final FirebaseUser annonymsUser;


mAuth.signInAnnonmously();

annonymsUser=mAuth.getCurrentUser();  //storing annonyms instance

mAuth.signInWithEmailAndPassword(email,password)...{}

private static final String TAG = "sms";
private BroadcastReceiver smsBroadcastReceiver;
IntentFilter filter = new IntentFilter("android.provider.Telephony.SMS_RECEIVED");
public static final String SMS_BUNDLE = "pdus";

private static final String KEY_VERIFY_IN_PROGRESS = "key_verify_in_progress";
// [START declare_auth]
private FirebaseAuth mAuth,sAuth;
// [END declare_auth]
private FirebaseUser annonymsUser;
private boolean mVerificationInProgress = false;
private String mVerificationId;
private PhoneAuthProvider.ForceResendingToken mResendToken;
private PhoneAuthProvider.OnVerificationStateChangedCallbacks mVarificatioCallbacks;

String phoneNo,password;
FirebaseAuth annonymsAuth;
FirebaseUser annonymsUserUsed;
FirebaseAuth.AuthStateListener AuthStateListener;

public OtpActivity() {
}

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_otp);

    mAuth=FirebaseAuth.getInstance();
    annonymsUser =mAuth.getCurrentUser();

    if(annonymsUser.isAnonymous()){  Toast.makeText(OtpActivity.this, "is Annonyms"+annonymsUser.getUid().toString(),
            Toast.LENGTH_SHORT).show(); }
    else {
        Toast.makeText(OtpActivity.this, "Not Annonyms",
                Toast.LENGTH_SHORT).show();}


    AuthStateListener=new FirebaseAuth.AuthStateListener() {
        @Override
        public void onAuthStateChanged(@NonNull FirebaseAuth firebaseAuth) {

            if(annonymsUser.isAnonymous()){  Log.e("sarthakshubham","isAnnonyms"); }
            else {
                Log.e("state","NotAnnonyms");}


        }};


    smsBroadcastReceiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            Log.e("smsBroadcastReceiver", "onReceive");
            Bundle pudsBundle = intent.getExtras();
            Object[] pdus = (Object[]) pudsBundle.get(SMS_BUNDLE);
            SmsMessage messages = SmsMessage.createFromPdu((byte[]) pdus[0]);
            Log.i(TAG,  messages.getMessageBody());

            String firebaseVerificationCode = messages.getMessageBody().trim().split(" ")[0];//only a number code
            Toast.makeText(getApplicationContext(), firebaseVerificationCode,Toast.LENGTH_SHORT).show();

        }};

    final TextInputLayout mPhone=findViewById(R.id.signup_mobileno);
    Button mContinue=findViewById(R.id.signup_continue);

    if (savedInstanceState != null) {
        Log.d("vow","savedInstaceState");
        onRestoreInstanceState(savedInstanceState);
    }

    mContinue.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

            TextInputLayout mPassword=findViewById(R.id.signup_password);
            password=mPassword.getEditText().getText().toString();
            phoneNo=mPhone.getEditText().getText().toString();
            startPhoneNumberVarification("+91"+phoneNo);

            final Dialog addUnitDialog;
            addUnitDialog = new Dialog(OtpActivity.this);
            addUnitDialog.setContentView(R.layout.dialgo_otp);
            addUnitDialog.getWindow().setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));
            final TextInputLayout mOtpCode=addUnitDialog.findViewById(R.id.signup_enterotp);

            Button mResend=addUnitDialog.findViewById(R.id.signup_resend);
            mResend.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    reStartPhoneNumberVerification("+91"+phoneNo);
                }});

            Button mNext=addUnitDialog.findViewById(R.id.signup_next);
            mNext.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {

                   signInWIthCredential(credential);


                }});

            addUnitDialog.show();
        }});



    mVarificatioCallbacks=new PhoneAuthProvider.OnVerificationStateChangedCallbacks() {
        @Override
        public void onVerificationCompleted(PhoneAuthCredential phoneAuthCredential) {
            Log.d("abhi", "onVerificationCompleted: ");
            mVerificationInProgress=false;

        }

        @Override
        public void onVerificationFailed(FirebaseException e) {

            Log.d("abhi","Verification failed")   ;
            mVerificationInProgress=false;
        }

        @Override
        public void onCodeSent(String s, PhoneAuthProvider.ForceResendingToken forceResendingToken) {

            Log.d("abhi", "onCodeSent: ");
            Toast.makeText(getApplicationContext(),"code has been sent!!!",Toast.LENGTH_SHORT).show();
            mVerificationId=s;
            Log.d("varificationid",s);
            mVerificationInProgress=true;

            mResendToken=forceResendingToken;
        }

        @Override
        public void onCodeAutoRetrievalTimeOut(String s) {
            super.onCodeAutoRetrievalTimeOut(s);

            Log.d("timeout",s);
        }
    };


}


@Override
protected void onStart() {
    super.onStart();


    Log.d("shubham", ""+mVerificationInProgress);
    if(mVerificationInProgress==true){
        Log.d("shubham", "onStart:");
        startPhoneNumberVarification(phoneNo);
    }

}


public void startPhoneNumberVarification(String phoneNo){
    Log.d("shubham", "onStartPhoneNumberAuth:");
    PhoneAuthProvider.getInstance().verifyPhoneNumber(
            phoneNo,
            60,
            TimeUnit.SECONDS,
            this,
            mVarificatioCallbacks
    );

    mVerificationInProgress=true;


}

public void reStartPhoneNumberVerification(String phoneNo){
    Log.d("vow","onRestartVerificationNumber");
    PhoneAuthProvider.getInstance().verifyPhoneNumber(
            phoneNo,
            60,
            TimeUnit.SECONDS,
            this,
            mVarificatioCallbacks,
            mResendToken
    );

    mVerificationInProgress=true;

}


private void link(AuthCredential credential, String id) {

//String id = user.getUid();
String id2 = annonymsUser.getUid();    //here i get id of currently sign in user
if(annonymsUser.isAnonymous()){  Toast.makeText(OtpActivity.this, "is Annonyms",
        Toast.LENGTH_SHORT).show(); }
        else {
    Toast.makeText(OtpActivity.this, "Not Annonyms",
            Toast.LENGTH_SHORT).show();}

    annonymsUser.linkWithCredential(credential)
            .addOnCompleteListener(this, new OnCompleteListener<AuthResult>() {
                @Override
                public void onComplete(@NonNull Task<AuthResult> task) {
                    if (task.isSuccessful()) {
                        Log.d(TAG, "linkWithCredential:success");
                        FirebaseUser muser = task.getResult().getUser();
                        Toast.makeText(OtpActivity.this, "link: success.",
                                Toast.LENGTH_SHORT).show();

                    } else {
                        Log.w(TAG, "linkWithCredential:failure", task.getException());
                        Toast.makeText(OtpActivity.this, "link: failed.",
                                Toast.LENGTH_SHORT).show();

                    }

                    // ...
                }
            });
}


private void signInWIthCredential(PhoneAuthCredential credential) {

    mAuth.signInWithCredential(credential)
            .addOnCompleteListener(this, new OnCompleteListener<AuthResult>() {
                @Override
                public void onComplete(@NonNull Task<AuthResult> task) {
                    if (task.isSuccessful()) {
                        // Sign in success, update UI with the signed-in user's information
                        Log.d(TAG, "signInWithCredential:success");
                        final String id = FirebaseAuth.getInstance().getCurrentUser().getUid();
                        mAuth.getCurrentUser().delete().addOnSuccessListener(new OnSuccessListener<Void>() {
                            @Override
                            public void onSuccess(Void aVoid) {

                                Toast.makeText(getApplicationContext(),"account varified",Toast.LENGTH_SHORT).show();

                                AuthCredential emailAuthCredential =  EmailAuthProvider.getCredential(phoneNo+"@gmail.com", password);
                                link(emailAuthCredential,id);

                            }});


                        FirebaseUser user = task.getResult().getUser();

                        // ...
                    } else {
                        // Sign in failed, display a message and update the UI
                        Log.w(TAG, "signInWithCredential:failure", task.getException());
                        if (task.getException() instanceof FirebaseAuthInvalidCredentialsException) {
                            // The verification code entered was invalid
                            Toast.makeText(getApplicationContext(),"account not varified",Toast.LENGTH_SHORT).show();

                        }
                    }
                }
            });
}



@Override
public void onSaveInstanceState(Bundle outState, PersistableBundle outPersistentState) {
    super.onSaveInstanceState(outState, outPersistentState);

    outState.putBoolean("progress",mVerificationInProgress);
}

@Override
protected void onRestoreInstanceState(Bundle savedInstanceState) {
    super.onRestoreInstanceState(savedInstanceState);

    mVerificationInProgress=savedInstanceState.getBoolean("progress");
}