public class SignInActivity extends AppCompatActivity {

    Button signInButton,signUpButton;
    EditText etEmail,etPassword;
    Spinner spUser;

    FirebaseAuth mAuth;
    FirebaseDatabase mDatabase;
    DatabaseReference mUserRef, mRoot;
    ProgressDialog progressDialog;

    String[] user;

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

        etEmail = (EditText) findViewById(R.id.email_edittext);
        etPassword = (EditText) findViewById(R.id.password_edittext);

        signUpButton = (Button) findViewById(R.id.btnSignUp);
        signInButton = (Button) findViewById(R.id.btnSignIn);
        spUser = (Spinner) findViewById(R.id.spUser);

        user=new String[]
                {
                        "Event Organizer","Guest"
                };

        ArrayAdapter<String> adapter = new ArrayAdapter<String>(SignInActivity.this,android.R.layout.simple_list_item_1,user);
        spUser.setAdapter(adapter);



        signInButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                progressDialog = new ProgressDialog(SignInActivity.this);
                progressDialog.setMessage("Loading...");
                progressDialog.show();

                String email = etEmail.getText().toString();
                String password = etPassword.getText().toString();

                if (TextUtils.isEmpty(email)) {
                    etEmail.setError("Email harus diisi!");
                } else if (TextUtils.isEmpty(password)) {
                    etPassword.setError("Password harus diisi!");
                } else {
                    signIn(email, password);

                }
            }
        });

        signUpButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                startActivity(new Intent(SignInActivity.this, SignUpActivity.class));
                finish();
            }
        });
    }

    private void signIn(final String email, String password) {
        mAuth.signInWithEmailAndPassword(email, password)
                .addOnCompleteListener(new OnCompleteListener<AuthResult>() {
                    @Override
                    public void onComplete(@NonNull Task<AuthResult> task) {
                        if (task.isSuccessful()) {
                            startActivity(new Intent(SignInActivity.this, MainActivity.class));
                            progressDialog.dismiss();
                            finish();

                        } else {
                            Toast.makeText(SignInActivity.this, task.getException().getMessage(), Toast.LENGTH_LONG).show();

                        }
                    }
                });
    }


    @Override
    protected void onStart() {
        super.onStart();
        if (mDatabase == null) {
            mDatabase = FirebaseDatabase.getInstance();
        }
        mAuth = FirebaseAuth.getInstance();
        mRoot = mDatabase.getReference();
        mUserRef = mRoot.child("users");
    }
}