]:
     """Return large pipes in the established API wire format."""
     rows = read_all(