From 3eccbaa8b869f1cac9af01f73d585a83bafd2b4e Mon Sep 17 00:00:00 2001
From: Florian Stinglmayr <fstinglmayr@gmail.com>
Date: Tue, 13 Jul 2021 17:46:06 +0200
Subject: [PATCH] only create filter provider if download is complete

---
 EDDB/API.cs        | 14 +++++++++++---
 MainWindow.xaml.cs | 15 ++++++++++-----
 2 files changed, 21 insertions(+), 8 deletions(-)

diff --git a/EDDB/API.cs b/EDDB/API.cs
index 76b75ea..bddb66f 100644
--- a/EDDB/API.cs
+++ b/EDDB/API.cs
@@ -10,6 +10,10 @@ namespace NonaBGS.EDDB {
 
         private string systems_file = null;
 
+        public delegate void DatabaseAvailableDelegate();
+
+        public event DatabaseAvailableDelegate SystemsAvailable;
+
         public string SystemsFile => systems_file;
 
         public string Cache {
@@ -27,13 +31,15 @@ namespace NonaBGS.EDDB {
             client.DownloadDataCompleted += Client_DownloadDataCompleted;
         }
 
-        private void DownloadFile(string url, string file) {
-            client.DownloadFileAsync(new Uri(url), file);
+        private void DownloadFile(string url, string file, DatabaseAvailableDelegate notifier) {
+            client.DownloadFileAsync(new Uri(url), file, notifier);
         }
 
         public void Download(bool force) {
             if (!HaveSystemsFile || force) {
-                DownloadFile(EDDB_SYSTEMS_ARCHIVE, systems_file);
+                DownloadFile(EDDB_SYSTEMS_ARCHIVE, systems_file, SystemsAvailable);
+            } else if (HaveSystemsFile) {
+                SystemsAvailable?.Invoke();
             }
         }
 
@@ -54,6 +60,8 @@ namespace NonaBGS.EDDB {
         }
 
         private void Client_DownloadDataCompleted(object sender, DownloadDataCompletedEventArgs e) {
+            DatabaseAvailableDelegate notifier = e.UserState as DatabaseAvailableDelegate;
+            notifier?.Invoke();
         }
     }
 }
diff --git a/MainWindow.xaml.cs b/MainWindow.xaml.cs
index 1d87232..d4bb90b 100644
--- a/MainWindow.xaml.cs
+++ b/MainWindow.xaml.cs
@@ -20,8 +20,6 @@ namespace NonaBGS {
         private Report report = new Report();
         private Config config = new Config();
         private API api = null;
-        private PopulatedSystems systems_db = null;
-        private SystemSuggestionProvider systems_provider = null;
 
         public Config Config => config;
 
@@ -54,12 +52,19 @@ namespace NonaBGS {
                 Log(e.Message);
             }
 
+            api.SystemsAvailable += Api_SystemsAvailable;
+
             try {
                 SyncDatabases();
+            } catch (Exception e) {
+                Log(e.Message);
+            }
+        }
 
-                systems_db = api.MakePopulatedSystems();
-                systems_provider = new SystemSuggestionProvider(systems_db);
-                system.Provider = systems_provider;
+        private void Api_SystemsAvailable() {
+            try {
+                var systems_db = api.MakePopulatedSystems();
+                system.Provider = new SystemSuggestionProvider(systems_db);
             } catch (Exception e) {
                 Log(e.Message);
             }