From 6ea26a800a2917844fbff57ceb20bac4b40e22db Mon Sep 17 00:00:00 2001
From: CJ van den Berg <cj@vdbonline.com>
Date: Wed, 8 Apr 2026 16:26:22 +0200
Subject: [PATCH] feat(gui): add cli option to set window class / app_id

---
 src/gui/wio/app.zig | 10 ++++++++++
 src/main.zig        |  5 ++++-
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/src/gui/wio/app.zig b/src/gui/wio/app.zig
index db02d154..e38f4b73 100644
--- a/src/gui/wio/app.zig
+++ b/src/gui/wio/app.zig
@@ -68,6 +68,10 @@ var title_buf: [512]u8 = undefined;
 var title_len: usize = 0;
 var title_dirty: std.atomic.Value(bool) = .init(false);
 
+// Window class / app_id - read on wio thread during window creation
+var window_class_buf: [256]u8 = undefined;
+var window_class_len: usize = 0;
+
 // Clipboard write (heap-allocated, transferred to wio thread)
 var clipboard_mutex: std.Thread.Mutex = .{};
 var clipboard_write: ?[]u8 = null;
@@ -90,8 +94,13 @@ var wio_font: gpu.Font = .{ .cell_size = .{ .x = 8, .y = 16 }, .backend = .{ .fr
 pub fn start() !std.Thread {
     tui_pid = thespian.self_pid().clone();
     font_name_len = 0;
+    window_class_len = 0;
     stop_requested.store(false, .release);
     loadConfig();
+    const class = thespian.env.get().str("window-class");
+    const copy_len = @min(class.len, window_class_buf.len);
+    @memcpy(window_class_buf[0..copy_len], class[0..copy_len]);
+    window_class_len = copy_len;
     return std.Thread.spawn(.{}, wioLoop, .{});
 }
 
@@ -380,6 +389,7 @@ fn wioLoop() void {
 
     var window = wio.createWindow(.{
         .title = "flow",
+        .app_id = if (window_class_len > 0) window_class_buf[0..window_class_len] else "flow",
         .size = .{ .width = 1280, .height = 720 },
         .scale = 1.0,
         .opengl = .{
diff --git a/src/main.zig b/src/main.zig
index 054340ca..41cd98e6 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -83,9 +83,10 @@ pub fn main() anyerror!void {
             .dark = "Use dark color scheme",
             .light = "Use light color scheme",
             .version = "Show build version and exit",
+            .class = "Set window class",
         };
 
-        pub const formats = .{ .frame_rate = "num", .trace_level = "num", .exec = "cmds" };
+        pub const formats = .{ .frame_rate = "num", .trace_level = "num", .exec = "cmds", .class = "name" };
 
         pub const switches = .{
             .project = 'p',
@@ -123,6 +124,7 @@ pub fn main() anyerror!void {
         dark: bool,
         light: bool,
         version: bool,
+        class: ?[]const u8,
 
         positional: struct {
             trailing: []const []const u8,
@@ -247,6 +249,7 @@ pub fn main() anyerror!void {
     if (args.frame_rate) |s| env.num_set("frame-rate", @intCast(s));
     env.proc_set("log", log_proc.ref());
     if (args.language) |s| env.str_set("language", s);
+    if (args.class) |s| env.str_set("window-class", s);
 
     var eh = thespian.make_exit_handler({}, print_exit_status);
     const tui_proc = try tui.spawn(a, &ctx, &eh, &env);