"""结构化 JSON 日志配置模块。"""
import logging
import json
from datetime import datetime, timezone


class JSONFormatter(logging.Formatter):
    """将日志记录格式化为 JSON 字符串，便于日志收集平台（如 ELK、Loki）解析。"""

    def format(self, record: logging.LogRecord) -> str:
        log_entry: dict = {
            "timestamp": datetime.now(timezone.utc).isoformat(),
            "level": record.levelname,
            "message": record.getMessage(),
            "logger": record.name,
            "module": record.module,
            "function": record.funcName,
            "line": record.lineno,
        }

        if record.exc_info:
            log_entry["exception"] = self.formatException(record.exc_info)

        # 从 extra 字段注入的可观测性上下文
        if hasattr(record, "user_id"):
            log_entry["user_id"] = record.user_id
        if hasattr(record, "request_id"):
            log_entry["request_id"] = record.request_id
        if hasattr(record, "path"):
            log_entry["path"] = record.path
        if hasattr(record, "method"):
            log_entry["method"] = record.method
        if hasattr(record, "duration_ms"):
            log_entry["duration_ms"] = record.duration_ms
        if hasattr(record, "status_code"):
            log_entry["status_code"] = record.status_code

        return json.dumps(log_entry, ensure_ascii=False)


def setup_logging(level: int = logging.INFO) -> None:
    """初始化全局 JSON 日志配置。

    应在应用启动时（import 其他模块之前）调用一次。
    """
    handler = logging.StreamHandler()
    handler.setFormatter(JSONFormatter())

    root_logger = logging.getLogger()
    # 清空已有 handlers，避免重复输出
    root_logger.handlers.clear()
    root_logger.addHandler(handler)
    root_logger.setLevel(level)

    # 降低 uvicorn/sqlalchemy 等第三方库的噪音
    logging.getLogger("uvicorn.access").setLevel(logging.WARNING)
    logging.getLogger("sqlalchemy.engine").setLevel(logging.WARNING)