### Improved

- Now we can switch the database adapter between IndexedDB and IDB without rebuilding (#747).
- No longer checking for the adapter by `Doctor`.

### Changes

- The default adapter is reverted to IDB to avoid memory leaks (#747).

### Fixed (?)

- Reverted QR code library to v1.4.4 (To make sure #752).

src/modules/features/SettingDialogue/settingUtils.ts

@@ -1,5 +1,10 @@
 import { escapeStringToHTML } from "octagonal-wheels/string";
-import { E2EEAlgorithmNames, type ObsidianLiveSyncSettings } from "../../../lib/src/common/types";
+import {
+    E2EEAlgorithmNames,
+    MILESTONE_DOCID,
+    NODEINFO_DOCID,
+    type ObsidianLiveSyncSettings,
+} from "../../../lib/src/common/types";
 import {
     pickCouchDBSyncSettings,
     pickBucketSyncSettings,
@@ -7,6 +12,7 @@ import {
     pickEncryptionSettings,
 } from "../../../lib/src/common/utils";
 import { getConfig, type AllSettingItemKey } from "./settingConstants";
+import { LOG_LEVEL_NOTICE, Logger } from "octagonal-wheels/common/logger";
 
 /**
  * Generates a summary of P2P configuration settings
@@ -76,3 +82,73 @@ export function getSummaryFromPartialSettings(setting: Partial<ObsidianLiveSyncS
     }
     return outputSummary;
 }
+
+// Migration or de-migration helper functions
+
+/**
+ * Copy document from one database to another for migration purposes
+ * @param docName document ID
+ * @param dbFrom source database
+ * @param dbTo destination database
+ * @returns
+ */
+export async function copyMigrationDocs(docName: string, dbFrom: PouchDB.Database, dbTo: PouchDB.Database) {
+    try {
+        const doc = await dbFrom.get(docName);
+        delete (doc as any)._rev;
+        await dbTo.put(doc);
+    } catch (e) {
+        if ((e as any).status === 404) {
+            return;
+        }
+        throw e;
+    }
+}
+
+type PouchDBOpenFunction = () => Promise<PouchDB.Database> | PouchDB.Database;
+
+/**
+ * Migrate databases from one to another
+ * @param operationName Name of the migration operation
+ * @param from source database
+ * @param openTo function to open destination database
+ * @returns True if migration succeeded
+ */
+export async function migrateDatabases(operationName: string, from: PouchDB.Database, openTo: PouchDBOpenFunction) {
+    const dbTo = await openTo();
+    await dbTo.info(); // ensure created
+    Logger(`Opening destination database for migration: ${operationName}.`, LOG_LEVEL_NOTICE, "migration");
+    // destroy existing data
+    await dbTo.destroy();
+    Logger(`Destroyed existing destination database for migration: ${operationName}.`, LOG_LEVEL_NOTICE, "migration");
+
+    const dbTo2 = await openTo();
+    const info2 = await dbTo2.info(); // ensure created
+    console.log(info2);
+    Logger(`Re-created destination database for migration: ${operationName}.`, LOG_LEVEL_NOTICE, "migration");
+
+    const info = await from.info();
+    const totalDocs = info.doc_count || 0;
+    const result = await from.replicate
+        .to(dbTo2, {
+            //@ts-ignore Missing in typedefs
+            style: "all_docs",
+        })
+        .on("change", (info) => {
+            Logger(
+                `Replicating... Docs replicated: ${info.docs_written} / ${totalDocs}`,
+                LOG_LEVEL_NOTICE,
+                "migration"
+            );
+        });
+    if (result.ok) {
+        Logger(`Replication completed for migration: ${operationName}.`, LOG_LEVEL_NOTICE, "migration");
+    } else {
+        throw new Error(`Replication failed for migration: ${operationName}.`);
+    }
+    await copyMigrationDocs(MILESTONE_DOCID, from, dbTo2);
+    await copyMigrationDocs(NODEINFO_DOCID, from, dbTo2);
+    Logger(`Copied migration documents for migration: ${operationName}.`, LOG_LEVEL_NOTICE, "migration");
+    await dbTo2.close();
+    return true;
+}