import android.Manifest
import android.content.ContentValues
import android.content.Context
import android.content.Intent
import android.content.pm.PackageManager
import android.database.sqlite.SQLiteDatabase
import android.database.sqlite.SQLiteOpenHelper
import android.net.Uri
import android.os.Bundle
import android.provider.MediaStore
import android.view.View
import androidx.appcompat.app.AppCompatActivity
import androidx.core.app.ActivityCompat
import androidx.core.content.ContextCompat
import androidx.core.content.FileProvider
import com.google.android.material.snackbar.Snackbar
import java.io.File
import java.io.IOException
import java.text.SimpleDateFormat
import java.util.*

class MainActivity : AppCompatActivity() {
    private lateinit var dbHelper: MyDatabaseHelper
    private lateinit var db: SQLiteDatabase

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        dbHelper = MyDatabaseHelper(this)
        db = dbHelper.writableDatabase

        // Check for camera permission and request it if necessary.
        if (ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
            ActivityCompat.requestPermissions(this, arrayOf(Manifest.permission.CAMERA), CAMERA_PERMISSION_REQUEST_CODE)
        } else {
            startCamera()
        }
    }

    override fun onRequestPermissionsResult(requestCode: Int, permissions: Array<out String>, grantResults: IntArray) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults)

        if (requestCode == CAMERA_PERMISSION_REQUEST_CODE && grantResults.isNotEmpty() && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
            startCamera()
        }
    }

    private fun startCamera() {
        // TODO: Connect to the Wi-Fi module and listen for data

        // TODO: When data is received, take a photo with the camera and display a pop-up message with the name
        val view: View = findViewById(android.R.id.content)
        val uid = "123456789"
        val name = "starfield"
        val message = "$name verified!"
        val duration = Snackbar.LENGTH_SHORT
        val snackbar = Snackbar.make(view, message, duration)
        snackbar.show()

        // Take a photo with the camera and save it to the database.
        val cameraIntent = Intent(MediaStore.ACTION_IMAGE_CAPTURE)
        startActivityForResult(cameraIntent, CAMERA_REQUEST_CODE)
    }

    override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
        super.onActivityResult(requestCode, resultCode, data)

        if (requestCode == CAMERA_REQUEST_CODE && resultCode == RESULT_OK) {
            val values = ContentValues().apply {
                put("name", "photo_${System.currentTimeMillis()}.jpg")
            }

            val uri = contentResolver.insert(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, values)

            try {
                contentResolver.openOutputStream(uri!!)?.use { outputStream ->
                    outputStream.write(data?.extras?.get("data") as ByteArray)
                }
            } catch (e: IOException) {
                e.printStackTrace()
            }

            db.insert("photos", null, values)
        }
    }

    companion object {

Kotlin online compiler

Write, Run & Share Kotlin code online using OneCompiler’s Kotlin online compiler for free. It’s a modern and fast online playground for Kotlin, supporting the latest version and ideal for learning, experimenting, and sharing code instantly.

About Kotlin

Kotlin is a statically typed, modern programming language developed by JetBrains. It runs on the JVM and is fully interoperable with Java. Kotlin is concise, expressive, and safe, and it’s officially supported by Google for Android app development.

Sample Code

The following is a simple Kotlin program that prints a greeting:

fun main() {
    println("Hello, OneCompiler!")
}

Taking inputs (stdin)

OneCompiler’s Kotlin editor supports stdin. You can provide input using the I/O tab. Here's a sample program that reads a line of input and prints a greeting:

fun main() {
    print("Enter your name: ")
    val name = readLine()
    println("Hello, $name")
}

Syntax Basics

Variables

val name: String = "OneCompiler"  // Immutable
var age: Int = 25                 // Mutable

Kotlin supports type inference, so explicit types are optional:

val city = "Hyderabad"
var count = 10

Conditionals

val score = 85
if (score >= 50) {
    println("Pass")
} else {
    println("Fail")
}

Loops

For loop

for (i in 1..5) {
    println(i)
}

While loop

var i = 1
while (i <= 5) {
    println(i)
    i++
}

Do-While loop

var j = 1
do {
    println(j)
    j++
} while (j <= 5)

Functions

fun add(a: Int, b: Int): Int {
    return a + b
}

fun greet(name: String) = "Hello, $name"

Collections

val items = listOf("apple", "banana", "cherry")
for (item in items) {
    println(item)
}

This guide provides a quick reference to Kotlin programming syntax and features. Start coding in Kotlin using OneCompiler’s Kotlin online compiler today!