don't download automatically, only when a new button is pressed

EDDB/API.cs

@@ -43,15 +43,27 @@ namespace NonaBGS.EDDB {
 
         private void DownloadFile(string url, string file, DatabaseAvailableDelegate notifier) {
             WebClient client = new WebClient();
-            client.DownloadDataCompleted += Client_DownloadDataCompleted;
+            client.DownloadFileCompleted += Client_DownloadFileCompleted;
             client.DownloadFileAsync(new Uri(url), file, notifier);
         }
 
+        private void Client_DownloadFileCompleted(object sender, System.ComponentModel.AsyncCompletedEventArgs e) {
+            DatabaseAvailableDelegate notifier = e.UserState as DatabaseAvailableDelegate;
+            notifier?.Invoke();
+        }
+
         private void TranslateStations() {
             if (!HaveStationsFile) {
                 return;
             }
 
+            var short_time = File.GetLastWriteTimeUtc(StationsFileShort);
+            var long_time = File.GetLastWriteTimeUtc(StationsFile);
+
+            if (HaveStationsFileShort && long_time <= short_time) {
+                return;
+            }
+
             Dictionary<int, List<string>> systems = new Dictionary<int, List<string>>();
 
             using (var str = new StreamReader(StationsFile)) {
@@ -89,6 +101,16 @@ namespace NonaBGS.EDDB {
             }
         }
 
+        public void CheckDatabases() {
+            if (HaveSystemsFile) {
+                SystemsAvailable?.Invoke();
+            }
+
+            if (HaveStationsFile) {
+                StationsAvailable?.Invoke();
+            }
+        }
+
         public void Download(bool force) {
             if (!HaveSystemsFile || force) {
                 DownloadFile(EDDB_SYSTEMS_ARCHIVE, systems_file, SystemsAvailable);
@@ -132,16 +154,9 @@ namespace NonaBGS.EDDB {
                 throw new InvalidOperationException("no local systems file downloaded");
             }
 
-            if (!HaveStationsFileShort) {
-                TranslateStations();
-            }
+            TranslateStations();
 
             return Stations.FromFile(StationsFileShort);
         }
-
-        private void Client_DownloadDataCompleted(object sender, DownloadDataCompletedEventArgs e) {
-            DatabaseAvailableDelegate notifier = e.UserState as DatabaseAvailableDelegate;
-            notifier?.Invoke();
-        }
     }
 }