"""日志装配。

两个格式档位：
- ``text``（默认）：人类可读，本地开发用 ``tail`` 看
- ``json``：一行一条 JSON，便于采集到 ELK/Loki

trace_id 通过 ``obs.tracing.get_trace_id`` 动态注入——用 filter 而非
formatter 参数，是为了让每条日志自动带上当前上下文的 trace_id，调用方
不需要在每条 log 里手动传。
"""

from __future__ import annotations

import json
import logging
import sys
from datetime import datetime

from obs.tracing import get_trace_id

_TEXT_FMT = "%(asctime)s %(levelname)-5s [%(trace_id)s] %(name)s | %(message)s"
_DATE_FMT = "%Y-%m-%d %H:%M:%S"

# 这些第三方 logger 在 INFO 级别过于聒噪，统一压到 WARNING
_NOISY_LOGGERS = (
    "httpx",
    "httpcore",
    "urllib3",
    "apscheduler.executors.default",
    "apscheduler.scheduler",
    "openai",
)


class _TraceIdFilter(logging.Filter):
    """把当前上下文的 trace_id 注入 LogRecord，缺省为 '-'。"""

    def filter(self, record: logging.LogRecord) -> bool:
        record.trace_id = get_trace_id() or "-"
        return True


class _JsonFormatter(logging.Formatter):
    """一行一条 JSON 的格式化器。"""

    def format(self, record: logging.LogRecord) -> str:
        payload = {
            "ts": datetime.fromtimestamp(record.created).isoformat(timespec="milliseconds"),
            "level": record.levelname,
            "logger": record.name,
            "trace_id": getattr(record, "trace_id", "-"),
            "message": record.getMessage(),
        }
        if record.exc_info:
            payload["exc"] = self.formatException(record.exc_info)
        # 允许调用方通过 logger.info("...", extra={"kv": {...}}) 附加结构化字段
        kv = getattr(record, "kv", None)
        if isinstance(kv, dict):
            payload.update(kv)
        return json.dumps(payload, ensure_ascii=False)


def setup_logging(level: str = "INFO", fmt: str = "text") -> None:
    """初始化根 logger。重复调用安全（先清空已有 handler）。"""
    root = logging.getLogger()
    root.setLevel(getattr(logging, str(level).upper(), logging.INFO))

    for handler in list(root.handlers):
        root.removeHandler(handler)

    handler = logging.StreamHandler(sys.stdout)
    handler.addFilter(_TraceIdFilter())
    if str(fmt).lower() == "json":
        handler.setFormatter(_JsonFormatter())
    else:
        handler.setFormatter(logging.Formatter(_TEXT_FMT, datefmt=_DATE_FMT))
    root.addHandler(handler)

    for name in _NOISY_LOGGERS:
        logging.getLogger(name).setLevel(logging.WARNING)


def get_logger(name: str) -> logging.Logger:
    """取 logger 的统一入口（留一层薄封装，将来换实现只改这里）。"""
    return logging.getLogger(name)