"""
EU-Utility - Widget Registry

Allows plugins to register widgets that appear in the Widgets tab.
"""

from typing import Dict, List, Callable, Optional
from dataclasses import dataclass
from PyQt6.QtWidgets import QWidget


@dataclass
class WidgetInfo:
    """Information about a registered widget."""
    id: str
    name: str
    description: str
    icon: str  # emoji or icon name
    creator: Callable[[], QWidget]  # Function that creates the widget
    plugin_id: str  # Which plugin registered this


class WidgetRegistry:
    """Registry for plugin-provided widgets."""
    
    _instance = None
    
    def __new__(cls):
        if cls._instance is None:
            cls._instance = super().__new__(cls)
            cls._instance._widgets: Dict[str, WidgetInfo] = {}
        return cls._instance
    
    def register_widget(
        self,
        widget_id: str,
        name: str,
        description: str,
        icon: str,
        creator: Callable[[], QWidget],
        plugin_id: str = "unknown"
    ):
        """Register a widget.
        
        Args:
            widget_id: Unique identifier for this widget type
            name: Display name
            description: Short description shown in UI
            icon: Emoji or icon name
            creator: Function that returns a QWidget instance
            plugin_id: ID of the plugin registering this widget
        """
        self._widgets[widget_id] = WidgetInfo(
            id=widget_id,
            name=name,
            description=description,
            icon=icon,
            creator=creator,
            plugin_id=plugin_id
        )
        print(f"[WidgetRegistry] Registered widget: {name} (from {plugin_id})")
    
    def unregister_widget(self, widget_id: str):
        """Unregister a widget."""
        if widget_id in self._widgets:
            del self._widgets[widget_id]
            print(f"[WidgetRegistry] Unregistered widget: {widget_id}")
    
    def get_widget(self, widget_id: str) -> Optional[WidgetInfo]:
        """Get widget info by ID."""
        return self._widgets.get(widget_id)
    
    def get_all_widgets(self) -> List[WidgetInfo]:
        """Get all registered widgets."""
        return list(self._widgets.values())
    
    def get_widgets_by_plugin(self, plugin_id: str) -> List[WidgetInfo]:
        """Get all widgets registered by a specific plugin."""
        return [w for w in self._widgets.values() if w.plugin_id == plugin_id]
    
    def create_widget(self, widget_id: str) -> Optional[QWidget]:
        """Create an instance of a registered widget."""
        info = self._widgets.get(widget_id)
        if info:
            try:
                return info.creator()
            except Exception as e:
                print(f"[WidgetRegistry] Error creating widget {widget_id}: {e}")
        return None
    
    def clear(self):
        """Clear all registered widgets."""
        self._widgets.clear()


# Global registry instance
def get_widget_registry() -> WidgetRegistry:
    """Get the global widget registry."""
    return WidgetRegistry()