"""
Purpose Agent Runtime — Event-driven execution engine for v3.0.

Provides:
  - PAEvent: canonical event schema
  - EventKind: enumerated event types  
  - Visibility: event visibility levels
  - EventBus: async pub/sub with backpressure and replay
  - RunState: typed execution state for checkpointing
  - Checkpointer: protocol for durable state persistence
  - InMemoryCheckpointer: testing
  - JSONLCheckpointer: file-based, portable
  - SQLiteCheckpointer: production, concurrent-safe
"""
from purpose_agent.runtime.events import PAEvent, EventKind, Visibility, create_event, TERMINAL_KINDS
from purpose_agent.runtime.event_bus import EventBus, parallel_merge
from purpose_agent.runtime.state import RunState, RunStatus, NodeState
from purpose_agent.runtime.checkpoint import (
    Checkpointer,
    InMemoryCheckpointer,
    JSONLCheckpointer, 
    SQLiteCheckpointer,
)

__all__ = [
    "PAEvent", "EventKind", "Visibility", "create_event", "TERMINAL_KINDS",
    "EventBus", "parallel_merge",
    "RunState", "RunStatus", "NodeState",
    "Checkpointer", "InMemoryCheckpointer", "JSONLCheckpointer", "SQLiteCheckpointer",
]