Check if window under test is hidden or minimized in refocus()

Took a moment to rewrite the intersection checking code to use
`std::set_intersection`. Maybe a tad more readable?

src/miral/basic_window_manager.cpp

@@ -17,8 +17,10 @@
 #include "basic_window_manager.h"
 #include "display_configuration_listeners.h"
 
+#include "mir_toolkit/common.h"
 #include "miral/window_manager_tools.h"
 
+#include <iterator>
 #include <mir/log.h>
 #include <mir/executor.h>
 #include <mir/scene/session.h>
@@ -291,25 +293,38 @@ void miral::BasicWindowManager::refocus(
     if (can_activate_window_for_session_in_workspace(application, workspaces_containing_window))
         return;
 
+    auto const is_hidden = [this](auto const& w)
+    {
+        auto const& info = info_for(w);
+        return info.state() != mir_window_state_hidden || info.state() == mir_window_state_minimized;
+    };
+
     // Try to activate to recently active window of any application in a shared workspace
     {
         miral::Window new_focus;
 
-        mru_active_windows.enumerate([&](miral::Window& window)
+        auto workspaces_containing_window_mut = workspaces_containing_window;
+        // Need to sort only once
+        std::sort(workspaces_containing_window_mut.begin(), workspaces_containing_window_mut.end());
+
+        mru_active_windows.enumerate([&](miral::Window& other_window)
             {
-                // select_active_window() calls set_focus_to() which updates mru_active_windows and changes window
-                auto const w = window;
+                if(is_hidden(other_window)) return true;
 
-                for (auto const& workspace : workspaces_containing(w))
-                {
-                    for (auto const& ww : workspaces_containing_window)
-                    {
-                        if (ww == workspace)
-                        {
-                            return !(new_focus = select_active_window(w));
-                        }
-                    }
-                }
+                auto workspaces_containing_other_window = workspaces_containing(other_window);
+                std::sort(workspaces_containing_other_window.begin(), workspaces_containing_other_window.end());
+
+                auto intersection = std::vector<std::shared_ptr<Workspace>>();
+
+                std::set_intersection(
+                    workspaces_containing_window_mut.begin(),
+                    workspaces_containing_window_mut.end(),
+                    workspaces_containing_other_window.begin(),
+                    workspaces_containing_other_window.end(),
+                    std::back_inserter(intersection));
+
+                if(!intersection.empty())
+                    return !(new_focus = select_active_window(other_window));
 
                 return true;
             });
@@ -328,14 +343,12 @@ void miral::BasicWindowManager::refocus(
             {
                 // select_active_window() calls set_focus_to() which updates mru_active_windows and changes window
                 auto const w = window;
+                if(is_hidden(w)) return true;
                 return !(new_focus = select_active_window(w));
             });
 
         if (new_focus) return;
     }
-
-    // Fallback to cycling through applications
-    focus_next_application();
 }
 
 void miral::BasicWindowManager::erase(miral::WindowInfo const& info)
@@ -2993,4 +3006,4 @@ void miral::BasicWindowManager::move_cursor_to(mir::geometry::PointF point)
             sink->handle_input(std::move(event));
         });
     });
-}
+}