# services/event_router.py
#
# ADR-012 §③: 單一入口 dispatch(event) — L0/L1/L2 分流
# W2-C: L2 優先走 Elephant Alpha Orchestrator；EA 不可用時 fallback AIOrchestrator
#
import asyncio
import logging
from typing import Any, Dict, Optional

from services.ai_orchestrator import AIOrchestrator
from services.telegram_templates import alert
from database.manager import get_session

logger = logging.getLogger(__name__)


async def _handle_l1(event: Dict[str, Any], session_id: str) -> Dict[str, Any]:
    """L1: semantic translation + reason analysis (Hermes)."""
    orchestrator = AIOrchestrator()
    return await orchestrator.handle_l1(event, session_id)


async def _handle_l2(event: Dict[str, Any], session_id: str) -> Dict[str, Any]:
    """
    L2: W2-C — EA Orchestrator 優先（動態路由 256K ctx）；
    EA 不可用（API key 未設或連線失敗）時 fallback AIOrchestrator。
    ADR-012: audit trail 由 EA._log_decision + triaged_alert 雙寫保證。
    """
    try:
        from services.elephant_service import elephant_service
        from services.elephant_alpha_orchestrator import elephant_orchestrator

        # 護欄：EA API key 未設定則直接 fallback，不嘗試連線
        if not elephant_service.api_key:
            raise RuntimeError("OPENROUTER_API_KEY not configured, using fallback")

        # 護欄：連線快取確認（W3-A cache 300s，不會每次都 ping）
        if not elephant_service.check_connection():
            raise RuntimeError("EA connection unavailable, using fallback")

        decision = await elephant_orchestrator.analyze_and_coordinate({
            "event": event,
            "tier": "L2",
            "session_id": session_id,
            "urgency": "high",
            "complexity": "medium",
            "task_type": event.get("event_type", "general_analysis"),
        })

        return {
            "source": "elephant_alpha",
            "priority": decision.priority,
            "confidence": decision.confidence,
            "execution_plan": decision.execution_plan,
            "agents_required": decision.agents_required,
            "reasoning": decision.reasoning,
        }

    except Exception as e:
        logger.warning(f"[EventRouter] EA L2 failed ({e}), fallback → AIOrchestrator")
        orchestrator = AIOrchestrator()
        return await orchestrator.handle_l2(event, session_id)


async def _handle_l0(event: Dict[str, Any]) -> Dict[str, Any]:
    """L0: return raw event (compatibility/monitoring)."""
    return {"status": "ok", "echo": event.get("event_type")}


async def dispatch(event: Dict[str, Any], admin_chat_ids: Optional[list] = None) -> Dict[str, Any]:
    """
    Main event routing entry (ADR-012 §③ — 唯一入口).
    Output format compatible with routes/bot_api_routes.
    """
    tier = _classify(event)
    session_id = f"evt:{event.get('event_type')}:{event.get('source', 'unknown')}"

    try:
        if tier == "L0":
            result = await _handle_l0(event)
        elif tier == "L1":
            result = await _handle_l1(event, session_id)
        elif tier == "L2":
            result = await _handle_l2(event, session_id)
        else:
            result = await _handle_l0(event)

        return {
            "tier": tier,
            "sent": 1,
            "errors": [],
            "latency_ms": 0,
            "payload": result,
        }
    except Exception as e:
        logger.exception(f"[EventRouter] dispatch failed: {e}")
        return {
            "tier": tier,
            "sent": 0,
            "errors": [str(e)],
            "latency_ms": 0,
            "payload": None,
        }


def _classify(event: Dict[str, Any]) -> str:
    sev = event.get("severity", "info")
    has_trace = bool(event.get("trace"))
    event_type = event.get("event_type", "")

    if sev in ("info", "success"):
        return "L0"
    if sev == "warning":
        return "L1" if has_trace else "L0"
    if sev == "alert":
        if event_type in {"price_threat", "db_connection_error", "crawler_timeout",
                          "nim_quota_exhausted", "embedding_failure"}:
            return "L2"
        return "L1"
    return "L0"