Added OTP.java

This class wraps the TOTP and HOTP functions in a method
called generateOTP which takes an instance of KeyInfo.

app/src/main/java/me/impy/aegis/MainActivity.java

@@ -6,12 +6,9 @@ import android.os.Bundle;
 import android.view.View;
 import android.widget.Button;
 import android.widget.TextView;
-import android.widget.Toast;
-
-import java.io.Serializable;
 
 import me.impy.aegis.crypto.KeyInfo;
-import me.impy.aegis.crypto.TOTP;
+import me.impy.aegis.crypto.OTP;
 
 public class MainActivity extends AppCompatActivity {
 
@@ -42,10 +39,14 @@ public class MainActivity extends AppCompatActivity {
             if (resultCode == RESULT_OK) {
                 KeyInfo info = (KeyInfo)data.getSerializableExtra("Keyinfo");
 
-                String nowTimeString = (Long.toHexString(System.currentTimeMillis() / 1000 / info.getPeriod()));
-                String totp = TOTP.generateTOTP(info.getSecret(), nowTimeString, info.getDigits(), info.getAlgorithm());
-
-                tvTotp.setText(totp);
+                String otp;
+                try {
+                    otp = OTP.generateOTP(info);
+                } catch (Exception e) {
+                    e.printStackTrace();
+                    return;
+                }
+                tvTotp.setText(otp);
             }
         }
     }

app/src/main/java/me/impy/aegis/ScannerActivity.java

@@ -54,12 +54,9 @@ public class ScannerActivity extends Activity implements ZXingScannerView.Result
 
         try {
             KeyInfo info = KeyInfo.FromURL(rawResult.getText());
-
-            //String nowTimeString = (Long.toHexString(System.currentTimeMillis() / 1000 / info.getPeriod()));
-            //Toast.makeText(this, TOTP.generateTOTP(info.getSecret(), nowTimeString, info.getDigits(), info.getAlgo()), Toast.LENGTH_LONG).show();
-
             Intent resultIntent = new Intent();
             resultIntent.putExtra("Keyinfo", info);
+
             setResult(Activity.RESULT_OK, resultIntent);
             finish();
         } catch (Exception e) {

app/src/main/java/me/impy/aegis/crypto/OTP.java

@@ -0,0 +1,25 @@
+package me.impy.aegis.crypto;
+
+public class OTP {
+    private OTP() {
+    }
+
+    public static String generateOTP(KeyInfo info) throws Exception {
+        String otp;
+
+        switch (info.getType()) {
+            case "totp":
+                String time = Long.toHexString(System.currentTimeMillis() / 1000 / info.getPeriod());
+                otp = TOTP.generateTOTP(info.getSecret(), time, info.getDigits(), info.getAlgorithm());
+                break;
+            case "hotp":
+                otp = HOTP.generateOTP(info.getSecret(), info.getCounter(), info.getDigits(), false, -1);
+                break;
+            default:
+                // this should never happen
+                throw new Exception("unsupported type");
+        }
+
+        return otp;
+    }
+}