package id.ac.ubharajaya.sistemakademik

import android.Manifest
import android.app.Activity
import android.content.Intent
import android.content.pm.PackageManager
import android.graphics.Bitmap
import android.location.Location
import android.os.Bundle
import android.provider.MediaStore
import android.util.Base64
import android.widget.Toast
import androidx.activity.ComponentActivity
import androidx.activity.compose.rememberLauncherForActivityResult
import androidx.activity.compose.setContent
import androidx.activity.enableEdgeToEdge
import androidx.activity.result.contract.ActivityResultContracts
import androidx.compose.foundation.Image
import androidx.compose.foundation.background
import androidx.compose.foundation.layout.*
import androidx.compose.foundation.shape.CircleShape
import androidx.compose.foundation.shape.RoundedCornerShape
import androidx.compose.foundation.text.KeyboardOptions
import androidx.compose.material.icons.Icons
import androidx.compose.material.icons.filled.*
import androidx.compose.material3.*
import androidx.compose.runtime.*
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.draw.clip
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.graphics.asImageBitmap
import androidx.compose.ui.graphics.vector.ImageVector
import androidx.compose.ui.layout.ContentScale
import androidx.compose.ui.platform.LocalContext
import androidx.compose.ui.text.font.FontWeight
import androidx.compose.ui.text.input.KeyboardType
import androidx.compose.ui.unit.dp
import androidx.compose.ui.unit.sp
import androidx.core.content.ContextCompat
import com.google.android.gms.location.LocationServices
import id.ac.ubharajaya.sistemakademik.ui.theme.SistemAkademikTheme
import org.json.JSONObject
import java.io.ByteArrayOutputStream
import java.net.HttpURLConnection
import java.net.URL
import java.text.SimpleDateFormat
import java.util.*
import kotlin.concurrent.thread

// =============== MAIN ACTIVITY & NAVIGATION ===============
class MainActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        enableEdgeToEdge()
        setContent {
            SistemAkademikTheme {
                AppNavigation(activity = this)
            }
        }
    }
}

@Composable
fun AppNavigation(activity: ComponentActivity) {
    var currentScreen by remember { mutableStateOf("login") }
    var npm by remember { mutableStateOf("") }
    var nama by remember { mutableStateOf("") }
    var loginTime by remember { mutableStateOf(0L) }

    when (currentScreen) {
        "login" -> LoginScreen(onLoginSuccess = { loggedInNpm, loggedInNama, time ->
            npm = loggedInNpm
            nama = loggedInNama
            loginTime = time
            currentScreen = "menu"
        })
        "menu" -> MenuScreen(
            nama = nama,
            npm = npm,
            onAbsenClick = { currentScreen = "absensi" },
            onRiwayatClick = { currentScreen = "riwayat" },
            onLogout = {
                currentScreen = "login"
                npm = ""
                nama = ""
            }
        )
        "absensi" -> AbsensiScreen(activity = activity, npm = npm, nama = nama, loginTime = loginTime, onNavigateBack = {
            currentScreen = "menu"
        })
        "riwayat" -> RiwayatScreen(onNavigateBack = { currentScreen = "menu" })
    }
}

// =============== LOGIN SCREEN ===============

@Composable
fun LoginScreen(onLoginSuccess: (npm: String, nama: String, loginTime: Long) -> Unit) {
    var npm by remember { mutableStateOf("") }
    var nama by remember { mutableStateOf("") }
    val context = LocalContext.current

    Column(
        modifier = Modifier.fillMaxSize().padding(32.dp),
        verticalArrangement = Arrangement.Center,
        horizontalAlignment = Alignment.CenterHorizontally
    ) {
        Text("Login Absensi", style = MaterialTheme.typography.headlineMedium, fontWeight = FontWeight.Bold)
        Spacer(Modifier.height(32.dp))

        OutlinedTextField(value = npm, onValueChange = { npm = it }, label = { Text("NPM") }, modifier = Modifier.fillMaxWidth(), singleLine = true, keyboardOptions = KeyboardOptions(keyboardType = KeyboardType.Number))
        Spacer(Modifier.height(16.dp))

        OutlinedTextField(value = nama, onValueChange = { nama = it }, label = { Text("Nama Lengkap") }, modifier = Modifier.fillMaxWidth(), singleLine = true, keyboardOptions = KeyboardOptions(keyboardType = KeyboardType.Text))
        Spacer(Modifier.height(32.dp))

        Button(
            onClick = {
                if (npm.isNotBlank() && nama.isNotBlank()) {
                    onLoginSuccess(npm, nama, System.currentTimeMillis())
                } else {
                    Toast.makeText(context, "NPM dan Nama tidak boleh kosong", Toast.LENGTH_SHORT).show()
                }
            },
            modifier = Modifier.fillMaxWidth().height(50.dp)
        ) {
            Text("LOGIN")
        }
    }
}

// =============== MENU SCREEN ===============

@OptIn(ExperimentalMaterial3Api::class)
@Composable
fun MenuScreen(nama: String, npm: String, onAbsenClick: () -> Unit, onRiwayatClick: () -> Unit, onLogout: () -> Unit) {
    Scaffold(
        topBar = {
            CenterAlignedTopAppBar(
                title = { Text("Menu Utama", color = Color.White) },
                navigationIcon = { IconButton(onClick = onLogout) { Icon(Icons.Default.ArrowBack, "Logout", tint = Color.White) } },
                colors = TopAppBarDefaults.centerAlignedTopAppBarColors(containerColor = Color(0xFF388E3C))
            )
        }
    ) { innerPadding ->
        Column(
            modifier = Modifier.padding(innerPadding).fillMaxSize().padding(16.dp),
            horizontalAlignment = Alignment.CenterHorizontally
        ) {
            Spacer(modifier = Modifier.height(16.dp))
            Card(modifier = Modifier.fillMaxWidth(), elevation = CardDefaults.cardElevation(defaultElevation = 2.dp)) {
                Column(
                    modifier = Modifier.fillMaxWidth().padding(vertical = 24.dp),
                    horizontalAlignment = Alignment.CenterHorizontally
                ) {
                    Text("Selamat Datang,", style = MaterialTheme.typography.bodyLarge, color = Color.Gray)
                    Spacer(modifier = Modifier.height(4.dp))
                    Text(nama, fontWeight = FontWeight.Bold, fontSize = 22.sp)
                    Text("($npm)", fontSize = 16.sp, color = Color.Gray)
                }
            }
            Spacer(modifier = Modifier.height(32.dp))
            MenuButton(text = "Absen Kehadiran", icon = Icons.Filled.CameraAlt, onClick = onAbsenClick)
            Spacer(modifier = Modifier.height(16.dp))
            MenuButton(text = "Riwayat Absensi", icon = Icons.Filled.History, onClick = onRiwayatClick)
        }
    }
}

@Composable
fun MenuButton(text: String, icon: ImageVector, onClick: () -> Unit) {
    Button(
        onClick = onClick,
        modifier = Modifier.fillMaxWidth().height(55.dp),
        shape = RoundedCornerShape(12.dp),
        colors = ButtonDefaults.buttonColors(containerColor = MaterialTheme.colorScheme.primary)
    ) {
        Row(verticalAlignment = Alignment.CenterVertically) {
            Icon(icon, contentDescription = null, modifier = Modifier.size(24.dp))
            Spacer(Modifier.width(12.dp))
            Text(text, fontSize = 16.sp)
        }
    }
}

// =============== RIWAYAT SCREEN (PLACEHOLDER) ===============

@OptIn(ExperimentalMaterial3Api::class)
@Composable
fun RiwayatScreen(onNavigateBack: () -> Unit) {
    Scaffold(
        topBar = {
            CenterAlignedTopAppBar(
                title = { Text("Riwayat Absensi", color = Color.White) },
                navigationIcon = { IconButton(onClick = onNavigateBack) { Icon(Icons.Default.ArrowBack, "Kembali", tint = Color.White) } },
                colors = TopAppBarDefaults.centerAlignedTopAppBarColors(containerColor = Color(0xFF388E3C))
            )
        }
    ) { innerPadding ->
        Box(modifier = Modifier.padding(innerPadding).fillMaxSize(), contentAlignment = Alignment.Center) {
            Text("Halaman Riwayat Absensi (Segera Hadir)")
        }
    }
}


// =============== ABSENSI SCREEN ===============

@OptIn(ExperimentalMaterial3Api::class)
@Composable
fun AbsensiScreen(activity: ComponentActivity, npm: String, nama: String, loginTime: Long, onNavigateBack: () -> Unit) {
    val context = LocalContext.current
    var lokasiStatus by remember { mutableStateOf("Mengecek izin lokasi...") }
    var isLocationReady by remember { mutableStateOf(false) }
    var foto by remember { mutableStateOf<Bitmap?>(null) }
    var isUploading by remember { mutableStateOf(false) }
    var userLocation by remember { mutableStateOf<Location?>(null) }
    var mataKuliah by remember { mutableStateOf("") }

    val fusedLocationClient = remember { LocationServices.getFusedLocationProviderClient(context) }

    val cameraLauncher = rememberLauncherForActivityResult(ActivityResultContracts.StartActivityForResult()) { result ->
        if (result.resultCode == Activity.RESULT_OK) {
            val bitmap = result.data?.extras?.get("data") as? Bitmap
            if (bitmap != null) foto = bitmap
        }
    }

    val requestPermissionLauncher = rememberLauncherForActivityResult(ActivityResultContracts.RequestMultiplePermissions()) { permissions ->
        if (permissions[Manifest.permission.ACCESS_FINE_LOCATION] == true) {
            lokasiStatus = "Mendapatkan koordinat..."
            try {
                fusedLocationClient.lastLocation.addOnSuccessListener { loc ->
                    if (loc != null) {
                        userLocation = loc
                        isLocationReady = true
                        lokasiStatus = "Lokasi berhasil didapatkan"
                    } else {
                        isLocationReady = false
                        lokasiStatus = "Gagal mendapatkan lokasi. Pastikan GPS aktif."
                    }
                }
            } catch (e: SecurityException) {
                isLocationReady = false
                lokasiStatus = "Izin lokasi dicabut."
            }
        } else {
            lokasiStatus = "Izin lokasi ditolak."
        }
    }

    LaunchedEffect(Unit) { requestPermissionLauncher.launch(arrayOf(Manifest.permission.ACCESS_FINE_LOCATION, Manifest.permission.CAMERA)) }

    Scaffold(
        topBar = {
            CenterAlignedTopAppBar(
                title = { Text("Absen Kehadiran", color = Color.White) },
                navigationIcon = { IconButton(onClick = onNavigateBack) { Icon(Icons.Default.ArrowBack, "Kembali", tint = Color.White) } },
                colors = TopAppBarDefaults.centerAlignedTopAppBarColors(containerColor = Color(0xFF388E3C))
            )
        }
    ) { innerPadding ->
        Column(
            modifier = Modifier.padding(innerPadding).fillMaxSize().padding(16.dp),
            horizontalAlignment = Alignment.CenterHorizontally
        ) {
            OutlinedTextField(
                value = mataKuliah,
                onValueChange = { mataKuliah = it },
                label = { Text("Mata Kuliah") },
                modifier = Modifier.fillMaxWidth(),
                singleLine = true
            )
            Spacer(Modifier.height(16.dp))
            Row(verticalAlignment = Alignment.CenterVertically) {
                Icon(if (isLocationReady) Icons.Filled.CheckCircle else Icons.Filled.Close, "Status Lokasi", tint = if (isLocationReady) Color(0xFF2E7D32) else Color.Red, modifier = Modifier.size(18.dp))
                Spacer(Modifier.width(8.dp))
                Text(lokasiStatus, color = if (isLocationReady) Color.DarkGray else Color.Red, fontSize = 14.sp)
            }
            Spacer(Modifier.height(16.dp))
            Box(Modifier.size(200.dp).clip(CircleShape).background(Color.LightGray), contentAlignment = Alignment.Center) {
                if (foto != null) {
                    Image(foto!!.asImageBitmap(), "Foto Selfie", Modifier.fillMaxSize(), contentScale = ContentScale.Crop)
                } else {
                    Icon(Icons.Filled.Person, "Placeholder", modifier = Modifier.size(70.dp), tint = Color.Gray)
                }
            }
            Spacer(Modifier.height(24.dp))
            Button(
                onClick = { cameraLauncher.launch(Intent(MediaStore.ACTION_IMAGE_CAPTURE)) },
                enabled = isLocationReady, // Button enabled only when location is ready
                modifier = Modifier.fillMaxWidth(0.8f).height(50.dp)
            ) {
                Text("1. AMBIL FOTO")
            }
            Spacer(Modifier.height(16.dp))
            if (isLocationReady && foto != null && mataKuliah.isNotBlank()) {
                if (isUploading) {
                    CircularProgressIndicator()
                } else {
                    Button(
                        onClick = {
                            isUploading = true
                            kirimKeServer(activity, npm, nama, userLocation?.latitude ?: 0.0, userLocation?.longitude ?: 0.0, foto!!, loginTime, mataKuliah) { success ->
                                if (success) {
                                    Toast.makeText(activity, "Absensi Berhasil!", Toast.LENGTH_LONG).show()
                                    onNavigateBack()
                                } else {
                                    isUploading = false
                                }
                            }
                        },
                        modifier = Modifier.fillMaxWidth(0.8f).height(50.dp),
                        colors = ButtonDefaults.buttonColors(containerColor = Color(0xFF1B5E20))
                    ) {
                        Text("2. KIRIM ABSENSI")
                    }
                }
            }
        }
    }
}

// =============== NETWORK & UTILS ===============

fun kirimKeServer(activity: Activity, npm: String, nama: String, lat: Double, lon: Double, img: Bitmap, loginTime: Long, mataKuliah: String, onFinish: (Boolean) -> Unit) {
    thread {
        var success = false
        try {
            val url = URL("https://n8n.lab.ubharajaya.ac.id/webhook/23c6993d-1792-48fb-ad1c-ffc78a3e6254")
            val conn = url.openConnection() as HttpURLConnection
            conn.requestMethod = "POST"
            conn.setRequestProperty("Content-Type", "application/json")
            conn.doOutput = true

            val json = JSONObject().apply {
                put("npm", npm)
                put("nama", nama)
                put("latitude", lat)
                put("longitude", lon)
                put("timestamp", loginTime)
                put("mata_kuliah", mataKuliah)
                put("foto_base64", bitmapToBase64(img))
            }

            conn.outputStream.write(json.toString().toByteArray())

            val code = conn.responseCode
            success = code == 200
            if (!success) {
                activity.runOnUiThread {
                    Toast.makeText(activity, "Gagal mengirim absensi. Kode: $code", Toast.LENGTH_LONG).show()
                }
            }
        } catch (e: Exception) {
            e.printStackTrace()
            activity.runOnUiThread {
                Toast.makeText(activity, "Error: Gagal terhubung ke server.", Toast.LENGTH_SHORT).show()
            }
        } finally {
            activity.runOnUiThread { onFinish(success) }
        }
    }
}

fun bitmapToBase64(bitmap: Bitmap): String {
    val outputStream = ByteArrayOutputStream()
    bitmap.compress(Bitmap.CompressFormat.JPEG, 70, outputStream)
    return Base64.encodeToString(outputStream.toByteArray(), Base64.NO_WRAP)
}