From 5a55a5c9add56123bc6c07a35a91394ca619c38e Mon Sep 17 00:00:00 2001
From: Xing Wang <xingwang1991@gmail.com>
Date: Mon, 11 Nov 2024 07:47:49 +0100
Subject: [PATCH] Store already added node viewer and load it when needed
 (#921)

In aiidalab-widgets-base/viewer.py, it creates a new viewer every time we select a new AiiDA node, and the viewer is not saved in the app, so we can not reuse it later. This PR stores the already added viewer and reuses it later.
---
 src/aiidalab_qe/app/result/__init__.py | 30 ++++++++++++++++++--------
 1 file changed, 21 insertions(+), 9 deletions(-)

diff --git a/src/aiidalab_qe/app/result/__init__.py b/src/aiidalab_qe/app/result/__init__.py
index a98bed779..f9a56019d 100644
--- a/src/aiidalab_qe/app/result/__init__.py
+++ b/src/aiidalab_qe/app/result/__init__.py
@@ -5,7 +5,6 @@
 from aiida.engine import ProcessState
 from aiida.engine.processes import control
 from aiidalab_widgets_base import (
-    AiidaNodeViewWidget,
     ProcessMonitor,
     ProcessNodesTreeWidget,
     WizardAppWidgetStep,
@@ -28,14 +27,10 @@ def __init__(self, **kwargs):
             (self, "process"),
             (self.process_tree, "value"),
         )
-
-        self.node_view = AiidaNodeViewWidget(layout={"width": "auto", "height": "auto"})
-        ipw.dlink(
-            (self.process_tree, "selected_nodes"),
-            (self.node_view, "node"),
-            transform=lambda nodes: nodes[0] if nodes else None,
-        )
-        self.process_status = ipw.VBox(children=[self.process_tree, self.node_view])
+        self.process_tree.observe(self._update_node_view, names="selected_nodes")
+        # keep track of the node views
+        self.node_views = {}
+        self.process_status = ipw.VBox(children=[self.process_tree])
 
         # Setup process monitor
         self.process_monitor = ProcessMonitor(
@@ -215,3 +210,20 @@ def _observe_process(self, _):
         self._update_state()
         self._update_kill_button_layout()
         self._update_clean_scratch_button_layout()
+
+    def _update_node_view(self, change):
+        """Callback for when the a new node is selected."""
+        from aiidalab_widgets_base.viewers import viewer
+
+        nodes = change["new"]
+        if not nodes:
+            return
+        # only show the first selected node
+        node = nodes[0]
+        # check if the viewer is already added
+        if node.uuid in self.node_views:
+            node_view = self.node_views[node.uuid]
+        else:
+            node_view = viewer(node)
+            self.node_views[node.uuid] = node_view
+        self.process_status.children = [self.process_tree, node_view]