feat: add focusing-client watch to mmsg

docs/ipc.md

@@ -27,6 +27,7 @@ description: Control mangowm programmatically using mmsg.
 | `get keymode` | Returns the current active keyboard mode (e.g., normal, insert). |
 | `get keyboardlayout` | Returns the active XKB layout (abbreviated). |
 | `get monitor <name>` | Returns full JSON details for a specific monitor. |
+| `get focusing-client` | Returns full JSON details for the client currently in focus. |
 | `get client <id>` | Returns full JSON details for a client with the given ID. |
 | `get tag <mon> <idx>` | Queries status of a specific tag on a monitor. |
 | `get all-clients` | Returns a JSON array of all active clients. |
@@ -45,6 +46,7 @@ mmsg get all-monitors
 Subscribes the client to real-time updates. When the state changes, the server pushes a new JSON object to the output stream.
 
 * `watch monitor <name>`
+* `watch focusing-client`
 * `watch client <id>`
 * `watch tags <mon_name>`
 * `watch all-monitors`

src/ipc/ipc.h

@@ -20,6 +20,7 @@ enum ipc_watch_type {
 	IPC_WATCH_KEYMODE,
 	IPC_WATCH_KB_LAYOUT,
 	IPC_WATCH_LAST_OPEN_SURFACE,
+	IPC_WATCH_FOCUSING_CLIENT
 };
 
 struct ipc_watch_client {
@@ -270,6 +271,13 @@ static void handle_command(int client_fd, const char *cmd_raw) {
 			return;
 		}
 		resp = build_monitor_json(m);
+	} else if (strcmp(cmd, "get focusing-client") == 0) {
+		if (selmon && selmon->sel) {
+			resp = build_client_json(selmon->sel);
+		} else {
+			send_static_json(client_fd, "{\"error\":\"no focused client\"}\n");
+			return;
+		}
 	} else if (strncmp(cmd, "get client ", 11) == 0) {
 		Client *c = client_by_id((uint32_t)atoi(cmd + 11));
 		if (!c) {
@@ -478,6 +486,8 @@ static bool handle_watch_command(int fd, const char *cmd,
 	if (strncmp(cmd, "watch monitor ", 14) == 0) {
 		type = IPC_WATCH_MONITOR;
 		arg = cmd + 14;
+	} else if (strcmp(cmd, "watch focusing-client") == 0) {
+		type = IPC_WATCH_FOCUSING_CLIENT;
 	} else if (strncmp(cmd, "watch client ", 13) == 0) {
 		type = IPC_WATCH_CLIENT;
 		client_id = (uint32_t)atoi(cmd + 13);
@@ -541,6 +551,17 @@ static bool handle_watch_command(int fd, const char *cmd,
 		}
 		break;
 	}
+	case IPC_WATCH_FOCUSING_CLIENT: {
+		if (selmon && selmon->sel) {
+			json = build_client_json(selmon->sel);
+		} else {
+			json = cJSON_CreateObject();
+			cJSON_AddNullToObject(json, "id");
+			cJSON_AddNullToObject(json, "title");
+			cJSON_AddNullToObject(json, "appid");
+		}
+		break;
+	}
 	case IPC_WATCH_CLIENT: {
 		Client *c = client_by_id(client_id);
 		if (c)
@@ -729,6 +750,38 @@ void ipc_notify_last_surface_ws_name(Monitor *m) {
 		free(json_str);
 }
 
+void ipc_notify_focusing_client(void) {
+	char *json_str = NULL;
+	size_t len = 0;
+	struct ipc_watch_client *wc, *tmp;
+	wl_list_for_each_safe(wc, tmp, &watch_clients, link) {
+		if (wc->type == IPC_WATCH_FOCUSING_CLIENT) {
+			if (!json_str) {
+				cJSON *json = NULL;
+				if (selmon && selmon->sel) {
+					json = build_client_json(selmon->sel);
+				} else {
+					json = cJSON_CreateObject();
+					cJSON_AddNullToObject(json, "id");
+					cJSON_AddNullToObject(json, "title");
+					cJSON_AddNullToObject(json, "appid");
+				}
+				char *raw = cJSON_PrintUnformatted(json);
+				cJSON_Delete(json);
+				if (!raw)
+					return;
+				len = strlen(raw);
+				json_str = malloc(len + 2);
+				snprintf(json_str, len + 2, "%s\n", raw);
+				free(raw);
+			}
+			if (send(wc->fd, json_str, len + 1, MSG_NOSIGNAL) < 0)
+				ipc_remove_watch_client(wc);
+		}
+	}
+	free(json_str);
+}
+
 void ipc_notify_client(Client *c) {
 	char *json_str = NULL;
 	size_t len = 0;

src/mango.c

@@ -5710,6 +5710,7 @@ void handle_print_status(struct wl_listener *listener, void *data) {
 
 	ipc_notify_keymode();
 	ipc_notify_kb_layout();
+	ipc_notify_focusing_client();
 	ipc_notify_all_tags();
 	ipc_notify_all_clients();
 	ipc_notify_all_monitors();