# 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**:
```kotlin
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**:
```kotlin
.apply() // Asynchronous - might not complete before app closes
```

**After**:
```kotlin
.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.