WdtWeatherSource refactoring.

1Weather/Network/Weather/WdtWeatherSource.swift

@@ -22,6 +22,7 @@ public class WdtWeatherSource: WeatherSource {
     private let log = Logger(componentName: "WdtWeatherSource")
     private static let updateUrlMega = "https://1weather.onelouder.com/feeds/onelouder/mega.php"
     private static let updateUrlMicro = "https://1weather.onelouder.com/feeds/onelouder2/fm.php"
+    private static let updateUrlHealth = "https://1weather.onelouder.com/feeds/onelouder/health.php"
     
     /// This queue is needed to synchronize access to locationsBeingUpdated. Also, to make logging more clear.
     private let internalQueue: OperationQueue = {
@@ -50,16 +51,13 @@ public class WdtWeatherSource: WeatherSource {
         }
     }
     
-    /// This method should only be run from the internalQueue.
-    private func updateWeatherInternal(for location: Location, type: WeatherUpdateType, completion: @escaping WeatherSourceCompletion) {
-        guard !locationsBeingUpdated.contains(location) else {
-            completion(nil, WdtWeatherSourceError.alreadyBeingUpdated)
-            return
-        }
-        locationsBeingUpdated.insert(location)
-        
+    private func buildURL(for location: Location, type: WeatherUpdateType, uvRequest: Bool) -> Result<URL, WdtWeatherSourceError> {
         var urlToUse = WdtWeatherSource.updateUrlMega
-        if type == .preferIncremental && location.lastWeatherUpdateDate != nil {
+        if uvRequest {
+            log.debug("Start update (health) for \(location)")
+            urlToUse = WdtWeatherSource.updateUrlHealth
+        }
+        else if type == .preferIncremental && location.lastWeatherUpdateDate != nil {
             urlToUse = WdtWeatherSource.updateUrlMicro
             log.debug("Start update (incremental) for \(location)")
         }
@@ -71,12 +69,10 @@ public class WdtWeatherSource: WeatherSource {
             log.error("Couldn't create URLComponents from \(urlToUse)")
             assertionFailure("Should never happen. The URL should be correct.")
             // Should never happen, but a lot of stuff that should never happen happens from time to time, so let's at least handle it gracefully in prod.
-            completion(nil, WdtWeatherSourceError.badUrl)
-            return
+            return .failure(.badUrl)
         }
         
         var queryParameters = [String: String]()
-        
         if let coordinates = location.coordinates {
             queryParameters["LAT"] = String(format: "%.5f", coordinates.latitude)
             queryParameters["LON"] = String(format: "%.5f", coordinates.longitude)
@@ -88,45 +84,54 @@ public class WdtWeatherSource: WeatherSource {
             queryParameters["COUNTRY"] = location.countryName
         }
         guard !queryParameters.isEmpty else {
-            completion(nil, WdtWeatherSourceError.insufficientLocationInfo)
             log.error("Not enough information about location.")
-            return
+            return .failure(.insufficientLocationInfo)
         }
         queryParameters["UNITS"] = "all"
         urlComponents.queryItems = queryParameters.map { URLQueryItem(name: $0, value: $1) }
         
         guard let url = urlComponents.url else {
             log.error("Couldn't create URL with params: \(queryParameters)")
-            completion(nil, WdtWeatherSourceError.badUrl)
-            return
+            return .failure(.badUrl)
         }
         log.debug("Network request (\(location)): \(url)")
-        
-        let urlSession = URLSession.shared
-        let dataTask = urlSession.dataTask(with: url) { [weak self] (data, reponse, error) in
-            guard let self = self else { return }
-            guard let data = data else {
-                self.log.debug("Network response (\(location)): error \(String(describing: error))")
-                completion(nil, WdtWeatherSourceError.networkError(error))
-                return
-            }
-            let responseBodyString = String(data: data, encoding: .utf8) ?? "<couldn't show as string"
-            self.log.debug("Network response (\(location)): \(responseBodyString)")
-            let decoder = XMLDecoder()
-            do {
-                let locationResponse = try decoder.decode(WdtLocationResponse.self, from: data)
-                guard let newLocation = try self.applyChangesTo(location: location, from: locationResponse) else {
-                    completion(nil, WdtWeatherSourceError.badServerResponse(error))
+        return .success(url)
+    }
+    
+    /// This method should only be run from the internalQueue.
+    private func updateWeatherInternal(for location: Location, type: WeatherUpdateType, completion: @escaping WeatherSourceCompletion) {
+        let urlBuildResult = buildURL(for: location, type: type, uvRequest: false)
+        switch urlBuildResult {
+        case .failure(let error):
+            completion(nil, error)
+            return
+        case .success(let url):
+            let urlSession = URLSession.shared
+            let dataTask = urlSession.dataTask(with: url) { [weak self] (data, reponse, error) in
+                guard let self = self else { return }
+                guard let data = data else {
+                    self.log.debug("Network response (\(location)): error \(String(describing: error))")
+                    completion(nil, WdtWeatherSourceError.networkError(error))
                     return
                 }
-                
-                completion(newLocation, nil)
-            }
-            catch {
-                completion(nil, WdtWeatherSourceError.badServerResponse(error))
+                let responseBodyString = String(data: data, encoding: .utf8) ?? "<couldn't show as string"
+                self.log.debug("Network response (\(location)): \(responseBodyString)")
+                let decoder = XMLDecoder()
+                do {
+                    let locationResponse = try decoder.decode(WdtLocationResponse.self, from: data)
+                    guard let newLocation = try self.applyChangesTo(location: location, from: locationResponse) else {
+                        completion(nil, WdtWeatherSourceError.badServerResponse(error))
+                        return
+                    }
+                    
+                    completion(newLocation, nil)
+                }
+                catch {
+                    completion(nil, WdtWeatherSourceError.badServerResponse(error))
+                }
             }
+            dataTask.resume()
         }
-        dataTask.resume()
     }
     
     private func applyChangesTo(location: Location, from locationResponse: WdtLocationResponse) throws -> Location? {