Fix 8 critical/high resilience issues across camera, preview, logger, settings, and admin

src/services/logger.ts

@@ -3,15 +3,23 @@ import * as FileSystem from 'expo-file-system/legacy';
 const logFileUri = FileSystem.documentDirectory + 'app_logs.txt';
 
 // Queue to serialize file operations and prevent race conditions
-let writeQueue = Promise.resolve();
+const logQueue: string[] = [];
+let isWriting = false;
 
-const enqueueWrite = (logLine: string) => {
-  writeQueue = writeQueue.then(async () => {
+const processLogQueue = async () => {
+  if (isWriting) return;
+  isWriting = true;
+  
+  while (logQueue.length > 0) {
+    const logLine = logQueue.shift();
+    if (!logLine) continue;
+    
     try {
-      const fileInfo = await FileSystem.getInfoAsync(logFileUri);
-      if (!fileInfo.exists) {
-        await FileSystem.writeAsStringAsync(logFileUri, logLine, { encoding: FileSystem.EncodingType.UTF8 });
-      } else {
+      if (logFileUri) {
+        const fileInfo = await FileSystem.getInfoAsync(logFileUri);
+        if (!fileInfo.exists) {
+          await FileSystem.writeAsStringAsync(logFileUri, '', { encoding: FileSystem.EncodingType.UTF8 });
+        }
         const current = await FileSystem.readAsStringAsync(logFileUri, { encoding: FileSystem.EncodingType.UTF8 });
         let newContent = current + logLine;
         if (newContent.length > 100000) {
@@ -21,12 +29,15 @@ const enqueueWrite = (logLine: string) => {
       }
     } catch (e) {
       console.warn('Failed to write to log file:', e);
-      // We catch here so the queue is not broken for subsequent logs
     }
-  }).catch((e) => {
-    console.error('Queue error:', e);
-  });
-  return writeQueue;
+  }
+  
+  isWriting = false;
+};
+
+const enqueueWrite = async (logLine: string) => {
+  logQueue.push(logLine);
+  processLogQueue(); // Intentionally unawaited to run in background
 };
 
 export const logger = {

src/services/settings.ts

@@ -61,7 +61,7 @@ export async function loadSettings(): Promise<AppSettings> {
 export async function saveSettings(settings: AppSettings): Promise<void> {
   try {
     const content = JSON.stringify(settings, null, 2);
-    await FileSystem.writeAsStringAsync(settingsFile.uri, content);
+    await settingsFile.write(content);
     console.log('Settings saved successfully:', content);
   } catch (e) {
     console.error('Failed to save settings:', e);