From e04ba0e033c4515095d1290019b21bec7a644204 Mon Sep 17 00:00:00 2001
From: LGUG2Z <LGUG2Z@fastmail.com>
Date: Fri, 1 Dec 2023 10:19:10 -0800
Subject: [PATCH] feat(win32): set foregroundlocktimeout explicitly

After another round of deep diving to find a workaround to all of the
mechanisms within Windows that prevent a process from changing the
focused window, I came across this gist which I saw setting
SPI_SETFOREGROUNDLOCKTIMEOUT to 0:
https://gist.github.com/EBNull/1419093

This tentatively seems like it works and it removes the need for the
alt_focus_hack setting.

However, according to this StackOverflow discussion, it seems like on
Win10+ changes to ForegroundLockTimeout in the registry are no longer
respected and changes made via SPI_SETFOREGROUNDLOCKTIMEOUT are not
persisted:
https://stackoverflow.com/questions/73735129/setforegroundwindow-relationship-between-the-foregroundlocktimeout-registry-val

Therefore on starting, komorebi will now check the value with
SPI_GETFOREGROUNDLOCKTIMEOUT and if it is not 0, it will be set to 0.

Logging has been added to inform the user of the changes that are
happening.
---
 komorebi/src/main.rs        |  2 ++
 komorebi/src/windows_api.rs | 38 +++++++++++++++++++++++++++++++++++++
 2 files changed, 40 insertions(+)

diff --git a/komorebi/src/main.rs b/komorebi/src/main.rs
index f328792ab..c67a3456f 100644
--- a/komorebi/src/main.rs
+++ b/komorebi/src/main.rs
@@ -496,6 +496,8 @@ fn main() -> Result<()> {
     // File logging worker guard has to have an assignment in the main fn to work
     let (_guard, _color_guard) = setup()?;
 
+    WindowsApi::foreground_lock_timeout()?;
+
     #[cfg(feature = "deadlock_detection")]
     detect_deadlocks();
 
diff --git a/komorebi/src/windows_api.rs b/komorebi/src/windows_api.rs
index 4ac889d68..57528456b 100644
--- a/komorebi/src/windows_api.rs
+++ b/komorebi/src/windows_api.rs
@@ -105,7 +105,9 @@ use windows::Win32::UI::WindowsAndMessaging::SET_WINDOW_POS_FLAGS;
 use windows::Win32::UI::WindowsAndMessaging::SHOW_WINDOW_CMD;
 use windows::Win32::UI::WindowsAndMessaging::SPIF_SENDCHANGE;
 use windows::Win32::UI::WindowsAndMessaging::SPI_GETACTIVEWINDOWTRACKING;
+use windows::Win32::UI::WindowsAndMessaging::SPI_GETFOREGROUNDLOCKTIMEOUT;
 use windows::Win32::UI::WindowsAndMessaging::SPI_SETACTIVEWINDOWTRACKING;
+use windows::Win32::UI::WindowsAndMessaging::SPI_SETFOREGROUNDLOCKTIMEOUT;
 use windows::Win32::UI::WindowsAndMessaging::SW_HIDE;
 use windows::Win32::UI::WindowsAndMessaging::SW_MAXIMIZE;
 use windows::Win32::UI::WindowsAndMessaging::SW_MINIMIZE;
@@ -679,6 +681,42 @@ impl WindowsApi {
             .process()
     }
 
+    #[tracing::instrument]
+    pub fn foreground_lock_timeout() -> Result<()> {
+        let mut value: u32 = 0;
+
+        Self::system_parameters_info_w(
+            SPI_GETFOREGROUNDLOCKTIMEOUT,
+            0,
+            std::ptr::addr_of_mut!(value).cast(),
+            SPIF_SENDCHANGE,
+        )?;
+
+        tracing::info!("current value of ForegroundLockTimeout is {value}");
+
+        if value != 0 {
+            tracing::info!("updating value of ForegroundLockTimeout to {value} in order to enable keyboard-driven focus updating");
+
+            Self::system_parameters_info_w(
+                SPI_SETFOREGROUNDLOCKTIMEOUT,
+                0,
+                0 as *mut c_void,
+                SPIF_SENDCHANGE,
+            )?;
+
+            Self::system_parameters_info_w(
+                SPI_GETFOREGROUNDLOCKTIMEOUT,
+                0,
+                std::ptr::addr_of_mut!(value).cast(),
+                SPIF_SENDCHANGE,
+            )?;
+
+            tracing::info!("updated value of ForegroundLockTimeout is now {value}");
+        }
+
+        Ok(())
+    }
+
     #[allow(dead_code)]
     pub fn focus_follows_mouse() -> Result<bool> {
         let mut is_enabled: BOOL = unsafe { std::mem::zeroed() };