"""KEFU_WS_DEBUG=1 时把 IM 收/发原始 content 写入 backend/ws_media_debug.log。"""

from __future__ import annotations

import json
import os
from datetime import datetime
from pathlib import Path
from typing import Any

_ENABLED: bool | None = None
_LOG_PATH: Path | None = None


def _is_enabled() -> bool:
    global _ENABLED
    if _ENABLED is None:
        _ENABLED = os.getenv("KEFU_WS_DEBUG", "").strip().lower() in ("1", "true", "yes")
    return _ENABLED


def _log_path() -> Path:
    global _LOG_PATH
    if _LOG_PATH is None:
        backend_dir = Path(__file__).resolve().parents[2]
        _LOG_PATH = backend_dir / "ws_media_debug.log"
    return _LOG_PATH


def log_im_message(
    *,
    direction: str,
    message_type: int | str,
    conversation_id: str = "",
    content: Any = None,
    fields: dict[str, Any] | None = None,
) -> None:
    if not _is_enabled():
        return
    try:
        ts = datetime.now().isoformat()
        if isinstance(content, (dict, list)):
            content_s = json.dumps(content, ensure_ascii=False, separators=(",", ":"))
        elif content is None:
            content_s = ""
        else:
            content_s = str(content)
        fields_s = ""
        if fields:
            fields_s = " | fields=" + json.dumps(fields, ensure_ascii=False, separators=(",", ":"))
        line = (
            f"{ts} {direction} type={message_type} conv={conversation_id} "
            f"content={content_s}{fields_s}\n"
        )
        path = _log_path()
        path.parent.mkdir(parents=True, exist_ok=True)
        with open(path, "a", encoding="utf-8") as f:
            f.write(line)
    except Exception:
        pass