feat(cosmic-theme): add color schemes for qt apps

cosmic-theme/src/output/qt56ct_output.rs

@@ -0,0 +1,113 @@
+use crate::Theme;
+use configparser::ini::Ini;
+use std::{
+    fs::{self, File},
+    path::PathBuf,
+};
+
+use super::OutputError;
+
+impl Theme {
+    /// The "version" of this theme.
+    ///
+    /// To avoid repeatedly overwriting the user's config, we use a version system.
+    ///
+    /// Increment this value when changes to qt{5,6}ct.conf are needed.
+    /// If the config's version is outdated, we update several sections.
+    /// Otherwise, only the light/dark mode is updated.
+    const COSMIC_QT_VERSION: u64 = 1;
+
+    /// Edits qt{5,6}ct.conf to use COSMIC styles if needed.
+    #[cold]
+    pub fn apply_qt56ct(is_dark: bool) -> Result<(), OutputError> {
+        let qt5ct_res = Self::apply_ct("qt5ct", is_dark);
+        let qt6ct_res = Self::apply_ct("qt6ct", is_dark);
+        qt5ct_res?;
+        qt6ct_res?;
+        Ok(())
+    }
+    #[must_use]
+    #[cold]
+    fn apply_ct(ct: &str, is_dark: bool) -> Result<(), OutputError> {
+        let path = Self::get_conf_path(ct)?;
+        let file_content = fs::read_to_string(&path).map_err(OutputError::Io)?;
+        let mut ini = Ini::new_cs();
+        ini.read(file_content).map_err(OutputError::Ini)?;
+
+        let old_version = ini
+            .getuint("Appearance", "cosmic_qt_version")
+            .map_err(OutputError::Ini)?
+            .unwrap_or_default();
+
+        let color_scheme_path = Self::get_qt_colors_path(is_dark)?;
+        let icon_theme = if is_dark { "breeze-dark" } else { "breeze" };
+
+        ini.set(
+            "Appearance",
+            "cosmic_qt_version",
+            Some(Theme::COSMIC_QT_VERSION.to_string()),
+        );
+
+        if old_version < Theme::COSMIC_QT_VERSION {
+            // Config is outdated, update it unconditionally!
+
+            ini.setstr(
+                "Appearance",
+                "color_scheme_path",
+                color_scheme_path.to_str(),
+            );
+            // Enable the above color scheme, instead of using the default color scheme of e.g. Breeze
+            ini.setstr("Appearance", "custom_palette", Some("true"));
+            // COSMIC icons are stuck in light mode, so use breeze icons instead
+            ini.setstr("Appearance", "icon_theme", Some(icon_theme));
+            // Use COSMIC dialogs instead of KDE's
+            ini.setstr("Appearance", "standard_dialogs", Some("xdgdesktopportal"));
+
+            // TODO: Add fonts section to match COSMIC
+        } else {
+            // Config is not outdated, check before updating light/dark mode only!
+
+            let old_color_scheme_path = ini
+                .get("Appearance", "color_scheme_path")
+                .unwrap_or_else(|| "CosmicPlease".to_owned());
+            if old_color_scheme_path.contains("Cosmic") {
+                ini.setstr(
+                    "Appearance",
+                    "color_scheme_path",
+                    color_scheme_path.to_str(),
+                );
+            }
+
+            let old_icon_theme = ini
+                .get("Appearance", "icon_theme")
+                .unwrap_or_else(|| "breeze".to_owned());
+            if old_icon_theme.contains("breeze") {
+                ini.setstr("Appearance", "icon_theme", Some(icon_theme));
+            }
+        }
+
+        ini.write(path).map_err(OutputError::Io)?;
+        Ok(())
+    }
+
+    /// Returns the file paths of the form `~/.config/ct/ct.conf`:
+    /// e.g. `~/.config/qt6ct/qt6ct.conf`.
+    ///
+    /// The file and its parent directory are created if they don't exist.
+    fn get_conf_path(ct: &str) -> Result<PathBuf, OutputError> {
+        let Some(mut config_dir) = dirs::config_dir() else {
+            return Err(OutputError::MissingConfigDir);
+        };
+        config_dir.push(&ct);
+        if !config_dir.exists() {
+            fs::create_dir_all(&config_dir).map_err(OutputError::Io)?;
+        }
+
+        let file_path = config_dir.join(ct.to_owned() + ".conf");
+        if !file_path.exists() {
+            File::create_new(&file_path).map_err(OutputError::Io)?;
+        }
+
+        Ok(file_path)
+    }
+}