/*
 * 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.dlab.backendapi.service.impl;

import com.epam.dlab.auth.UserInfo;
import com.epam.dlab.backendapi.dao.ExploratoryDAO;
import com.epam.dlab.backendapi.dao.ExploratoryLibDAO;
import com.epam.dlab.backendapi.dao.ImageExploratoryDao;
import com.epam.dlab.backendapi.domain.EndpointDTO;
import com.epam.dlab.backendapi.resources.dto.ImageInfoRecord;
import com.epam.dlab.backendapi.service.EndpointService;
import com.epam.dlab.backendapi.service.ImageExploratoryService;
import com.epam.dlab.backendapi.util.RequestBuilder;
import com.epam.dlab.constants.ServiceConsts;
import com.epam.dlab.dto.UserInstanceDTO;
import com.epam.dlab.dto.UserInstanceStatus;
import com.epam.dlab.dto.exploratory.ExploratoryStatusDTO;
import com.epam.dlab.dto.exploratory.ImageStatus;
import com.epam.dlab.exceptions.ResourceAlreadyExistException;
import com.epam.dlab.exceptions.ResourceNotFoundException;
import com.epam.dlab.model.ResourceType;
import com.epam.dlab.model.exploratory.Image;
import com.epam.dlab.model.library.Library;
import com.epam.dlab.rest.client.RESTService;
import com.epam.dlab.rest.contracts.ExploratoryAPI;
import com.google.common.collect.Lists;
import com.google.inject.Inject;
import com.google.inject.Singleton;
import com.google.inject.name.Named;
import lombok.extern.slf4j.Slf4j;

import java.util.List;
import java.util.Map;
import java.util.function.Predicate;
import java.util.stream.Collectors;

@Singleton
@Slf4j
public class ImageExploratoryServiceImpl implements ImageExploratoryService {

	private static final String IMAGE_EXISTS_MSG = "Image with name %s is already exist in project %s";
	private static final String IMAGE_NOT_FOUND_MSG = "Image with name %s was not found for user %s";

	@Inject
	private ExploratoryDAO exploratoryDAO;
	@Inject
	private ImageExploratoryDao imageExploratoryDao;
	@Inject
	private ExploratoryLibDAO libDAO;
	@Inject
	@Named(ServiceConsts.PROVISIONING_SERVICE_NAME)
	private RESTService provisioningService;
	@Inject
	private RequestBuilder requestBuilder;
	@Inject
	private EndpointService endpointService;

	@Override
	public String createImage(UserInfo user, String exploratoryName, String imageName, String imageDescription) {

		UserInstanceDTO userInstance = exploratoryDAO.fetchRunningExploratoryFields(user.getName(), exploratoryName);

		if (imageExploratoryDao.exist(imageName, userInstance.getProject())) {
			log.error(String.format(IMAGE_EXISTS_MSG, imageName, userInstance.getProject()));
			throw new ResourceAlreadyExistException(String.format(IMAGE_EXISTS_MSG, imageName, userInstance.getProject()));
		}
		final List<Library> libraries = libDAO.getLibraries(user.getName(), exploratoryName);

		imageExploratoryDao.save(Image.builder()
				.name(imageName)
				.description(imageDescription)
				.status(ImageStatus.CREATING)
				.user(user.getName())
				.libraries(fetchExploratoryLibs(libraries))
				.computationalLibraries(fetchComputationalLibs(libraries))
				.dockerImage(userInstance.getImageName())
				.exploratoryId(userInstance.getId())
				.project(userInstance.getProject())
				.endpoint(userInstance.getEndpoint())
				.build());

		exploratoryDAO.updateExploratoryStatus(new ExploratoryStatusDTO()
				.withUser(user.getName())
				.withExploratoryName(exploratoryName)
				.withStatus(UserInstanceStatus.CREATING_IMAGE));

		EndpointDTO endpointDTO = endpointService.get(userInstance.getEndpoint());
		return provisioningService.post(endpointDTO.getUrl() + ExploratoryAPI.EXPLORATORY_IMAGE,
				user.getAccessToken(),
				requestBuilder.newExploratoryImageCreate(user, userInstance, imageName, endpointDTO), String.class);
	}

	@Override
	public void finishImageCreate(Image image, String exploratoryName, String newNotebookIp) {
		log.debug("Returning exploratory status with name {} to RUNNING for user {}",
				exploratoryName, image.getUser());
		exploratoryDAO.updateExploratoryStatus(new ExploratoryStatusDTO()
				.withUser(image.getUser())
				.withExploratoryName(exploratoryName)
				.withStatus(UserInstanceStatus.RUNNING));
		imageExploratoryDao.updateImageFields(image);
		if (newNotebookIp != null) {
			log.debug("Changing exploratory ip with name {} for user {} to {}", exploratoryName, image.getUser(),
					newNotebookIp);
			exploratoryDAO.updateExploratoryIp(image.getUser(), newNotebookIp, exploratoryName);
		}

	}

	@Override
	public List<ImageInfoRecord> getNotFailedImages(String user, String dockerImage, String project, String endpoint) {
		return imageExploratoryDao.getImages(user, dockerImage, project, endpoint, ImageStatus.CREATED, ImageStatus.CREATING);
	}

	@Override
	public ImageInfoRecord getImage(String user, String name, String project, String endpoint) {
		return imageExploratoryDao.getImage(user, name, project, endpoint).orElseThrow(() ->
				new ResourceNotFoundException(String.format(IMAGE_NOT_FOUND_MSG, name, user)));
	}

	@Override
	public List<ImageInfoRecord> getImagesForProject(String project) {
		return imageExploratoryDao.getImagesForProject(project);
	}

	private Map<String, List<Library>> fetchComputationalLibs(List<Library> libraries) {
		return libraries.stream()
				.filter(resourceTypePredicate(ResourceType.COMPUTATIONAL))
				.collect(Collectors.toMap(Library::getResourceName, Lists::newArrayList, this::merge));
	}

	private List<Library> merge(List<Library> oldValue, List<Library> newValue) {
		oldValue.addAll(newValue);
		return oldValue;
	}

	private List<Library> fetchExploratoryLibs(List<Library> libraries) {
		return libraries.stream()
				.filter(resourceTypePredicate(ResourceType.EXPLORATORY))
				.collect(Collectors.toList());
	}

	private Predicate<Library> resourceTypePredicate(ResourceType resourceType) {
		return l -> resourceType == l.getType();
	}
}