log.py

"""
日志模块 - 使用环境变量配置
"""

import os
import sys
import threading
from datetime import datetime

# 日志级别定义
LOG_LEVELS = {"debug": 0, "info": 1, "warning": 2, "error": 3, "critical": 4}

# 线程锁，用于文件写入同步
_file_lock = threading.Lock()

# 文件写入状态标志
_file_writing_disabled = False
_disable_reason = None


def _get_current_log_level():
    """获取当前日志级别"""
    level = os.getenv("LOG_LEVEL", "info").lower()
    return LOG_LEVELS.get(level, LOG_LEVELS["info"])


def _get_log_file_path():
    """获取日志文件路径"""
    return os.getenv("LOG_FILE", "log.txt")


def _clear_log_file():
    """清空日志文件（在启动时调用）"""
    global _file_writing_disabled, _disable_reason

    try:
        log_file = _get_log_file_path()
        with _file_lock:
            with open(log_file, "w", encoding="utf-8") as f:
                f.write("")  # 清空文件
    except (PermissionError, OSError, IOError) as e:
        # 检测只读文件系统或权限问题，禁用文件写入
        _file_writing_disabled = True
        _disable_reason = str(e)
        print(
            f"Warning: File system appears to be read-only or permission denied. "
            f"Disabling log file writing: {e}",
            file=sys.stderr,
        )
        print("Log messages will continue to display in console only.", file=sys.stderr)
    except Exception as e:
        # 其他异常仍然输出警告但不禁用写入（可能是临时问题）
        print(f"Warning: Failed to clear log file: {e}", file=sys.stderr)


def _write_to_file(message: str):
    """线程安全地写入日志文件"""
    global _file_writing_disabled, _disable_reason

    # 如果文件写入已被禁用，直接返回
    if _file_writing_disabled:
        return

    try:
        log_file = _get_log_file_path()
        with _file_lock:
            with open(log_file, "a", encoding="utf-8") as f:
                f.write(message + "\n")
                f.flush()  # 强制刷新到磁盘，确保实时写入
    except (PermissionError, OSError, IOError) as e:
        # 检测只读文件系统或权限问题，禁用文件写入
        _file_writing_disabled = True
        _disable_reason = str(e)
        print(
            f"Warning: File system appears to be read-only or permission denied. "
            f"Disabling log file writing: {e}",
            file=sys.stderr,
        )
        print("Log messages will continue to display in console only.", file=sys.stderr)
    except Exception as e:
        # 其他异常仍然输出警告但不禁用写入（可能是临时问题）
        print(f"Warning: Failed to write to log file: {e}", file=sys.stderr)


def _log(level: str, message: str):
    """
    内部日志函数
    """
    level = level.lower()
    if level not in LOG_LEVELS:
        print(f"Warning: Unknown log level '{level}'", file=sys.stderr)
        return

    # 检查日志级别
    current_level = _get_current_log_level()
    if LOG_LEVELS[level] < current_level:
        return

    # 截断日志消息到最多500个字符
    #if len(message) > 500:
        #message = message[:500] + "..."

    # 格式化日志消息
    timestamp = datetime.now().strftime("%Y-%m-%d %H:%M:%S")
    entry = f"[{timestamp}] [{level.upper()}] {message}"

    # 输出到控制台
    if level in ("error", "critical"):
        print(entry, file=sys.stderr)
    else:
        print(entry)

    # 实时写入文件
    _write_to_file(entry)


def set_log_level(level: str):
    """设置日志级别提示"""
    level = level.lower()
    if level not in LOG_LEVELS:
        print(f"Warning: Unknown log level '{level}'. Valid levels: {', '.join(LOG_LEVELS.keys())}")
        return False

    print(f"Note: To set log level '{level}', please set LOG_LEVEL environment variable")
    return True


class Logger:
    """支持 log('info', 'msg') 和 log.info('msg') 两种调用方式"""

    def __call__(self, level: str, message: str):
        """支持 log('info', 'message') 调用方式"""
        _log(level, message)

    def debug(self, message: str):
        """记录调试信息"""
        _log("debug", message)

    def info(self, message: str):
        """记录一般信息"""
        _log("info", message)

    def warning(self, message: str):
        """记录警告信息"""
        _log("warning", message)

    def error(self, message: str):
        """记录错误信息"""
        _log("error", message)

    def critical(self, message: str):
        """记录严重错误信息"""
        _log("critical", message)

    def get_current_level(self) -> str:
        """获取当前日志级别名称"""
        current_level = _get_current_log_level()
        for name, value in LOG_LEVELS.items():
            if value == current_level:
                return name
        return "info"

    def get_log_file(self) -> str:
        """获取当前日志文件路径"""
        return _get_log_file_path()


# 导出全局日志实例
log = Logger()

# 导出的公共接口
__all__ = ["log", "set_log_level", "LOG_LEVELS"]

# 在模块加载时清空日志文件
_clear_log_file()

# 使用说明:
# 1. 设置日志级别: export LOG_LEVEL=debug (或在.env文件中设置)
# 2. 设置日志文件: export LOG_FILE=log.txt (或在.env文件中设置)