<uses-permission android:name="android.permission.READ_PHONE_STATE" />
<uses-permission android:name="android.permission.CALL_PHONE" />
<uses-permission android:name="android.permission.ANSWER_PHONE_CALLS" />
<uses-permission android:name="android.permission.ACTION_CHANGE_DEFAULT_DIALER" />
<uses-feature android:name="android.software.PHONE_APP" android:required="true" />

<!-- I made this new activity to handle calls-->
<activity
android:name=".IncomingCallActivity"
android:exported="true">
<intent-filter>
<action android:name="android.intent.action.ANSWER" />
<action android:name="android.intent.action.CALL" />
<category android:name="android.intent.category.DEFAULT" />
<data android:scheme="tel" />
</intent-filter>
</activity>


<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
<action android:name="android.intent.action.DIAL" />
<category android:name="android.intent.category.DEFAULT" />
<data android:scheme="tel" />

<action android:name="android.intent.action.CALL_BUTTON" />
</intent-filter>

class MainActivity : ComponentActivity() {

private val permissions = arrayOf(
android.Manifest.permission.READ_PHONE_STATE,
android.Manifest.permission.CALL_PHONE
)
private val requestCode = 123


@OptIn(ExperimentalMaterial3Api::class)
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)



if (ContextCompat.checkSelfPermission(
this,
android.Manifest.permission.READ_PHONE_STATE
) == PackageManager.PERMISSION_GRANTED
) {
val telecomManager = getSystemService(TelecomManager::class.java)
val defaultDialerPackage = telecomManager?.defaultDialerPackage

// Check if the app is the default dialer
if (packageName != defaultDialerPackage) {
val intent = Intent(TelecomManager.ACTION_CHANGE_DEFAULT_DIALER)
intent.putExtra(
TelecomManager.EXTRA_CHANGE_DEFAULT_DIALER_PACKAGE_NAME,
packageName
)
startActivity(intent)
}
}




if (!arePermissionsGranted()) {
requestPermissions(permissions, requestCode)
} else {
// Permissions are already granted, register as the default dialer
registerAsDefaultDialer()
}
}

private fun arePermissionsGranted(): Boolean {
val permissionsToRequest = mutableListOf<String>()
for (permission in permissions) {
if (ContextCompat.checkSelfPermission(this, permission) != PackageManager.PERMISSION_GRANTED) {
permissionsToRequest.add(permission)
}
}

if (permissionsToRequest.isNotEmpty()) {
// Request missing permissions
ActivityCompat.requestPermissions(this, permissionsToRequest.toTypedArray(), requestCode)
return false
}

// If all permissions are granted, register as the default dialer
registerAsDefaultDialer()

return permissionsToRequest.isEmpty()
}

private fun registerAsDefaultDialer() {
val telecomManager = getSystemService(Context.TELECOM_SERVICE) as TelecomManager
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
if (!packageName.equals(telecomManager.defaultDialerPackage)) {
val intent = Intent(TelecomManager.ACTION_CHANGE_DEFAULT_DIALER)
intent.putExtra(
TelecomManager.EXTRA_CHANGE_DEFAULT_DIALER_PACKAGE_NAME,
packageName
)
startActivity(intent)
}
} else {
// Prior to Android Q, there is no need to register as the default dialer
}
}

override fun onRequestPermissionsResult(
requestCode: Int,
permissions: Array<out String>,
grantResults: IntArray
) {
when (requestCode) {
this.requestCode -> {
if (grantResults.isNotEmpty() && grantResults.all { it == PackageManager.PERMISSION_GRANTED }) {
// Permissions granted, now register as the default dialer
registerAsDefaultDialer()
}
}
else -> super.onRequestPermissionsResult(requestCode, permissions, grantResults)
}
}

}