makes spicetify follow os theme. thanks https://gist.github.com/jerblack/1d05bbcebb50ad55c312e4d7cf1bc909

main.go

package main

import (
	"log"
)

const (
	regKey  = `Software\Microsoft\Windows\CurrentVersion\Themes\Personalize`
	regName = `AppsUseLightTheme`
)

func main() {
	regNotifyChangeKeyValue, err := getRegNotifyChangeKeyValueProc()
	if err != nil {
		log.Fatal(err)
	}

	changed := monitor(regNotifyChangeKeyValue)
	for {
		<-changed

		if !isSpotifyRunning() {
			continue
		}

		err := apply()
		if err != nil {
			log.Println(err)
		}
	}
}

monitor.go

package main

import (
	"log"
	"syscall"

	"golang.org/x/sys/windows/registry"
)

func getRegNotifyChangeKeyValueProc() (*syscall.Proc, error) {
	advapi32, err := syscall.LoadDLL("Advapi32.dll")
	if err != nil {
		return nil, err
	}

	proc, err := advapi32.FindProc("RegNotifyChangeKeyValue")
	if err != nil {
		return nil, err
	}

	return proc, nil
}

func monitor(regNotifyChangeKeyValue *syscall.Proc) <-chan struct{} {
	notifier := make(chan struct{})

	go func() {
		k, err := registry.OpenKey(registry.CURRENT_USER, regKey, syscall.KEY_NOTIFY|registry.QUERY_VALUE)
		if err != nil {
			log.Fatal(err)
		}

		getVal := func() uint64 {
			val, _, err := k.GetIntegerValue(regName)
			if err != nil {
				log.Fatal(err)
			}
			return val
		}

		old := getVal()
		for {
			regNotifyChangeKeyValue.Call(uintptr(k), 0, 0x00000001|0x00000004, 0, 0) //nolint:errcheck
			val := getVal()
			if val != old {
				old = val
				notifier <- struct{}{}
			}
		}
	}()

	return notifier
}

os_theme.patch

diff --git a/go.mod b/go.mod
index 3203f5c..a2a2054 100644
--- a/go.mod
+++ b/go.mod
@@ -7,5 +7,6 @@ require (
	github.com/mattn/go-colorable v0.1.8
	github.com/smartystreets/goconvey v1.6.4 // indirect
	golang.org/x/net v0.0.0-20210226172049-e18ecbb05110
+	golang.org/x/sys v0.0.0-20220209214540-3681064d5158 // indirect
	gopkg.in/ini.v1 v1.62.0 // indirect
)
diff --git a/go.sum b/go.sum
index dd6ab0b..f5ae308 100644
--- a/go.sum
+++ b/go.sum
@@ -21,6 +21,8 @@ golang.org/x/sys v0.0.0-20200116001909-b77594299b42/go.mod h1:h1NjWce9XRLGQEsW7w
golang.org/x/sys v0.0.0-20200223170610-d5e6a3e2c0ae/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
golang.org/x/sys v0.0.0-20201119102817-f84b799fce68 h1:nxC68pudNYkKU6jWhgrqdreuFiOQWj1Fs7T3VrH4Pjw=
golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20220209214540-3681064d5158 h1:rm+CHSpPEEW2IsXUib1ThaHIjuBVZjxNgSKmBLFfD4c=
+golang.org/x/sys v0.0.0-20220209214540-3681064d5158/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
diff --git a/src/cmd/cmd.go b/src/cmd/cmd.go
index 29c2c04..b6cabb4 100644
--- a/src/cmd/cmd.go
+++ b/src/cmd/cmd.go
@@ -10,6 +10,7 @@ import (

	"github.com/go-ini/ini"
	"github.com/khanhas/spicetify-cli/src/utils"
+	"golang.org/x/sys/windows/registry"
)

var (
@@ -110,21 +111,29 @@ func InitPaths() {
	utils.CheckExistAndCreate(appDestPath)
}

+func isOsThemeDark() bool {
+	k, err := registry.OpenKey(registry.CURRENT_USER, `Software\Microsoft\Windows\CurrentVersion\Themes\Personalize`, registry.QUERY_VALUE)
+	if err != nil {
+		utils.PrintError("could not open registry key: " + err.Error())
+		os.Exit(1)
+	}
+	val, _, err := k.GetIntegerValue("SystemUsesLightTheme")
+	if err != nil {
+		utils.PrintError("could not read SystemUsesLightTheme value: " + err.Error())
+		os.Exit(1)
+	}
+	k.Close()
+
+	return val == 0
+}
+
// InitSetting parses theme settings and gets color section.
func InitSetting() {
	replaceColors = settingSection.Key("replace_colors").MustBool(false)
	injectCSS = settingSection.Key("inject_css").MustBool(false)
	overwriteAssets = settingSection.Key("overwrite_assets").MustBool(false)

-	themeName := settingSection.Key("current_theme").String()
-
-	if len(themeName) == 0 {
-		injectCSS = false
-		replaceColors = false
-		overwriteAssets = false
-		return
-	}
-
+	themeName := "Ziro"
	themeFolder = getThemeFolder(themeName)

	colorPath := filepath.Join(themeFolder, "color.ini")
@@ -165,7 +174,10 @@ func InitSetting() {
		return
	}

-	schemeName := settingSection.Key("color_scheme").String()
+	schemeName := "purple-light"
+	if isOsThemeDark() {
+		schemeName = "purple-dark"
+	}
	if len(schemeName) == 0 {
		colorSection = sections[1]
		return

spicetify.go

package main

import (
	"os/exec"
)

func isSpotifyRunning() bool {
	ps, _ := exec.LookPath("powershell.exe")
	ret := exec.Command(ps,
		"-NoProfile",
		"-NonInteractive",
		`$spotify = Get-Process Spotify; if ($spotify) { exit 0 } else { exit 1}`,
	).Run()

	return ret == nil
}

func apply() error {
	return exec.Command(`C:\Users\dakyskye\spicetify-cli\spicetify.exe`, "apply").Run()
}