Merge 34e64cbe4dc7f134fe37e4ea12940cefcaaf3821 into 1f59e814f90c3f489f48d68262cb1bf640bf6181

bitchat/Views/Components/CommandSuggestionsView.swift

@@ -6,6 +6,9 @@
 //
 
 import SwiftUI
+#if os(macOS)
+import AppKit
+#endif
 
 struct CommandSuggestionsView: View {
     @EnvironmentObject private var privateConversationModel: PrivateConversationModel
@@ -14,6 +17,16 @@ struct CommandSuggestionsView: View {
 
     @Binding var messageText: String
 
+    /// Row highlighted for keyboard navigation (macOS). Reset whenever the
+    /// filtered list changes so the highlight never outlives its list.
+    @State private var selectedIndex = 0
+    #if os(macOS)
+    /// Arrow keys never reach SwiftUI while the composer's field editor has
+    /// focus (the single-line field consumes moveUp:/moveDown: itself), so
+    /// navigation uses a local key monitor scoped to the panel's lifetime.
+    @State private var keyMonitor: Any?
+    #endif
+
     /// The command already typed in full, once arguments have begun.
     private var typedCommandAlias: String? {
         guard messageText.hasPrefix("/"),
@@ -43,23 +56,91 @@ struct CommandSuggestionsView: View {
         // off-center.
         if !filteredCommands.isEmpty {
             let isUsageReminder = typedCommandAlias != nil
+            let commands = filteredCommands
             VStack(alignment: .leading, spacing: 0) {
-                ForEach(filteredCommands) { command in
+                ForEach(Array(commands.enumerated()), id: \.element.id) { index, command in
                     Button {
                         // In usage-reminder mode the row is informational; an
                         // insert here would wipe the arguments being typed.
                         guard !isUsageReminder else { return }
-                        messageText = command.alias + " "
+                        accept(command)
                     } label: {
                         buttonRow(for: command)
                     }
                     .buttonStyle(.plain)
+                    .background(rowHighlight(index: index, isUsageReminder: isUsageReminder))
                 }
             }
             .themedOverlayPanel()
+            .onChange(of: commands) { _ in
+                selectedIndex = 0
+            }
+            #if os(macOS)
+            .onAppear { installKeyMonitor() }
+            .onDisappear { removeKeyMonitor() }
+            #endif
         }
     }
-    
+
+    /// Inserts the command with a trailing space, ready for arguments.
+    private func accept(_ command: CommandInfo) {
+        messageText = command.alias + " "
+    }
+
+    private func rowHighlight(index: Int, isUsageReminder: Bool) -> Color {
+        #if os(macOS)
+        if !isUsageReminder && index == selectedIndex {
+            return palette.secondary.opacity(0.15)
+        }
+        #endif
+        return .clear
+    }
+
+    #if os(macOS)
+    private func installKeyMonitor() {
+        guard keyMonitor == nil else { return }
+        keyMonitor = NSEvent.addLocalMonitorForEvents(matching: .keyDown) { event in
+            handleKeyDown(event)
+        }
+    }
+
+    private func removeKeyMonitor() {
+        if let keyMonitor {
+            NSEvent.removeMonitor(keyMonitor)
+        }
+        keyMonitor = nil
+    }
+
+    /// Standard autocomplete navigation: arrows move the highlight,
+    /// return/tab insert the highlighted command. Returning nil consumes the
+    /// event, so return completes instead of sending while the list is up;
+    /// the usage-reminder row stays informational and passes everything
+    /// through (return sends the composed command).
+    private func handleKeyDown(_ event: NSEvent) -> NSEvent? {
+        let commands = filteredCommands
+        guard !commands.isEmpty,
+              typedCommandAlias == nil,
+              event.modifierFlags.intersection([.command, .option, .control]).isEmpty else {
+            return event
+        }
+
+        switch event.keyCode {
+        case 126: // up arrow
+            selectedIndex = max(0, selectedIndex - 1)
+            return nil
+        case 125: // down arrow
+            selectedIndex = min(commands.count - 1, selectedIndex + 1)
+            return nil
+        case 36, 48: // return, tab
+            accept(commands[min(selectedIndex, commands.count - 1)])
+            return nil
+        default:
+            return event
+        }
+    }
+    #endif
+
+
     private func buttonRow(for command: CommandInfo) -> some View {
         HStack {
             Text(command.alias)