Can update virtual directory

lib/ui/dialogs/virtual_directory_dialog.dart

@@ -0,0 +1,137 @@
+import 'package:comunic/helpers/settings_helper.dart';
+import 'package:comunic/ui/widgets/safe_state.dart';
+import 'package:comunic/utils/intl_utils.dart';
+import 'package:flutter/cupertino.dart';
+import 'package:flutter/material.dart';
+
+/// Show a dialog to offer the user to pick a virtual directory
+///
+/// @author Pierre HUBERT
+
+enum VirtualDirectoryTargetType { USER }
+
+enum _CheckStatus { EMPTY, PENDING, VALID, INVALID }
+
+Future<String> showVirtualDirectoryDialog({
+  @required BuildContext context,
+  @required String initialDirectory,
+  @required int id,
+  @required VirtualDirectoryTargetType type,
+}) async {
+  assert(context != null);
+  assert(initialDirectory != null);
+  assert(id != null);
+  assert(type != null);
+
+  return await showDialog<String>(
+      context: context,
+      builder: (c) => _VirtualDirectoryPicker(
+          type: type, id: id, initialDirectory: initialDirectory));
+}
+
+class _VirtualDirectoryPicker extends StatefulWidget {
+  final String initialDirectory;
+  final int id;
+  final VirtualDirectoryTargetType type;
+
+  const _VirtualDirectoryPicker({
+    Key key,
+    @required this.initialDirectory,
+    @required this.id,
+    @required this.type,
+  })  : assert(initialDirectory != null),
+        assert(id != null),
+        assert(type != null),
+        super(key: key);
+
+  @override
+  __VirtualDirectoryPickerState createState() =>
+      __VirtualDirectoryPickerState();
+}
+
+class __VirtualDirectoryPickerState extends SafeState<_VirtualDirectoryPicker> {
+  TextEditingController _controller;
+  var _status = _CheckStatus.VALID;
+
+  String get _currentValue => _controller.text;
+
+  @override
+  void initState() {
+    super.initState();
+    _controller = TextEditingController(text: widget.initialDirectory);
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return AlertDialog(
+      title: Text(tr("Choose a virtual directory")),
+
+      // Dialog content
+      content: TextField(
+        controller: _controller,
+        onChanged: (s) => _checkValue(),
+        decoration: InputDecoration(
+          alignLabelWithHint: true,
+          labelText: tr("Virtual directory"),
+          helperText: _status == _CheckStatus.PENDING
+              ? tr("Checking availability...")
+              : (_status == _CheckStatus.VALID
+                  ? tr("You can use this virtual directory.")
+                  : null),
+          errorText: _status == _CheckStatus.INVALID
+              ? tr("This virtual directory is invalid / unvailable !")
+              : null,
+        ),
+      ),
+
+      // Dialog action
+      actions: <Widget>[
+        // Cancel
+        MaterialButton(
+          onPressed: () => Navigator.of(context).pop(),
+          child: Text(tr("Cancel").toUpperCase()),
+        ),
+
+        // Confirm
+        MaterialButton(
+          onPressed:
+              _status == _CheckStatus.VALID || _status == _CheckStatus.EMPTY
+                  ? () => Navigator.of(context).pop(_currentValue)
+                  : null,
+          child: Text(tr("Confirm").toUpperCase()),
+        ),
+      ],
+    );
+  }
+
+  void _setStatus(_CheckStatus s) => setState(() => _status = s);
+
+  /// Check new given value
+  void _checkValue() async {
+    final value = _currentValue;
+    try {
+      _setStatus(_CheckStatus.PENDING);
+
+      if (value.length == 0) {
+        _setStatus(_CheckStatus.EMPTY);
+        return;
+      }
+
+      // Validate directory. This will throw in case of failure
+      switch (widget.type) {
+        case VirtualDirectoryTargetType.USER:
+          await SettingsHelper.checkUserDirectoryAvailability(value);
+          break;
+      }
+
+      if (_currentValue == value) {
+        _setStatus(_CheckStatus.VALID);
+      }
+    } catch (e, stack) {
+      if (_currentValue == value) {
+        print("Could not validate given directory! $e\n$stack");
+        _setStatus(_CheckStatus.INVALID);
+      }
+    }
+  }
+}