# 🔧 Troubleshooting Guide

## Common Issues & Solutions

### 🚨 Build Issues

#### Issue 1: Gradle Sync Failed
**Error**: `Gradle sync failed: Failed to resolve...`

**Solutions**:
1. Clean project: `Build` → `Clean Project`
2. Invalidate caches: `File` → `Invalidate Caches / Restart`
3. Sync Gradle: `File` → `Sync Now`
4. Delete `.gradle` folder and try again
5. Check internet connection (gradle downloads dependencies)

---

#### Issue 2: Missing Dependencies
**Error**: `Unresolved reference: LocationValidator` atau similar

**Solutions**:
1. Verify file exists in correct package structure
2. Check package declaration at top of file
3. Rebuild project: `Build` → `Rebuild Project`
4. Check that all imports are present
5. File → Invalidate Caches / Restart

---

#### Issue 3: Kotlin Syntax Error
**Error**: `Type mismatch: inferred type is String? but Boolean was expected`

**Solutions**:
1. Check null-safety: use `?.` or `!!` appropriately
2. Verify data class properties match their types
3. Look for missing type annotations
4. Check imports for correct classes

---

### 📍 Location Issues

#### Issue 1: GPS Not Acquiring Location
**Error**: "Lokasi tidak tersedia"

**Causes & Solutions**:
- ❌ Location permission not granted
  → Check Settings → Apps → Permissions → Location (Allow)

- ❌ Location services disabled
  → Enable in Settings → Location → Location Services

- ❌ Cold start GPS (takes time to acquire)
  → Wait 30-60 seconds for GPS to warm up
  → Or enable "Use high accuracy" in location settings

- ❌ Testing in emulator
  → Use Extended Controls → Location to simulate GPS
  → Or use GPX file for GPS simulation

**Quick Check**:
```kotlin
// Test if GPS is available
val hasLocationPermission = ContextCompat.checkSelfPermission(
    context, Manifest.permission.ACCESS_FINE_LOCATION
) == PackageManager.PERMISSION_GRANTED

// Test if location services enabled
val locationManager = context.getSystemService(Context.LOCATION_SERVICE) as LocationManager
val isGPSEnabled = locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER)
```

---

#### Issue 2: Location Always Invalid
**Error**: "✗ Lokasi tidak valid (2500m, maksimal 100m)"

**Causes & Solutions**:
- ❌ Reference coordinates wrong
  → Update `REFERENCE_LATITUDE` dan `REFERENCE_LONGITUDE` di `AttendanceConfig.kt`
  → Verify with Google Maps

- ❌ Radius too small
  → Increase `ALLOWED_RADIUS_METERS` temporarily for testing
  → Default is 100m, try 200m or 300m

- ❌ Testing from wrong location
  → Go to actual campus location
  → Or use emulator GPS simulation

**How to Fix**:
```kotlin
// File: AttendanceConfig.kt
const val REFERENCE_LATITUDE = -7.025    // ← Update this
const val REFERENCE_LONGITUDE = 110.415  // ← Update this
const val ALLOWED_RADIUS_METERS = 100.0  // ← Or increase this
```

**How to Verify Reference Coordinates**:
1. Go to campus location with device
2. Open Google Maps
3. Long-click on map → Coordinates appear at top
4. Copy latitude and longitude
5. Update in `AttendanceConfig.kt`

---

#### Issue 3: Distance Calculation Wrong
**Error**: Shows 5000m distance when clearly close to reference

**Causes & Solutions**:
- ❌ Latitude/longitude swapped
  → Check: latitude is first, longitude is second
  → Format should be: (-7.025, 110.415) not (110.415, -7.025)

- ❌ Wrong location acquired
  → Check Logcat: `Log.d("Location", "Lat: $lat, Lon: $lon")`
  → Verify with Google Maps

- ❌ Haversine formula bug
  → Run unit tests: `./gradlew test`
  → Check LocationValidatorTest results

**Debug Steps**:
```kotlin
// Add logging to MainActivity
Log.d("AbsensiApp", "Reference: -7.0, 110.4")
Log.d("AbsensiApp", "Student: ${state.location?.latitude}, ${state.location?.longitude}")
Log.d("AbsensiApp", "Distance: ???")

// Or test manually
val distance = LocationValidator.calculateDistance(
    -7.0, 110.4,
    -7.0035, 110.4042
)
Log.d("Distance Test", "Result: $distance meters")
```

---

### 📸 Camera Issues

#### Issue 1: Camera Permission Denied
**Error**: "Izin kamera ditolak"

**Solutions**:
1. Open Settings → Apps → YourApp → Permissions
2. Find "Camera" permission
3. Tap it → Select "Allow"
4. Return to app and try again

**For Emulator**:
1. Device Manager → Create/Edit device
2. Verify "Camera" is checked in hardware
3. Set Camera: "Emulated"

---

#### Issue 2: Photo Not Captured
**Error**: Camera opens but no photo saved

**Causes & Solutions**:
- ❌ User canceled camera intent
  → Just tap button again to retry

- ❌ Storage permission issue (older Android)
  → Grant `WRITE_EXTERNAL_STORAGE` in Settings

- ❌ Camera intent failure
  → Check if device has camera: `hasSystemFeature(PackageManager.FEATURE_CAMERA)`

**Debug**:
```kotlin
// Check in logcat
Log.d("Camera", "Result Code: $resultCode")
Log.d("Camera", "Data: ${result.data}")
Log.d("Camera", "Bitmap: ${bitmap != null}")
```

---

#### Issue 3: Photo Preview Not Showing
**Error**: PhotoPreviewCard shows "Belum ada foto"

**Causes & Solutions**:
- ❌ Bitmap is null
  → Check Activity.RESULT_OK returned
  → Verify `result.data?.extras?.getParcelable` working

- ❌ UI not updating
  → Ensure state.copy() is called
  → Check LaunchedEffect dependencies

**Quick Fix**:
```kotlin
// Add logging
if (bitmap != null) {
    Log.d("Photo", "Bitmap size: ${bitmap.width}x${bitmap.height}")
    state = state.copy(foto = bitmap)
} else {
    Log.d("Photo", "Bitmap is null!")
}
```

---

### 🌐 Network Issues

#### Issue 1: Cannot Connect to Webhook
**Error**: "Gagal kirim ke server" or timeout

**Causes & Solutions**:
- ❌ No internet connection
  → Check WiFi/mobile data enabled
  → Ping google.com to verify

- ❌ Wrong webhook URL
  → Verify in `AttendanceConfig.kt`
  → Copy exact URL from N8n dashboard

- ❌ Firewall/VPN blocking
  → Disable VPN temporarily
  → Check if institution firewall allows HTTPS

- ❌ N8n server down
  → Test with curl: `curl -X POST https://n8n.lab.ubharajaya.ac.id/webhook/...`
  → Check N8n status page

**Webhook URL Check**:
```kotlin
// File: AttendanceConfig.kt
const val WEBHOOK_PRODUCTION = "https://n8n.lab.ubharajaya.ac.id/webhook/23c6993d-1792-48fb-ad1c-ffc78a3e6254"
// ↑ Copy exact URL, no typos!
```

---

#### Issue 2: Server Returns 400/500 Error
**Error**: "Absensi ditolak server" with error code

**Causes & Solutions**:
- **Status 400**: Data format wrong
  → Verify JSON structure matches expectations
  → Check all fields are present (npm, nama, lat, lon, foto)
  → Check foto is valid Base64

- **Status 401**: Authentication failed
  → Add authentication token if required
  → Contact server admin

- **Status 500**: Server error
  → Check N8n workflow logs
  → Verify database connection
  → Retry after server is fixed

**Test with Test Webhook First**:
```kotlin
// In MainActivity
isTest = true  // Set this to test first
// Check results at: https://n8n.lab.ubharajaya.ac.id/webhook-test/...
```

---

#### Issue 3: Timeout (Takes Too Long)
**Error**: Request hangs for 30+ seconds then fails

**Solutions**:
1. Check network speed: Test with speed.test.com
2. Reduce photo size: Decrease `PHOTO_QUALITY` in `AttendanceConfig.kt`
3. Increase timeout: Change `API_TIMEOUT_MS` (but not recommended)
4. Check server response time (might be slow)

```kotlin
// File: AttendanceConfig.kt
const val PHOTO_QUALITY = 70      // Reduce from 80 to 70
const val API_TIMEOUT_MS = 30000  // Current 30 seconds
```

---

### ⚙️ Permission Issues

#### Issue 1: Permission Dialog Not Appearing
**Error**: App crashes or silently fails

**Solutions**:
1. Verify permission in `AndroidManifest.xml`:
   ```xml
   <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
   <uses-permission android:name="android.permission.CAMERA"/>
   <uses-permission android:name="android.permission.INTERNET"/>
   ```

2. Check permission launcher is called:
   ```kotlin
   LaunchedEffect(Unit) {
       locationPermissionLauncher.launch(
           Manifest.permission.ACCESS_FINE_LOCATION
       )
   }
   ```

3. For Android 12+, check targetSdk:
   ```gradle
   targetSdk = 36
   ```

---

#### Issue 2: Permission Stuck on Denied
**Error**: User clicks "Deny" and can't recover

**Solutions**:
1. User must go to Settings manually:
   → Settings → Apps → YourApp → Permissions → Allow

2. Add UI hint in app:
   ```kotlin
   if (state.errorMessage?.contains("Izin") == true) {
       Button("Buka Pengaturan") {
           val intent = Intent(Settings.ACTION_APPLICATION_DETAILS_SETTINGS)
           startActivity(intent)
       }
   }
   ```

---

### 💾 Data & State Issues

#### Issue 1: Form Not Validating
**Error**: Submit button always disabled or always enabled

**Causes & Solutions**:
- ❌ Validation logic wrong
  → Check `LocationValidator.isLocationValid()` implementation
  → Run unit tests: `./gradlew test`

- ❌ State not updating
  → Verify state.copy() being called
  → Check all conditions in button enabled state

**Validation Checklist**:
```kotlin
// Button should be enabled only when ALL true:
val canSubmit = (
    state.location != null &&                    // Location acquired
    state.foto != null &&                        // Photo taken
    state.validationResult.isValid &&            // Location valid
    !state.isLoadingSubmit                       // Not currently submitting
)

SubmitButtonWithLoader(
    // ...
    isEnabled = canSubmit  // ← Check this
)
```

---

#### Issue 2: State Lost on Screen Rotation
**Error**: Form data disappears when device rotates

**Solutions**:
This is normal - Compose restores state automatically via `remember {}`

To persist across full app restart:
```kotlin
// Would need ViewModel + SavedStateHandle (advanced feature)
// Currently: state is reset on process death (acceptable for MVP)
```

---

#### Issue 3: Photo Bitmap Memory Issue
**Error**: "OutOfMemoryError: Bitmap too large" or app crashes

**Solutions**:
1. Reduce photo quality:
   ```kotlin
   const val PHOTO_QUALITY = 60  // Reduce from 80
   ```

2. Compress after capture:
   ```kotlin
   // In bitmapToBase64:
   bitmap.compress(Bitmap.CompressFormat.JPEG, PHOTO_QUALITY, outputStream)
   ```

3. For low-memory devices:
   - Scale down bitmap before encoding
   - Or use WebP format (better compression)

---

### 🧪 Testing Issues

#### Issue 1: Unit Tests Not Running
**Error**: "No tests found" or tests fail

**Solutions**:
1. Run from command line:
   ```bash
   ./gradlew test
   ```

2. Or in Android Studio:
   - Right-click test file → Run 'LocationValidatorTest'
   - Or use Test Configuration

3. Verify test file location:
   ```
   app/src/test/java/.../LocationValidatorTest.kt  ✓ Correct
   app/src/androidTest/java/.../LocationValidatorTest.kt  ✗ Wrong
   ```

---

#### Issue 2: Manual Testing Stuck
**Error**: Can't reproduce the flow

**Quick Test Checklist**:
- [ ] Device/emulator has internet
- [ ] Location services enabled
- [ ] All permissions granted
- [ ] Camera app works
- [ ] Webhook URL correct

**Fastest Flow**:
1. Grant permissions automatically
2. Hardcode valid location (for testing)
3. Take photo
4. Click submit
5. Should complete in < 10 seconds

---

### 🎨 UI Issues

#### Issue 1: Layout Cut Off on Small Screens
**Error**: Buttons/text not visible

**Solutions**:
1. Already implemented: `verticalScroll(rememberScrollState())`
2. Reduce padding: `modifier.padding(16.dp)` → `modifier.padding(8.dp)`
3. Use `Column` scrolling instead of fixed height

```kotlin
Column(
    modifier = modifier
        .fillMaxSize()
        .padding(16.dp)
        .verticalScroll(rememberScrollState())  // ← This allows scrolling
)
```

---

#### Issue 2: Dark Mode Not Working
**Error**: Text hard to read or colors wrong

**Solutions**:
1. Theme already supports dynamic colors (Material 3)
2. Verify `Theme.kt` has proper dark/light variants
3. Test: Settings → Display → Dark theme → On/Off

---

#### Issue 3: Loading Spinner Not Showing
**Error**: Button says "Mengirim..." but no spinner

**Solutions**:
1. Check `isLoading` state is true:
   ```kotlin
   state = state.copy(isLoadingSubmit = true)
   ```

2. Verify spinner code in `SubmitButtonWithLoader`:
   ```kotlin
   if (isLoading) {
       CircularProgressIndicator(...)  // ← Should show
   }
   ```

---

## 🆘 Emergency Troubleshooting

### App Crashes on Launch
1. Check Logcat for full error stack trace
2. Look for line number where crash happens
3. Most common: Missing permission or dependency
4. Try: `Build` → `Clean Project` → `Rebuild Project`

### Complete State Reset
```bash
# Uninstall app completely
./gradlew uninstallDebug

# Clean all build artifacts
./gradlew clean

# Rebuild everything
./gradlew installDebug
```

### Last Resort: Check Dependencies
```gradle
// Verify all dependencies installed
./gradlew dependencies

// Check for conflicts
./gradlew dependencyInsight --dependency location-services
```

---

## 📊 Debugging Commands

### View All Logs
```bash
adb logcat
```

### Filter Specific Tags
```bash
adb logcat | grep "AbsensiApp"
adb logcat | grep "N8nService"
adb logcat | grep "LocationValidator"
```

### Clear Logs
```bash
adb logcat -c
```

### Install Debug App
```bash
./gradlew installDebug
```

### Uninstall App
```bash
adb uninstall id.ac.ubharajaya.sistemakademik
```

### View App Logs in Real-time
```bash
adb logcat *:S AbsensiApp:D
```

---

## 🔍 Verification Checklist

Before declaring bug fixed, verify:

- [ ] Issue is reproducible
- [ ] Logs show no errors
- [ ] All permissions granted
- [ ] Internet connection active
- [ ] Coordinates correct
- [ ] Server responding
- [ ] Photo quality acceptable
- [ ] Location accuracy good
- [ ] Form submission successful
- [ ] Data received at webhook

---

**Still stuck?** 
1. Re-read QUICK_REFERENCE.md
2. Check DOKUMENTASI.md for detailed explanations
3. Review TESTING_CHECKLIST.md for testing procedures
4. Check ARCHITECTURE.md for design understanding
5. Look at comments in actual code files

---

**Last Updated**: January 14, 2026  
**Version**: 1.0