auth/AUTO_LOGIN_FIX.md

Auto-Login Fix - Token Persistence Issue

Problem

User reported that after "clearing the app", they were logged out and had to re-enter phone number and OTP to sign in.

Root Cause Analysis

What "Clearing the App" Means

There are different ways to "clear" an app in Android:

1. Force Stop (Settings → Apps → [App] → Force Stop)

   • ✅ Expected: Tokens should persist
   • Tokens stored in EncryptedSharedPreferences should remain

2. Clear App Data (Settings → Apps → [App] → Storage → Clear Data)

   • ⚠️ Expected: Tokens will be deleted
   • This deletes ALL app data including EncryptedSharedPreferences
   • User will need to sign in again (this is normal Android behavior)

3. Uninstall/Reinstall

   • ⚠️ Expected: Tokens will be deleted
   • User will need to sign in again

4. Close/Reopen App (Normal usage)

   • ✅ Expected: Tokens should persist
   • User should remain logged in

Issues Found

1. Network Errors Clearing Tokens

   • Problem: If there was a network error during token validation, tokens were being cleared
   • Impact: User would be logged out even if tokens were still valid
   • Fix: Distinguish between network errors and authentication errors

2. Token Save Timing

   • Problem: Using .apply() for token storage (asynchronous)
   • Impact: Tokens might not be saved immediately before app closes
   • Fix: Changed to .commit() for synchronous save (ensures tokens are saved)

Fixes Applied

1. Improved Error Handling in MainViewModel

File: MainViewModel.kt

Changes:

• Added network error detection
• Only clear tokens on authentication errors, not network errors
• Better error messages for users

Logic:

if (isNetworkError) {
    // Don't clear tokens - they might still be valid
    // User might be offline
    return@launch
}

2. Synchronous Token Saving

File: TokenManager.kt

Changes:

• Changed from .apply() to .commit() for token saving
• Ensures tokens are saved synchronously before app closes

Before:

.apply() // Asynchronous - might not complete before app closes

After:

.commit() // Synchronous - ensures tokens are saved immediately

How It Works Now

Normal App Usage (Close/Reopen)

1. User signs in → Tokens saved to EncryptedSharedPreferences
2. User closes app → Tokens remain in storage
3. User reopens app → MainViewModel.init() checks for tokens
4. If tokens exist → Validates tokens
5. If tokens valid → User automatically logged in ✅
6. If tokens expired → Attempts refresh
7. If refresh succeeds → User logged in ✅
8. If refresh fails → User needs to sign in again

Network Error Handling

1. App starts → Checks for tokens
2. Network error occurs → Tokens NOT cleared
3. User sees "Network error" message
4. When network available → Tokens still valid, user can retry

Authentication Error Handling

1. App starts → Checks for tokens
2. Authentication error (401, invalid token) → Tokens cleared
3. User needs to sign in again

Testing Scenarios

✅ Should Keep User Logged In

• Close app normally and reopen
• Force stop app and reopen
• Restart phone and reopen app
• Network error during token validation (tokens preserved)

⚠️ Will Log User Out (Expected Behavior)

• Clear app data from Android settings
• Uninstall and reinstall app
• Refresh token expired (7 days of inactivity)
• Authentication error (invalid/expired tokens)

Important Notes

1. Clearing App Data: If user clears app data from Android settings, tokens will be deleted. This is expected Android behavior - clearing app data removes all stored data.

2. Token Expiration:

   • Access tokens: 15 minutes
   • Refresh tokens: 7 days (with activity)
   • If refresh token expires, user must sign in again

3. Network Errors: Network errors no longer cause tokens to be cleared. User will see an error message but tokens remain valid.

User Experience

Before Fix

• ❌ Network errors could log user out
• ❌ Tokens might not be saved if app closed quickly
• ❌ Unclear error messages

After Fix

• ✅ Network errors don't log user out
• ✅ Tokens saved synchronously (guaranteed)
• ✅ Clear error messages (network vs auth errors)
• ✅ Better user experience

Debugging

To check if tokens are being saved:

1. Sign in to the app
2. Check logs for "User authenticated successfully"
3. Close app completely
4. Reopen app
5. Check logs for token validation

If tokens are missing:

• Check if app data was cleared
• Check if refresh token expired
• Check logs for authentication errors

Summary

The fix ensures:

1. ✅ Tokens persist when app is closed/reopened normally
2. ✅ Network errors don't clear tokens
3. ✅ Tokens are saved synchronously
4. ✅ Better error handling and user feedback
5. ✅ Clear distinction between network and auth errors

Note: If user clears app data from Android settings, they will need to sign in again. This is normal Android behavior and cannot be prevented.