"""
세션/워커 생성·해제·스케일 이벤트를 기록하고 대시보드로 전달
"""
from __future__ import annotations

import os
import time
import json
from collections import deque
from typing import Dict, Any, List
from threading import Lock

LOG_DIR = "logs"
os.makedirs(LOG_DIR, exist_ok=True)

SESSION_EVENT_LOG_PATH = os.path.join(LOG_DIR, "session_events.jsonl")
SESSION_EVENT_MAX_BYTES = 5 * 1024 * 1024  # 5MB
SESSION_EVENT_BACKUP_COUNT = 3

# 메모리 내 최근 이벤트 버퍼 (대시보드 실시간 전송용)
_recent_events: deque = deque(maxlen=200)
_events_lock = Lock()


def _rotate_if_needed() -> None:
    try:
        if os.path.exists(SESSION_EVENT_LOG_PATH) and os.path.getsize(SESSION_EVENT_LOG_PATH) >= SESSION_EVENT_MAX_BYTES:
            ts = time.strftime("%Y%m%d-%H%M%S")
            rotated_path = os.path.join(LOG_DIR, f"session_events_{ts}.jsonl")
            os.replace(SESSION_EVENT_LOG_PATH, rotated_path)

            rotated = [
                os.path.join(LOG_DIR, f) for f in os.listdir(LOG_DIR)
                if f.startswith("session_events_") and f.endswith(".jsonl")
            ]
            rotated.sort(key=lambda p: os.path.getmtime(p), reverse=True)
            for old in rotated[SESSION_EVENT_BACKUP_COUNT:]:
                try:
                    os.remove(old)
                except Exception:
                    pass
    except Exception:
        pass


def log_session_event(
    event_type: str,  # "session_create", "session_destroy", "worker_scale_up", "worker_scale_down", "pool_reap", etc.
    model_type: str = "",
    session_id: str = "",
    details: Dict[str, Any] | None = None
) -> None:
    """
    세션/워커 이벤트 기록
    - JSONL 파일로 영구 저장 (로테이션)
    - 메모리 버퍼에 최근 이벤트 유지 (대시보드 실시간 전송)
    """
    record = {
        "timestamp": time.time(),
        "event_type": event_type,
        "model_type": model_type,
        "session_id": session_id,
        "details": details or {}
    }
    
    try:
        _rotate_if_needed()
        with open(SESSION_EVENT_LOG_PATH, "a", encoding="utf-8") as f:
            f.write(json.dumps(record, ensure_ascii=False) + "\n")
    except Exception:
        pass
    
    with _events_lock:
        _recent_events.append(record)


def get_recent_events(limit: int = 100) -> List[Dict[str, Any]]:
    """최근 이벤트 반환 (대시보드 API용)"""
    with _events_lock:
        return list(_recent_events)[-limit:]


def read_events_from_file(limit: int = 200) -> List[Dict[str, Any]]:
    """파일에서 최근 이벤트 읽기 (초기 로드용)"""
    events = []
    try:
        if not os.path.exists(SESSION_EVENT_LOG_PATH):
            return events
        
        with open(SESSION_EVENT_LOG_PATH, "r", encoding="utf-8") as f:
            lines = f.readlines()
        
        for line in lines[-limit:]:
            try:
                events.append(json.loads(line.strip()))
            except Exception:
                pass
    except Exception:
        pass
    
    return events