from typing import List, Optional

from .plugin import Plugin, PluginRegistry


class PluginLoader:
    def __init__(self, registry: Optional[PluginRegistry] = None):
        self.registry = registry or PluginRegistry()
        self._entry_point_name = 'errorfix.plugins'

    def load_entry_points(self) -> List[Plugin]:
        plugins = []
        try:
            import importlib.metadata
            eps = importlib.metadata.entry_points()
            if hasattr(eps, 'select'):
                entry_points = eps.select(group=self._entry_point_name)
            else:
                entry_points = eps.get(self._entry_point_name, [])

            for ep in entry_points:
                try:
                    plugin_class = ep.load()
                    plugin = plugin_class()
                    self.registry.register(plugin)
                    plugins.append(plugin)
                except Exception as e:
                    print(f"Warning: Failed to load plugin {ep.name}: {e}")
        except Exception as e:
            print(f"Warning: Could not load entry points: {e}")
        return plugins

    def load_plugin_module(self, module_name: str) -> Plugin:
        module = __import__(module_name, fromlist=[''])
        if not hasattr(module, 'register'):
            raise ValueError(f"Module {module_name} does not have a 'register' function")

        plugin = module.register()
        if not isinstance(plugin, Plugin):
            raise ValueError("register() must return a Plugin instance")

        self.registry.register(plugin)
        return plugin

    def load_from_path(self, path: str) -> List[Plugin]:
        import importlib.util

        plugins = []
        import os
        if os.path.isdir(path):
            for filename in os.listdir(path):
                if filename.endswith('.py') and not filename.startswith('_'):
                    module_name = filename[:-3]
                    file_path = os.path.join(path, filename)
                    spec = importlib.util.spec_from_file_location(module_name, file_path)
                    if spec and spec.loader:
                        module = importlib.util.module_from_spec(spec)
                        spec.loader.exec_module(module)
                        if hasattr(module, 'register'):
                            plugin = module.register()
                            if isinstance(plugin, Plugin):
                                self.registry.register(plugin)
                                plugins.append(plugin)
        return plugins

    def discover_and_load(self) -> List[Plugin]:
        plugins = self.load_entry_points()
        return plugins

    def get_registry(self) -> PluginRegistry:
        return self.registry