Dashboard cards: rebuild deployable dists

plugins/computers/api/routes.py

@@ -994,3 +994,73 @@ def dashboard_quiet():
     # down the list, not the order the rows came out of the table.
     rows.sort(key=lambda r: (r['quietdays'] is not None, -(r['quietdays'] or 0)))
     return success_response(rows[:50])
+
+
+@computers_bp.route('/dashboard/sharedmachines', methods=['GET'])
+@jwt_required()
+@require_permission('computers.view')
+def dashboard_sharedmachines():
+    """Machine numbers claimed by more than one PC, with nothing filed under
+    them.
+
+    Several devices genuinely sharing a number is legitimate - part markers do
+    it - and those are modelled: each device is its own asset filed `partof` the
+    operation, so the operation has CHILD ASSETS. Two PCs carrying the same
+    machine number by mistake looks identical from a count and has none. That
+    distinction is the whole card; without it this would list correct data
+    alongside faults and get ignored.
+
+    Promoted from `flask relationships check-shared-machines`, which answers the
+    same question and which nobody will remember to run. This one found seven
+    mis-numbered bays that had been that way for weeks.
+    """
+    from shopdb.api import AssetRelationship, RelationshipType
+    from sqlalchemy.orm import aliased
+
+    controls = RelationshipType.query.filter_by(
+        relationshiptype='controls').first()
+    partof = RelationshipType.query.filter_by(relationshiptype='partof').first()
+    if not controls:
+        return success_response([])
+
+    pcasset = aliased(Asset)
+    machineasset = aliased(Asset)
+
+    rows = (db.session.query(machineasset.assetid, machineasset.assetnumber,
+                             pcasset.assetnumber)
+            .select_from(AssetRelationship)
+            .join(pcasset, AssetRelationship.sourceassetid == pcasset.assetid)
+            .join(machineasset,
+                  AssetRelationship.targetassetid == machineasset.assetid)
+            .filter(AssetRelationship.relationshiptypeid ==
+                    controls.relationshiptypeid,
+                    AssetRelationship.label == 'collector:machine',
+                    AssetRelationship.isactive.is_(True))
+            .all())
+
+    bymachine = {}
+    for assetid, machinenumber, pcnumber in rows:
+        bymachine.setdefault((assetid, machinenumber), []).append(pcnumber)
+
+    out = []
+    for (assetid, machinenumber), pcs in bymachine.items():
+        if len(pcs) < 2:
+            continue
+        children = 0
+        if partof:
+            children = (AssetRelationship.query
+                        .filter_by(targetassetid=assetid,
+                                   relationshiptypeid=partof.relationshiptypeid,
+                                   isactive=True)
+                        .count())
+        if children:
+            continue   # modelled: the devices are assets in their own right
+        out.append({
+            'assetid': assetid,
+            'machinenumber': machinenumber,
+            'pccount': len(pcs),
+            'pcs': ', '.join(sorted(p for p in pcs if p)),
+        })
+
+    out.sort(key=lambda r: -r['pccount'])
+    return success_response(out)