/**
 * 审计日志模块 —— 领域类型与哈希链(纯逻辑,不碰 IO)。
 *
 * 语义锚点:ADR-0039(横切、只追加、哈希链、≥180 天保留、三级可见性)。
 *
 * 本模块是横切能力,单向依赖:业务 service → audit 模块。审计不反向依赖任何
 * 业务 service,只认下面这组与领域无关的原语(action 词表 + 记录形状),
 * 所以可以整体摘除或替换成独立审计服务而不牵动业务代码。
 */

import { createHash } from "node:crypto";

/* ---------------------------------------------------------------- 动作词表 */

/**
 * 审计动作词表。覆盖需求点名的全部关键写操作。
 * 值是稳定标识(入库、进查询过滤器、可 grep),改值等于改历史口径,不要动。
 */
export const AUDIT_ACTIONS = {
  // 文件夹/项目:创建、删除、移动、重命名
  folderCreate: "folder.create",
  folderRename: "folder.rename",
  folderMove: "folder.move",
  folderDelete: "folder.delete",
  projectCreate: "project.create",
  projectRename: "project.rename",
  projectMove: "project.move",
  projectDelete: "project.delete",

  // 归档/取消归档(= 回收站软删的还原侧 + 彻底删除)
  folderRestore: "folder.restore",
  projectRestore: "project.restore",
  nodePurge: "node.purge",

  // 个人与 Group 权限的授予、修改、收回(含 MANAGE/EDIT/VIEW)
  permissionGrant: "permission.grant",
  permissionUpdate: "permission.update",
  permissionRevoke: "permission.revoke",

  // 项目独立权限的开启、关闭及变更
  independentEnable: "project.independent_permission.enable",
  independentDisable: "project.independent_permission.disable",
  independentChange: "project.independent_permission.change",

  // 文件编辑提交(含冲突合并后的提交)与冲突检测事件
  fileUpload: "file.upload",
  fileRename: "file.rename",
  fileDelete: "file.delete",
  fileCommit: "file.commit",
  fileConflictDetected: "file.conflict_detected",

  // 导出
  exportRun: "export.run",

  // 网站管理员高危操作(根目录创建走 folder/project.create + actorIsAdmin 标记)
  adminForceAdjust: "admin.force_adjust",

  // Group 的创建、删除、成员增删、嵌套关系变更
  groupCreate: "group.create",
  groupUpdate: "group.update",
  groupDelete: "group.delete",
  groupRestore: "group.restore",
  groupMemberAdd: "group.member_add",
  groupMemberRemove: "group.member_remove",
  groupReparent: "group.reparent",

  // 保留策略归档(日志自身的生命周期事件)
  retentionArchive: "audit.retention_archive",
} as const;

export type AuditAction = (typeof AUDIT_ACTIONS)[keyof typeof AUDIT_ACTIONS];

/** 全部动作值,查询层用它校验过滤器、前端用它渲染下拉。 */
export const ALL_AUDIT_ACTIONS: readonly string[] = Object.values(AUDIT_ACTIONS);

/** 动作分组 —— 仅供查询 UI 折叠展示,不参与任何判定。 */
export const AUDIT_ACTION_GROUPS: ReadonlyArray<{
  readonly key: string;
  readonly label: string;
  readonly actions: readonly string[];
}> = [
  {
    key: "node",
    label: "文件夹/项目",
    actions: [
      AUDIT_ACTIONS.folderCreate, AUDIT_ACTIONS.folderRename, AUDIT_ACTIONS.folderMove, AUDIT_ACTIONS.folderDelete,
      AUDIT_ACTIONS.projectCreate, AUDIT_ACTIONS.projectRename, AUDIT_ACTIONS.projectMove, AUDIT_ACTIONS.projectDelete,
      AUDIT_ACTIONS.folderRestore, AUDIT_ACTIONS.projectRestore, AUDIT_ACTIONS.nodePurge,
    ],
  },
  {
    key: "permission",
    label: "权限",
    actions: [
      AUDIT_ACTIONS.permissionGrant, AUDIT_ACTIONS.permissionUpdate, AUDIT_ACTIONS.permissionRevoke,
      AUDIT_ACTIONS.independentEnable, AUDIT_ACTIONS.independentDisable, AUDIT_ACTIONS.independentChange,
    ],
  },
  {
    key: "file",
    label: "文件",
    actions: [
      AUDIT_ACTIONS.fileUpload, AUDIT_ACTIONS.fileCommit, AUDIT_ACTIONS.fileRename,
      AUDIT_ACTIONS.fileDelete, AUDIT_ACTIONS.fileConflictDetected,
    ],
  },
  { key: "export", label: "导出", actions: [AUDIT_ACTIONS.exportRun] },
  {
    key: "group",
    label: "Group",
    actions: [
      AUDIT_ACTIONS.groupCreate, AUDIT_ACTIONS.groupUpdate, AUDIT_ACTIONS.groupDelete,
      AUDIT_ACTIONS.groupRestore, AUDIT_ACTIONS.groupMemberAdd, AUDIT_ACTIONS.groupMemberRemove,
      AUDIT_ACTIONS.groupReparent,
    ],
  },
  {
    key: "admin",
    label: "管理员高危",
    actions: [AUDIT_ACTIONS.adminForceAdjust, AUDIT_ACTIONS.retentionArchive],
  },
];

/* ---------------------------------------------------------------- 记录形状 */

export type AuditObjectType =
  | "FOLDER" | "PROJECT" | "FILE" | "GRANT" | "EXPORT_JOB" | "GROUP" | "SYSTEM";

export type AuditResult = "SUCCESS" | "FAILURE";

/** 操作人身份(从 FileLibActor 摘出的最小面,审计模块不 import 业务类型)。 */
export interface AuditActor {
  readonly userId: string;
  /** 姓名快照。缺失时调用方回落 userId —— 审计字段要求「用户ID + 用户名」。 */
  readonly displayName?: string | undefined;
  readonly isWebsiteAdmin?: boolean | undefined;
}

/** 客户端信息(可选;从请求头提取,见 requestContext)。 */
export interface AuditClient {
  readonly ip?: string | undefined;
  readonly userAgent?: string | undefined;
}

/** 一条待写入的审计记录。 */
export interface AuditRecordInput {
  readonly action: string;
  readonly actor: AuditActor;
  readonly objectType: AuditObjectType;
  readonly objectId: string;
  readonly objectName: string;
  /** 节点 pathIds,或文件的 `<pathIds>:<filePath>`。前缀匹配即子树查询。 */
  readonly objectPath: string;
  readonly result?: AuditResult | undefined;
  readonly failureReason?: string | undefined;
  readonly before?: unknown;
  readonly after?: unknown;
  readonly context?: Record<string, unknown> | undefined;
  readonly client?: AuditClient | undefined;
}

/* ---------------------------------------------------------------- 哈希链 */

/**
 * 规范化载荷 → sha256(prevHash + payload)。ADR-0039:改动参与哈希的字段集合
 * 会使既有链整体失配 —— 那是需要新 ADR 与重锚流程的破坏性变更,不是重构。
 *
 * 规范化的关键是 key 排序:JSON.stringify 的键序取决于对象构造顺序,
 * 不排序的话同一条记录换个写法就算出不同哈希,校验会假报篡改。
 */
export function canonicalize(value: unknown): string {
  if (value === null || value === undefined) return "null";
  if (typeof value !== "object") return JSON.stringify(value) ?? "null";
  if (Array.isArray(value)) return `[${value.map(canonicalize).join(",")}]`;
  const entries = Object.entries(value as Record<string, unknown>)
    .filter(([, v]) => v !== undefined)
    .sort(([a], [b]) => (a < b ? -1 : a > b ? 1 : 0));
  return `{${entries.map(([k, v]) => `${JSON.stringify(k)}:${canonicalize(v)}`).join(",")}}`;
}

/** 参与哈希的字段集合。改这里等于换链算法,历史链会整体失配。 */
export interface HashableEntry {
  readonly organizationId: string;
  readonly seq: bigint | number;
  readonly occurredAt: Date;
  readonly action: string;
  readonly result: AuditResult;
  readonly failureReason: string | null;
  readonly actorUserId: string;
  readonly actorName: string;
  readonly actorIsAdmin: boolean;
  readonly objectType: AuditObjectType;
  readonly objectId: string;
  readonly objectName: string;
  readonly objectPath: string;
  readonly beforeValue: unknown;
  readonly afterValue: unknown;
  readonly context: unknown;
  readonly clientIp: string | null;
  readonly userAgent: string | null;
}

export function computeEntryHash(entry: HashableEntry, prevHash: string | null): string {
  const payload = canonicalize({
    organizationId: entry.organizationId,
    seq: entry.seq.toString(),
    occurredAt: entry.occurredAt.toISOString(),
    action: entry.action,
    result: entry.result,
    failureReason: entry.failureReason,
    actorUserId: entry.actorUserId,
    actorName: entry.actorName,
    actorIsAdmin: entry.actorIsAdmin,
    objectType: entry.objectType,
    objectId: entry.objectId,
    objectName: entry.objectName,
    objectPath: entry.objectPath,
    beforeValue: entry.beforeValue ?? null,
    afterValue: entry.afterValue ?? null,
    context: entry.context ?? null,
    clientIp: entry.clientIp,
    userAgent: entry.userAgent,
  });
  return createHash("sha256").update(`${prevHash ?? ""}\n${payload}`).digest("hex");
}

/* ---------------------------------------------------------------- 保留策略 */

/** ADR-0039:保留期下限 180 天。配置只能调高,不能调低。 */
export const AUDIT_RETENTION_DAYS_MIN = 180;

/** 生效保留天数;配置低于下限时按下限执行(合规底线不可调低)。 */
export function resolveRetentionDays(raw?: string | undefined): number {
  if (raw === undefined || raw.trim() === "") return AUDIT_RETENTION_DAYS_MIN;
  const parsed = Number(raw.trim());
  if (!Number.isSafeInteger(parsed) || parsed < AUDIT_RETENTION_DAYS_MIN) {
    return AUDIT_RETENTION_DAYS_MIN;
  }
  return parsed;
}

/** 姓名快照:缺 displayName 时回落 userId,保证字段永不为空。 */
export function actorName(actor: AuditActor): string {
  const name = actor.displayName?.trim();
  return name === undefined || name === "" ? actor.userId : name;
}