feat: improve plugin support

src/plugin.py

@@ -16,10 +16,37 @@
 # You should have received a copy of the GNU General Public License
 # along with this program. If not, see <https://www.gnu.org/licenses/>.
 
-from .setting import AdwcustomizerSetting
+#from .setting import AdwcustomizerSetting
+
+from dataclasses import dataclass
+from importlib import import_module
+import os
+import sys
+import importlib.util
 
 
-class AdwcustomizerPluginBase:
+@dataclass
+class Meta:
+    name: str
+    description: str
+    version: str
+
+    def __str__(self) -> str:
+        return f'{self.name}: {self.version}'
+
+
+class IPluginRegistry(type):
+    plugin_registries = list()
+
+    def __init__(cls, name, bases, attrs):
+        super().__init__(cls)
+        if name != 'AdwcustomizerPluginCore':
+            IPluginRegistry.plugin_registries.append(cls)
+
+
+class AdwcustomizerPluginCore(metaclass=IPluginRegistry):
+    meta: Meta
+
     def __init__(self):
         self.title = None
 
@@ -62,3 +89,98 @@ class AdwcustomizerPluginBase:
 
     def save(self):
         raise NotImplementedError()
+
+
+class PluginUseCase:
+    def __init__(self, directory) -> None:
+        self.plugins_package = directory
+        self.modules = []
+
+    def __check_loaded_plugin_state(self, plugin_module):
+        if len(IPluginRegistry.plugin_registries) > 0:
+            latest_module = IPluginRegistry.plugin_registries[-1]
+            latest_module_name = latest_module.__module__
+            current_module_name = plugin_module.__name__
+            if current_module_name == latest_module_name:
+                print(f'Successfully imported module `{current_module_name}`')
+                self.modules.append(latest_module)
+            else:
+                print(
+                    f'Expected to import -> `{current_module_name}` but got -> `{latest_module_name}`'
+                )
+            # clear plugins from the registry when we're done with them
+            IPluginRegistry.plugin_registries.clear()
+        else:
+            print(f'No plugin found in registry for module: {plugin_module}')
+
+    def __search_for_plugins_in(self, plugins_path, package_name):
+        print(f"plugins path: {plugins_path}")
+        sys.path.append(plugins_path)
+
+        for m in os.listdir(plugins_path):
+            module = import_module(m)
+            self.__check_loaded_plugin_state(module)
+            print(dir(module))
+
+    def discover_plugins(self, reload: bool):
+        """
+        Discover the plugin classes contained in Python files, given a
+        list of directory names to scan.
+        """
+        if reload:
+            print("Reload")
+            self.modules.clear()
+            IPluginRegistry.plugin_registries.clear()
+            print(
+                f'Searching for plugins under package {self.plugins_package}')
+            package_name = os.path.basename(
+                os.path.normpath(self.plugins_package))
+            self.__search_for_plugins_in(self.plugins_package, package_name)
+
+    @staticmethod
+    def register_plugin(module: type, logger) -> AdwcustomizerPluginCore:
+        """
+        Create a plugin instance from the given module
+        :param module: module to initialize
+        :param logger: logger for the module to use
+        :return: a high level plugin
+        """
+        return module(logger)
+
+    @staticmethod
+    def hook_plugin(plugin: AdwcustomizerPluginCore):
+        """
+        Return a function accepting commands.
+        """
+        return plugin.invoke
+
+
+class PluginEngine:
+    def __init__(self, **args) -> None:
+        self.use_case = PluginUseCase(os.path.join(
+            os.environ["HOME"],
+            ".gradience_plugins"))
+
+    def start(self) -> None:
+        self.__reload_plugins()
+        self.__invoke_on_plugins('Q')
+
+    def __reload_plugins(self) -> None:
+        """Reset the list of all plugins and initiate the walk over the main
+        provided plugin package to load all available plugins
+        """
+        self.use_case.discover_plugins(True)
+
+    def __invoke_on_plugins(self, command: chr):
+        """Apply all of the plugins on the argument supplied to this function
+        """
+        for module in self.use_case.modules:
+            plugin = self.use_case.register_plugin(module)
+            delegate = self.use_case.hook_plugin(plugin)
+            plugin = delegate(command=command)
+            print(f'Loaded plugin: {plugin}')
+
+
+if __name__ == "__main__":
+    engine = PluginEngine()
+    engine.start()

src/plugins/gdm/__init__.py

@@ -0,0 +1 @@
+from .main import *

src/plugins/gdm/main.py

@@ -0,0 +1,10 @@
+from adwcustomizer.plugin import AdwcustomizerPluginCore
+
+class GDMPlugin(AdwcustomizerPluginCore):
+    def validate(self):
+        print("validate")
+    def apply(self, dark_theme=False):
+        print("apply")
+
+    def save(self):
+        print("save")

src/plugins/shell/__init__.py

@@ -0,0 +1 @@
+from .main import *

src/plugins/shell/main.py

@@ -0,0 +1,10 @@
+from adwcustomizer.plugin import AdwcustomizerPluginCore
+
+class ShellPlugin(AdwcustomizerPluginCore):
+    def validate(self):
+        print("validate")
+    def apply(self, dark_theme=False):
+        print("apply")
+
+    def save(self):
+        print("save")