service: switch to plugin architecture for theme backends

README.md

 # Ximper Unified Theme Switcher
 
-**Version:** 0.1.0
+**Version:** 0.2.0
 
-
-**Authors:** Ximper, Fiersik  
+**Authors:** Ximper, Fiersik
 
 ## Description
-**Ximper Unified Theme Switcher**
 
-Designed to switch themes (Kvantum and GTK3) to suitable ones, simultaneously with changing the style of your system.
+Unified Theme Switcher automatically switches themes across multiple toolkits when you change the system color scheme (light/dark). Uses a plugin architecture — each toolkit backend is a separate plugin.
+
+## Architecture
+
+The service is written in [ContenT](https://gitlab.eterfund.ru/ximperlinux/content) language. Plugins are compiled separately via `content build-lib` and loaded at runtime.
+
+## Plugins
+
+### Plugin types
+
+**Config-managed plugins** declare `prefix()`, `default_light()`, `default_dark()`. The service stores `{PREFIX}_LIGHT_THEME` and `{PREFIX}_DARK_THEME` in its config and passes the resolved theme name to `apply()`.
+
+**Self-managed plugins** don't have `prefix()`. They receive just the mode (`"light"` or `"dark"`) in `apply()` and handle everything internally.
+
+### Plugin interface
+
+Every plugin must implement:
+
+| Function | Required | Description |
+|----------|----------|-------------|
+| `is_available (): bool` | Yes | Check if the backend is available |
+| `apply (theme: string)` | Yes | Apply a theme (name or mode) |
+| `prefix (): string` | No | Config variable prefix (e.g. `"KV"`) |
+| `default_light (): string` | No | Default light theme name |
+| `default_dark (): string` | No | Default dark theme name |
+
+### Creating a plugin
+
+**Config-managed** (service stores theme names):
+
+```
+namespace my_toolkit {
+    func prefix (): string { return "MY" }
+    func default_light (): string { return "MyLight" }
+    func default_dark (): string { return "MyDark" }
+
+    func is_available (): bool {
+        result = command ("-v", "my-toolkit-manager")
+        return !is_empty (result)
+    }
+
+    func apply (theme: string) {
+        print ("Applying: {theme}")
+        my-toolkit-manager ("--set", theme)
+    }
+}
+```
+
+**Self-managed** (plugin handles everything):
+
+```
+namespace color_scheme {
+    func is_available (): bool {
+        # check if gsettings schema exists
+        return true
+    }
+
+    func apply (mode: string) {
+        scheme = "default"
+        if mode == "dark" {
+            scheme = "prefer-dark"
+        }
+        gsettings ("set", "org.gnome.desktop.interface", "color-scheme", scheme)
+    }
+}
+```
+
+### Building and installing a plugin
+
+```bash
+# Build
+content build-lib my_plugin.ct -o my_plugin.sh
+
+# Install system-wide
+sudo cp my_plugin.sh /usr/share/ximper-unified-theme-switcher/plugins/
+
+# Install per-user
+mkdir -p ~/.local/share/ximper-unified-theme-switcher/plugins/
+cp my_plugin.sh ~/.local/share/ximper-unified-theme-switcher/plugins/
+```
+
+See `examples/plugins/` for more examples.
+
+## Building
+
+```bash
+meson setup _build
+meson compile -C _build
+sudo meson install -C _build
+```
+
+Requires the [ContenT](https://gitlab.eterfund.ru/ximperlinux/content) compiler.
 
 ## Issues and Suggestions
+
 If you have any questions or suggestions, please create them in the [Issues section](https://gitlab.eterfund.ru/ximperlinux/ximper-unified-theme-switcher/issues).
 
 ## License
-**Copyright © 2024 Etersoft**
-
----
-# TODO
-
-## GUI
-- [ ] Notification that the service is off and a suggestion to turn it on.
-- [x] Make the interface more user-friendly:
-  - [ ] Add theme presets for all toolkits?
-  - [ ] Rename Kvantum (to QT) and GTK3 (to GTK) headers?
 
-## Service
-- [ ] Switch themes for GTK4? (often break with libadwaita updates, difficult to implement).
-- [ ] Support other environments (e.g., Hyprland, Cinnamon):
-  - [x] Create a mode where the service monitors changes in the config file instead of the org.gnome.desktop.interface schema (possibly unnecessary).
+**Copyright © 2024-2026 Etersoft**

examples/plugins/color_scheme.ct

+namespace color_scheme {
+    SCHEMA = "org.gnome.desktop.interface"
+
+    func is_available (): bool {
+        schemas = gsettings ("list-schemas")
+        if regex.match (schemas, SCHEMA) {
+            keys = gsettings ("list-keys", SCHEMA)
+            if regex.match (keys, "color-scheme") {
+                return true
+            }
+        }
+        return false
+    }
+
+    func apply (mode: string) {
+        scheme = "default"
+        if mode == "dark" {
+            scheme = "prefer-dark"
+        }
+        print ("Updating color-scheme: {scheme}")
+        gsettings ("set", SCHEMA, "color-scheme", scheme)
+    }
+}

examples/plugins/cursor_theme.ct

+namespace cursor_theme {
+    SCHEMA = "org.gnome.desktop.interface"
+
+    func prefix (): string { return "CURSOR" }
+    func default_light (): string { return "Adwaita" }
+    func default_dark (): string { return "Adwaita" }
+
+    func is_available (): bool {
+        schemas = gsettings ("list-schemas")
+        if regex.match (schemas, SCHEMA) {
+            keys = gsettings ("list-keys", SCHEMA)
+            if regex.match (keys, "cursor-theme") {
+                return true
+            }
+        }
+        return false
+    }
+
+    func apply (theme: string) {
+        print ("Updating cursor theme: {theme}")
+        gsettings ("set", SCHEMA, "cursor-theme", theme)
+    }
+}

examples/plugins/icon_theme.ct

+namespace icon_theme {
+    SCHEMA = "org.gnome.desktop.interface"
+
+    func prefix (): string { return "ICON" }
+    func default_light (): string { return "Adwaita" }
+    func default_dark (): string { return "Adwaita" }
+
+    func is_available (): bool {
+        schemas = gsettings ("list-schemas")
+        if regex.match (schemas, SCHEMA) {
+            keys = gsettings ("list-keys", SCHEMA)
+            if regex.match (keys, "icon-theme") {
+                return true
+            }
+        }
+        return false
+    }
+
+    func apply (theme: string) {
+        print ("Updating icon theme: {theme}")
+        gsettings ("set", SCHEMA, "icon-theme", theme)
+    }
+}

service/meson.build

@@ -5,8 +5,6 @@ content = find_program('content')
 
 service_ct_sources = files(
     'src/config.ct',
-    'src/kvantum.ct',
-    'src/gtk3.ct',
     'src/themes.ct',
     'src/main.ct',
 )
@@ -21,6 +19,25 @@ service_bin = custom_target(
     install_mode: 'r-xr-xr-x',
 )
 
+plugin_dir = join_paths(get_option('datadir'), 'ximper-unified-theme-switcher', 'plugins')
+
+kvantum_plugin = custom_target(
+    'plugin-kvantum',
+    input: files('plugins/kvantum.ct'),
+    output: 'kvantum.sh',
+    command: [content, 'build-lib', '@INPUT@', '-o', '@OUTPUT@'],
+    install: true,
+    install_dir: plugin_dir,
+)
+
+gtk3_plugin = custom_target(
+    'plugin-gtk3',
+    input: files('plugins/gtk3.ct'),
+    output: 'gtk3.sh',
+    command: [content, 'build-lib', '@INPUT@', '-o', '@OUTPUT@'],
+    install: true,
+    install_dir: plugin_dir,
+)
 
 install_data(
     './data/ximper-unified-theme-switcher.service',

service/src/gtk3.ct → service/plugins/gtk3.ct

-GTK3_SCHEMA = "org.gnome.desktop.interface"
+namespace gtk3 {
+    GTK3_SCHEMA = "org.gnome.desktop.interface"
 
-func check_gsettings_schema (): bool {
-    schemas = gsettings ("list-schemas")
-    if regex.match (schemas, GTK3_SCHEMA) {
-        keys = gsettings ("list-keys", GTK3_SCHEMA)
-        if regex.match (keys, "color-scheme") {
-            return true
-        }
-    }
-    return false
-}
-
-class Gtk3Theme {
-    DEFAULT_LIGHT = "adw-gtk3"
-    DEFAULT_DARK = "adw-gtk3-dark"
+    func prefix (): string { return "GTK3" }
+    func default_light (): string { return "adw-gtk3" }
+    func default_dark (): string { return "adw-gtk3-dark" }
 
     func is_available (): bool {
-        return check_gsettings_schema ()
-    }
-
-    func init_defaults (cfg_path: string) {
-        if is_empty (cfg_get (cfg_path, "GTK3_DARK_THEME")) {
-            cfg_set (cfg_path, "GTK3_LIGHT_THEME", this.DEFAULT_LIGHT)
-            cfg_set (cfg_path, "GTK3_DARK_THEME", this.DEFAULT_DARK)
+        schemas = gsettings ("list-schemas")
+        if regex.match (schemas, GTK3_SCHEMA) {
+            keys = gsettings ("list-keys", GTK3_SCHEMA)
+            if regex.match (keys, "color-scheme") {
+                return true
+            }
         }
+        return false
     }
 
-    func update (mode: string, cfg_path: string) {
-        print ("Updating GTK3 theme to {mode}...")
-        if mode == "light" {
-            theme = cfg_get (cfg_path, "GTK3_LIGHT_THEME")
-            gsettings ("set", GTK3_SCHEMA, "gtk-theme", theme)
-        } else if mode == "dark" {
-            theme = cfg_get (cfg_path, "GTK3_DARK_THEME")
-            gsettings ("set", GTK3_SCHEMA, "gtk-theme", theme)
-        }
+    func apply (theme: string) {
+        print ("Updating GTK3 theme: {theme}")
+        gsettings ("set", GTK3_SCHEMA, "gtk-theme", theme)
     }
 }

service/plugins/kvantum.ct

+namespace kvantum {
+    func prefix (): string { return "KV" }
+    func default_light (): string { return "KvGnome" }
+    func default_dark (): string { return "KvGnomeDark" }
+
+    func is_available (): bool {
+        result = command ("-v", "kvantummanager")
+        return !is_empty (result)
+    }
+
+    func apply (theme: string) {
+        print ("Updating Kvantum theme: {theme}")
+        kvantummanager ("--set", theme)
+    }
+}

service/src/kvantum.ct

-class KvantumTheme {
-    DEFAULT_LIGHT = "KvGnome"
-    DEFAULT_DARK = "KvGnomeDark"
-
-    func is_available (): bool {
-        result = command ("-v", "kvantummanager")
-        if is_empty (result) {
-            return false
-        }
-        return true
-    }
-
-    func init_defaults (cfg_path: string) {
-        if is_empty (cfg_get (cfg_path, "KV_DARK_THEME")) {
-            cfg_set (cfg_path, "KV_LIGHT_THEME", this.DEFAULT_LIGHT)
-            cfg_set (cfg_path, "KV_DARK_THEME", this.DEFAULT_DARK)
-        }
-    }
-
-    func update (mode: string, cfg_path: string) {
-        print ("Updating Kvantum theme to {mode}...")
-        if mode == "light" {
-            theme = cfg_get (cfg_path, "KV_LIGHT_THEME")
-            kvantummanager ("--set", theme)
-        } else if mode == "dark" {
-            theme = cfg_get (cfg_path, "KV_DARK_THEME")
-            kvantummanager ("--set", theme)
-        }
-    }
-}

service/src/main.ct

 FORCE_FILE_REACTION = false
 
+func check_gsettings_schema (): bool {
+    schemas = gsettings ("list-schemas")
+    if regex.match (schemas, "org.gnome.desktop.interface") {
+        keys = gsettings ("list-keys", "org.gnome.desktop.interface")
+        if regex.match (keys, "color-scheme") {
+            return true
+        }
+    }
+    return false
+}
+
 func check_and_update_themes (new_theme: string) {
     cfg_path = cfg_check ()
     themes_init_defaults (cfg_path)

service/src/themes.ct

-# Реестр тем — добавьте новый экземпляр в массив
-kv_theme = KvantumTheme ()
-gtk_theme = Gtk3Theme ()
+PLUGIN_DIR = "/usr/share/ximper-unified-theme-switcher/plugins"
+HOME_PLUGIN_DIR = env.HOME .. "/.local/share/ximper-unified-theme-switcher/plugins"
 
-THEMES = [kv_theme, gtk_theme]
+plugin.load_dir (PLUGIN_DIR)
+if fs.exists (HOME_PLUGIN_DIR) {
+    plugin.load_dir (HOME_PLUGIN_DIR)
+}
 
 func themes_init_defaults (cfg_path: string) {
-    foreach t in THEMES {
-        t.init_defaults (cfg_path)
+    foreach name in plugin.list ().split (" ") {
+        if !is_empty (name) {
+            if plugin.has (name, "prefix") {
+                prefix = plugin.call (name, "prefix")
+                light_key = prefix .. "_LIGHT_THEME"
+                dark_key = prefix .. "_DARK_THEME"
+                if is_empty (cfg_get (cfg_path, dark_key)) {
+                    cfg_set (cfg_path, light_key, plugin.call (name, "default_light"))
+                    cfg_set (cfg_path, dark_key, plugin.call (name, "default_dark"))
+                }
+            }
+        }
     }
 }
 
 func themes_update (mode: string, cfg_path: string) {
-    foreach t in THEMES {
-        if t.is_available () {
-            t.update (mode, cfg_path)
+    suffix = "_LIGHT_THEME"
+    if mode == "dark" {
+        suffix = "_DARK_THEME"
+    }
+
+    foreach name in plugin.list ().split (" ") {
+        if !is_empty (name) {
+            available = plugin.call (name, "is_available")
+            if available == "true" {
+                if plugin.has (name, "prefix") {
+                    prefix = plugin.call (name, "prefix")
+                    theme = cfg_get (cfg_path, prefix .. suffix)
+                    plugin.call (name, "apply", theme)
+                } else {
+                    plugin.call (name, "apply", mode)
+                }
+            }
         }
     }
 }

ximper-unified-theme-switcher.spec

@@ -29,11 +29,29 @@ BuildRequires: meson
 %package service
 Summary: Service for Ximper unified theme switcher
 Group: System/Configuration/Other
-Requires: Kvantum libgio
+Requires: libgio
 
 %description service
 Service for Ximper unified theme switcher.
 
+%package plugin-kvantum
+Summary: Kvantum plugin for Ximper unified theme switcher
+Group: System/Configuration/Other
+Requires: %name-service
+Requires: Kvantum
+
+%description plugin-kvantum
+Kvantum theme switching plugin for Ximper unified theme switcher.
+
+%package plugin-gtk3
+Summary: GTK3 plugin for Ximper unified theme switcher
+Group: System/Configuration/Other
+Requires: %name-service
+Requires: libgio
+
+%description plugin-gtk3
+GTK3 theme switching plugin for Ximper unified theme switcher.
+
 %package gui
 Summary: GUI for Ximper unified theme switcher
 Group: System/Configuration/Other
@@ -46,6 +64,8 @@ GUI for Ximper unified theme switcher.
 Summary: Default set of themes for Ximper linux
 Group: System/Configuration/Other
 Requires: %name-service
+Requires: %name-plugin-kvantum
+Requires: %name-plugin-gtk3
 Requires: gtk3-theme-adw-gtk3
 Requires: kvantum-theme-kvlibadwaita
 
@@ -66,8 +86,15 @@ Default set of themes for Ximper linux distro
 %files service
 %_bindir/%name-service
 %_user_unitdir/%{name}*
+%dir %_datadir/%name/plugins
 %dir %_sysconfdir/%name
 
+%files plugin-kvantum
+%_datadir/%name/plugins/kvantum.sh
+
+%files plugin-gtk3
+%_datadir/%name/plugins/gtk3.sh
+
 %files gui -f %name-gui.lang
 %_bindir/%name-gui