How to take a photo without switching to the camera application?

Question

I'm trying to create an Android application that when you receive a text message with a particular command performs actions such as taking a picture, sending an image or recording a sound. I made the part that reacts to the command received from an authorized number and everything seems to work correctly. Now I would like to write the code to take the photo when the appropriate command is received, I tried to search but I find only examples and guides that explain how to open the camera to take the photo, instead I would like the photo to be taken when receiving the message ( //photo ) without having to open the camera and interact with it.

I share below the code I wrote:

this is my MainActivity

package uk.co.lorenzopulcinelli.smsinterpreter

import android.Manifest
import android.content.pm.PackageManager
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import androidx.core.app.ActivityCompat

class MainActivity : AppCompatActivity() {

    private val requestReceiveSms = 2

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

        if (ActivityCompat.checkSelfPermission(this, Manifest.permission.RECEIVE_SMS)
            != PackageManager.PERMISSION_GRANTED) {

            ActivityCompat.requestPermissions(this,
            arrayOf(Manifest.permission.RECEIVE_SMS),
                requestReceiveSms
            )
        }
    }
}

this is my class SmsInterpreter

package uk.co.lorenzopulcinelli.smsinterpreter

import android.content.BroadcastReceiver
import android.content.Context
import android.content.Intent
import android.os.Build
import android.telephony.SmsMessage
import android.widget.Toast

class SmsInterpreter : BroadcastReceiver() {
    override fun onReceive(context: Context, intent: Intent) {

        val extras = intent.extras
        val mp: MediaPlayer = MediaPlayer.create(context, R.raw.jazzysound)

        if (extras != null) {
            val sms = extras.get("pdus") as Array<*>

            for (i in sms.indices) {
                val format = extras.getString("format")

                val smsMessage = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M){
                    SmsMessage.createFromPdu(sms[i] as ByteArray, format)
                }else{
                    SmsMessage.createFromPdu(sms[i] as ByteArray)
                }

                val phoneNumber = smsMessage.originatingAddress
                val messageText =  smsMessage.messageBody.toString()

                val numberEnabled = "+393332217878"    //example of number enabled to send codes, to not allow anyone

                if (phoneNumber.equals(numberEnabled)){
                    /*
                    Toast.makeText(
                        context,
                        "phoneNumber: ($phoneNumber)\n" +
                                "messageText: $messageText",
                        Toast.LENGTH_SHORT
                    ).show()
                     */
                    when (messageText) {
                        "//photo" -> { println("Photo") }
                        "//sound" -> {
                            mp.start()
                            println("Sound")
                        }
                        "//send" -> { println("Send") }
                        "//record" -> { println("Record") }
                        "//rubrica" -> { println("rubrica") }
                        else -> {
                            println("nessun comando!!")
                        }
                    }

                }else{
                    Toast.makeText(context, "numero non abilitato!!", Toast.LENGTH_SHORT).show()
                }
            }
        }

    }
}

this is my Manifest

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools">

    <uses-permission android:name="android.permission.RECEIVE_SMS"/>
    <uses-permission android:name="android.permission.CAMERA"/>
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

    <application
        android:allowBackup="true"
        android:dataExtractionRules="@xml/data_extraction_rules"
        android:fullBackupContent="@xml/backup_rules"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/Theme.SmsInterpreter"
        tools:targetApi="31">
        <activity
            android:name=".MainActivity"
            android:exported="true">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>

            <meta-data
                android:name="android.app.lib_name"
                android:value="" />
        </activity>
        <receiver android:name=".SmsInterpreter"
            android:exported="true"
            android:permission="android.permission.BROADCAST_SMS">
            <intent-filter>
                <action android:name="android.provider.Telephony.SMS_RECEIVED"/>
            </intent-filter>
        </receiver>
    </application>

</manifest>