/**
 * GraphQL Context - Apollo Router 下传的请求上下文
 *
 * Apollo Router 通过 headers 传递以下信息到子图：
 * - authorization: JWT token（透传）
 * - x-user-id: 已认证用户 ID
 * - x-user-role: 用户角色
 * - x-dataScope: 数据范围（ALL / SCHOOL / GRADE / CLASS / STUDENT）
 * - x-request-id: 请求追踪 ID
 *
 * 子图从 HTTP headers 提取后构造 GraphqlContext，注入 Resolver。
 */
export type DataScope = "ALL" | "SCHOOL" | "GRADE" | "CLASS" | "STUDENT";

export interface GraphqlContextInput {
  userId?: string;
  userRole?: string;
  dataScope?: DataScope;
  requestId?: string;
  jwt?: string;
}

export class GraphqlContext {
  readonly userId?: string;
  readonly userRole?: string;
  readonly dataScope: DataScope;
  readonly requestId: string;
  readonly jwt?: string;

  constructor(input: GraphqlContextInput) {
    this.userId = input.userId;
    this.userRole = input.userRole;
    this.dataScope = input.dataScope ?? "ALL";
    this.requestId = input.requestId ?? "unknown";
    this.jwt = input.jwt;
  }

  /** 是否管理员（全量可见） */
  get isAdmin(): boolean {
    return this.dataScope === "ALL" || this.userRole === "admin";
  }

  /** 是否已认证 */
  get isAuthenticated(): boolean {
    return !!this.userId;
  }

  /** 从 HTTP headers 构造（NestJS @Context 提取） */
  static fromHeaders(
    headers: Record<string, string | undefined>,
  ): GraphqlContext {
    return new GraphqlContext({
      userId: headers["x-user-id"],
      userRole: headers["x-user-role"],
      dataScope: headers["x-datapscope"] as DataScope | undefined,
      requestId: headers["x-request-id"],
      jwt: headers["authorization"]?.replace(/^Bearer\s+/i, ""),
    });
  }
}