implement saving image, sharing image, reading settings and chapters view

lib/utils/file_type.dart

@@ -0,0 +1,19 @@
+import 'dart:typed_data';
+
+import 'package:mime/mime.dart';
+
+class FileType {
+  final String ext;
+  final String mime;
+
+  const FileType(this.ext, this.mime);
+}
+
+FileType detectFileType(List<int> data) {
+  var mime = lookupMimeType('no-file', headerBytes: data);
+  var ext = mime == null ? '' : extensionFromMime(mime);
+  if(ext == 'jpe') {
+    ext = 'jpg';
+  }
+  return FileType(".$ext", mime ?? 'application/octet-stream');
+}

lib/utils/io.dart

@@ -6,14 +6,15 @@ import 'package:flutter/services.dart';
 import 'package:venera/foundation/app.dart';
 import 'package:venera/utils/ext.dart';
 import 'package:path/path.dart' as p;
+import 'package:share_plus/share_plus.dart' as s;
 
 export 'dart:io';
 
-
 class FilePath {
   const FilePath._();
 
-  static String join(String path1, String path2, [String? path3, String? path4, String? path5]) {
+  static String join(String path1, String path2,
+      [String? path3, String? path4, String? path5]) {
     return p.join(path1, path2, path3, path4, path5);
   }
 }
@@ -121,7 +122,7 @@ class DirectoryPicker {
   final _methodChannel = const MethodChannel("venera/method_channel");
 
   Future<Directory?> pickDirectory() async {
-    if(App.isWindows || App.isLinux) {
+    if (App.isWindows || App.isLinux) {
       var d = await FilePicker.platform.getDirectoryPath();
       _directory = d;
       return d == null ? null : Directory(d);
@@ -138,15 +139,50 @@ class DirectoryPicker {
   }
 
   Future<void> dispose() async {
-    if(_directory == null) {
+    if (_directory == null) {
       return;
     }
-    if(App.isAndroid && _directory != null) {
+    if (App.isAndroid && _directory != null) {
       return Directory(_directory!).deleteIgnoreError(recursive: true);
     }
-    if(App.isIOS || App.isMacOS) {
+    if (App.isIOS || App.isMacOS) {
       await _methodChannel.invokeMethod("stopAccessingSecurityScopedResource");
     }
   }
 }
 
+Future<void> saveFile(
+    {required Uint8List data, required String filename}) async {
+  var res = await FilePicker.platform.saveFile(
+    bytes: data,
+    fileName: filename,
+    lockParentWindow: true,
+  );
+  if (App.isDesktop && res != null) {
+    await File(res).writeAsBytes(data);
+  }
+}
+
+class Share {
+  static void shareFile({
+    required Uint8List data,
+    required String filename,
+    required String mime,
+  }) {
+    if (!App.isWindows) {
+      s.Share.shareXFiles(
+        [s.XFile.fromData(data, mimeType: mime)],
+        fileNameOverrides: [filename],
+      );
+    } else {
+      // write to cache
+      var file = File(FilePath.join(Directory.systemTemp.path, filename));
+      file.writeAsBytesSync(data);
+      s.Share.shareXFiles([s.XFile(file.path)]);
+    }
+  }
+
+  static void shareText(String text) {
+    s.Share.share(text);
+  }
+}