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package main
import (
"fmt"
"io"
"log"
"net/http"
"os"
"path/filepath"
"strings"
"github.com/godbus/dbus/v5"
)
const (
serviceName = "org.freedesktop.portal.Desktop"
objectPath = "/org/freedesktop/portal/desktop"
interfaceName = "org.freedesktop.portal.Settings"
)
type ColorScheme string
const (
PreferDark ColorScheme = "prefer-dark"
PreferLight ColorScheme = "prefer-light"
)
// getColorScheme reads the current color scheme from GNOME D-Bus
func getColorScheme(conn *dbus.Conn) (ColorScheme, error) {
obj := conn.Object(serviceName, objectPath)
// ReadOne returns a variant
call := obj.Call(interfaceName+".ReadOne", 0, "org.gnome.desktop.interface", "color-scheme")
if call.Err != nil {
return "", fmt.Errorf("failed to call ReadOne: %w", call.Err)
}
// The response is a single variant
if len(call.Body) != 1 {
return "", fmt.Errorf("unexpected response length: %d", len(call.Body))
}
variant, ok := call.Body[0].(dbus.Variant)
if !ok {
return "", fmt.Errorf("expected variant, got %T", call.Body[0])
}
// Extract the string from the variant
value, ok := variant.Value().(string)
if !ok {
return "", fmt.Errorf("unexpected value type: %T", variant.Value())
}
cs := ColorScheme(value)
if cs != PreferDark && cs != PreferLight {
return "", fmt.Errorf("invalid color scheme value: %s", value)
}
return cs, nil
}
// writeAlacrittyColorConfig writes the Alacritty config file with the appropriate theme
func writeAlacrittyColorConfig(cs ColorScheme, darkTheme, lightTheme, programName string) error {
theme := darkTheme
if cs == PreferLight {
theme = lightTheme
}
configHome := os.Getenv("XDG_CONFIG_HOME")
if configHome == "" {
homeDir, err := os.UserHomeDir()
if err != nil {
return fmt.Errorf("failed to get home directory: %w", err)
}
configHome = filepath.Join(homeDir, ".config")
}
configPath := filepath.Join(configHome, "alacritty", "alacritty-colors-autogen.toml")
content := fmt.Sprintf("# !! THIS FILE IS GENERATED BY %s\ngeneral.import = [\"%s\"]", programName, theme)
log.Printf("Writing color scheme %s with theme %s\n", cs, theme)
if err := os.WriteFile(configPath, []byte(content), 0644); err != nil {
return fmt.Errorf("failed to write config file: %w", err)
}
return nil
}
// listenForColorSchemeChange subscribes to D-Bus signals for color scheme changes
func listenForColorSchemeChange(conn *dbus.Conn, darkTheme, lightTheme, programName string) error {
if err := conn.AddMatchSignal(dbus.WithMatchInterface(interfaceName), dbus.WithMatchMember("SettingChanged")); err != nil {
return fmt.Errorf("failed to add match rule: %w", err)
}
// Create signal channel
signals := make(chan *dbus.Signal, 10)
conn.Signal(signals)
log.Println("Listening for color scheme changes...")
var previousColorScheme ColorScheme
// Process signals
for sig := range signals {
if sig.Name != interfaceName+".SettingChanged" {
continue
}
if len(sig.Body) < 3 {
log.Printf("Unexpected signal body length: %d\n", len(sig.Body))
continue
}
interfaceName, ok := sig.Body[0].(string)
if !ok || interfaceName != "org.gnome.desktop.interface" {
continue
}
key, ok := sig.Body[1].(string)
if !ok || key != "color-scheme" {
continue
}
// Body[2] is a variant
variant, ok := sig.Body[2].(dbus.Variant)
if !ok {
log.Printf("Failed to extract variant from signal, got %T\n", sig.Body[2])
continue
}
// Extract the string value directly from the variant
newValue, ok := variant.Value().(string)
if !ok {
log.Printf("Unexpected variant value type: %T, value: %v\n", variant.Value(), variant.Value())
continue
}
newColorScheme := ColorScheme(newValue)
// Only change if different from previous
if previousColorScheme == newColorScheme {
log.Printf("Color scheme already set to %s\n", newColorScheme)
continue
}
previousColorScheme = newColorScheme
log.Printf("Color scheme changed to %s\n", newColorScheme)
if err := writeAlacrittyColorConfig(newColorScheme, darkTheme, lightTheme, programName); err != nil {
log.Printf("Error writing config: %v\n", err)
}
}
return nil
}
// getThemeDirectory returns the theme cache directory, creating it if necessary
func getThemeDirectory() (string, error) {
homeDir, err := os.UserHomeDir()
if err != nil {
return "", fmt.Errorf("failed to get home directory: %w", err)
}
cacheDir := filepath.Join(homeDir, ".cache", "alacritty-change-color-scheme", "themes")
// Create cache directory if it doesn't exist
if err := os.MkdirAll(cacheDir, 0755); err != nil {
return "", fmt.Errorf("failed to create cache directory: %w", err)
}
return cacheDir, nil
}
// downloadTheme downloads a specific theme file from GitHub
func downloadTheme(themeName, targetPath string) error {
repos := []struct {
owner string
repo string
rev string
}{
{"alacritty", "alacritty-theme", "95a7d695605863ede5b7430eb80d9e80f5f504bc"},
{"anhsirk0", "alacritty-themes", "5a2c194a682ec75d46553f9a9d6c43fbf39c689d"},
}
client := &http.Client{}
fileName := themeName + ".toml"
// Try each repository
for _, repo := range repos {
rawURL := fmt.Sprintf("https://raw.githubusercontent.com/%s/%s/%s/themes/%s",
repo.owner, repo.repo, repo.rev, fileName)
log.Printf("Attempting to download %s from %s/%s...\n", fileName, repo.owner, repo.repo)
resp, err := client.Get(rawURL)
if err != nil {
log.Printf("Failed to fetch from %s/%s: %v\n", repo.owner, repo.repo, err)
continue
}
defer resp.Body.Close()
if resp.StatusCode == 200 {
out, err := os.Create(targetPath)
if err != nil {
return fmt.Errorf("failed to create file: %w", err)
}
defer out.Close()
if _, err := io.Copy(out, resp.Body); err != nil {
return fmt.Errorf("failed to write file: %w", err)
}
log.Printf("Successfully downloaded %s\n", fileName)
return nil
}
if resp.StatusCode == 404 {
log.Printf("Theme not found in %s/%s\n", repo.owner, repo.repo)
continue
}
return fmt.Errorf("unexpected status %d from %s/%s", resp.StatusCode, repo.owner, repo.repo)
}
return fmt.Errorf("theme %s not found in any repository", themeName)
}
// patchDayfoxTheme patches the dayfox theme to fix white color contrast issues
func patchDayfoxTheme(path string) error {
content, err := os.ReadFile(path)
if err != nil {
return fmt.Errorf("failed to read theme file: %w", err)
}
text := string(content)
// Check if already patched
if strings.Contains(text, "# PATCHED") {
log.Printf("Theme already patched, skipping\n")
return nil
}
// Apply patches - replace white colors with foreground colors
// because many applications use white where foreground should be used
replacements := map[string]string{
`white = "#f2e9e1"`: `white = "#908a85"`, // normal white
`white = "#f4ece6"`: `white = "#9f9791"`, // bright white
`white = "#cec6bf"`: `white = "#85827f"`, // dim white
}
for old, new := range replacements {
text = strings.ReplaceAll(text, old, new)
}
// Add patched marker
text = "# PATCHED\n" + text
if err := os.WriteFile(path, []byte(text), 0644); err != nil {
return fmt.Errorf("failed to write patched theme: %w", err)
}
log.Printf("Successfully patched dayfox theme\n")
return nil
}
// getThemePath resolves and validates a theme file path, downloading if necessary
func getThemePath(themeDir, themeName string) (string, error) {
path := filepath.Join(themeDir, themeName+".toml")
// Check if file exists
if _, err := os.Stat(path); os.IsNotExist(err) {
log.Printf("Theme %s not found locally, downloading...\n", themeName)
if err := downloadTheme(themeName, path); err != nil {
return "", fmt.Errorf("failed to download theme: %w", err)
}
}
// Always patch dayfox (idempotent with marker check)
if themeName == "dayfox" {
if err := patchDayfoxTheme(path); err != nil {
return "", fmt.Errorf("failed to patch dayfox theme: %w", err)
}
}
absPath, err := filepath.EvalSymlinks(path)
if err != nil {
return "", fmt.Errorf("failed to resolve theme path %s: %w", path, err)
}
return absPath, nil
}
func main() {
programName := os.Args[0]
// Fixed theme names
darkThemeName := "alacritty_0_12"
lightThemeName := "dayfox"
// Get theme directory
themeDir, err := getThemeDirectory()
if err != nil {
log.Fatalf("Failed to get theme directory: %v\n", err)
}
// Resolve theme paths
darkTheme, err := getThemePath(themeDir, darkThemeName)
if err != nil {
log.Fatalf("Error resolving dark theme: %v\n", err)
}
lightTheme, err := getThemePath(themeDir, lightThemeName)
if err != nil {
log.Fatalf("Error resolving light theme: %v\n", err)
}
log.Printf("Dark theme: %s\n", darkTheme)
log.Printf("Light theme: %s\n", lightTheme)
// Connect to D-Bus session bus
conn, err := dbus.SessionBus()
if err != nil {
log.Fatalf("Failed to connect to session bus: %v\n", err)
}
defer conn.Close()
// Get current color scheme
currentColorScheme, err := getColorScheme(conn)
if err != nil {
log.Fatalf("Failed to get current color scheme: %v\n", err)
}
log.Printf("Current color scheme: %s\n", currentColorScheme)
// Write initial config
if err := writeAlacrittyColorConfig(currentColorScheme, darkTheme, lightTheme, programName); err != nil {
log.Fatalf("Failed to write initial config: %v\n", err)
}
// Listen for changes (blocks)
if err := listenForColorSchemeChange(conn, darkTheme, lightTheme, programName); err != nil {
log.Fatalf("Failed to listen for color scheme changes: %v\n", err)
}
}
|