/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package com.epam.datalab.backendapi.service.impl;

import com.epam.datalab.auth.UserInfo;
import com.epam.datalab.backendapi.annotation.*;
import com.epam.datalab.backendapi.dao.BaseDAO;
import com.epam.datalab.backendapi.dao.ComputationalDAO;
import com.epam.datalab.backendapi.dao.ExploratoryDAO;
import com.epam.datalab.backendapi.dao.ExploratoryLibDAO;
import com.epam.datalab.backendapi.domain.EndpointDTO;
import com.epam.datalab.backendapi.domain.NotebookTemplate;
import com.epam.datalab.backendapi.domain.RequestId;
import com.epam.datalab.backendapi.resources.dto.LibInfoRecord;
import com.epam.datalab.backendapi.resources.dto.LibKey;
import com.epam.datalab.backendapi.resources.dto.LibraryStatus;
import com.epam.datalab.backendapi.service.EndpointService;
import com.epam.datalab.backendapi.service.LibraryService;
import com.epam.datalab.backendapi.util.RequestBuilder;
import com.epam.datalab.constants.ServiceConsts;
import com.epam.datalab.dto.LibraryGroups;
import com.epam.datalab.dto.UserInstanceDTO;
import com.epam.datalab.dto.UserInstanceStatus;
import com.epam.datalab.dto.computational.UserComputationalResource;
import com.epam.datalab.dto.exploratory.LibInstallDTO;
import com.epam.datalab.dto.exploratory.LibStatus;
import com.epam.datalab.dto.exploratory.LibraryInstallDTO;
import com.epam.datalab.exceptions.DatalabException;
import com.epam.datalab.model.library.Library;
import com.epam.datalab.rest.client.RESTService;
import com.epam.datalab.rest.contracts.ComputationalAPI;
import com.epam.datalab.rest.contracts.ExploratoryAPI;
import com.google.inject.Inject;
import com.google.inject.Singleton;
import com.google.inject.name.Named;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.StringUtils;
import org.bson.Document;

import java.util.*;
import java.util.stream.Collectors;
import java.util.stream.Stream;

import static com.epam.datalab.backendapi.domain.AuditActionEnum.INSTALL_LIBS;
import static com.epam.datalab.backendapi.domain.AuditResourceTypeEnum.COMPUTE;
import static com.epam.datalab.backendapi.domain.AuditResourceTypeEnum.NOTEBOOK;
import static com.epam.datalab.backendapi.domain.NotebookTemplate.*;
import static com.epam.datalab.dto.LibraryGroups.*;


@Slf4j
@Singleton
public class LibraryServiceImpl implements LibraryService {
    private static final String COMPUTATIONAL_NOT_FOUND_MSG = "Computational with name %s was not found";
    private static final String LIB_ALREADY_INSTALLED = "Library %s is already installing";

    private final ExploratoryDAO exploratoryDAO;
    private final ExploratoryLibDAO libraryDAO;
    private final RequestBuilder requestBuilder;
    private final RESTService provisioningService;
    private final RequestId requestId;
    private final EndpointService endpointService;

    @Inject
    public LibraryServiceImpl(ExploratoryDAO exploratoryDAO, ExploratoryLibDAO libraryDAO, RequestBuilder requestBuilder,
                              @Named(ServiceConsts.PROVISIONING_SERVICE_NAME) RESTService provisioningService,
                              RequestId requestId, EndpointService endpointService, ComputationalDAO computationalDAO) {
        this.exploratoryDAO = exploratoryDAO;
        this.libraryDAO = libraryDAO;
        this.requestBuilder = requestBuilder;
        this.provisioningService = provisioningService;
        this.requestId = requestId;
        this.endpointService = endpointService;
    }


    @Override
    @SuppressWarnings("unchecked")
    public List<Document> getLibs(String user, String project, String exploratoryName, String computationalName) {
        if (StringUtils.isEmpty(computationalName)) {
            return (List<Document>) libraryDAO.findExploratoryLibraries(user, project, exploratoryName)
                    .getOrDefault(ExploratoryLibDAO.EXPLORATORY_LIBS, new ArrayList<>());
        } else {
            Document document = (Document) libraryDAO.findComputationalLibraries(user, project,
                    exploratoryName, computationalName)
                    .getOrDefault(ExploratoryLibDAO.COMPUTATIONAL_LIBS, new Document());
            return (List<Document>) document.getOrDefault(computationalName, new ArrayList<>());
        }
    }

    @Override
    @SuppressWarnings("unchecked")
    public List<LibInfoRecord> getLibInfo(String user, String project, String exploratoryName) {
        Document document = libraryDAO.findAllLibraries(user, project, exploratoryName);

        Map<LibKey, List<LibraryStatus>> model = new LinkedHashMap<>();
        if (document.get(ExploratoryLibDAO.EXPLORATORY_LIBS) != null) {
            List<Document> exploratoryLibs = (List<Document>) document.get(ExploratoryLibDAO.EXPLORATORY_LIBS);
            exploratoryLibs.forEach(e -> populateModel(exploratoryName, e, model, "notebook"));
        }
        if (document.get(ExploratoryLibDAO.COMPUTATIONAL_LIBS) != null) {
            Document computationalLibs = getLibsOfActiveComputationalResources(document);
            populateComputational(computationalLibs, model, "cluster");
        }

        LinkedList<LibInfoRecord> libInfoRecords = new LinkedList<>();
        for (Map.Entry<LibKey, List<LibraryStatus>> entry : model.entrySet()) {
            libInfoRecords.addFirst(new LibInfoRecord(entry.getKey(), entry.getValue()));
        }

        return libInfoRecords;
    }

    @Audit(action = INSTALL_LIBS, type = COMPUTE)
    @Override
    public String installComputationalLibs(@User UserInfo ui, @Project String project, String expName, @ResourceName String compName,
                                           List<LibInstallDTO> libs, @Info String auditInfo) {
        final UserInstanceDTO userInstance = exploratoryDAO.fetchExploratoryFields(ui.getName(), project, expName, compName);
        EndpointDTO endpointDTO = endpointService.get(userInstance.getEndpoint());
        final String uuid = provisioningService.post(endpointDTO.getUrl() + ComputationalAPI.COMPUTATIONAL_LIB_INSTALL,
                ui.getAccessToken(),
                toComputationalLibraryInstallDto(ui, project, expName, compName, libs, userInstance, endpointDTO),
                String.class);
        requestId.put(ui.getName(), uuid);
        return uuid;
    }

    @Audit(action = INSTALL_LIBS, type = NOTEBOOK)
    @Override
    public String installExploratoryLibs(@User UserInfo ui, @Project String project, @ResourceName String expName, List<LibInstallDTO> libs, @Info String auditInfo) {
        final UserInstanceDTO userInstance = exploratoryDAO.fetchRunningExploratoryFields(ui.getName(), project, expName);
        EndpointDTO endpointDTO = endpointService.get(userInstance.getEndpoint());
        final String uuid = provisioningService.post(endpointDTO.getUrl() + ExploratoryAPI.EXPLORATORY_LIB_INSTALL,
                ui.getAccessToken(), toExploratoryLibraryInstallDto(ui, project, expName, libs, userInstance, endpointDTO),
                String.class);
        requestId.put(ui.getName(), uuid);
        return uuid;
    }

    @Override
    public List<String> getExploratoryLibGroups(UserInfo userInfo, String projectName, String exploratoryName) {
        UserInstanceDTO userInstanceDTO = exploratoryDAO.fetchExploratoryFields(userInfo.getName(), projectName, exploratoryName);
        final String templateName = userInstanceDTO.getTemplateName();
        List<LibraryGroups> groups = new ArrayList<>(Arrays.asList(GROUP_PIP3, GROUP_OTHERS, GROUP_OS_PKG));

        if (isTemplateGroup(templateName, Stream.of(JUPYTER, ZEPPELIN))) {
            groups.addAll(Arrays.asList(GROUP_R_PKG, GROUP_JAVA));
        }
        if (isTemplateGroup(templateName, Stream.of(DEEP_LEARNING, TENSOR))) {
            groups.add(GROUP_JAVA);
        }
        if (isTemplateGroup(templateName, Stream.of(RSTUDIO, TENSOR_RSTUDIO))) {
            groups.add(GROUP_R_PKG);
        }
        if (isTemplateGroup(templateName, Stream.of(DEEP_LEARNING_GCP, TENSOR_GCP))) {
            groups.add(GROUP_JAVA);
        }

        return groups
                .stream()
                .map(LibraryGroups::toString)
                .collect(Collectors.toList());
    }

    @Override
    public List<String> getComputeLibGroups() {
        return Stream.of(GROUP_PIP3, GROUP_OTHERS, GROUP_R_PKG, GROUP_OS_PKG, GROUP_JAVA)
                .map(LibraryGroups::toString)
                .collect(Collectors.toList());
    }

    private boolean isTemplateGroup(String templateName, Stream<NotebookTemplate> templateStream) {
        return templateStream
                .map(NotebookTemplate::getName)
                .anyMatch(name -> name.equals(templateName));
    }

    private LibraryInstallDTO toExploratoryLibraryInstallDto(UserInfo userInfo, String project, String exploratoryName,
                                                             List<LibInstallDTO> libs, UserInstanceDTO userInstance, EndpointDTO endpointDTO) {
        final List<LibInstallDTO> libsToInstall = libs.stream()
                .map(lib -> toLibInstallDto(lib, libraryDAO.getLibrary(userInfo.getName(), project, exploratoryName,
                        lib.getGroup(), lib.getName())))
                .peek(l -> libraryDAO.addLibrary(userInfo.getName(), project, exploratoryName, l, l.isOverride()))
                .collect(Collectors.toList());
        return requestBuilder.newLibInstall(userInfo, userInstance, endpointDTO, libsToInstall);
    }

    private LibraryInstallDTO toComputationalLibraryInstallDto(UserInfo userInfo, String project, String expName,
                                                               String compName, List<LibInstallDTO> libs,
                                                               UserInstanceDTO userInstance, EndpointDTO endpointDTO) {

        final UserComputationalResource computationalResource = getComputationalResource(compName, userInstance);
        final List<LibInstallDTO> libsToInstall = libs.stream()
                .map(lib -> toLibInstallDto(lib, libraryDAO.getLibrary(userInfo.getName(), project,
                        expName, compName, lib.getGroup(), lib.getName())))
                .peek(l -> libraryDAO.addLibrary(userInfo.getName(), project, expName, compName,
                        l, l.isOverride()))
                .collect(Collectors.toList());
        return requestBuilder.newLibInstall(userInfo, userInstance, computationalResource, libsToInstall, endpointDTO);
    }

    private UserComputationalResource getComputationalResource(String computationalName,
                                                               UserInstanceDTO userInstance) {
        return userInstance.getResources()
                .stream()
                .filter(computational -> computational.getComputationalName().equals(computationalName))
                .findAny()
                .orElseThrow(() -> new DatalabException(String.format(COMPUTATIONAL_NOT_FOUND_MSG, computationalName)));
    }

    private LibInstallDTO toLibInstallDto(LibInstallDTO lib, Library existingLibrary) {
        final LibInstallDTO l = new LibInstallDTO(lib.getGroup(), lib.getName(), lib.getVersion());
        l.setStatus(LibStatus.INSTALLING.toString());
        l.setOverride(shouldOverride(existingLibrary));
        return l;
    }

    private boolean shouldOverride(Library library) {
        if (Objects.nonNull(library) && library.getStatus() == LibStatus.INSTALLING) {
            throw new DatalabException(String.format(LIB_ALREADY_INSTALLED, library.getName()));
        } else {
            return Objects.nonNull(library);
        }
    }

    @SuppressWarnings("unchecked")
    private Document getLibsOfActiveComputationalResources(Document document) {
        Document computationalLibs = (Document) document.get(ExploratoryLibDAO.COMPUTATIONAL_LIBS);

        if (document.get(ExploratoryDAO.COMPUTATIONAL_RESOURCES) != null) {
            List<Document> computationalResources = (List<Document>) document.get(ExploratoryDAO
                    .COMPUTATIONAL_RESOURCES);

            Set<String> terminated = computationalResources.stream()
                    .filter(doc -> doc.getString(BaseDAO.STATUS).equalsIgnoreCase(UserInstanceStatus.TERMINATED
                            .toString()))
                    .map(doc -> doc.getString("computational_name")).collect(Collectors.toSet());

            terminated.forEach(computationalLibs::remove);
        }

        return computationalLibs;
    }


    private void populateModel(String exploratoryName, Document document, Map<LibKey, List<LibraryStatus>> model,
                               String resourceType) {
        String name = document.getString(ExploratoryLibDAO.LIB_NAME);
        String version = document.getString(ExploratoryLibDAO.LIB_VERSION);
        String group = document.getString(ExploratoryLibDAO.LIB_GROUP);
        String status = document.getString(ExploratoryLibDAO.STATUS);
        List<String> availableVersions = (List<String>) document.get(ExploratoryLibDAO.LIB_AVAILABLE_VERSION);
        List<String> addedPackages = (List<String>) document.get(ExploratoryLibDAO.LIB_ADDED_PACKAGES);
        String error = document.getString(ExploratoryLibDAO.ERROR_MESSAGE);

        LibKey libKey = new LibKey(name, version, group);
        List<LibraryStatus> statuses = model.getOrDefault(libKey, new ArrayList<>());

        if (statuses.isEmpty()) {
            model.put(libKey, statuses);
        }

        statuses.add(new LibraryStatus(exploratoryName, resourceType, status, error, availableVersions, addedPackages));
    }

    @SuppressWarnings("unchecked")
    private void populateComputational(Document computationalLibs, Map<LibKey, List<LibraryStatus>> model, String
            resourceType) {
        for (Map.Entry<String, Object> entry : computationalLibs.entrySet()) {
            if (entry.getValue() != null) {
                List<Document> docs = (List<Document>) entry.getValue();
                docs.forEach(e -> populateModel(entry.getKey(), e, model, resourceType));
            }
        }
    }
}