from __future__ import annotations

import logging
import os
from contextlib import contextmanager
from typing import Callable, Iterator


class JobLogIdFilter(logging.Filter):
    """
    仅允许写入“属于指定 job_log_id”的 LogRecord。
    依赖 setup_logging() 安装的 LogRecordFactory 注入字段：connecthub_job_log_id。
    """

    def __init__(self, *, job_log_id: int) -> None:
        super().__init__()
        self.job_log_id = int(job_log_id)

    def filter(self, record: logging.LogRecord) -> bool:  # noqa: A003
        try:
            return getattr(record, "connecthub_job_log_id", None) == self.job_log_id
        except Exception:
            return False


class SafeBufferingHandler(logging.Handler):
    """
    只用于“尽力捕获”运行日志：
    - emit 内部全 try/except，任何异常都吞掉，绝不影响任务执行
    - 有最大字节限制，超过后写入截断标记并停止追加
    """

    def __init__(self, *, max_bytes: int = 200_000, level: int = logging.INFO) -> None:
        super().__init__(level=level)
        self.max_bytes = max_bytes
        self._buf: list[str] = []
        self._size_bytes = 0
        self._truncated = False

    def emit(self, record: logging.LogRecord) -> None:  # noqa: D401
        try:
            if self._truncated:
                return
            try:
                msg = self.format(record)
            except Exception:
                return
            line = msg + "\n"
            try:
                b = line.encode("utf-8", errors="replace")
            except Exception:
                return

            if self._size_bytes + len(b) > self.max_bytes:
                self._buf.append("[TRUNCATED] run_log exceeded max_bytes\n")
                self._truncated = True
                return

            self._buf.append(line)
            self._size_bytes += len(b)
        except Exception:
            # 双保险：任何异常都不能冒泡
            return

    def get_text(self) -> str:
        try:
            return "".join(self._buf)
        except Exception:
            return ""


@contextmanager
def capture_logs(
    *,
    max_bytes: int = 200_000,
    job_log_id: int | None = None,
    file_path: str | None = None,
) -> Iterator[Callable[[], str]]:
    """
    捕获当前进程（root logger）输出的日志文本。
    任何问题都不应影响业务执行。
    """
    root = logging.getLogger()
    handler = SafeBufferingHandler(max_bytes=max_bytes)
    handler.setLevel(logging.INFO)
    handler.setFormatter(
        logging.Formatter(fmt="%(asctime)s %(levelname)s %(name)s %(message)s", datefmt="%Y-%m-%d %H:%M:%S")
    )

    file_handler: logging.Handler | None = None
    flt: JobLogIdFilter | None = None
    if job_log_id is not None:
        try:
            flt = JobLogIdFilter(job_log_id=int(job_log_id))
            handler.addFilter(flt)
        except Exception:
            flt = None

    if file_path:
        try:
            parent = os.path.dirname(file_path)
            if parent:
                os.makedirs(parent, exist_ok=True)
            fh = logging.FileHandler(file_path, encoding="utf-8")
            fh.setLevel(logging.INFO)
            fh.setFormatter(
                logging.Formatter(fmt="%(asctime)s %(levelname)s %(name)s %(message)s", datefmt="%Y-%m-%d %H:%M:%S")
            )
            if flt is not None:
                fh.addFilter(flt)
            file_handler = fh
        except Exception:
            file_handler = None

    try:
        root.addHandler(handler)
    except Exception:
        # 无法挂载则降级为空
        yield lambda: ""
        return

    if file_handler is not None:
        try:
            root.addHandler(file_handler)
        except Exception:
            try:
                file_handler.close()
            except Exception:
                pass
            file_handler = None

    try:
        yield handler.get_text
    finally:
        try:
            root.removeHandler(handler)
        except Exception:
            pass
        if file_handler is not None:
            try:
                root.removeHandler(file_handler)
            except Exception:
                pass
            try:
                file_handler.close()
            except Exception:
                pass