Added file sorting

lib/screen/pages/files/files.dart

@@ -16,10 +16,55 @@ class Files extends StatefulWidget {
   State<Files> createState() => _FilesState();
 }
 
+class BetterSortOption {
+  String displayName;
+  int Function(CacheableFile, CacheableFile) compare;
+
+  BetterSortOption({required this.displayName, required this.compare});
+}
+
+enum SortOption {
+  name,
+  date,
+  size
+}
+
+class SortOptions {
+  static Map<SortOption, BetterSortOption> options = {
+    SortOption.name: BetterSortOption(
+      displayName: "Name",
+      compare: (CacheableFile a, CacheableFile b) => a.name.compareTo(b.name)
+    ),
+    SortOption.date: BetterSortOption(
+      displayName: "Datum",
+      compare: (CacheableFile a, CacheableFile b) => a.modifiedAt!.compareTo(b.modifiedAt!)
+    ),
+    SortOption.size: BetterSortOption(
+      displayName: "Größe",
+      compare: (CacheableFile a, CacheableFile b) {
+        if(a.isDirectory || b.isDirectory) return a.isDirectory ? 1 : 0;
+        if(a.size == null) return 0;
+        if(b.size == null) return 1;
+        return a.size!.compareTo(b.size!);
+      }
+    )
+  };
+
+  static String getDisplayName(SortOption option) {
+    return options[option]?.displayName ?? "";
+  }
+
+  static BetterSortOption getOption(SortOption option) {
+    return options[option]!;
+  }
+}
+
 class _FilesState extends State<Files> {
   FilesProps props = FilesProps();
   ListFilesResponse? data;
 
+  SortOption currentSort = SortOption.name;
+
   @override
   void initState() {
     super.initState();
@@ -36,24 +81,34 @@ class _FilesState extends State<Files> {
 
   @override
   Widget build(BuildContext context) {
+    if(data == null) return SizedBox.shrink();
+    List<CacheableFile> files = data!.files.toList()..sort(SortOptions.getOption(currentSort).compare);
+
     return Scaffold(
       appBar: AppBar(
-        title: Text(widget.path.length > 0 ? widget.path.last : "Dateien"),
+        title: Text(widget.path.isNotEmpty ? widget.path.last : "Dateien"),
         actions: [
           IconButton(
             icon: const Icon(Icons.search),
             onPressed: () => {},
           ),
-          IconButton(
+          PopupMenuButton<SortOption>(
             icon: const Icon(Icons.sort),
-            onPressed: () => {},
-          )
+            itemBuilder: (context) {
+              return SortOptions.options.keys.map((key) => PopupMenuItem<SortOption>(value: key, child: Text(SortOptions.getDisplayName(key)))).toList();
+            },
+            onSelected: (e) {
+              setState(() {
+                currentSort = e;
+              });
+            },
+          ),
         ],
       ),
       body: data == null ? const Center(child: CircularProgressIndicator()) : data!.files.isEmpty ? const ErrorView(icon: Icons.folder_off_rounded, text: "Der Ordner ist leer") : ListView.builder(
-          itemCount: data!.files.toList().length,
+          itemCount: files.length,
           itemBuilder: (context, index) {
-            CacheableFile file = data!.files.toList().skip(index).first;
+            CacheableFile file = files.toList().skip(index).first;
             return FileElement(file, widget.path);
           },
         ),