# ============================================================
# 审计合规导出与保留脱敏 v1（moduleId: core-audit-export, 可重生 ✅）
# plan.md §3.6 / 矩阵「全审计」：合规导出（json/csv）+ 敏感字段脱敏
# ============================================================
from __future__ import annotations                    # 前向类型引用

import csv                                              # CSV 导出
import io                                               # 内存流
import json                                             # JSON 序列化
from datetime import datetime                          # 时间戳
from typing import Any                                 # 类型标注

REDACTED = "***REDACTED***"
# 精确敏感键集合（避免子串误伤 worldKey/monkey 等字段）
_SENSITIVE_KEYS = frozenset({
    "token", "access_token", "refresh_token", "id_token", "session_token",
    "password", "passwd", "secret", "client_secret", "api_key", "apikey",
    "authorization", "credential", "credentials", "private_key",
})


def _is_sensitive_key(key: str) -> bool:
    low = str(key).lower().strip()
    return low in _SENSITIVE_KEYS or low.endswith("_secret")


def sanitize_value(value: Any) -> Any:
    """递归脱敏：敏感键名的值替换为掩码，其余原样保留。"""
    if isinstance(value, dict):
        return {
            k: (REDACTED if _is_sensitive_key(k) else sanitize_value(v))
            for k, v in value.items()
        }
    if isinstance(value, list):
        return [sanitize_value(v) for v in value]
    return value


def sanitize_event(event: dict[str, Any]) -> dict[str, Any]:
    """对单条审计事件脱敏（顶层与嵌套均覆盖敏感键）。"""
    return sanitize_value(dict(event))


def export_events(events: list[dict[str, Any]], fmt: str = "json") -> str:
    """导出当前作用域审计事件（脱敏后）。

    fmt: json（列表 + 元信息）/ csv（表头 + 行）。
    """
    cleaned = [sanitize_event(e) for e in events]
    if fmt == "json":
        try:                                           # 完整 Merkle 根（矩阵 104 行）
            from server.agent_core.audit_merkle import merkle_root
            merkle = merkle_root(events)
        except Exception:
            merkle = None
        payload = {
            "exportedAt": _now_iso(),
            "count": len(cleaned),
            "chainOk": None,                            # 调用方可通过 verify 填充
            "merkleRoot": merkle,                       # 二叉树 Merkle 根（可复算校验）
            "events": cleaned,
        }
        return json.dumps(payload, ensure_ascii=False, indent=1)
    if fmt == "csv":
        buf = io.StringIO()
        writer = csv.writer(buf)
        if cleaned:
            writer.writerow(sorted(cleaned[0].keys()))
            for ev in cleaned:
                row = []
                for key in sorted(cleaned[0].keys()):
                    val = ev.get(key)
                    if isinstance(val, (dict, list)):
                        val = json.dumps(val, ensure_ascii=False, sort_keys=True, default=str)
                    row.append("" if val is None else str(val))
                writer.writerow(row)
        return buf.getvalue()
    raise ValueError(f"unsupported export format: {fmt!r}")


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