✨ Think with messages

lib/screens/chat/room.dart

@@ -34,6 +34,7 @@ import "package:island/widgets/chat/call_button.dart";
 import "package:island/widgets/chat/chat_input.dart";
 import "package:island/widgets/chat/chat_link_attachments.dart";
 import "package:island/widgets/chat/public_room_preview.dart";
+import "package:island/screens/thought/think_sheet.dart";
 
 class ChatRoomScreen extends HookConsumerWidget {
   final String id;
@@ -145,6 +146,10 @@ class ChatRoomScreen extends HookConsumerWidget {
     final attachments = useState<List<UniversalFile>>([]);
     final attachmentProgress = useState<Map<String, Map<int, double>>>({});
 
+    // Selection mode state
+    final isSelectionMode = useState<bool>(false);
+    final selectedMessages = useState<Set<String>>({});
+
     var isLoading = false;
     var isScrollingToMessage = false; // Flag to prevent scroll conflicts
 
@@ -284,6 +289,53 @@ class ChatRoomScreen extends HookConsumerWidget {
       return () => messageController.removeListener(onTextChange);
     }, [messageController]);
 
+    // Selection functions
+    void toggleSelectionMode() {
+      isSelectionMode.value = !isSelectionMode.value;
+      if (!isSelectionMode.value) {
+        selectedMessages.value = {};
+      }
+    }
+
+    void toggleMessageSelection(String messageId) {
+      final newSelection = Set<String>.from(selectedMessages.value);
+      if (newSelection.contains(messageId)) {
+        newSelection.remove(messageId);
+      } else {
+        newSelection.add(messageId);
+      }
+      selectedMessages.value = newSelection;
+    }
+
+    void openThinkingSheet() {
+      if (selectedMessages.value.isEmpty) return;
+
+      // Convert selected message IDs to message data
+      final selectedMessageData =
+          messages.valueOrNull
+              ?.where((msg) => selectedMessages.value.contains(msg.id))
+              .map(
+                (msg) => {
+                  'id': msg.id,
+                  'content': msg.content,
+                  'senderId': msg.senderId,
+                  'createdAt': msg.createdAt.toIso8601String(),
+                  'attachments': msg.attachments,
+                },
+              )
+              .toList() ??
+          [];
+
+      ThoughtSheet.show(
+        context,
+        attachedMessages: selectedMessageData,
+        attachedPosts: [], // Could be extended to include posts
+      );
+
+      // Exit selection mode after opening
+      toggleSelectionMode();
+    }
+
     final compactHeader = isWideScreen(context);
 
     Widget onlineIndicator() => Row(
@@ -571,26 +623,60 @@ class ChatRoomScreen extends HookConsumerWidget {
         final messageWidget = chatIdentity.when(
           skipError: true,
           data:
-              (identity) => MessageItem(
+              (identity) => GestureDetector(
+                onLongPress: () {
+                  if (!isSelectionMode.value) {
+                    toggleSelectionMode();
+                    toggleMessageSelection(message.id);
+                  }
+                },
+                onTap: () {
+                  if (isSelectionMode.value) {
+                    toggleMessageSelection(message.id);
+                  }
+                },
+                child: Container(
+                  color:
+                      selectedMessages.value.contains(message.id)
+                          ? Theme.of(
+                            context,
+                          ).colorScheme.primaryContainer.withOpacity(0.3)
+                          : null,
+                  child: Stack(
+                    children: [
+                      MessageItem(
                         key: settings.disableAnimation ? key : null,
                         message: message,
                         isCurrentUser: identity?.id == message.senderId,
-                onAction: (action) {
+                        onAction:
+                            isSelectionMode.value
+                                ? null
+                                : (action) {
                                   switch (action) {
                                     case MessageItemAction.delete:
-                      messagesNotifier.deleteMessage(message.id);
+                                      messagesNotifier.deleteMessage(
+                                        message.id,
+                                      );
                                     case MessageItemAction.edit:
-                      messageEditingTo.value = message.toRemoteMessage();
+                                      messageEditingTo.value =
+                                          message.toRemoteMessage();
                                       messageController.text =
                                           messageEditingTo.value?.content ?? '';
                                       attachments.value =
                                           messageEditingTo.value!.attachments
-                              .map((e) => UniversalFile.fromAttachment(e))
+                                              .map(
+                                                (e) =>
+                                                    UniversalFile.fromAttachment(
+                                                      e,
+                                                    ),
+                                              )
                                               .toList();
                                     case MessageItemAction.forward:
-                      messageForwardingTo.value = message.toRemoteMessage();
+                                      messageForwardingTo.value =
+                                          message.toRemoteMessage();
                                     case MessageItemAction.reply:
-                      messageReplyingTo.value = message.toRemoteMessage();
+                                      messageReplyingTo.value =
+                                          message.toRemoteMessage();
                                     case MessageItemAction.resend:
                                       messagesNotifier.retryMessage(message.id);
                                   }
@@ -607,6 +693,36 @@ class ChatRoomScreen extends HookConsumerWidget {
                         },
                         progress: attachmentProgress.value[message.id],
                         showAvatar: isLastInGroup,
+                        isSelectionMode: isSelectionMode.value,
+                        isSelected: selectedMessages.value.contains(message.id),
+                        onToggleSelection: toggleMessageSelection,
+                        onEnterSelectionMode: () {
+                          if (!isSelectionMode.value) {
+                            toggleSelectionMode();
+                          }
+                        },
+                      ),
+                      if (selectedMessages.value.contains(message.id))
+                        Positioned(
+                          top: 8,
+                          right: 8,
+                          child: Container(
+                            width: 24,
+                            height: 24,
+                            decoration: BoxDecoration(
+                              color: Theme.of(context).colorScheme.primary,
+                              shape: BoxShape.circle,
+                            ),
+                            child: Icon(
+                              Icons.check,
+                              size: 16,
+                              color: Theme.of(context).colorScheme.onPrimary,
+                            ),
+                          ),
+                        ),
+                    ],
+                  ),
+                ),
               ),
           loading:
               () => MessageItem(
@@ -756,6 +872,7 @@ class ChatRoomScreen extends HookConsumerWidget {
                     ),
                   ),
                 ),
+                if (!isSelectionMode.value)
                   chatRoom.when(
                     data:
                         (room) => Column(
@@ -791,7 +908,8 @@ class ChatRoomScreen extends HookConsumerWidget {
                               onUploadAttachment: uploadAttachment,
                               onDeleteAttachment: (index) async {
                                 final attachment = attachments.value[index];
-                              if (attachment.isOnCloud && !attachment.isLink) {
+                                if (attachment.isOnCloud &&
+                                    !attachment.isLink) {
                                   final client = ref.watch(apiClientProvider);
                                   await client.delete(
                                     '/drive/files/${attachment.data.id}',
@@ -859,6 +977,43 @@ class ChatRoomScreen extends HookConsumerWidget {
                 ),
               ),
             ),
+          // Selection mode toolbar
+          if (isSelectionMode.value)
+            Positioned(
+              left: 0,
+              right: 0,
+              bottom: 0,
+              child: Container(
+                color: Theme.of(context).colorScheme.surface,
+                padding: EdgeInsets.only(
+                  left: 16,
+                  right: 16,
+                  top: 8,
+                  bottom: MediaQuery.of(context).padding.bottom + 8,
+                ),
+                child: Row(
+                  children: [
+                    IconButton(
+                      icon: const Icon(Icons.close),
+                      onPressed: toggleSelectionMode,
+                      tooltip: 'Cancel selection',
+                    ),
+                    const SizedBox(width: 8),
+                    Text(
+                      '${selectedMessages.value.length} selected',
+                      style: Theme.of(context).textTheme.titleMedium,
+                    ),
+                    const Spacer(),
+                    if (selectedMessages.value.isNotEmpty)
+                      FilledButton.icon(
+                        onPressed: openThinkingSheet,
+                        icon: Icon(Symbols.smart_toy),
+                        label: const Text('AI Think'),
+                      ),
+                  ],
+                ),
+              ),
+            ),
         ],
       ),
     );

lib/widgets/chat/message_item.dart

@@ -43,6 +43,10 @@ class MessageItem extends HookConsumerWidget {
   final Map<int, double>? progress;
   final bool showAvatar;
   final Function(String messageId) onJump;
+  final bool isSelectionMode;
+  final bool isSelected;
+  final Function(String messageId)? onToggleSelection;
+  final Function()? onEnterSelectionMode;
 
   const MessageItem({
     super.key,
@@ -52,6 +56,10 @@ class MessageItem extends HookConsumerWidget {
     required this.progress,
     required this.showAvatar,
     required this.onJump,
+    this.isSelectionMode = false,
+    this.isSelected = false,
+    this.onToggleSelection,
+    this.onEnterSelectionMode,
   });
 
   static const kFlashDuration = 300;
@@ -110,6 +118,8 @@ class MessageItem extends HookConsumerWidget {
               isMobile: isMobile,
               remoteMessage: remoteMessage,
               message: message,
+              onToggleSelection: onToggleSelection,
+              onEnterSelectionMode: onEnterSelectionMode,
             ),
       );
     }
@@ -182,9 +192,18 @@ class MessageItem extends HookConsumerWidget {
           child: InkWell(
             mouseCursor: MouseCursor.defer,
             focusColor: Colors.transparent,
-            onLongPress: showActionMenu,
+            onLongPress: () {
+              if (isSelectionMode && onToggleSelection != null) {
+                onToggleSelection!(message.id);
+              } else {
+                showActionMenu();
+              }
+            },
             onSecondaryTap: showActionMenu,
             onTap: () {
+              if (isSelectionMode && onToggleSelection != null) {
+                onToggleSelection!(message.id);
+              } else {
                 // Jump to related message
                 if ([
                       'messages.update',
@@ -194,6 +213,7 @@ class MessageItem extends HookConsumerWidget {
                     message.meta['message_id'] != null) {
                   onJump(message.meta['message_id']);
                 }
+              }
             },
             child: SizedBox(
               width: double.infinity,
@@ -271,6 +291,8 @@ class MessageActionSheet extends StatefulWidget {
   final bool isMobile;
   final dynamic remoteMessage;
   final LocalChatMessage message;
+  final Function(String messageId)? onToggleSelection;
+  final Function()? onEnterSelectionMode;
 
   const MessageActionSheet({
     super.key,
@@ -283,6 +305,8 @@ class MessageActionSheet extends StatefulWidget {
     required this.isMobile,
     required this.remoteMessage,
     required this.message,
+    this.onToggleSelection,
+    this.onEnterSelectionMode,
   });
 
   @override
@@ -461,6 +485,21 @@ class _MessageActionSheetState extends State<MessageActionSheet> {
               },
             ),
 
+            // AI Selection action
+            _ActionListTile(
+              leading: Icon(Symbols.smart_toy),
+              title: Text('Select for AI'),
+              onTap: () {
+                if (widget.onEnterSelectionMode != null) {
+                  widget.onEnterSelectionMode!();
+                  if (widget.onToggleSelection != null) {
+                    widget.onToggleSelection!(widget.message.id);
+                  }
+                }
+                Navigator.pop(context);
+              },
+            ),
+
             if (widget.translatableLanguage) const Divider(),
             if (widget.translatableLanguage)
               _ActionListTile(