Auto detect light/dark mode, changing the theme accordingly

crates/hyfetch/src/bin/hyfetch.rs

@@ -87,7 +87,16 @@ fn main() -> Result<()> {
     };
 
     let color_mode = options.mode.unwrap_or(config.mode);
-    let theme = config.light_dark;
+    let auto_detect_light_dark = options
+        .auto_detect_light_dark
+        .unwrap_or_else(|| config.auto_detect_light_dark.unwrap_or(false));
+    let theme = if auto_detect_light_dark {
+        let res = det_bg();
+        res?.map(|bg| bg.theme())
+            .unwrap_or(config.light_dark.unwrap_or_default())
+    } else {
+        config.light_dark.unwrap_or_default()
+    };
 
     // Check if it's June (pride month)
     let now =
@@ -131,7 +140,12 @@ fn main() -> Result<()> {
     } else if let Some(lightness) = options.lightness {
         color_profile.with_lightness(AssignLightness::Replace(lightness))
     } else {
-        color_profile.with_lightness_adaptive(config.lightness(), theme)
+        color_profile.with_lightness_adaptive(
+            config
+                .lightness
+                .unwrap_or_else(|| Config::default_lightness(theme)),
+            theme,
+        )
     };
     debug!(?color_profile, "lightened color profile");
 
@@ -187,6 +201,22 @@ fn load_config(path: &PathBuf) -> Result<Option<Config>> {
     Ok(Some(config))
 }
 
+fn det_bg() -> Result<Option<Srgb<u8>>, terminal_colorsaurus::Error> {
+    if !io::stdout().is_terminal() {
+        return Ok(None);
+    }
+
+    background_color(QueryOptions::default())
+        .map(|terminal_colorsaurus::Color { r, g, b }| Some(Srgb::new(r, g, b).into_format()))
+        .or_else(|err| {
+            if matches!(err, terminal_colorsaurus::Error::UnsupportedTerminal) {
+                Ok(None)
+            } else {
+                Err(err)
+            }
+        })
+}
+
 /// Creates config interactively.
 ///
 /// The config is automatically stored to file.
@@ -197,21 +227,10 @@ fn create_config(
     backend: Backend,
     debug_mode: bool,
 ) -> Result<Config> {
-    // Detect terminal environment (doesn't work for all terminal emulators,
-    // especially on Windows)
-    let det_bg = if io::stdout().is_terminal() {
-        match background_color(QueryOptions::default()) {
-            Ok(bg) => Some(Srgb::<u16>::new(bg.r, bg.g, bg.b).into_format::<u8>()),
-            Err(terminal_colorsaurus::Error::UnsupportedTerminal) => None,
-            Err(err) => {
-                return Err(err).context("failed to get terminal background color");
-            },
-        }
-    } else {
-        None
-    };
+    let det_bg = det_bg()?;
     debug!(?det_bg, "detected background color");
     let det_ansi = supports_color::on(supports_color::Stream::Stdout).map(|color_level| {
+        #[allow(clippy::if_same_then_else)]
         if color_level.has_16m {
             AnsiMode::Rgb
         } else if color_level.has_256 {
@@ -230,7 +249,7 @@ fn create_config(
 
     let asc = get_distro_ascii(distro, backend).context("failed to get distro ascii")?;
     let asc = asc.to_normalized().context("failed to normalize ascii")?;
-    let theme = det_bg.map(|bg| bg.theme()).unwrap_or(TerminalTheme::Light);
+    let theme = det_bg.map(|bg| bg.theme()).unwrap_or_default();
     let color_mode = det_ansi.unwrap_or(AnsiMode::Ansi256);
     let mut title = format!(
         "Welcome to {logo} Let's set up some colors first.",
@@ -1001,7 +1020,8 @@ fn create_config(
     let config = Config {
         preset,
         mode: color_mode,
-        light_dark: theme,
+        light_dark: Some(theme),
+        auto_detect_light_dark: Some(det_bg.is_some()),
         lightness: Some(lightness),
         color_align,
         backend,

crates/hyfetch/src/cli_options.rs

@@ -31,6 +31,7 @@ pub struct Options {
     pub print_font_logo: bool,
     pub test_print: bool,
     pub ask_exit: bool,
+    pub auto_detect_light_dark: Option<bool>,
 }
 
 pub fn options() -> OptionParser<Options> {
@@ -170,6 +171,10 @@ BACKEND={{{backends}}}",
         .help("Ask for input before exiting")
         .switch()
         .hide();
+    let auto_detect_light_dark = long("auto-detect-light-dark")
+        .help("Enables hyfetch to detect light/dark terminal background in runtime")
+        .argument("BOOL")
+        .optional();
 
     construct!(Options {
         config,
@@ -188,6 +193,7 @@ BACKEND={{{backends}}}",
         // hidden
         test_print,
         ask_exit,
+        auto_detect_light_dark,
     })
     .to_options()
     .header(

crates/hyfetch/src/models.rs

@@ -9,7 +9,8 @@ use crate::types::{AnsiMode, Backend, TerminalTheme};
 pub struct Config {
     pub preset: Preset,
     pub mode: AnsiMode,
-    pub light_dark: TerminalTheme,
+    pub auto_detect_light_dark: Option<bool>,
+    pub light_dark: Option<TerminalTheme>,
     pub lightness: Option<Lightness>,
     pub color_align: ColorAlignment,
     pub backend: Backend,
@@ -31,11 +32,6 @@ impl Config {
             },
         }
     }
-
-    pub fn lightness(&self) -> Lightness {
-        self.lightness
-            .unwrap_or_else(|| Self::default_lightness(self.light_dark))
-    }
 }
 
 mod args_serde {

crates/hyfetch/src/types.rs

@@ -36,6 +36,12 @@ pub enum TerminalTheme {
     Dark,
 }
 
+impl Default for TerminalTheme {
+    fn default() -> Self {
+        Self::Light
+    }
+}
+
 #[derive(
     Copy,
     Clone,