From 4f730ef4e81466868daf77e4e2eb2aba774b857b Mon Sep 17 00:00:00 2001
From: Alexis Jacomy <alexis.jacomy@gmail.com>
Date: Thu, 4 Jul 2024 16:50:30 +0200
Subject: [PATCH] editor: improves switch types cache handling

This commit fixes #7946.

Details:
- Adds a `?` to handle case where switch types have not been loaded yet
  in SwitchList.tsx
- Adds a very simple cache to useSwitchTypes to avoid reloading switch
  types any time a new component mounts with that hook
---
 .../rangeEdition/speedSection/SwitchList.tsx  |  2 +-
 .../tools/switchEdition/useSwitchTypes.ts     | 51 ++++++++++++-------
 2 files changed, 35 insertions(+), 18 deletions(-)

diff --git a/front/src/applications/editor/tools/rangeEdition/speedSection/SwitchList.tsx b/front/src/applications/editor/tools/rangeEdition/speedSection/SwitchList.tsx
index 51c9b809852..8cca0566b6d 100644
--- a/front/src/applications/editor/tools/rangeEdition/speedSection/SwitchList.tsx
+++ b/front/src/applications/editor/tools/rangeEdition/speedSection/SwitchList.tsx
@@ -64,7 +64,7 @@ const SwitchList: React.FC<SwitchListProps> = ({
               <span className="align-self-end">{`${t('Editor.obj-types.Switch')} ${swId}`}</span>
             </div>
             <div className="d-flex ml-4">
-              {switchPositionsByType[type].map((optPosition, posIndex) => {
+              {switchPositionsByType[type]?.map((optPosition, posIndex) => {
                 const isPositionNull = optPosition === 'Any';
                 const isButtonIncompatible =
                   Object.keys(selectedSwitches).length > 1 &&
diff --git a/front/src/applications/editor/tools/switchEdition/useSwitchTypes.ts b/front/src/applications/editor/tools/switchEdition/useSwitchTypes.ts
index 30eb1471eae..cf10d33e249 100644
--- a/front/src/applications/editor/tools/switchEdition/useSwitchTypes.ts
+++ b/front/src/applications/editor/tools/switchEdition/useSwitchTypes.ts
@@ -6,7 +6,7 @@ import { osrdEditoastApi } from 'common/api/osrdEditoastApi';
 
 import type { SwitchType } from './types';
 
-// Client prefered order
+// Client preferred order
 const trackNodeTypeOrder = [
   'link',
   'point_switch',
@@ -15,30 +15,47 @@ const trackNodeTypeOrder = [
   'double_slip_switch',
 ];
 
+let switchTypesCache: Record<number, SwitchType[]> = {};
+
 export default function useSwitchTypes(infraID: number | undefined) {
-  const [data, setData] = useState<SwitchType[]>([]);
+  const [data, setData] = useState<SwitchType[]>(
+    !isNil(infraID) ? switchTypesCache[infraID] || [] : []
+  );
   const [getInfraSwitchTypes, { isLoading, error }] =
     osrdEditoastApi.endpoints.getInfraByInfraIdSwitchTypes.useLazyQuery({});
+  const invalidateCache = useCallback(() => {
+    switchTypesCache = {};
+  }, [switchTypesCache]);
 
   const fetch = useCallback(
     async (infraId?: number) => {
-      // reset
+      // Reset state:
       setData([]);
+
+      if (isNil(infraId)) {
+        return;
+      }
+
+      // Check cache first:
+      if (switchTypesCache[infraId]) {
+        setData(switchTypesCache[infraId]);
+        return;
+      }
+
       try {
-        if (!isNil(infraId)) {
-          const resp = getInfraSwitchTypes({ infraId });
-          const result = await resp.unwrap();
-          if (result) {
-            const orderedData = [...result] as SwitchType[];
-            orderedData.sort(
-              (a, b) => trackNodeTypeOrder.indexOf(a.id) - trackNodeTypeOrder.indexOf(b.id)
-            );
-            setData(orderedData);
-          } else {
-            setData([]);
-          }
-          resp.unsubscribe();
+        const resp = getInfraSwitchTypes({ infraId }, true);
+        const result = await resp.unwrap();
+        if (result) {
+          const orderedData = [...result] as SwitchType[];
+          orderedData.sort(
+            (a, b) => trackNodeTypeOrder.indexOf(a.id) - trackNodeTypeOrder.indexOf(b.id)
+          );
+          setData(orderedData);
+          switchTypesCache[infraId] = orderedData;
+        } else {
+          setData([]);
         }
+        resp.unsubscribe();
       } catch (e) {
         console.error(e);
       }
@@ -50,5 +67,5 @@ export default function useSwitchTypes(infraID: number | undefined) {
     fetch(infraID);
   }, [infraID, fetch]);
 
-  return { data, isLoading, error };
+  return { data, isLoading, error, invalidateCache };
 }