Adding bunkTransferTokens

- Added bunkTransferTokens: bulk transfer tokens to multiple receivers
- usage: floWebWallet.bunkTransferTokens(sender, privKey, token, receivers)
sender: floID of sender
privKey: private key of sender
token: token to send
receivers: an object representing receiver floID and amount
ie, {receiverID1: amount1, receiverID2: amount2....}
eg: {Fxyz: 123, Fpqr:321, Fabc: 987}

scripts/flo-webwallet.js

@@ -110,4 +110,85 @@
         })
     }
 
+    function waitForConfirmation(txid, max_retry = -1, retry_timeout = 20) {
+        return new Promise((resolve, reject) => {
+            setTimeout(function () {
+                floBlockchainAPI.getTx(txid).then(tx => {
+                    if (!tx)
+                        return reject("Transaction not found");
+                    if (tx.confirmations)
+                        return resolve(tx);
+                    else if (max_retry === 0)    //no more retries
+                        return reject(false);
+                    else {
+                        max_retry = max_retry < 0 ? -1 : max_retry - 1; //decrease retry count (unless infinite retries)
+                        waitForConfirmation(txid, max_retry, retry_timeout)
+                            .then(result => resolve(result))
+                            .catch(error => reject(error))
+                    }
+                }).catch(error => reject(error))
+            }, retry_timeout * 1000)
+        })
+    }
+
+    function sendRawTransaction(receiver, utxo, vout, scriptPubKey, data, wif) {
+        var trx = bitjs.transaction();
+        trx.addinput(utxo, vout, scriptPubKey)
+        trx.addoutput(receiver, floBlockchainAPI.sendAmt);
+        trx.addflodata(data);
+        var signedTxHash = trx.sign(wif, 1);
+        return floBlockchainAPI.broadcastTx(signedTxHash);
+    }
+
+    function sendTokens_raw(privKey, receiverID, token, amount, utxo, vout, scriptPubKey) {
+        return new Promise((resolve, reject) => {
+            sendRawTransaction(receiverID, utxo, vout, scriptPubKey, `send ${amount} ${token}#`, privKey)
+                .then(txid => resolve([receiverID, txid]))
+                .catch(error => reject([receiverID, error]))
+        })
+    }
+
+    //bulk transfer tokens
+    floWebWallet.bunkTransferTokens = function (sender, privKey, token, receivers) {
+        return new Promise((resolve, reject) => {
+            if (typeof receivers !== 'object')
+                return reject("receivers must be object in format {receiver1: amount1, receiver2:amount2...}")
+
+            let receiver_list = Object.keys(receivers), amount_list = Object.values(receivers);
+            let invalidReceivers = receiver_list.filter(id => !floCrypto.validateFloID(id));
+            let invalidAmount = amount_list.filter(val => typeof val !== 'number' || val <= 0);
+            if (invalidReceivers.length)
+                return reject(`Invalid receivers: ${invalidReceivers}`);
+            else if (invalidAmount.length)
+                return reject(`Invalid amounts: ${invalidAmount}`);
+
+            //check for token balance
+            floTokenAPI.getBalance(sender, token).then(token_balance => {
+                let total_token_amout = amount_list.reduce((a, e) => a + e, 0);
+                if (total_token_amout > token_balance)
+                    return reject(`Insufficient ${token}# balance`);
+
+                //split utxos
+                floBlockchainAPI.splitUTXOs(sender, privKey, receiver_list.length).then(split_txid => {
+                    //wait for the split utxo to get confirmation
+                    waitForConfirmation(split_txid).then(split_tx => {
+                        //send tokens using the split-utxo
+                        var scriptPubKey = split_tx.vout[0].scriptPubKey.hex;
+                        let promises = [];
+                        for (let i in receiver_list)
+                            promises.push(sendTokens_raw(privKey, receiver_list[i], token, amount_list[i], split_txid, i, scriptPubKey));
+                        Promise.allSettled(promises).then(results => {
+                            let success = Object.fromEntries(results.filter(r => r.status == 'fulfilled').map(r => r.value));
+                            let failed = Object.fromEntries(results.filter(r => r.status == 'rejected').map(r => r.reason));
+                            resolve(success, failed);
+                        })
+                    }).catch(error => reject(error))
+                }).catch(error => reject(error))
+
+            }).catch(error => reject(error))
+
+
+        })
+    }
+
 })(window.floWebWallet = {});