package ru.ulstu.grant.service;

import org.apache.commons.lang3.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import org.springframework.validation.Errors;
import ru.ulstu.deadline.model.Deadline;
import ru.ulstu.deadline.service.DeadlineService;
import ru.ulstu.file.model.FileDataDto;
import ru.ulstu.file.service.FileService;
import ru.ulstu.grant.model.Grant;
import ru.ulstu.grant.model.GrantDto;
import ru.ulstu.grant.repository.GrantRepository;
import ru.ulstu.name.BaseService;
import ru.ulstu.paper.model.Paper;
import ru.ulstu.paper.model.PaperDto;
import ru.ulstu.paper.service.PaperService;
import ru.ulstu.project.model.Project;
import ru.ulstu.project.model.ProjectDto;
import ru.ulstu.project.service.ProjectService;
import ru.ulstu.timeline.service.EventService;
import ru.ulstu.user.model.User;
import ru.ulstu.user.service.UserService;

import java.io.IOException;
import java.text.ParseException;
import java.util.Arrays;
import java.util.Collections;
import java.util.Date;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;

import static java.util.stream.Collectors.toList;
import static org.springframework.util.ObjectUtils.isEmpty;
import static ru.ulstu.core.util.StreamApiUtils.convert;
import static ru.ulstu.grant.model.Grant.GrantStatus.APPLICATION;

@Service
public class GrantService extends BaseService {
    private final Logger log = LoggerFactory.getLogger(GrantService.class);

    private final GrantRepository grantRepository;
    private final ProjectService projectService;
    private final DeadlineService deadlineService;
    private final FileService fileService;
    private final UserService userService;
    private final PaperService paperService;
    private final EventService eventService;
    private final GrantNotificationService grantNotificationService;
    private final KiasService kiasService;

    public GrantService(GrantRepository grantRepository,
                        FileService fileService,
                        DeadlineService deadlineService,
                        ProjectService projectService,
                        UserService userService,
                        PaperService paperService,
                        EventService eventService,
                        GrantNotificationService grantNotificationService,
                        KiasService kiasService) {
        this.grantRepository = grantRepository;
        this.kiasService = kiasService;
        this.baseRepository = grantRepository;
        this.fileService = fileService;
        this.deadlineService = deadlineService;
        this.projectService = projectService;
        this.userService = userService;
        this.paperService = paperService;
        this.eventService = eventService;
        this.grantNotificationService = grantNotificationService;
    }

    public List<Grant> findAll() {
        return grantRepository.findAll();
    }

    public List<GrantDto> findAllDto() {
        return convert(findAll(), GrantDto::new);
    }

    public GrantDto findOneDto(Integer id) {
        return new GrantDto(grantRepository.findOne(id));
    }

    @Transactional
    public Integer create(GrantDto grantDto) throws IOException {
        Grant newGrant = copyFromDto(new Grant(), grantDto);
        newGrant = grantRepository.save(newGrant);
        eventService.createFromObject(newGrant, Collections.emptyList());
        grantNotificationService.sendCreateNotification(newGrant);
        return newGrant.getId();
    }

    private Grant copyFromDto(Grant grant, GrantDto grantDto) throws IOException {
        grant.setComment(grantDto.getComment());
        grant.setStatus(grantDto.getStatus() == null ? APPLICATION : grantDto.getStatus());
        grant.setTitle(grantDto.getTitle());
        if (grantDto.getProject() != null && grantDto.getProject().getId() != null) {
            grant.setProject(projectService.findById(grantDto.getProject().getId()));
        }
        grant.setDeadlines(deadlineService.saveOrCreate(grantDto.getDeadlines()));
        grant.setFiles(fileService.saveOrCreate(grantDto.getFiles().stream()
                .filter(f -> !f.isDeleted())
                .collect(toList())));
        grant.getAuthors().clear();
        if (grantDto.getAuthorIds() != null && !grantDto.getAuthorIds().isEmpty()) {
            grantDto.getAuthorIds().forEach(authorIds -> grant.getAuthors().add(userService.findById(authorIds)));
        }
        if (grantDto.getLeaderId() != null) {
            grant.setLeader(userService.findById(grantDto.getLeaderId()));
        }
        grant.getPapers().clear();
        if (grantDto.getPaperIds() != null && !grantDto.getPaperIds().isEmpty()) {
            grantDto.getPaperIds().forEach(paperIds -> grant.getPapers().add(paperService.findPaperById(paperIds)));
        }
        return grant;
    }

    public void createProject(GrantDto grantDto) throws IOException {
        grantDto.setProject(
                new ProjectDto(projectService.save(new ProjectDto(grantDto.getTitle()))));
    }

    @Transactional
    public Integer update(GrantDto grantDto) throws IOException {
        Grant grant = grantRepository.findOne(grantDto.getId());
        Set<User> oldAuthors = new HashSet<>(grant.getAuthors());
        User oldLeader = grant.getLeader();
        for (FileDataDto file : grantDto.getFiles().stream()
                .filter(f -> f.isDeleted() && f.getId() != null)
                .collect(toList())) {
            fileService.delete(file.getId());
        }
        grantDto.getRemovedDeadlineIds().forEach(deadlineService::remove);
        grantRepository.save(copyFromDto(grant, grantDto));

        grant.getAuthors().forEach(author -> {
            if (!oldAuthors.contains(author)) {
                grantNotificationService.sendAuthorsChangeNotification(grant, oldAuthors);
            }
        });
        oldAuthors.forEach(oldAuthor -> {
            if (!grant.getAuthors().contains(oldAuthor)) {
                grantNotificationService.sendAuthorsChangeNotification(grant, oldAuthors);
            }
        });
        if (grant.getLeader() != oldLeader) {
            grantNotificationService.sendLeaderChangeNotification(grant, oldLeader);
        }
        eventService.updateGrantDeadlines(grant);
        return grant.getId();
    }

    @Transactional
    public void delete(Integer grantId) throws IOException {
        Grant grant = grantRepository.findOne(grantId);
        grantRepository.delete(grant);
    }

    public List<Grant.GrantStatus> getGrantStatuses() {
        return Arrays.asList(Grant.GrantStatus.values());
    }

    @Transactional
    public Grant create(String title, Project projectId, Date deadlineDate, User user, Paper paper) {
        Grant grant = new Grant();
        grant.setTitle(title);
        grant.setComment("Комментарий к гранту 1");
        grant.setProject(projectId);
        grant.setStatus(APPLICATION);
        grant.getDeadlines().add(new Deadline(deadlineDate, "первый дедлайн"));
        grant.getAuthors().add(user);
        grant.setLeader(user);
        grant.getPapers().add(paper);
        grant = grantRepository.save(grant);

        eventService.createFromObject(grant, Collections.emptyList());
        grantNotificationService.sendCreateNotification(grant);

        return grant;
    }

    public boolean save(GrantDto grantDto, Errors errors) throws IOException {
        grantDto.setName(grantDto.getTitle());
        filterEmptyDeadlines(grantDto);
        checkEmptyDeadlines(grantDto, errors);
        checkEmptyLeader(grantDto, errors);
        checkUniqueName(grantDto, errors, grantDto.getId(), "title", "Грант с таким именем уже существует");
        if (errors.hasErrors()) {
            return false;
        }
        if (isEmpty(grantDto.getId())) {
            create(grantDto);
        } else {
            update(grantDto);
        }
        return true;
    }

    public boolean saveFromKias(GrantDto grantDto) throws IOException {
        grantDto.setName(grantDto.getTitle());
        String title = checkUniqueName(grantDto, grantDto.getId()); //проверка уникальности имени
        if (title != null) {
            Grant grantFromDB = grantRepository.findByTitle(title); //грант с таким же названием из бд
            if (checkSameDeadline(grantDto, grantFromDB.getId())) { //если дедайны тоже совпадают
                return false;
            } else { //иначе грант уже был в системе, но в другом году, поэтому надо создать
                create(grantDto);
                return true;
            }
        } else { //иначе такого гранта ещё нет, поэтому надо создать
            create(grantDto);
            return true;
        }
    }

    private void checkEmptyLeader(GrantDto grantDto, Errors errors) {
        if (grantDto.getLeaderId().equals(-1)) {
            errors.rejectValue("leaderId", "errorCode", "Укажите руководителя");
        }
    }

    private void checkEmptyDeadlines(GrantDto grantDto, Errors errors) {
        if (grantDto.getDeadlines().isEmpty()) {
            errors.rejectValue("deadlines", "errorCode", "Не может быть пусто");
        }
    }

    private boolean checkSameDeadline(GrantDto grantDto, Integer id) {
        Date date = grantDto.getDeadlines().get(0).getDate(); //дата с сайта киас
        Date foundGrantDate = deadlineService.findByGrantIdAndDate(id, date);
        return foundGrantDate != null && foundGrantDate.compareTo(date) == 0;
    }

    public List<User> getGrantAuthors(GrantDto grantDto) {
        List<User> filteredUsers = userService.filterByAgeAndDegree(grantDto.isHasAge(), grantDto.isHasDegree());
        if (grantDto.isWasLeader()) {
            filteredUsers = checkContains(filteredUsers, getCompletedGrantLeaders());
        }
        if (grantDto.isHasBAKPapers()) {
            filteredUsers = checkContains(filteredUsers, getBAKAuthors());
        }
        if (grantDto.isHasScopusPapers()) {
            filteredUsers = checkContains(filteredUsers, getScopusAuthors());
        }
        return filteredUsers;
    }

    private List<User> checkContains(List<User> filteredUsers, List<User> checkUsers) {
        return filteredUsers.stream()
                .filter(checkUsers::contains)
                .collect(toList());
    }

    private List<User> getCompletedGrantLeaders() {
        return grantRepository.findByStatus(Grant.GrantStatus.COMPLETED)
                .stream()
                .map(Grant::getLeader)
                .collect(toList());
    }

    public List<PaperDto> getGrantPapers(List<Integer> paperIds) {
        return paperService.findAllSelect(paperIds);
    }

    public List<PaperDto> getAllUncompletedPapers() {
        return paperService.findAllNotCompleted();
    }

    public void attachPaper(GrantDto grantDto) {
        if (!grantDto.getPaperIds().isEmpty()) {
            grantDto.getPapers().clear();
            grantDto.setPapers(getGrantPapers(grantDto.getPaperIds()));
        } else {
            grantDto.getPapers().clear();
        }
    }

    public void removeDeadline(GrantDto grantDto, Integer deadlineId) {
        if (grantDto.getDeadlines().get(deadlineId).getId() != null) {
            grantDto.getRemovedDeadlineIds().add(grantDto.getDeadlines().get(deadlineId).getId());
        }
        grantDto.getDeadlines().remove((int) deadlineId);
    }

    private List<User> getCompletedPapersAuthors(Paper.PaperType type) {
        List<Paper> papers = paperService.findAllCompletedByType(type);
        return papers.stream()
                .filter(paper -> paper.getAuthors() != null)
                .flatMap(paper -> paper.getAuthors().stream())
                .collect(toList());
    }

    private List<User> getBAKAuthors() {
        return getCompletedPapersAuthors(Paper.PaperType.VAK)
                .stream()
                .distinct()
                .collect(toList());
    }

    private List<User> getScopusAuthors() {
        List<User> authors = getCompletedPapersAuthors(Paper.PaperType.SCOPUS);
        return authors
                .stream()
                .filter(author -> Collections.frequency(authors, author) > 3)
                .collect(toList());
    }

    public void filterEmptyDeadlines(GrantDto grantDto) {
        grantDto.setDeadlines(grantDto.getDeadlines().stream()
                .filter(dto -> dto.getDate() != null || !org.springframework.util.StringUtils.isEmpty(dto.getDescription()))
                .collect(Collectors.toList()));
    }

    @Transactional
    public void createFromKias() throws IOException, ParseException {
        for (GrantDto grantDto : kiasService.getNewGrantsDto()) {
            if (saveFromKias(grantDto)) {
                log.debug("GrantScheduler.loadGrantsFromKias new grant was loaded");
            } else {
                log.debug("GrantScheduler.loadGrantsFromKias grant wasn't loaded, cause it's already exists");
            }
        }
    }

    public List<GrantDto> findAllActiveDto() {
        return convert(findAllActive(), GrantDto::new);
    }

    private List<Grant> findAllActive() {
        return grantRepository.findAllActive();
    }

    public Grant findGrantById(Integer grantId) {
        return grantRepository.findOne(grantId);
    }
}