import type { CourseRecord } from '@/lib/course-framework/types';
import { readCourseRecord } from '@/lib/course-framework/store';
import { readFrozenLearningPackageRecord } from '@/lib/makelore-course/package';

type CoursePublicationState = Pick<CourseRecord, 'publication' | 'externalPublication'>;

/** A frozen course id is a one-shot immutable product identity. */
export class FrozenLearningCourseMutationError extends Error {
  constructor(public readonly courseId: string) {
    super(`课程 ${courseId} 已冻结，不能继续生成或重新生成；如需修改，请新建课程`);
    this.name = 'FrozenLearningCourseMutationError';
  }
}

/**
 * Enforce the single immutable-course rule at every source mutation boundary.
 *
 * The frozen record is authoritative: Works can successfully finalize an
 * archive and then fail before writing the later external-publication receipt.
 * Legacy publication receipts remain additional evidence for courses created
 * before aggregate finalization was introduced.
 */
export async function assertLearningCourseMutable(
  courseId: string,
  knownRecord?: CoursePublicationState | null,
): Promise<void> {
  const [frozen, record] = await Promise.all([
    readFrozenLearningPackageRecord(courseId),
    knownRecord === undefined ? readCourseRecord(courseId) : Promise.resolve(knownRecord),
  ]);
  if (frozen || record?.publication || record?.externalPublication) {
    throw new FrozenLearningCourseMutationError(courseId);
  }
}