feat: extract text editor and allow editing (#150)

js/src/lib/firestore-particles.ts

@@ -81,16 +81,26 @@ const particleConverter: FirestoreDataConverter<Particle> = {
       case "file":
       case "text":
       case "quest":
-      case "paper":
+      case "paper": {
+        // Firestore stores timestamps as `Timestamp`; zod expects `Date`. Text
+        // particles carry `properties.edited_at`, so coerce it if present.
+        const properties =
+          type === "text" && raw.properties?.edited_at
+            ? {
+                ...raw.properties,
+                edited_at: (raw.properties.edited_at as Timestamp).toDate(),
+              }
+            : raw.properties;
         return ParticleSchema.parse({
           id: snap.id,
           type: raw.type,
-          properties: raw.properties,
+          properties,
           created_at: (raw.created_at as Timestamp).toDate(),
           created_by_human_id: raw.created_by_human_id,
           updated_at: raw.updated_at ? (raw.updated_at as Timestamp).toDate() : undefined,
           reactions: raw.reactions ?? undefined,
         });
+      }
       default:
         throw new Error(`Unknown particle type: ${type}`);
     }
@@ -296,6 +306,21 @@ export async function updateParticleProperties<T extends ParticleType>(
   });
 }
 
+// Edits the body of a text particle and stamps `properties.edited_at` so
+// readers can see that the message was edited (distinct from `updated_at`,
+// which is bumped by any write — visibility, reactions, etc.).
+export async function editTextParticleContent(
+  docPath: string,
+  content: string,
+): Promise<void> {
+  const particleRef = typedDoc(docPath);
+  await updateDoc(particleRef, {
+    "properties.content": content,
+    "properties.edited_at": serverTimestamp(),
+    updated_at: serverTimestamp(),
+  });
+}
+
 export async function updateParticleVisibleTo(
   docPath: string,
   visibleTo: string[],