From bc89cc20fc653b6117baf373f09f575e84e09d66 Mon Sep 17 00:00:00 2001
From: Drew Weymouth <dweymouth@gmail.com>
Date: Thu, 18 Jul 2024 18:25:14 -0700
Subject: [PATCH 1/2] prevent sleep on Windows when playing

---
 backend/app.go                 | 10 ++++++++++
 backend/nosleep_unsupported.go |  7 +++++++
 backend/nosleep_windows.go     | 22 ++++++++++++++++++++++
 3 files changed, 39 insertions(+)
 create mode 100644 backend/nosleep_unsupported.go
 create mode 100644 backend/nosleep_windows.go

diff --git a/backend/app.go b/backend/app.go
index 2390eaf..50268d7 100644
--- a/backend/app.go
+++ b/backend/app.go
@@ -127,6 +127,16 @@ func StartupApp(appName, displayAppName, appVersionTag, latestReleaseURL string)
 		_, _ = a.ImageManager.GetCoverThumbnail(coverID)
 	})
 
+	a.PlaybackManager.OnPlaying(func() {
+		SetSystemSleepDisabled(true)
+	})
+	a.PlaybackManager.OnPaused(func() {
+		SetSystemSleepDisabled(false)
+	})
+	a.PlaybackManager.OnStopped(func() {
+		SetSystemSleepDisabled(false)
+	})
+
 	// Start IPC server if another not already running in a different instance
 	if cli == nil {
 		ipc.DestroyConn() // cleanup socket possibly orphaned by crashed process
diff --git a/backend/nosleep_unsupported.go b/backend/nosleep_unsupported.go
new file mode 100644
index 0000000..b082169
--- /dev/null
+++ b/backend/nosleep_unsupported.go
@@ -0,0 +1,7 @@
+//go:build !windows
+
+package backend
+
+func SetSystemSleepDisabled(disable bool) {
+	// no-op
+}
diff --git a/backend/nosleep_windows.go b/backend/nosleep_windows.go
new file mode 100644
index 0000000..6a10d2d
--- /dev/null
+++ b/backend/nosleep_windows.go
@@ -0,0 +1,22 @@
+//go:build windows
+
+package backend
+
+import "syscall"
+
+const (
+	ES_CONTINUOUS      uint = 0x80000000
+	ES_SYSTEM_REQUIRED uint = 0x00000001
+)
+
+func SetSystemSleepDisabled(disable bool) {
+	kernel32 := syscall.NewLazyDLL("kernel32.dll")
+	executionState := kernel32.NewProc("SetThreadExecutionState")
+
+	uType := ES_CONTINUOUS
+	if disable {
+		uType |= ES_SYSTEM_REQUIRED
+	}
+
+	syscall.SyscallN(executionState.Addr(), 1, uintptr(uType), 0, 0)
+}

From 80e53c2971f512519f458ff53d3b9ab25b47f83d Mon Sep 17 00:00:00 2001
From: Drew Weymouth <dweymouth@gmail.com>
Date: Fri, 19 Jul 2024 07:29:57 -0700
Subject: [PATCH 2/2] load DLL only once

---
 backend/nosleep_windows.go | 20 +++++++++++++++++---
 1 file changed, 17 insertions(+), 3 deletions(-)

diff --git a/backend/nosleep_windows.go b/backend/nosleep_windows.go
index 6a10d2d..d605e5a 100644
--- a/backend/nosleep_windows.go
+++ b/backend/nosleep_windows.go
@@ -2,16 +2,30 @@
 
 package backend
 
-import "syscall"
+import (
+	"sync/atomic"
+	"syscall"
+)
 
 const (
 	ES_CONTINUOUS      uint = 0x80000000
 	ES_SYSTEM_REQUIRED uint = 0x00000001
 )
 
+var (
+	sleepDisabled  atomic.Bool
+	executionState *syscall.LazyProc
+)
+
 func SetSystemSleepDisabled(disable bool) {
-	kernel32 := syscall.NewLazyDLL("kernel32.dll")
-	executionState := kernel32.NewProc("SetThreadExecutionState")
+	if old := sleepDisabled.Swap(disable); old == disable {
+		return
+	}
+
+	if executionState == nil {
+		kernel32 := syscall.NewLazyDLL("kernel32.dll")
+		executionState = kernel32.NewProc("SetThreadExecutionState")
+	}
 
 	uType := ES_CONTINUOUS
 	if disable {