feat: complete migration logic

src/seqta/utils/migration/migration-iframe.ts

@@ -0,0 +1,103 @@
+// This goes in your migration.html's script
+interface Data {
+  id: string;
+  blob: Blob;
+  type: 'image' | 'video';
+}
+
+const openDB = (): Promise<IDBDatabase> => {
+  return new Promise((resolve, reject) => {
+    const request = indexedDB.open('MyDatabase', 1);
+    request.onerror = () => reject(request.error);
+    request.onsuccess = () => resolve(request.result);
+  });
+};
+
+const blobToBase64 = (blob: Blob): Promise<string> => {
+  return new Promise((resolve, reject) => {
+    const reader = new FileReader();
+    reader.onloadend = () => {
+      const base64 = reader.result as string;
+      resolve(base64.split(',')[1]); // Remove data URL prefix
+    };
+    reader.onerror = () => reject(reader.error);
+    reader.readAsDataURL(blob);
+  });
+};
+
+const getAllBackgrounds = async (): Promise<Data[]> => {
+  const db = await openDB();
+  const tx = db.transaction('backgrounds', 'readonly');
+  const store = tx.objectStore('backgrounds');
+  const request = store.getAll();
+
+  return new Promise((resolve, reject) => {
+    request.onsuccess = () => resolve(request.result);
+    request.onerror = () => reject(request.error);
+  });
+};
+
+const startMigration = async () => {
+  try {
+    console.info('Starting background extraction...');
+    const backgrounds = await getAllBackgrounds();
+    console.info(`Found ${backgrounds.length} backgrounds`);
+
+    window.parent.postMessage({ type: 'GET_LAST_PROCESSED_ID' }, '*');
+
+    const lastProcessedId = await new Promise<string | null>(resolve => {
+      const handler = (event: MessageEvent) => {
+        if (event.data.type === 'LAST_PROCESSED_ID') {
+          window.removeEventListener('message', handler);
+          resolve(event.data.id);
+        }
+      };
+      window.addEventListener('message', handler);
+    });
+
+    const remainingBackgrounds = lastProcessedId 
+      ? backgrounds.slice(backgrounds.findIndex(b => b.id === lastProcessedId) + 1)
+      : backgrounds;
+
+    console.info(`Processing ${remainingBackgrounds.length} remaining backgrounds`);
+
+    for (let i = 0; i < remainingBackgrounds.length; i++) {
+      const background = remainingBackgrounds[i];
+      const base64Data = await blobToBase64(background.blob);
+      
+      window.parent.postMessage({
+        type: 'BACKGROUND_DATA',
+        payload: {
+          id: background.id,
+          data: base64Data,
+          mediaType: background.type,
+          total: backgrounds.length,
+          processed: i + 1
+        }
+      }, '*');
+
+      await new Promise(resolve => setTimeout(resolve, 100));
+    }
+
+    window.parent.postMessage({ type: 'MIGRATION_COMPLETE' }, '*');
+
+  } catch (error: any) {
+    console.error('Extraction failed:', error);
+    window.parent.postMessage({
+      type: 'MIGRATION_ERROR',
+      error: error.message || 'Unknown error'
+    }, '*');
+  }
+};
+
+window.addEventListener('message', (event) => {
+  switch (event.data.type) {
+    case 'PING':
+      window.parent.postMessage({ type: 'PONG' }, '*');
+      break;
+      
+    case 'START_MIGRATION':
+      startMigration();
+      break;
+  }
+});