minor bug fixes

lib/src/util/reboot.dart

@@ -0,0 +1,44 @@
+import 'dart:io';
+
+import 'package:archive/archive_io.dart';
+import 'package:reboot_launcher/src/util/locate_binary.dart';
+import 'package:http/http.dart' as http;
+import 'package:crypto/crypto.dart';
+import 'package:shared_preferences/shared_preferences.dart';
+
+const _rebootUrl =
+    "https://nightly.link/UWUFN/Universal-Walking-Simulator/workflows/msbuild/master/Release.zip";
+
+Future<DateTime?> _getLastUpdate(SharedPreferences preferences) async {
+  var timeInMillis = preferences.getInt("last_update");
+  return timeInMillis != null ? DateTime.fromMillisecondsSinceEpoch(timeInMillis) : null;
+}
+
+Future<File> downloadRebootDll(SharedPreferences preferences) async {
+  var now = DateTime.now();
+  var oldRebootDll = locateBinary("reboot.dll");
+  var lastUpdate = await _getLastUpdate(preferences);
+  var exists = await oldRebootDll.exists();
+  if(lastUpdate != null && now.difference(lastUpdate).inHours <= 24 && exists){
+    return oldRebootDll;
+  }
+
+  var response = await http.get(Uri.parse(_rebootUrl));
+  var tempZip = File("${Platform.environment["Temp"]}/reboot.zip")
+    ..writeAsBytesSync(response.bodyBytes);
+  await extractFileToDisk(tempZip.path, binariesDirectory);
+  locateBinary("Project Reboot.pdb").delete();
+  var rebootDll = locateBinary("Project Reboot.dll");
+  if (!(await rebootDll.exists())) {
+    throw Exception("Missing reboot dll");
+  }
+
+  preferences.setInt("last_update", now.millisecondsSinceEpoch);
+  if (exists && sha1.convert(await oldRebootDll.readAsBytes()) == sha1.convert(await rebootDll.readAsBytes())) {
+    rebootDll.delete();
+    return oldRebootDll;
+  }
+
+  await rebootDll.rename(oldRebootDll.path);
+  return oldRebootDll;
+}