# ============================================================
# 审计事件独立介质镜像 v1（moduleId: core-audit-mirror, 可重生 ✅）
# plan.md §3.6 / 矩阵「审计 append-only 且可检测篡改」：
# APS_AUDIT_MIRROR=1 时，write_audit 将每条事件同步镜像到独立
# append-only JSONL（按租户/项目隔离）；业务进程改 world 无法抹掉
# 独立介质证据。镜像尽力而为：写入失败只记日志，不影响业务写。
# ============================================================
from __future__ import annotations                    # 前向类型引用

import json                                            # JSONL 序列化
import logging                                         # 失败日志
import os                                              # 环境变量
import threading                                       # 并发写锁
from datetime import datetime                          # 时间戳
from pathlib import Path                               # 路径处理
from typing import Any                                 # 类型标注

logger = logging.getLogger(__name__)


def mirror_enabled() -> bool:
    """镜像开关：APS_AUDIT_MIRROR=1（或 true/yes）时启用。"""
    raw = (os.environ.get("APS_AUDIT_MIRROR") or "").strip().lower()
    return raw in ("1", "true", "yes", "on")


def _default_mirror_dir() -> str:
    env = os.environ.get("APS_AUDIT_MIRROR_DIR")
    if env:
        return env
    try:
        from server.aps_home import path_under_data
        return str(path_under_data("audit-mirror"))
    except Exception:
        return os.path.join("server", "data", "audit-mirror")


def _safe_scope(value: str) -> str:
    cleaned = "".join(c for c in (value or "default") if c.isalnum() or c in "-_")
    return cleaned[:64] or "default"


class AuditMirror:
    """独立 append-only 审计事件镜像（按租户/项目隔离，JSONL）。"""

    def __init__(self, tenant_uuid: str = "platform", world_key: str = "default",
                 mirror_dir: str | None = None) -> None:
        self.tenant_uuid = _safe_scope(tenant_uuid)
        self.world_key = _safe_scope(world_key)
        base = Path(mirror_dir or _default_mirror_dir())
        self.path = base / self.tenant_uuid / f"{self.world_key}.jsonl"
        self._lock = threading.Lock()

    def _ensure_dir(self) -> None:
        self.path.parent.mkdir(parents=True, exist_ok=True)

    def append_event(self, event: dict[str, Any]) -> dict[str, Any] | None:
        """追加一条审计事件镜像（原子：单行写入 + flush + fsync）。"""
        record = {
            "event": event,
            "mirroredAt": _now_iso(),
        }
        with self._lock:
            try:
                self._ensure_dir()
                # 跨进程文件锁防并发 append 行交错（矩阵 116 行）
                from server.agent_core.audit_filelock import locked_append
                with locked_append(self.path) as f:
                    f.write(json.dumps(record, ensure_ascii=False, sort_keys=True) + "\n")
                return record
            except OSError as exc:
                logger.warning("audit mirror append failed (%s): %s", self.path, exc)
                return None

    def read_events(self) -> list[dict[str, Any]]:
        """读取镜像中的全部事件（损坏行跳过并记日志）。"""
        if not self.path.exists():
            return []
        with self._lock:
            try:
                text = self.path.read_text(encoding="utf-8")
            except OSError as exc:
                logger.warning("audit mirror read failed (%s): %s", self.path, exc)
                return []
        events: list[dict[str, Any]] = []
        for line in text.splitlines():
            line = line.strip()
            if not line:
                continue
            try:
                record = json.loads(line)
                if isinstance(record, dict) and isinstance(record.get("event"), dict):
                    events.append(record["event"])
            except json.JSONDecodeError:
                logger.warning("audit mirror corrupt line in %s", self.path)
        return events

    def count(self) -> int:
        return len(self.read_events())


def _now_iso() -> str:
    from server.timeutil import fmt_dt
    return fmt_dt(datetime.now())