"""内存日志缓冲:供后台「系统日志」页查看应用运行日志。

把应用日志(stdout)同时捕获到进程内环形缓冲(deque),提供级别/关键字/条数
过滤查询。缓冲在进程重启后清零;需要持久化的审计请另行落库。
"""
from __future__ import annotations

import logging
from collections import deque

_BUFFER: deque[dict] = deque(maxlen=2000)

_LEVEL_ORDER = {"DEBUG": 10, "INFO": 20, "WARNING": 30, "ERROR": 40, "CRITICAL": 50}


class MemoryLogHandler(logging.Handler):
    """把日志记录写入内存环形缓冲。"""

    def __init__(self) -> None:
        super().__init__()
        # format() 会在有 exc_info 时自动附带异常堆栈文本
        self.setFormatter(logging.Formatter("%(message)s"))

    def emit(self, record: logging.LogRecord) -> None:
        try:
            entry = {
                "ts": record.created,
                "level": record.levelname,
                "logger": record.name,
                "message": self.format(record),
            }
            _BUFFER.append(entry)
        except Exception:  # noqa: BLE001  日志采集绝不影响业务
            self.handleError(record)


class _SQLNoiseFilter(logging.Filter):
    """过滤 SQLAlchemy 的 DEBUG/INFO 回显(只留警告以上)。"""

    def filter(self, record: logging.LogRecord) -> bool:
        return not (
            record.name.startswith("sqlalchemy.") and record.levelno < logging.WARNING
        )


def get_entries(
    min_level: str | None = None,
    keyword: str | None = None,
    limit: int = 200,
) -> list[dict]:
    """按条件查询缓冲日志,最新在前。"""
    min_no = _LEVEL_ORDER.get((min_level or "").upper(), 0)
    kw = (keyword or "").strip().lower()
    items = list(_BUFFER)
    items.reverse()
    out: list[dict] = []
    for e in items:
        if _LEVEL_ORDER.get(e["level"], 0) < min_no:
            continue
        if kw and kw not in e["message"].lower() and kw not in e["logger"].lower():
            continue
        out.append(e)
        if len(out) >= limit:
            break
    return out


def setup_logging(level: str = "INFO", log_file: str = "") -> None:
    """配置应用日志:stdout(容器收集) + 内存环形缓冲(Admin 日志页) + 可选滚动文件(持久化)。

    幂等:重复调用不会重复挂 handler(文件 handler 按 abspath 判重,相对/绝对
    路径指向同一文件视为同一个)。文件写入基础设施失败只记 warning,绝不
    影响启动与业务 —— 与 _safe_write_ingest_failure 同级约束:可观测性
    基础设施不许拖垮主流程。
    """
    import os
    from logging.handlers import RotatingFileHandler

    root = logging.getLogger()
    if root.level == logging.NOTSET or root.level > logging.INFO:
        root.setLevel(getattr(logging, level.upper(), logging.INFO))

    if not any(isinstance(h, MemoryLogHandler) for h in root.handlers):
        handler = MemoryLogHandler()
        handler.setLevel(logging.INFO)
        handler.addFilter(_SQLNoiseFilter())
        root.addHandler(handler)

    if not log_file:
        return

    # 滚动上限:单文件 10MB × 当前+5 份 ≈ 60MB,足够回溯数周的关键事件,
    # 又不会吃满磁盘。格式含时间/级别/logger 名,便于事后 grep 排查。
    target = os.path.abspath(log_file)
    if any(
        isinstance(h, RotatingFileHandler) and getattr(h, "baseFilename", None) == target
        for h in root.handlers
    ):
        return
    try:
        os.makedirs(os.path.dirname(target), exist_ok=True)
        file_handler = RotatingFileHandler(
            target,
            maxBytes=10 * 1024 * 1024,
            backupCount=5,
            encoding="utf-8",
        )
        file_handler.setFormatter(
            logging.Formatter("%(asctime)s %(levelname)s %(name)s %(message)s")
        )
        file_handler.setLevel(logging.INFO)
        file_handler.addFilter(_SQLNoiseFilter())
        root.addHandler(file_handler)
        logging.getLogger(__name__).info("文件日志已启用: %s", log_file)
    except PermissionError:
        # 容器场景最常见:挂载卷目录属主是 root,进程是非 root 用户。
        # 修复方向:镜像内预创建目录并 chown(Dockerfile),或重建空卷。
        logging.getLogger(__name__).warning(
            "启用文件日志失败(%s):无写权限。容器部署请确认镜像已预创建该目录"
            "并 chown 给运行用户(compose 卷挂载点默认 root 属主);"
            "宿主机直跑请检查目录权限。本次仅保留 stdout/内存日志。",
            log_file,
        )
    except Exception:
        logging.getLogger(__name__).warning(
            "启用文件日志失败(%s),仅保留 stdout/内存日志", log_file, exc_info=True,
        )