import { AnyEntity, EntityManager, EntityName, EntityRepository } from '@mikro-orm/core';
import { forkEntityManager } from '../orm.js';
import { StudentRepository } from './users/student-repository.js';
import { Student } from '../entities/users/student.entity.js';
import { Teacher } from '../entities/users/teacher.entity.js';
import { TeacherRepository } from './users/teacher-repository.js';
import { Class } from '../entities/classes/class.entity.js';
import { ClassRepository } from './classes/class-repository.js';
import { ClassJoinRequest } from '../entities/classes/class-join-request.entity.js';
import { ClassJoinRequestRepository } from './classes/class-join-request-repository.js';
import { TeacherInvitationRepository } from './classes/teacher-invitation-repository.js';
import { TeacherInvitation } from '../entities/classes/teacher-invitation.entity.js';
import { Assignment } from '../entities/assignments/assignment.entity.js';
import { AssignmentRepository } from './assignments/assignment-repository.js';
import { GroupRepository } from './assignments/group-repository.js';
import { Group } from '../entities/assignments/group.entity.js';
import { Submission } from '../entities/assignments/submission.entity.js';
import { SubmissionRepository } from './assignments/submission-repository.js';
import { Question } from '../entities/questions/question.entity.js';
import { QuestionRepository } from './questions/question-repository.js';
import { Answer } from '../entities/questions/answer.entity.js';
import { AnswerRepository } from './questions/answer-repository.js';
import { LearningObject } from '../entities/content/learning-object.entity.js';
import { LearningObjectRepository } from './content/learning-object-repository.js';
import { LearningPath } from '../entities/content/learning-path.entity.js';
import { LearningPathRepository } from './content/learning-path-repository.js';
import { AttachmentRepository } from './content/attachment-repository.js';
import { Attachment } from '../entities/content/attachment.entity.js';
import { LearningPathNode } from '../entities/content/learning-path-node.entity.js';
import { LearningPathTransition } from '../entities/content/learning-path-transition.entity.js';

let entityManager: EntityManager | undefined;

/**
 * Execute all the database operations within the function f in a single transaction.
 */
export function transactional<T>(f: () => Promise<T>) {
    entityManager?.transactional(f);
}

function repositoryGetter<T extends AnyEntity, R extends EntityRepository<T>>(entity: EntityName<T>): () => R {
    let cachedRepo: R | undefined;
    return (): R => {
        if (!cachedRepo) {
            if (!entityManager) {
                entityManager = forkEntityManager();
            }
            cachedRepo = entityManager.getRepository(entity) as R;
        }
        return cachedRepo;
    };
}

/* Users */
export const getStudentRepository = repositoryGetter<Student, StudentRepository>(Student);
export const getTeacherRepository = repositoryGetter<Teacher, TeacherRepository>(Teacher);

/* Classes */
export const getClassRepository = repositoryGetter<Class, ClassRepository>(Class);
export const getClassJoinRequestRepository = repositoryGetter<ClassJoinRequest, ClassJoinRequestRepository>(ClassJoinRequest);
export const getTeacherInvitationRepository = repositoryGetter<TeacherInvitation, TeacherInvitationRepository>(TeacherInvitation);

/* Assignments */
export const getAssignmentRepository = repositoryGetter<Assignment, AssignmentRepository>(Assignment);
export const getGroupRepository = repositoryGetter<Group, GroupRepository>(Group);
export const getSubmissionRepository = repositoryGetter<Submission, SubmissionRepository>(Submission);

/* Questions and answers */
export const getQuestionRepository = repositoryGetter<Question, QuestionRepository>(Question);
export const getAnswerRepository = repositoryGetter<Answer, AnswerRepository>(Answer);

/* Learning content */
export const getLearningObjectRepository = repositoryGetter<LearningObject, LearningObjectRepository>(LearningObject);
export const getLearningPathRepository = repositoryGetter<LearningPath, LearningPathRepository>(LearningPath);
export const getLearningPathNodeRepository = repositoryGetter(LearningPathNode);
export const getLearningPathTransitionRepository = repositoryGetter(LearningPathTransition);
export const getAttachmentRepository = repositoryGetter<Attachment, AttachmentRepository>(Attachment);