Add the code to send the fee to Agorise in the case the transfer Asset is BTS.

This is the easiest case because we only need to calculate the fee as a percentage of the transfer and add it to the Transaction.

app/src/main/java/cy/agorise/bitsybitshareswallet/fragments/SendTransactionFragment.kt

@@ -35,6 +35,7 @@ import cy.agorise.graphenej.crypto.SecureRandomGenerator
 import cy.agorise.graphenej.models.AccountProperties
 import cy.agorise.graphenej.models.DynamicGlobalProperties
 import cy.agorise.graphenej.models.JsonRpcResponse
+import cy.agorise.graphenej.operations.TransferOperation
 import cy.agorise.graphenej.operations.TransferOperationBuilder
 import io.reactivex.android.schedulers.AndroidSchedulers
 import io.reactivex.schedulers.Schedulers
@@ -55,9 +56,6 @@ class SendTransactionFragment : ConnectedFragment(), ZXingScannerView.ResultHand
     companion object {
         private const val TAG = "SendTransactionFragment"
 
-        /** The account used to send the fees */
-        private val FEE_ACCOUNT = UserAccount("1.2.390320", "agorise")
-
         // Camera Permission
         private const val REQUEST_CAMERA_PERMISSION = 1
 
@@ -68,6 +66,12 @@ class SendTransactionFragment : ConnectedFragment(), ZXingScannerView.ResultHand
         private const val RESPONSE_BROADCAST_TRANSACTION = 4
     }
 
+    /** The account used to send the fees */
+    private val AGORISE_ACCOUNT = UserAccount("1.2.390320", "agorise")
+
+    /** Core BTS token */
+    private val BTS = Asset("1.3.0")
+
     private var isCameraPreviewVisible = false
     private var isToAccountCorrect = false
     private var isAmountCorrect = false
@@ -80,6 +84,8 @@ class SendTransactionFragment : ConnectedFragment(), ZXingScannerView.ResultHand
 
     private var selectedAssetSymbol = ""
 
+    private var selectedAssetToBTSExchangeRatio = 1.0
+
     /** Current user account */
     private var mUserAccount: UserAccount? = null
 
@@ -157,11 +163,21 @@ class SendTransactionFragment : ConnectedFragment(), ZXingScannerView.ResultHand
             override fun onItemSelected(parent: AdapterView<*>?, view: View?, position: Int, id: Long) {
                 val balance = mBalancesDetailsAdapter!!.getItem(position)!!
                 selectedAssetSymbol = balance.symbol
+                val asset = Asset(balance.id)
 
                 val amount = balance.amount.toDouble() / Math.pow(10.0, balance.precision.toDouble())
 
                 tvAvailableAssetAmount.text =
                         String.format("%." + Math.min(balance.precision, 8) + "f %s", amount, balance.symbol)
+
+                // Obtain current selected asset to BTS exchange rate
+                if (balance.symbol == "BTS")
+                    selectedAssetToBTSExchangeRatio = 1.0
+                else {
+                    // TODO obtain exchange ratio when selected asset is not BTS
+//                var id = mNetworkService?.sendMessage(GetRequiredFees(exchangeOperation, asset),
+//                    GetRequiredFees.REQUIRED_API)
+                }
             }
         }
 
@@ -401,6 +417,10 @@ class SendTransactionFragment : ConnectedFragment(), ZXingScannerView.ResultHand
         }
     }
 
+    /**
+     * Starts the Send Transfer operation procedure, creating a [TransferOperation] and sending a call to the
+     * NetworkService to obtain the [DynamicGlobalProperties] object needed to successfully send a Transfer
+     */
     private fun startSendTransferOperation() {
         // Create TransferOperation
         if (mNetworkService!!.isConnected) {
@@ -416,7 +436,7 @@ class SendTransactionFragment : ConnectedFragment(), ZXingScannerView.ResultHand
 
             val privateKey = ECKey.fromPrivate(DumpedPrivateKey.fromBase58(null, wifKey).key.privKeyBytes)
 
-            // Add memo if exists
+            // Add memo if it is not empty
             val memoMsg = tietMemo.text.toString()
             if (memoMsg.isNotEmpty()) {
                 val nonce = Math.abs(SecureRandomGenerator.getSecureRandom().nextLong()).toBigInteger()
@@ -427,18 +447,53 @@ class SendTransactionFragment : ConnectedFragment(), ZXingScannerView.ResultHand
                 operationBuilder.setMemo(memo)
             }
 
+            // Object that will contain all operations to be sent at once
             val operations = ArrayList<BaseOperation>()
-            operations.add(operationBuilder.build())
+            // Transfer from the current user to the selected one
+            val transferOperation = operationBuilder.build()
+            operations.add(transferOperation)
+
+            // Transfer operation to be sent as a fee to Agorise
+            val feeOperation = getAgoriseFeeOperation(transferOperation)
+            if (feeOperation != null)
+                operations.add(feeOperation)
 
             transaction = Transaction(privateKey, null, operations)
 
-            val id = mNetworkService!!.sendMessage(GetDynamicGlobalProperties(),
+            val id = mNetworkService?.sendMessage(GetDynamicGlobalProperties(),
                 GetDynamicGlobalProperties.REQUIRED_API)
-            responseMap[id] =  RESPONSE_GET_DYNAMIC_GLOBAL_PARAMETERS
+            if (id != null ) responseMap[id] =  RESPONSE_GET_DYNAMIC_GLOBAL_PARAMETERS
         } else
             Log.d(TAG, "Network Service is not connected")
     }
 
+    /**
+     * Obtains the correct [TransferOperation] object to send the fee to Agorise. This operation has to always send
+     * BTS so, depending on the Asset selected there are three possible options:
+     * a)   The Asset is BTS, this is the easiest case because we only need to calculate the fee as a percentage
+     *      of transferOperation's AssetAmount
+     * b)   The Asset is other than BTS and the user has enough BTS to pay the fee, in this case we need to calculate
+     *      the fee in BTS taking into account the Asset <-> BTS exchange rate.
+     * c)   The Asset is other than BTS but the user has not enough BTS to pay the fee, this is the most complex
+     *      scenario because we first need to calculate the fee in BTS taking into account the Asset <-> BTS exchange
+     *      rate, then create an exchange operation to obtain that amount of BTS and finally send that BTS as a fee to
+     *      Agorise.
+     */
+    private fun getAgoriseFeeOperation(transferOperation: TransferOperation): TransferOperation? {
+        if (transferOperation.assetAmount?.asset?.equals(BTS) == true) {
+            // The transfer operation is already in BTS so the fee amount can be easily calculated
+            val fee = transferOperation.assetAmount?.multiplyBy(Constants.FEE_PERCENTAGE) ?: return null
+
+            return TransferOperationBuilder()
+                .setSource(mUserAccount)
+                .setDestination(AGORISE_ACCOUNT)
+                .setTransferAmount(fee)
+                .build()
+        }
+        // TODO obtain fee amount when the asset to transfer is not BTS
+        return null
+    }
+
     override fun onCreateOptionsMenu(menu: Menu, inflater: MenuInflater) {
         inflater.inflate(R.menu.menu_send_transaction, menu)
     }
@@ -456,6 +511,7 @@ class SendTransactionFragment : ConnectedFragment(), ZXingScannerView.ResultHand
 
     override fun onResume() {
         super.onResume()
+
         if (isCameraPreviewVisible)
             startCameraPreview()
     }