From 34c613a77683ab0e2beac36276315d037ba222a5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Andr=C3=A9=20Desgualdo=20Pereira?= <desgua@gmail.com>
Date: Thu, 30 Apr 2026 13:36:03 -0300
Subject: [PATCH] add swapfocus patch

---
 config.def.h |  1 +
 dwl.c        | 45 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 46 insertions(+)

diff --git a/config.def.h b/config.def.h
index 8a6eda0..23e502d 100644
--- a/config.def.h
+++ b/config.def.h
@@ -132,6 +132,7 @@ static const Key keys[] = {
 	{ MODKEY,                    XKB_KEY_Return,      zoom,             {0} },
 	{ MODKEY,                    XKB_KEY_Tab,         view,             {0} },
 	{ MODKEY|WLR_MODIFIER_SHIFT, XKB_KEY_c,           killclient,       {0} },
+	{ MODKEY,                    XKB_KEY_s,           swapfocus,        {0} },
 	{ MODKEY,                    XKB_KEY_t,           setlayout,        {.v = &layouts[0]} },
 	{ MODKEY,                    XKB_KEY_f,           setlayout,        {.v = &layouts[1]} },
 	{ MODKEY,                    XKB_KEY_m,           setlayout,        {.v = &layouts[2]} },
diff --git a/dwl.c b/dwl.c
index 101a45f..dac34a6 100644
--- a/dwl.c
+++ b/dwl.c
@@ -332,6 +332,7 @@ static void setsel(struct wl_listener *listener, void *data);
 static void setup(void);
 static void spawn(const Arg *arg);
 static void startdrag(struct wl_listener *listener, void *data);
+static void swapfocus(const Arg *arg);
 static void tag(const Arg *arg);
 static void tagmon(const Arg *arg);
 static void tile(Monitor *m);
@@ -375,6 +376,7 @@ static struct wlr_xdg_activation_v1 *activation;
 static struct wlr_xdg_decoration_manager_v1 *xdg_decoration_mgr;
 static struct wl_list clients; /* tiling order */
 static struct wl_list fstack;  /* focus order */
+static Client *prevclient = NULL;
 static struct wlr_idle_notifier_v1 *idle_notifier;
 static struct wlr_idle_inhibit_manager_v1 *idle_inhibit_mgr;
 static struct wlr_layer_shell_v1 *layer_shell;
@@ -1330,6 +1332,8 @@ destroynotify(struct wl_listener *listener, void *data)
 {
 	/* Called when the xdg_toplevel is destroyed. */
 	Client *c = wl_container_of(listener, c, destroy);
+	if (c == prevclient)
+		prevclient = NULL;
 	wl_list_remove(&c->destroy.link);
 	wl_list_remove(&c->set_title.link);
 	wl_list_remove(&c->fullscreen.link);
@@ -1424,6 +1428,11 @@ focusclient(Client *c, int lift)
 			wlr_xdg_popup_destroy(popup);
 	}
 
+	/* Capture the client losing focus as the previous client */
+	if (old_c && !client_is_unmanaged(old_c) && old_c != c) {
+		prevclient = old_c;
+	}
+
 	/* Put the new client atop the focus stack and select its monitor */
 	if (c && !client_is_unmanaged(c)) {
 		wl_list_remove(&c->flink);
@@ -2679,6 +2688,42 @@ spawn(const Arg *arg)
 	}
 }
 
+void
+swapfocus(const Arg *arg)
+{
+	Client *c;
+	int found = 0;
+
+	if (!prevclient)
+		return;
+
+	/* Verify the client still exists in the list of managed windows */
+	wl_list_for_each(c, &clients, link) {
+		if (c == prevclient) {
+			found = 1;
+			break;
+		}
+	}
+
+	if (found && !client_is_unmanaged(prevclient)) {
+		/* Get the bitmask of currently visible tags on the prevclient's monitor */
+		unsigned int visible_tags = prevclient->mon->tagset[prevclient->mon->seltags];
+
+		/* Check if the client's tags are currently visible */
+		if (!(prevclient->tags & visible_tags)) {
+			/* Tag is NOT visible: Switch tags and monitor only.
+			 * dwl's view() calls arrange(), which automatically focuses the 
+			 * top-most window in the focus stack for that tag. */
+			Arg a = {.ui = prevclient->tags};
+			selmon = prevclient->mon;
+			view(&a);
+		} else {
+			/* Tag IS visible: Just swap focus within the same view */
+			focusclient(prevclient, 1);
+		}
+	}
+}
+
 void
 startdrag(struct wl_listener *listener, void *data)
 {
-- 
2.53.0