"""Simple event bus for decoupled component communication."""

from typing import Dict, List, Callable, Any
from dataclasses import dataclass
from enum import Enum


class EventType(Enum):
    """Types of simulation events."""
    SIMULATION_STATE_CHANGED = "simulation_state_changed"
    WORLD_TICK_COMPLETED = "world_tick_completed"
    ENTITY_ADDED = "entity_added"
    ENTITY_REMOVED = "entity_removed"
    SELECTION_CHANGED = "selection_changed"
    TIMING_UPDATE = "timing_update"


@dataclass
class Event:
    """Event data structure."""
    type: EventType
    data: Dict[str, Any]
    timestamp: float = None

    def __post_init__(self):
        import time
        if self.timestamp is None:
            self.timestamp = time.time()


class EventBus:
    """Simple event bus for decoupled communication."""

    def __init__(self):
        self._subscribers: Dict[EventType, List[Callable]] = {}
        self._event_history: List[Event] = []
        self._max_history = 1000

    def subscribe(self, event_type: EventType, callback: Callable[[Event], None]):
        """Subscribe to an event type."""
        if event_type not in self._subscribers:
            self._subscribers[event_type] = []
        self._subscribers[event_type].append(callback)

    def unsubscribe(self, event_type: EventType, callback: Callable[[Event], None]):
        """Unsubscribe from an event type."""
        if event_type in self._subscribers:
            try:
                self._subscribers[event_type].remove(callback)
            except ValueError:
                pass

    def publish(self, event: Event):
        """Publish an event to all subscribers."""
        # Store in history
        self._event_history.append(event)
        if len(self._event_history) > self._max_history:
            self._event_history.pop(0)

        # Notify subscribers
        if event.type in self._subscribers:
            for callback in self._subscribers[event.type]:
                try:
                    callback(event)
                except Exception as e:
                    print(f"Error in event callback: {e}")

    def get_recent_events(self, event_type: EventType = None, count: int = 10) -> List[Event]:
        """Get recent events, optionally filtered by type."""
        events = self._event_history
        if event_type:
            events = [e for e in events if e.type == event_type]
        return events[-count:]

    def clear_history(self):
        """Clear event history."""
        self._event_history.clear()