# ✅ Fix: History Screen Close App Issue

## 📋 Problem Identified
**Issue**: App crash ketika membuka riwayat absensi (History Screen)

### Root Causes:
1. **Missing null/empty string checks** - Field seperti `nama`, `npm`, `mataPelajaran`, `message` dapat kosong atau null, menyebabkan rendering error
2. **No exception handling** - Tidak ada try-catch wrapper di `AttendanceCard` composable
3. **Date formatting error** - `dateFormatter.format()` bisa throw exception jika timestamp invalid

## 🔧 Solutions Applied

### 1. **Wrapped AttendanceCard dengan Try-Catch**
```kotlin
@Composable
fun AttendanceCard(
    attendance: Attendance,
    dateFormatter: SimpleDateFormat
) {
    try {
        // ... semua logika rendering ...
    } catch (e: Exception) {
        // Fallback UI menampilkan error message
        Card(
            modifier = Modifier.fillMaxWidth(),
            colors = CardDefaults.cardColors(
                containerColor = MaterialTheme.colorScheme.errorContainer
            )
        ) {
            Column(...) {
                Text("Error menampilkan data absensi")
                Text(e.message ?: "Unknown error")
            }
        }
    }
}
```

### 2. **Added Null/Empty Safety Checks**
```kotlin
// Sebelum:
Text(text = attendance.nama)  // ❌ Crash jika kosong

// Sesudah:
Text(text = attendance.nama.takeIf { it.isNotEmpty() } ?: "N/A")  // ✅ Safe
Text(text = attendance.mataPelajaran.takeIf { it.isNotEmpty() } ?: "-")  // ✅ Safe
Text(text = attendance.npm.takeIf { it.isNotEmpty() } ?: "N/A")  // ✅ Safe
```

### 3. **Protected Date Formatting**
```kotlin
// Sebelum:
Text(text = "📅 ${dateFormatter.format(Date(attendance.timestamp))}")  // ❌ Can crash

// Sesudah:
try {
    Text(text = "📅 ${dateFormatter.format(Date(attendance.timestamp))}")
} catch (e: Exception) {
    Text(text = "📅 ${attendance.timestamp}")  // Fallback ke raw timestamp
}
```

### 4. **Protected Distance Calculation**
```kotlin
val (distanceFromCampus, isWithinRadius) = try {
    if (attendance.latitude.isFinite() && attendance.longitude.isFinite()) {
        val distance = calculateDistance(...)
        Pair(distance, distance <= AppConfig.ATTENDANCE_RADIUS_METERS)
    } else {
        Pair(0f, false)
    }
} catch (e: Exception) {
    Pair(0f, false)
}
```

## ✅ Improvements

| Aspek | Sebelum | Sesudah |
|-------|---------|--------|
| **Null Safety** | ❌ No checks | ✅ All fields safe |
| **Exception Handling** | ❌ None | ✅ Try-catch with fallback |
| **Empty String Handling** | ❌ Crashes | ✅ Shows "-" or "N/A" |
| **Error Display** | ❌ Crash | ✅ Error card shown |
| **Stability** | ❌ Unstable | ✅ Stable |

## 🧪 Test Cases

### Test 1: View History dengan Data Valid
```
1. Buka AttendanceScreen
2. Submit absensi dengan lengkap
3. Buka History
✅ Expected: Riwayat ditampilkan dengan sempurna
```

### Test 2: View History dengan Data Kosong
```
1. Buka History (tanpa submit apapun)
✅ Expected: Tampilkan "Belum ada riwayat kehadiran"
```

### Test 3: View History dengan Data Partial
```
1. Submit absensi dengan mataPelajaran kosong
2. Buka History
✅ Expected: Tampilkan "-" untuk mata kuliah, tidak crash
```

### Test 4: Multiple Records
```
1. Submit 5 kali
2. Buka History
✅ Expected: Semua 5 record ditampilkan, sorted by timestamp DESC
```

## 📝 Files Modified
- `presentation/screens/HistoryScreen.kt` - Added comprehensive error handling

## 🚀 Expected Result
✅ App tidak lagi crash ketika membuka History Screen
✅ Menampilkan error message yang user-friendly jika ada data issue
✅ Graceful fallback untuk berbagai edge cases