import {
    getClassJoinRequestRepository,
    getClassRepository,
    getGroupRepository,
    getQuestionRepository,
    getStudentRepository,
    getSubmissionRepository,
} from '../data/repositories.js';
import { AssignmentDTO } from '../interfaces/assignment.js';
import { ClassDTO, mapToClassDTO } from '../interfaces/class.js';
import { GroupDTO, mapToGroupDTO, mapToGroupDTOId } from '../interfaces/group.js';
import { mapToStudent, mapToStudentDTO, StudentDTO } from '../interfaces/student.js';
import { mapToSubmissionDTO, mapToSubmissionDTOId, SubmissionDTO, SubmissionDTOId } from '../interfaces/submission.js';
import { getAllAssignments } from './assignments.js';
import { mapToQuestionDTO, mapToQuestionId, QuestionDTO, QuestionId } from '../interfaces/question.js';
import { mapToStudentRequest, mapToStudentRequestDTO } from '../interfaces/student-request.js';
import { Student } from '../entities/users/student.entity.js';
import { NotFoundException } from '../exceptions/not-found-exception.js';
import { fetchClass } from './classes.js';

export async function getAllStudents(full: boolean): Promise<StudentDTO[] | string[]> {
    const studentRepository = getStudentRepository();
    const users = await studentRepository.findAll();

    if (full) {
        return users.map(mapToStudentDTO);
    }

    return users.map((user) => user.username);
}

export async function fetchStudent(username: string): Promise<Student> {
    const studentRepository = getStudentRepository();
    const user = await studentRepository.findByUsername(username);

    if (!user) {
        throw new NotFoundException('Student with username not found');
    }

    return user;
}

export async function getStudent(username: string): Promise<StudentDTO> {
    const user = await fetchStudent(username);
    return mapToStudentDTO(user);
}

export async function createStudent(userData: StudentDTO): Promise<StudentDTO> {
    const studentRepository = getStudentRepository();

    const newStudent = mapToStudent(userData);
    await studentRepository.save(newStudent, { preventOverwrite: true });
    return userData;
}

export async function deleteStudent(username: string): Promise<StudentDTO> {
    const studentRepository = getStudentRepository();

    const student = await fetchStudent(username); // Throws error if it does not exist

    await studentRepository.deleteByUsername(username);
    return mapToStudentDTO(student);
}

export async function getStudentClasses(username: string, full: boolean): Promise<ClassDTO[] | string[]> {
    const student = await fetchStudent(username);

    const classRepository = getClassRepository();
    const classes = await classRepository.findByStudent(student);

    if (full) {
        return classes.map(mapToClassDTO);
    }

    return classes.map((cls) => cls.classId!);
}

export async function getStudentAssignments(username: string, full: boolean): Promise<AssignmentDTO[]> {
    const student = await fetchStudent(username);

    const classRepository = getClassRepository();
    const classes = await classRepository.findByStudent(student);

    return (await Promise.all(classes.map(async (cls) => await getAllAssignments(cls.classId!, full)))).flat();
}

export async function getStudentGroups(username: string, full: boolean): Promise<GroupDTO[]> {
    const student = await fetchStudent(username);

    const groupRepository = getGroupRepository();
    const groups = await groupRepository.findAllGroupsWithStudent(student);

    if (full) {
        return groups.map(mapToGroupDTO);
    }

    return groups.map(mapToGroupDTOId);
}

export async function getStudentSubmissions(username: string, full: boolean): Promise<SubmissionDTO[] | SubmissionDTOId[]> {
    const student = await fetchStudent(username);

    const submissionRepository = getSubmissionRepository();
    const submissions = await submissionRepository.findAllSubmissionsForStudent(student);

    if (full) {
        return submissions.map(mapToSubmissionDTO);
    }

    return submissions.map(mapToSubmissionDTOId);
}

export async function getStudentQuestions(username: string, full: boolean): Promise<QuestionDTO[] | QuestionId[]> {
    const student = await fetchStudent(username);

    const questionRepository = getQuestionRepository();
    const questions = await questionRepository.findAllByAuthor(student);

    const questionsDTO = questions.map(mapToQuestionDTO);

    if (full) {
        return questionsDTO;
    }

    return questionsDTO.map(mapToQuestionId);
}

export async function createClassJoinRequest(studentUsername: string, classId: string) {
    const requestRepo = getClassJoinRequestRepository();

    const student = await fetchStudent(studentUsername); // Throws error if student not found
    const cls = await fetchClass(classId);

    const request = mapToStudentRequest(student, cls);
    await requestRepo.save(request, { preventOverwrite: true });
    return mapToStudentRequestDTO(request);
}

export async function getJoinRequestsByStudent(studentUsername: string) {
    const requestRepo = getClassJoinRequestRepository();

    const student = await fetchStudent(studentUsername);

    const requests = await requestRepo.findAllRequestsBy(student);
    return requests.map(mapToStudentRequestDTO);
}

export async function deleteClassJoinRequest(studentUsername: string, classId: string) {
    const requestRepo = getClassJoinRequestRepository();

    const student = await fetchStudent(studentUsername);
    const cls = await fetchClass(classId);

    const request = await requestRepo.findByStudentAndClass(student, cls);

    if (!request) {
        throw new NotFoundException('Join request not found');
    }

    await requestRepo.deleteBy(student, cls);
    return mapToStudentRequestDTO(request);
}