SWF-21 preliminary fetch function for transactions

- when an account is tapped from `AccountsTableViewInterfaceController`, we will grab the `accountAlias` and pass to this function

SynchronyFinancial/SynchronyFinancial WatchKit Extension/FetchData.swift

@@ -74,4 +74,37 @@ class FetchData {
             }
         }
     }
+
+    static func fetchTransactionsFor(accountAlias: String, completion: @escaping ([Transaction], Error?) -> Void) {
+        // get the transaction header and set value for account alias to the selected account
+        var header = Defaults.headerForTransaction
+        header["account_alias"] = accountAlias
+        var transactions: [Transaction] = []
+        let formatter = DateFormatter()
+        formatter.locale = Locale.current
+        formatter.dateFormat = "yyyyMMdd"
+
+        Alamofire.request(Defaults.TRANS_HISTORY_URL, method: .post, parameters: header, encoding: JSONEncoding.default, headers: Defaults.authHeader).responseJSON { payload in
+            switch payload.result {
+            case .success(let value):
+                let dict = JSON(value).dictionaryValue
+                guard dict["status"]?.dictionaryValue["response_code"]?.string == "0" else { return }
+
+                // let's parse just processed transactions for now
+                dict["processed_transaction_list"]?.arrayValue.forEach {
+                    if let desc = $0["description"].string,
+                        let date = formatter.date(from: $0["transaction_date"].stringValue),
+                        let amountString = $0["transaction_amount"].string,
+                        let amount = Double(amountString) {
+                        let type: TransactionType = $0["payment_amount_type"].stringValue == "" ? .purchase : .reimbursement
+                        transactions.append(Transaction(type: type, amount: amount, merchantID: desc, date: date))
+                    }
+                }
+                completion(transactions, nil)
+            case .failure(let error):
+                NSLog("Error: %s", error.localizedDescription)
+                completion([], error)
+            }
+        }
+    }
 }