Fix/windows install directory confirmation (#16783)

* fix(windows): warn before removing installation directory

Signed-off-by: fufesou <linlong1266@gmail.com>

* fix(windows): show inline installation directory warning

Signed-off-by: fufesou <linlong1266@gmail.com>

* refactor(windows): simplify installation directory warning

Key the warning widget by its path and remove the optional widget test suite.

Signed-off-by: fufesou <linlong1266@gmail.com>

* fix(windows): limit installation warnings to the selected directory

Share install-directory-not-empty-tip between inline and confirmation warnings, and remove the separate previous-installation warning.

Signed-off-by: fufesou <linlong1266@gmail.com>

* fix(windows): skip directory warnings when reinstalling in place

Signed-off-by: fufesou <linlong1266@gmail.com>

---------

Signed-off-by: fufesou <linlong1266@gmail.com>

flutter/lib/desktop/pages/install_page.dart

@@ -3,6 +3,7 @@ import 'dart:convert';
 import 'package:file_picker/file_picker.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_hbb/common.dart';
+import 'package:flutter_hbb/desktop/widgets/install_directory_confirmation.dart';
 import 'package:flutter_hbb/desktop/widgets/tabbar_widget.dart';
 import 'package:flutter_hbb/models/platform_model.dart';
 import 'package:flutter_hbb/models/state_model.dart';
@@ -164,27 +165,46 @@ class _InstallPageBodyState extends State<_InstallPageBody>
             children: [
               Text(translate('Installation'),
                   style: Theme.of(context).textTheme.headlineMedium),
-              Row(
+              Table(
+                columnWidths: const {
+                  0: IntrinsicColumnWidth(),
+                  2: IntrinsicColumnWidth(),
+                },
+                defaultVerticalAlignment: TableCellVerticalAlignment.middle,
                 children: [
-                  Text('${translate('Installation Path')}:')
-                      .marginOnly(right: 10),
-                  Expanded(
-                    child: TextField(
-                      controller: controller,
-                      readOnly: true,
-                      decoration: InputDecoration(
-                        contentPadding: EdgeInsets.all(0.75 * em),
+                  TableRow(
+                    children: [
+                      Text('${translate('Installation Path')}:')
+                          .marginOnly(right: 10),
+                      TextField(
+                        controller: controller,
+                        readOnly: true,
+                        decoration: InputDecoration(
+                          contentPadding: EdgeInsets.all(0.75 * em),
+                        ),
+                      ).workaroundFreezeLinuxMint().marginOnly(right: 10),
+                      Obx(
+                        () => OutlinedButton.icon(
+                          icon: Icon(Icons.folder_outlined, size: 16),
+                          onPressed:
+                              btnEnabled.value ? selectInstallPath : null,
+                          style: buttonStyle,
+                          label: Text(translate('Change Path')),
+                        ),
                       ),
-                    ).workaroundFreezeLinuxMint().marginOnly(right: 10),
+                    ],
+                  ),
+                  TableRow(
+                    children: [
+                      const SizedBox.shrink(),
+                      ValueListenableBuilder<TextEditingValue>(
+                        valueListenable: controller,
+                        builder: (context, value, child) =>
+                            InstallDirectoryWarning(directoryPath: value.text),
+                      ).marginOnly(right: 10),
+                      const SizedBox.shrink(),
+                    ],
                   ),
-                  Obx(
-                    () => OutlinedButton.icon(
-                      icon: Icon(Icons.folder_outlined, size: 16),
-                      onPressed: btnEnabled.value ? selectInstallPath : null,
-                      style: buttonStyle,
-                      label: Text(translate('Change Path')),
-                    ),
-                  )
                 ],
               ).marginSymmetric(vertical: 2 * em),
               Option(startmenu, label: 'Create start menu shortcuts')
@@ -277,7 +297,9 @@ class _InstallPageBodyState extends State<_InstallPageBody>
         ));
   }
 
-  void install() {
+  Future<void> install() async {
+    if (!btnEnabled.value) return;
+    final installPath = controller.text;
     do_install() {
       btnEnabled.value = false;
       cancelEnabled.value = false;
@@ -286,10 +308,18 @@ class _InstallPageBodyState extends State<_InstallPageBody>
       if (startmenu.value) args += ' startmenu';
       if (desktopicon.value) args += ' desktopicon';
       if (printer.value) args += ' printer';
-      bind.installInstallMe(options: args, path: controller.text);
+      bind.installInstallMe(options: args, path: installPath);
     }
 
-    do_install();
+    btnEnabled.value = false;
+    try {
+      final confirmed =
+          await confirmInstallDirectory(this.context, targetPath: installPath);
+      if (!mounted || !confirmed) return;
+      do_install();
+    } finally {
+      if (mounted && !showProgress.value) btnEnabled.value = true;
+    }
   }
 
   void selectInstallPath() async {

flutter/lib/desktop/widgets/install_directory_confirmation.dart

@@ -0,0 +1,96 @@
+import 'dart:io';
+
+import 'package:flutter/material.dart';
+import 'package:flutter_hbb/common.dart';
+import 'package:flutter_hbb/models/platform_model.dart';
+import 'package:path/path.dart' as path;
+
+const _nonemptyDirectoryWarning = 'install-directory-not-empty-tip';
+
+Future<bool> confirmInstallDirectory(BuildContext context,
+    {required String targetPath}) async {
+  try {
+    final needsWarning = await _needsDirectoryWarning(targetPath);
+    if (!context.mounted) return false;
+    if (!needsWarning) return true;
+    return await _showDirectoryDialog(
+        context, '${translate(_nonemptyDirectoryWarning)}\n$targetPath');
+  } on FileSystemException catch (error) {
+    debugPrint('Failed to inspect installation directory: $error');
+    if (context.mounted) {
+      await _showDirectoryDialog(context, error.toString(), isError: true);
+    }
+    return false;
+  }
+}
+
+Future<bool> _needsDirectoryWarning(String directoryPath) async {
+  if (bind.mainIsInstalled() &&
+      path.equals(directoryPath, bind.installInstallPath())) {
+    return false;
+  }
+  final directory = Directory(directoryPath);
+  return await directory.exists() &&
+      !await directory.list(followLinks: false).isEmpty;
+}
+
+Future<bool> _showDirectoryDialog(BuildContext context, String message,
+    {bool isError = false}) async {
+  final confirmed = await showDialog<bool>(
+    context: context,
+    builder: (dialogContext) => AlertDialog(
+      scrollable: true,
+      title: Text(translate(isError ? 'Error' : 'Warning')),
+      content: SelectableText(message),
+      actions: [
+        dialogButton(isError ? 'OK' : 'Cancel',
+            isOutline: !isError,
+            onPressed: () => Navigator.of(dialogContext).pop(false)),
+        if (!isError)
+          dialogButton('Continue',
+              onPressed: () => Navigator.of(dialogContext).pop(true)),
+      ],
+    ),
+  );
+  return confirmed == true;
+}
+
+class InstallDirectoryWarning extends StatefulWidget {
+  InstallDirectoryWarning({required this.directoryPath})
+      : super(key: ValueKey(directoryPath));
+
+  final String directoryPath;
+
+  @override
+  State<InstallDirectoryWarning> createState() =>
+      _InstallDirectoryWarningState();
+}
+
+class _InstallDirectoryWarningState extends State<InstallDirectoryWarning> {
+  static const _spacing = 8.0;
+  late final Future<bool> _needsWarning =
+      _needsDirectoryWarning(widget.directoryPath);
+
+  @override
+  Widget build(BuildContext context) {
+    return FutureBuilder<bool>(
+      future: _needsWarning,
+      builder: (context, snapshot) {
+        if (!snapshot.hasError && snapshot.data != true) {
+          return const SizedBox.shrink();
+        }
+        return Padding(
+          padding: const EdgeInsets.symmetric(vertical: _spacing),
+          child: Text(
+              snapshot.hasError
+                  ? '${translate('Error')}: ${snapshot.error}'
+                  : translate(_nonemptyDirectoryWarning),
+              style: TextStyle(
+                  color: snapshot.hasError
+                      ? Theme.of(context).colorScheme.error
+                      : Colors.orange.shade700)),
+        );
+      },
+    );
+  }
+}