Add "Copy to clipboard" button to message action sheet

lib/model/binding.dart

@@ -1,3 +1,4 @@
+import 'package:device_info_plus/device_info_plus.dart' as device_info_plus;
 import 'package:flutter/foundation.dart';
 import 'package:url_launcher/url_launcher.dart' as url_launcher;
 export 'package:url_launcher/url_launcher.dart' show LaunchMode;
@@ -72,6 +73,38 @@ abstract class ZulipBinding {
     Uri url, {
     url_launcher.LaunchMode mode = url_launcher.LaunchMode.platformDefault,
   });
+
+  /// Provides device and operating system information,
+  /// via package:device_info_plus.
+  ///
+  /// This wraps [device_info_plus.DeviceInfoPlugin.deviceInfo].
+  Future<BaseDeviceInfo> deviceInfo();
+}
+
+/// Like [device_info_plus.BaseDeviceInfo], but without things we don't use.
+abstract class BaseDeviceInfo {
+  BaseDeviceInfo();
+}
+
+/// Like [device_info_plus.AndroidDeviceInfo], but without things we don't use.
+class AndroidDeviceInfo extends BaseDeviceInfo {
+  /// The Android SDK version.
+  ///
+  /// Possible values are defined in:
+  ///   https://developer.android.com/reference/android/os/Build.VERSION_CODES.html
+  final int sdkInt;
+
+  AndroidDeviceInfo({required this.sdkInt});
+}
+
+/// Like [device_info_plus.IosDeviceInfo], but without things we don't use.
+class IosDeviceInfo extends BaseDeviceInfo {
+  /// The current operating system version.
+  ///
+  /// See: https://developer.apple.com/documentation/uikit/uidevice/1620043-systemversion
+  final String systemVersion;
+
+  IosDeviceInfo({required this.systemVersion});
 }
 
 /// A concrete binding for use in the live application.
@@ -103,4 +136,14 @@ class LiveZulipBinding extends ZulipBinding {
   }) {
     return url_launcher.launchUrl(url, mode: mode);
   }
+
+  @override
+  Future<BaseDeviceInfo> deviceInfo() async {
+    final deviceInfo = await device_info_plus.DeviceInfoPlugin().deviceInfo;
+    return switch (deviceInfo) {
+      device_info_plus.AndroidDeviceInfo(:var version)   => AndroidDeviceInfo(sdkInt: version.sdkInt),
+      device_info_plus.IosDeviceInfo(:var systemVersion) => IosDeviceInfo(systemVersion: systemVersion),
+      _                                                  => throw UnimplementedError(),
+    };
+  }
 }

lib/widgets/action_sheet.dart

@@ -1,9 +1,11 @@
 import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
 import 'package:share_plus/share_plus.dart';
 
 import '../api/exception.dart';
 import '../api/model/model.dart';
 import '../api/route/messages.dart';
+import 'clipboard.dart';
 import 'compose_box.dart';
 import 'dialog.dart';
 import 'draggable_scrollable_modal_bottom_sheet.dart';
@@ -28,6 +30,7 @@ void showMessageActionSheet({required BuildContext context, required Message mes
           message: message,
           messageListContext: context,
         ),
+        CopyButton(message: message, messageListContext: context),
       ]);
     });
 }
@@ -87,6 +90,53 @@ class ShareButton extends MessageActionSheetMenuItemButton {
   };
 }
 
+/// Fetch and return the raw Markdown content for [messageId],
+/// showing an error dialog on failure.
+Future<String?> fetchRawContentWithFeedback({
+  required BuildContext context,
+  required int messageId,
+  required String errorDialogTitle,
+}) async {
+    Message? fetchedMessage;
+    String? errorMessage;
+    // TODO, supported by reusable code:
+    // - (?) Retry with backoff on plausibly transient errors.
+    // - If request(s) take(s) a long time, show snackbar with cancel
+    //   button, like "Still working on quote-and-reply…".
+    //   On final failure or success, auto-dismiss the snackbar.
+    try {
+      fetchedMessage = await getMessageCompat(PerAccountStoreWidget.of(context).connection,
+        messageId: messageId,
+        applyMarkdown: false,
+      );
+      if (fetchedMessage == null) {
+        errorMessage = 'That message does not seem to exist.';
+      }
+    } catch (e) {
+      switch (e) {
+        case ZulipApiException():
+          errorMessage = e.message;
+        // TODO specific messages for common errors, like network errors
+        //   (support with reusable code)
+        default:
+          errorMessage = 'Could not fetch message source.';
+      }
+    }
+
+    if (!context.mounted) return null;
+
+    if (fetchedMessage == null) {
+      assert(errorMessage != null);
+      // TODO(?) give no feedback on error conditions we expect to
+      //   flag centrally in event polling, like invalid auth,
+      //   user/realm deactivated. (Support with reusable code.)
+      await showErrorDialog(context: context,
+        title: errorDialogTitle, message: errorMessage);
+    }
+
+    return fetchedMessage?.content;
+}
+
 class QuoteAndReplyButton extends MessageActionSheetMenuItemButton {
   QuoteAndReplyButton({
     super.key,
@@ -121,42 +171,11 @@ class QuoteAndReplyButton extends MessageActionSheetMenuItemButton {
         message: message,
       );
 
-    Message? fetchedMessage;
-    String? errorMessage;
-    // TODO, supported by reusable code:
-    // - (?) Retry with backoff on plausibly transient errors.
-    // - If request(s) take(s) a long time, show snackbar with cancel
-    //   button, like "Still working on quote-and-reply…".
-    //   On final failure or success, auto-dismiss the snackbar.
-    try {
-      fetchedMessage = await getMessageCompat(PerAccountStoreWidget.of(messageListContext).connection,
-        messageId: message.id,
-        applyMarkdown: false,
-      );
-      if (fetchedMessage == null) {
-        errorMessage = 'That message does not seem to exist.';
-      }
-    } catch (e) {
-      switch (e) {
-        case ZulipApiException():
-          errorMessage = e.message;
-        // TODO specific messages for common errors, like network errors
-        //   (support with reusable code)
-        default:
-          errorMessage = 'Could not fetch message source.';
-      }
-    }
-
-    if (!messageListContext.mounted) return;
-
-    if (fetchedMessage == null) {
-      assert(errorMessage != null);
-      // TODO(?) give no feedback on error conditions we expect to
-      //   flag centrally in event polling, like invalid auth,
-      //   user/realm deactivated. (Support with reusable code.)
-      await showErrorDialog(context: messageListContext,
-        title: 'Quotation failed', message: errorMessage);
-    }
+    final rawContent = await fetchRawContentWithFeedback(
+      context: messageListContext,
+      messageId: message.id,
+      errorDialogTitle: 'Quotation failed',
+    );
 
     if (!messageListContext.mounted) return;
 
@@ -167,10 +186,43 @@ class QuoteAndReplyButton extends MessageActionSheetMenuItemButton {
     composeBoxController.contentController
       .registerQuoteAndReplyEnd(PerAccountStoreWidget.of(messageListContext), tag,
         message: message,
-        rawContent: fetchedMessage?.content,
+        rawContent: rawContent,
       );
     if (!composeBoxController.contentFocusNode.hasFocus) {
       composeBoxController.contentFocusNode.requestFocus();
     }
   };
 }
+
+class CopyButton extends MessageActionSheetMenuItemButton {
+  CopyButton({
+    super.key,
+    required super.message,
+    required super.messageListContext,
+  });
+
+  @override get icon => Icons.copy;
+
+  @override get label => 'Copy message text';
+
+  @override get onPressed => (BuildContext context) async {
+    // Close the message action sheet. We won't be showing request progress,
+    // but hopefully it won't take long at all, and
+    // fetchRawContentWithFeedback has a TODO for giving feedback if it does.
+    Navigator.of(context).pop();
+
+    final rawContent = await fetchRawContentWithFeedback(
+      context: messageListContext,
+      messageId: message.id,
+      errorDialogTitle: 'Copying failed',
+    );
+
+    if (rawContent == null) return;
+
+    if (!messageListContext.mounted) return;
+
+    // TODO(i18n)
+    copyWithPopup(context: context, successContent: const Text('Message copied'),
+      data: ClipboardData(text: rawContent));
+  };
+}

lib/widgets/clipboard.dart

@@ -1,7 +1,8 @@
-import 'package:device_info_plus/device_info_plus.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
 
+import '../model/binding.dart';
+
 /// Copies [data] to the clipboard and shows a popup on success.
 ///
 /// Must have a [Scaffold] ancestor.
@@ -17,26 +18,18 @@ void copyWithPopup({
   required Widget successContent,
 }) async {
   await Clipboard.setData(data);
-  final deviceInfo = await DeviceInfoPlugin().deviceInfo;
-
-  // https://github.com/dart-lang/linter/issues/4007
-  // ignore: use_build_context_synchronously
-  if (!context.mounted) {
-    return;
-  }
+  final deviceInfo = await ZulipBinding.instance.deviceInfo();
 
-  final bool shouldShowSnackbar;
-  switch (deviceInfo) {
-    case AndroidDeviceInfo(:var version):
-      // Android 13+ shows its own popup on copying to the clipboard,
-      // so we suppress ours, following the advice at:
-      //   https://developer.android.com/develop/ui/views/touch-and-input/copy-paste#duplicate-notifications
-      // TODO(android-sdk-33): Simplify this and dartdoc
-      shouldShowSnackbar = version.sdkInt <= 32;
-    default:
-      shouldShowSnackbar = true;
-  }
+  if (!context.mounted) return;
 
+  final shouldShowSnackbar = switch (deviceInfo) {
+    // Android 13+ shows its own popup on copying to the clipboard,
+    // so we suppress ours, following the advice at:
+    //   https://developer.android.com/develop/ui/views/touch-and-input/copy-paste#duplicate-notifications
+    // TODO(android-sdk-33): Simplify this and dartdoc
+    AndroidDeviceInfo(:var sdkInt) => sdkInt <= 32,
+    _                              => true,
+  };
   if (shouldShowSnackbar) {
     ScaffoldMessenger.of(context).showSnackBar(
       SnackBar(behavior: SnackBarBehavior.floating, content: successContent));

test/flutter_checks.dart

@@ -4,7 +4,11 @@ import 'dart:ui';
 import 'package:checks/checks.dart';
 import 'package:flutter/foundation.dart';
 import 'package:flutter/painting.dart';
+import 'package:flutter/services.dart';
 
+extension ClipboardDataChecks on Subject<ClipboardData> {
+  Subject<String?> get text => has((d) => d.text, 'text');
+}
 
 extension ValueNotifierChecks<T> on Subject<ValueNotifier<T>> {
   Subject<T> get value => has((c) => c.value, 'value');

test/model/binding.dart

@@ -59,6 +59,7 @@ class TestZulipBinding extends ZulipBinding {
 
     launchUrlResult = true;
     _launchUrlCalls = null;
+    deviceInfoResult = _defaultDeviceInfoResult;
   }
 
   /// The current global store offered to a [GlobalStoreWidget].
@@ -126,4 +127,15 @@ class TestZulipBinding extends ZulipBinding {
     (_launchUrlCalls ??= []).add((url: url, mode: mode));
     return launchUrlResult;
   }
+
+  /// The value that `ZulipBinding.instance.deviceInfo()` should return.
+  ///
+  /// See also [takeDeviceInfoCalls].
+  BaseDeviceInfo deviceInfoResult = _defaultDeviceInfoResult;
+  static final _defaultDeviceInfoResult = AndroidDeviceInfo(sdkInt: 33);
+
+  @override
+  Future<BaseDeviceInfo> deviceInfo() {
+    return Future(() => deviceInfoResult);
+  }
 }

test/test_clipboard.dart

@@ -0,0 +1,27 @@
+import 'package:flutter/services.dart';
+
+// Inspired by MockClipboard in test code in the Flutter tree:
+//   https://github.com/flutter/flutter/blob/de26ad0a8/packages/flutter/test/widgets/clipboard_utils.dart
+class MockClipboard {
+  MockClipboard();
+
+  dynamic clipboardData;
+
+  Future<Object?> handleMethodCall(MethodCall methodCall) async {
+    switch (methodCall.method) {
+      case 'Clipboard.getData':
+        return clipboardData;
+      case 'Clipboard.hasStrings':
+        final clipboardDataMap = clipboardData as Map<String, dynamic>?;
+        final text = clipboardDataMap?['text'] as String?;
+        return {'value': text != null && text.isNotEmpty};
+      case 'Clipboard.setData':
+        clipboardData = methodCall.arguments;
+      default:
+        if (methodCall.method.startsWith('Clipboard.')) {
+          throw UnimplementedError();
+        }
+    }
+    return null;
+  }
+}