feat: implement snapshot restore functionality and enhance graph state management

src/components/admin/KnowledgeGraph.jsx

@@ -25,9 +25,12 @@ const KnowledgeGraph = () => {
   const [showExcludeNodes, setShowExcludeNodes] = useState(false);
   const [isAnalyzing, setIsAnalyzing] = useState(false);
   const [analyzeError, setAnalyzeError] = useState(null);
+  const [isRestoring, setIsRestoring] = useState(false);
 
-  const { topics, relations, reload, updateTopic, deleteTopic, addRelation, removeRelation, bulkSave } =
-    useGraphData();
+  const {
+    topics, relations, snapshotMeta,
+    reload, updateTopic, deleteTopic, addRelation, removeRelation, bulkSave, restoreSnapshot,
+  } = useGraphData();
 
   // ── Canvas sizing ────────────────────────────────────────────────────────────
 
@@ -177,6 +180,24 @@ const KnowledgeGraph = () => {
     }
   }, [selectedNode, deleteTopic]);
 
+  // ── Snapshot restore ─────────────────────────────────────────────────────────
+
+  const handleRestore = useCallback(async () => {
+    if (
+      !confirm(
+        `Restore the graph to the snapshot from ${new Date(snapshotMeta?.ts).toLocaleTimeString([], { hour: '2-digit', minute: '2-digit' })}?\n\nThis will undo the last Analyze & Optimize run. The snapshot will be cleared after restoring.`,
+      )
+    )
+      return;
+    setIsRestoring(true);
+    try {
+      await restoreSnapshot();
+      setSelectedNode(null);
+    } finally {
+      setIsRestoring(false);
+    }
+  }, [restoreSnapshot, snapshotMeta]);
+
   // ── AI graph analysis ────────────────────────────────────────────────────────
 
   const analyzeGraph = useCallback(async () => {
@@ -309,6 +330,9 @@ Do not return the entire graph — only the actions to take.`;
           analyzeError={analyzeError}
           disabled={topics.length === 0}
           onApplied={reload}
+          snapshotMeta={snapshotMeta}
+          onRestore={handleRestore}
+          isRestoring={isRestoring}
         />
         <NodeDetailPanel
           selectedNode={selectedNode}

src/components/admin/graph/GraphControls.jsx

@@ -1,10 +1,10 @@
-import { RefreshCw, AlertCircle } from 'lucide-react';
+import { RotateCcw, RefreshCw, AlertCircle } from 'lucide-react';
 import Button from '../../ui/Button';
 import SuggestionsQueue from '../SuggestionsQueue';
 
 /**
  * Sidebar controls panel: the exclude-nodes toggle, the AI analysis button,
- * and the R42 suggestions queue.
+ * the snapshot restore row, and the R42 suggestions queue.
  *
  * Kept intentionally thin — all async logic lives in the KnowledgeGraph
  * orchestrator and is injected via props.
@@ -17,7 +17,14 @@ export default function GraphControls({
   analyzeError,
   disabled,
   onApplied,
+  snapshotMeta,
+  onRestore,
+  isRestoring,
 }) {
+  const snapshotLabel = snapshotMeta
+    ? new Date(snapshotMeta.ts).toLocaleTimeString([], { hour: '2-digit', minute: '2-digit' })
+    : null;
+
   return (
     <div className="mb-6 pb-4 border-b border-bg-warm space-y-3">
       <label className="flex items-center gap-2 text-sm text-fg-muted cursor-pointer">
@@ -30,18 +37,33 @@ export default function GraphControls({
         Show Excluded Nodes (Reference Material)
       </label>
 
-      <div>
+      <div className="space-y-2">
         <Button
           onClick={onAnalyze}
-          disabled={isAnalyzing || disabled}
+          disabled={isAnalyzing || isRestoring || disabled}
           className="w-full flex justify-center items-center gap-2"
         >
           <RefreshCw size={16} className={isAnalyzing ? 'animate-spin' : ''} />
           {isAnalyzing ? 'Analyzing Graph…' : 'Analyze & Optimize Graph'}
         </Button>
 
+        {/* Restore row — only visible after a bulkSave has written a snapshot */}
+        {snapshotMeta && (
+          <button
+            onClick={onRestore}
+            disabled={isAnalyzing || isRestoring}
+            className="w-full flex items-center justify-center gap-1.5 text-xs text-fg-muted hover:text-teal disabled:opacity-40 disabled:cursor-not-allowed py-1 transition-colors"
+            title={`Restore graph to state from ${snapshotLabel} (${snapshotMeta.topicCount} topics, ${snapshotMeta.relationCount} relations)`}
+          >
+            <RotateCcw size={12} className={isRestoring ? 'animate-spin' : ''} />
+            {isRestoring
+              ? 'Restoring…'
+              : `Restore to ${snapshotLabel} · ${snapshotMeta.topicCount}t ${snapshotMeta.relationCount}r`}
+          </button>
+        )}
+
         {analyzeError && (
-          <p className="mt-2 text-xs text-red-600 flex items-start gap-1">
+          <p className="text-xs text-red-600 flex items-start gap-1">
             <AlertCircle size={14} className="shrink-0 mt-0.5" />
             {analyzeError}
           </p>

src/hooks/useGraphData.js

@@ -10,11 +10,20 @@ import * as db from '../lib/db';
  * Relation shape contract: source and target are always plain strings.
  * The normalization in db.getRelations() enforces this at the DB boundary;
  * the filter here drops any orphaned edges whose endpoints no longer exist.
+ *
+ * Snapshot contract:
+ *   bulkSave() writes a snapshot of the CURRENT state to PocketBase before
+ *   overwriting it — so the admin can always roll back one step. snapshotMeta
+ *   is non-null whenever a rollback point exists; restoreSnapshot() applies it
+ *   and then clears it so it cannot be applied twice.
  */
 export function useGraphData() {
   const [topics, setTopics] = useState([]);
   const [relations, setRelations] = useState([]);
 
+  // { ts: number, topicCount: number, relationCount: number }
+  const [snapshotMeta, setSnapshotMeta] = useState(null);
+
   // Refs that always hold the latest state — lets mutation callbacks avoid
   // stale-closure bugs without including state in their dependency arrays.
   const topicsRef = useRef([]);
@@ -41,11 +50,19 @@ export function useGraphData() {
     return () => window.removeEventListener('respellion:kb-updated', reload);
   }, [reload]);
 
+  // On mount, check whether a snapshot from a previous session exists.
+  useEffect(() => {
+    db.getGraphSnapshot().then(snap => {
+      if (snap?.ts) {
+        setSnapshotMeta({ ts: snap.ts, topicCount: snap.topicCount, relationCount: snap.relationCount });
+      }
+    });
+  }, []);
+
   // ── Single-topic mutations ───────────────────────────────────────────────────
 
   /**
    * Persist a topic update and mirror it into local state.
-   * Automatically locks learning_relevance when the admin changes it.
    * Returns the saved topic object.
    */
   const updateTopic = useCallback(async (topic) => {
@@ -74,7 +91,7 @@ export function useGraphData() {
 
   /**
    * Add a relation if not already present.
-   * Returns true if the relation was added, false if it was a duplicate.
+   * Returns true if added, false if it was a duplicate.
    */
   const addRelation = useCallback(async (relation) => {
     const isDup = relationsRef.current.some(
@@ -99,24 +116,60 @@ export function useGraphData() {
   // ── Bulk mutations (used by AI analysis) ────────────────────────────────────
 
   /**
-   * Atomically replace the entire graph in PocketBase and local state.
-   * Called by analyzeGraph after all AI actions have been applied locally.
+   * Snapshot the current graph then replace everything in PocketBase and local
+   * state. The snapshot is written BEFORE the destructive delete-all/create-all
+   * so it survives a mid-operation failure.
+   *
+   * Called by analyzeGraph after all AI actions have been applied in memory.
    */
   const bulkSave = useCallback(async (newTopics, newRelations) => {
+    // Persist a rollback point of the state we are about to overwrite.
+    await db.saveGraphSnapshot(topicsRef.current, relationsRef.current);
+    setSnapshotMeta({
+      ts: Date.now(),
+      topicCount: topicsRef.current.length,
+      relationCount: relationsRef.current.length,
+    });
+
     await db.saveTopics(newTopics);
     await db.saveRelations(newRelations);
     setTopics(newTopics);
     setRelations(newRelations);
   }, []);
 
+  /**
+   * Load the latest snapshot from PocketBase and apply it as the current graph.
+   * Clears the snapshot afterwards so the admin cannot restore the same point
+   * twice (which would silently re-apply the AI changes they just rolled back).
+   *
+   * Returns true on success, false if no snapshot exists.
+   */
+  const restoreSnapshot = useCallback(async () => {
+    const snap = await db.getGraphSnapshot();
+    if (!snap?.topics) return false;
+
+    // Apply without taking a new snapshot — we don't want to overwrite
+    // the only rollback point we have.
+    await db.saveTopics(snap.topics);
+    await db.saveRelations(snap.relations);
+    setTopics(snap.topics);
+    setRelations(snap.relations);
+
+    await db.clearGraphSnapshot();
+    setSnapshotMeta(null);
+    return true;
+  }, []);
+
   return {
     topics,
     relations,
+    snapshotMeta,
     reload,
     updateTopic,
     deleteTopic,
     addRelation,
     removeRelation,
     bulkSave,
+    restoreSnapshot,
   };
 }

src/lib/db.js

@@ -284,6 +284,60 @@ export function setSetting(key, value) {
   return pbUpsert('settings', `key="${key}"`, { value: String(value) }, { key, value: String(value) });
 }
 
+// ── Graph Snapshots ───────────────────────────────────────────────────────────
+//
+// A single "latest" snapshot is persisted in the settings collection before
+// every bulk graph write. This survives browser/tab close and lets the admin
+// roll back an AI analysis that produced unwanted results.
+//
+// The value is stored as a JSON string because the settings collection only
+// has a plain text `value` field. Large graphs (150+ topics) can produce
+// ~100 KB of JSON, which SQLite handles without issue.
+
+const SNAPSHOT_KEY = 'graph_snapshot:latest';
+
+/**
+ * Persist the current graph state as a rollback point.
+ * Called by useGraphData.bulkSave() before overwriting the graph.
+ *
+ * @param {object[]} topics    — the graph state to preserve
+ * @param {object[]} relations — the graph state to preserve
+ */
+export async function saveGraphSnapshot(topics, relations) {
+  const payload = JSON.stringify({
+    ts: Date.now(),
+    topicCount: topics.length,
+    relationCount: relations.length,
+    topics,
+    relations,
+  });
+  return setSetting(SNAPSHOT_KEY, payload);
+}
+
+/**
+ * Read the latest snapshot back from PocketBase.
+ * Returns null when no snapshot exists or the stored value is malformed.
+ *
+ * @returns {{ ts: number, topicCount: number, relationCount: number, topics: object[], relations: object[] } | null}
+ */
+export async function getGraphSnapshot() {
+  const raw = await getSetting(SNAPSHOT_KEY, null);
+  if (!raw) return null;
+  try {
+    return JSON.parse(raw);
+  } catch {
+    return null;
+  }
+}
+
+/**
+ * Delete the stored snapshot (e.g. after a successful restore so the
+ * admin cannot accidentally restore twice).
+ */
+export function clearGraphSnapshot() {
+  return setSetting(SNAPSHOT_KEY, '');
+}
+
 // ── Curriculum Versions (v2) ──────────────────────────────────────────────────
 
 export async function getCurriculumVersions(status) {