Add config import and export

Services/ConfigService.cs

@@ -61,18 +61,35 @@ public static class ConfigService
         return backupPath;
     }
 
-    public static LauncherConfig Restore(string sourcePath)
+    public static string ExportTo(string destinationPath, LauncherConfig config)
     {
-        if (!File.Exists(sourcePath))
+        if (string.IsNullOrWhiteSpace(destinationPath))
         {
-            throw new FileNotFoundException("The selected config file was not found.", sourcePath);
+            throw new ArgumentException("Choose a destination path for the exported config.", nameof(destinationPath));
         }
 
-        string json = File.ReadAllText(sourcePath);
-        LauncherConfig config = JsonSerializer.Deserialize<LauncherConfig>(json, JsonOptions)
-            ?? throw new InvalidDataException("The selected config file could not be read.");
+        string? destinationFolder = Path.GetDirectoryName(destinationPath);
+        if (!string.IsNullOrWhiteSpace(destinationFolder))
+        {
+            Directory.CreateDirectory(destinationFolder);
+        }
 
         NormalizeDisplayModes(config);
+        string json = JsonSerializer.Serialize(config, JsonOptions);
+        File.WriteAllText(destinationPath, json);
+        return destinationPath;
+    }
+
+    public static LauncherConfig ImportFrom(string sourcePath)
+    {
+        LauncherConfig config = ReadConfigFile(sourcePath);
+        Save(config);
+        return config;
+    }
+
+    public static LauncherConfig Restore(string sourcePath)
+    {
+        LauncherConfig config = ReadConfigFile(sourcePath);
         Save(config);
         return config;
     }
@@ -135,6 +152,61 @@ public static class ConfigService
         return config;
     }
 
+    private static LauncherConfig ReadConfigFile(string sourcePath)
+    {
+        if (!File.Exists(sourcePath))
+        {
+            throw new FileNotFoundException("The selected config file was not found.", sourcePath);
+        }
+
+        string json = File.ReadAllText(sourcePath);
+        LauncherConfig config;
+        try
+        {
+            config = JsonSerializer.Deserialize<LauncherConfig>(json, JsonOptions)
+                ?? throw new InvalidDataException("The selected config file could not be read.");
+        }
+        catch (JsonException ex)
+        {
+            throw new InvalidDataException("The selected file is not a valid Taskbar Launcher config.", ex);
+        }
+
+        ValidateConfig(config);
+        NormalizeDisplayModes(config);
+        return config;
+    }
+
+    private static void ValidateConfig(LauncherConfig config)
+    {
+        if (config.Items is null)
+        {
+            throw new InvalidDataException("The selected config is missing launcher items.");
+        }
+
+        foreach (LauncherItem item in config.Items)
+        {
+            ValidateItem(item);
+        }
+    }
+
+    private static void ValidateItem(LauncherItem item)
+    {
+        if (item.Children is null)
+        {
+            throw new InvalidDataException($"The item '{item.Title}' has an invalid children list.");
+        }
+
+        if (!Enum.IsDefined(item.Type))
+        {
+            throw new InvalidDataException($"The item '{item.Title}' has an invalid type.");
+        }
+
+        foreach (LauncherItem child in item.Children)
+        {
+            ValidateItem(child);
+        }
+    }
+
     private static void NormalizeDisplayModes(LauncherConfig config)
     {
         foreach (LauncherItem item in config.Items)