chore: export repeated methods into lib

lib/state.py

@@ -0,0 +1,72 @@
+"""Unified state representation utilities for MDP state encoding
+Used by both experiments/ and sim/ components for consistent state handling
+"""
+from typing import Any, Callable
+
+
+def make_state_repr(page: str = None, product_id: str = None, event_name: str = None) -> str:
+    """create canonical state representation string from components
+    format: page|productId|eventName
+    """
+    p = page or 'unk'
+    pid = product_id or 'none'
+    en = event_name or 'unknown'
+    return f"{p}|{pid}|{en}"
+
+
+def event_to_state(evt: Any) -> str:
+    """convert event object/dict to state string
+    supports both object attributes and dict keys
+    """
+    if isinstance(evt, dict):
+        return make_state_repr(
+            page=evt.get('page'),
+            product_id=evt.get('productId'),
+            event_name=evt.get('eventName') or evt.get('event_type')
+        )
+    return make_state_repr(
+        page=getattr(evt, 'page', None),
+        product_id=getattr(evt, 'productId', None),
+        event_name=getattr(evt, 'eventName', None) or getattr(evt, 'event_type', None)
+    )
+
+
+def parse_state(state_str: str) -> dict:
+    """parse state string back to components
+    returns: {'page': str, 'productId': str, 'eventName': str}
+    """
+    parts = state_str.split('|')
+    return {
+        'page': parts[0] if len(parts) > 0 and parts[0] != 'unk' else None,
+        'productId': parts[1] if len(parts) > 1 and parts[1] != 'none' else None,
+        'eventName': parts[2] if len(parts) > 2 and parts[2] != 'unknown' else None
+    }
+
+
+def get_event_name(evt: Any) -> str:
+    """extract event name from event object/dict"""
+    if isinstance(evt, dict):
+        return evt.get('eventName') or evt.get('event_type') or ''
+    return getattr(evt, 'eventName', None) or getattr(evt, 'event_type', None) or ''
+
+
+def get_timestamp(evt: Any) -> Any:
+    """extract timestamp from event object/dict"""
+    if isinstance(evt, dict):
+        return evt.get('ts') or evt.get('timestamp')
+    return getattr(evt, 'ts', None) or getattr(evt, 'timestamp', None)
+
+
+def create_state_fn() -> Callable:
+    """factory for state representation function"""
+    return event_to_state
+
+
+def create_event_name_fn() -> Callable:
+    """factory for event name extraction function"""
+    return get_event_name
+
+
+def create_timestamp_fn() -> Callable:
+    """factory for timestamp extraction function (returns raw value, use features.parse_timestamp to convert)"""
+    return get_timestamp