import csv
import json
import os
from datetime import datetime
from zoneinfo import ZoneInfo


LOG_DIR = "logs"
EVENT_LOG_PATH = os.path.join(LOG_DIR, "event_log.csv")
LOG_COLUMNS = ["date", "time", "user", "action", "status", "details"]
KST = ZoneInfo("Asia/Seoul")


def user_label(user) -> str:
    if not user:
        return ""
    return getattr(user, "email", None) or getattr(user, "name", None) or str(getattr(user, "id", ""))


def log_event(user, action: str, status: str = "success", details: dict | str | None = None):
    os.makedirs(LOG_DIR, exist_ok=True)
    now = datetime.now(KST)
    file_exists = os.path.exists(EVENT_LOG_PATH)
    details_text = ""
    if isinstance(details, dict):
        details_text = json.dumps(details, ensure_ascii=False)
    elif details is not None:
        details_text = str(details)

    with open(EVENT_LOG_PATH, "a", encoding="utf-8-sig", newline="") as f:
        writer = csv.DictWriter(f, fieldnames=LOG_COLUMNS)
        if not file_exists or os.path.getsize(EVENT_LOG_PATH) == 0:
            writer.writeheader()
        writer.writerow(
            {
                "date": now.strftime("%Y-%m-%d"),
                "time": now.strftime("%H:%M:%S"),
                "user": user_label(user),
                "action": action,
                "status": status,
                "details": details_text,
            }
        )