/*
 * 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.Audit;
import com.epam.datalab.backendapi.annotation.BudgetLimited;
import com.epam.datalab.backendapi.annotation.Info;
import com.epam.datalab.backendapi.annotation.Project;
import com.epam.datalab.backendapi.annotation.ResourceName;
import com.epam.datalab.backendapi.annotation.User;
import com.epam.datalab.backendapi.dao.ComputationalDAO;
import com.epam.datalab.backendapi.dao.ExploratoryDAO;
import com.epam.datalab.backendapi.domain.EndpointDTO;
import com.epam.datalab.backendapi.domain.ProjectDTO;
import com.epam.datalab.backendapi.domain.RequestId;
import com.epam.datalab.backendapi.resources.dto.ComputationalCreateFormDTO;
import com.epam.datalab.backendapi.resources.dto.ComputationalTemplatesDTO;
import com.epam.datalab.backendapi.resources.dto.SparkStandaloneClusterCreateForm;
import com.epam.datalab.backendapi.service.ComputationalService;
import com.epam.datalab.backendapi.service.EndpointService;
import com.epam.datalab.backendapi.service.InfrastructureTemplateService;
import com.epam.datalab.backendapi.service.ProjectService;
import com.epam.datalab.backendapi.service.TagService;
import com.epam.datalab.backendapi.util.RequestBuilder;
import com.epam.datalab.constants.ServiceConsts;
import com.epam.datalab.dto.UserInstanceDTO;
import com.epam.datalab.dto.UserInstanceStatus;
import com.epam.datalab.dto.aws.computational.ClusterConfig;
import com.epam.datalab.dto.base.DataEngineType;
import com.epam.datalab.dto.base.computational.ComputationalBase;
import com.epam.datalab.dto.base.computational.FullComputationalTemplate;
import com.epam.datalab.dto.computational.ComputationalClusterConfigDTO;
import com.epam.datalab.dto.computational.ComputationalStatusDTO;
import com.epam.datalab.dto.computational.ComputationalTerminateDTO;
import com.epam.datalab.dto.computational.SparkStandaloneClusterResource;
import com.epam.datalab.dto.computational.UserComputationalResource;
import com.epam.datalab.exceptions.DatalabException;
import com.epam.datalab.exceptions.ResourceNotFoundException;
import com.epam.datalab.rest.client.RESTService;
import com.epam.datalab.rest.contracts.ComputationalAPI;
import com.google.inject.Inject;
import com.google.inject.Singleton;
import com.google.inject.name.Named;
import lombok.extern.slf4j.Slf4j;

import java.util.Collection;
import java.util.EnumMap;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import java.util.stream.Collectors;

import static com.epam.datalab.backendapi.domain.AuditActionEnum.CREATE;
import static com.epam.datalab.backendapi.domain.AuditActionEnum.RECONFIGURE;
import static com.epam.datalab.backendapi.domain.AuditActionEnum.START;
import static com.epam.datalab.backendapi.domain.AuditActionEnum.STOP;
import static com.epam.datalab.backendapi.domain.AuditActionEnum.TERMINATE;
import static com.epam.datalab.backendapi.domain.AuditActionEnum.UPDATE;
import static com.epam.datalab.backendapi.domain.AuditResourceTypeEnum.COMPUTE;
import static com.epam.datalab.dto.UserInstanceStatus.CREATING;
import static com.epam.datalab.dto.UserInstanceStatus.FAILED;
import static com.epam.datalab.dto.UserInstanceStatus.RECONFIGURING;
import static com.epam.datalab.dto.UserInstanceStatus.STARTING;
import static com.epam.datalab.dto.UserInstanceStatus.STOPPING;
import static com.epam.datalab.dto.UserInstanceStatus.TERMINATING;
import static com.epam.datalab.dto.base.DataEngineType.CLOUD_SERVICE;
import static com.epam.datalab.dto.base.DataEngineType.SPARK_STANDALONE;
import static com.epam.datalab.rest.contracts.ComputationalAPI.COMPUTATIONAL_CREATE_CLOUD_SPECIFIC;

@Singleton
@Slf4j
public class ComputationalServiceImpl implements ComputationalService {

    private static final String COULD_NOT_UPDATE_THE_STATUS_MSG_FORMAT = "Could not update the status of " +
            "computational resource {} for user {}";
    private static final EnumMap<DataEngineType, String> DATA_ENGINE_TYPE_TERMINATE_URLS;
    private static final String DATAENGINE_NOT_PRESENT_FORMAT = "There is no %s dataengine %s for exploratory %s";
    private static final String RUNNING_COMP_RES_NOT_FOUND = "Running computational resource with " +
            "name %s for exploratory %s not found";

    static {
        DATA_ENGINE_TYPE_TERMINATE_URLS = new EnumMap<>(DataEngineType.class);
        DATA_ENGINE_TYPE_TERMINATE_URLS.put(SPARK_STANDALONE, ComputationalAPI.COMPUTATIONAL_TERMINATE_SPARK);
        DATA_ENGINE_TYPE_TERMINATE_URLS.put(CLOUD_SERVICE, ComputationalAPI.COMPUTATIONAL_TERMINATE_CLOUD_SPECIFIC);
    }

    private final ProjectService projectService;
    private final ExploratoryDAO exploratoryDAO;
    private final ComputationalDAO computationalDAO;
    private final RESTService provisioningService;
    private final RequestBuilder requestBuilder;
    private final RequestId requestId;
    private final TagService tagService;
    private final EndpointService endpointService;
    private final InfrastructureTemplateService templateService;

    @Inject
    public ComputationalServiceImpl(ProjectService projectService, ExploratoryDAO exploratoryDAO, ComputationalDAO computationalDAO,
                                    @Named(ServiceConsts.PROVISIONING_SERVICE_NAME) RESTService provisioningService,
                                    RequestBuilder requestBuilder, RequestId requestId, TagService tagService,
                                    EndpointService endpointService, InfrastructureTemplateService templateService) {
        this.projectService = projectService;
        this.exploratoryDAO = exploratoryDAO;
        this.computationalDAO = computationalDAO;
        this.provisioningService = provisioningService;
        this.requestBuilder = requestBuilder;
        this.requestId = requestId;
        this.tagService = tagService;
        this.endpointService = endpointService;
        this.templateService = templateService;
    }


    @Override
    public ComputationalTemplatesDTO getComputationalNamesAndTemplates(UserInfo user, String project, String endpoint) {
        List<FullComputationalTemplate> computationalTemplates = templateService.getComputationalTemplates(user, project, endpoint);
        List<UserInstanceDTO> userInstances = exploratoryDAO.fetchExploratoryFieldsForProjectWithComp(project);

        List<String> projectComputations = userInstances
                .stream()
                .map(UserInstanceDTO::getResources)
                .flatMap(Collection::stream)
                .map(UserComputationalResource::getComputationalName)
                .collect(Collectors.toList());
        List<String> userComputations = userInstances
                .stream()
                .filter(instance -> instance.getUser().equalsIgnoreCase(user.getName()))
                .map(UserInstanceDTO::getResources)
                .flatMap(Collection::stream)
                .map(UserComputationalResource::getComputationalName)
                .collect(Collectors.toList());

        return new ComputationalTemplatesDTO(computationalTemplates, userComputations, projectComputations);
    }

    @BudgetLimited
    @Audit(action = CREATE, type = COMPUTE)
    @Override
    public boolean createSparkCluster(@User UserInfo userInfo, @ResourceName String resourceName, SparkStandaloneClusterCreateForm form, @Project String project,
                                      @Info String auditInfo) {
        final ProjectDTO projectDTO = projectService.get(project);
        final UserInstanceDTO instance =
                exploratoryDAO.fetchExploratoryFields(userInfo.getName(), project, form.getNotebookName());
        final SparkStandaloneClusterResource compResource = createInitialComputationalResource(form);
        compResource.setTags(tagService.getResourceTags(userInfo, instance.getEndpoint(), project,
                form.getCustomTag()));
        if (computationalDAO.addComputational(userInfo.getName(), form.getNotebookName(), project, compResource)) {
            try {
                EndpointDTO endpointDTO = endpointService.get(instance.getEndpoint());
                ComputationalBase<?> dto = requestBuilder.newComputationalCreate(userInfo, projectDTO, instance, form, endpointDTO);

                String uuid =
                        provisioningService.post(endpointDTO.getUrl() + ComputationalAPI.COMPUTATIONAL_CREATE_SPARK,
                                userInfo.getAccessToken(), dto, String.class);
                requestId.put(userInfo.getName(), uuid);
                return true;
            } catch (RuntimeException e) {
                try {
                    updateComputationalStatus(userInfo.getName(), project, form.getNotebookName(), form.getName(), FAILED);
                } catch (DatalabException d) {
                    log.error(COULD_NOT_UPDATE_THE_STATUS_MSG_FORMAT, form.getName(), userInfo.getName(), d);
                }
                throw e;
            }
        } else {
            log.debug("Computational with name {} is already existing for user {}", form.getName(),
                    userInfo.getName());
            return false;
        }
    }

    @Audit(action = TERMINATE, type = COMPUTE)
    @Override
    public void terminateComputational(@User UserInfo userInfo, String resourceCreator, @Project String project, String exploratoryName, @ResourceName String computationalName,
                                       @Info String auditInfo) {
        try {
            updateComputationalStatus(resourceCreator, project, exploratoryName, computationalName, TERMINATING);

            final UserInstanceDTO userInstanceDTO = exploratoryDAO.fetchExploratoryFields(resourceCreator, project, exploratoryName);
            UserComputationalResource compResource = computationalDAO.fetchComputationalFields(resourceCreator, project, exploratoryName, computationalName);

            final DataEngineType dataEngineType = compResource.getDataEngineType();
            EndpointDTO endpointDTO = endpointService.get(userInstanceDTO.getEndpoint());
            ComputationalTerminateDTO dto = requestBuilder.newComputationalTerminate(resourceCreator, userInstanceDTO, compResource, endpointDTO);

            final String provisioningUrl = Optional.ofNullable(DATA_ENGINE_TYPE_TERMINATE_URLS.get(dataEngineType))
                    .orElseThrow(UnsupportedOperationException::new);
            final String uuid = provisioningService.post(endpointDTO.getUrl() + provisioningUrl, userInfo.getAccessToken(), dto, String.class);
            requestId.put(resourceCreator, uuid);
        } catch (RuntimeException re) {
            try {
                updateComputationalStatus(resourceCreator, project, exploratoryName, computationalName, FAILED);
            } catch (DatalabException e) {
                log.error(COULD_NOT_UPDATE_THE_STATUS_MSG_FORMAT, computationalName, resourceCreator, e);
            }
            throw re;
        }
    }

    @BudgetLimited
    @Audit(action = CREATE, type = COMPUTE)
    @Override
    public boolean createDataEngineService(@User UserInfo userInfo, @ResourceName String resourceName, ComputationalCreateFormDTO formDTO,
                                           UserComputationalResource computationalResource, @Project String project, @Info String auditInfo) {
        final ProjectDTO projectDTO = projectService.get(project);
        final UserInstanceDTO instance = exploratoryDAO.fetchExploratoryFields(userInfo.getName(), project, formDTO
                .getNotebookName());
        final Map<String, String> tags = tagService.getResourceTags(userInfo, instance.getEndpoint(), project,
                formDTO.getCustomTag());
        computationalResource.setTags(tags);
        boolean isAdded = computationalDAO.addComputational(userInfo.getName(), formDTO.getNotebookName(), project,
                computationalResource);

        if (isAdded) {
            try {
                EndpointDTO endpointDTO = endpointService.get(instance.getEndpoint());
                String uuid =
                        provisioningService.post(endpointDTO.getUrl() + COMPUTATIONAL_CREATE_CLOUD_SPECIFIC,
                                userInfo.getAccessToken(),
                                requestBuilder.newComputationalCreate(userInfo, projectDTO, instance, formDTO, endpointDTO),
                                String.class);
                requestId.put(userInfo.getName(), uuid);
                return true;
            } catch (Exception t) {
                try {
                    updateComputationalStatus(userInfo.getName(), project, formDTO.getNotebookName(),
                            formDTO.getName(), FAILED);
                } catch (DatalabException e) {
                    log.error(COULD_NOT_UPDATE_THE_STATUS_MSG_FORMAT, formDTO.getName(), userInfo.getName(), e);
                }
                throw new DatalabException("Could not send request for creation the computational resource " + formDTO
                        .getName() + ": " + t.getLocalizedMessage(), t);
            }
        } else {
            log.debug("Used existing computational resource {} for user {}", formDTO.getName(), userInfo.getName());
            return false;
        }
    }

    @Audit(action = STOP, type = COMPUTE)
    @Override
    public void stopSparkCluster(@User UserInfo userInfo, String resourceCreator, @Project String project, String expName, @ResourceName String compName, @Info String auditInfo) {
        final UserInstanceDTO userInstance = exploratoryDAO.fetchExploratoryFields(resourceCreator, project, expName, true);
        final UserInstanceStatus requiredStatus = UserInstanceStatus.RUNNING;
        if (computationalWithStatusResourceExist(compName, userInstance, requiredStatus)) {
            log.debug("{} spark cluster {} for userInstance {}", STOPPING.toString(), compName, expName);
            updateComputationalStatus(resourceCreator, project, expName, compName, STOPPING);
            EndpointDTO endpointDTO = endpointService.get(userInstance.getEndpoint());
            final String uuid = provisioningService.post(endpointDTO.getUrl() + ComputationalAPI.COMPUTATIONAL_STOP_SPARK,
                    userInfo.getAccessToken(),
                    requestBuilder.newComputationalStop(resourceCreator, userInstance, compName, endpointDTO),
                    String.class);
            requestId.put(resourceCreator, uuid);
        } else {
            throw new IllegalStateException(String.format(DATAENGINE_NOT_PRESENT_FORMAT, requiredStatus.toString(), compName, expName));
        }
    }

    @BudgetLimited
    @Audit(action = START, type = COMPUTE)
    @Override
    public void startSparkCluster(@User UserInfo userInfo, String expName, @ResourceName String compName, @Project String project, @Info String auditInfo) {
        final UserInstanceDTO userInstance = exploratoryDAO.fetchExploratoryFields(userInfo.getName(), project, expName, true);
        final UserInstanceStatus requiredStatus = UserInstanceStatus.STOPPED;
        if (computationalWithStatusResourceExist(compName, userInstance, requiredStatus)) {
            log.debug("{} spark cluster {} for userInstance {}", STARTING.toString(), compName, expName);
            updateComputationalStatus(userInfo.getName(), project, expName, compName, STARTING);
            EndpointDTO endpointDTO = endpointService.get(userInstance.getEndpoint());
            final String uuid = provisioningService.post(endpointDTO.getUrl() + ComputationalAPI.COMPUTATIONAL_START_SPARK,
                    userInfo.getAccessToken(),
                    requestBuilder.newComputationalStart(userInfo, userInstance, compName, endpointDTO),
                    String.class);
            requestId.put(userInfo.getName(), uuid);
        } else {
            throw new IllegalStateException(String.format(DATAENGINE_NOT_PRESENT_FORMAT, requiredStatus.toString(), compName, expName));
        }
    }

    @Audit(action = RECONFIGURE, type = COMPUTE)
    @Override
    public void updateSparkClusterConfig(@User UserInfo userInfo, @Project String project, String exploratoryName, @ResourceName String computationalName, List<ClusterConfig> config, @Info String auditInfo) {
        final String userName = userInfo.getName();
        final String token = userInfo.getAccessToken();
        final UserInstanceDTO userInstanceDTO = exploratoryDAO
                .fetchExploratoryFields(userName, project, exploratoryName, true);
        final UserComputationalResource compResource = userInstanceDTO
                .getResources()
                .stream()
                .filter(cr -> cr.getComputationalName().equals(computationalName) && cr.getStatus().equals(UserInstanceStatus.RUNNING.toString()))
                .findAny()
                .orElseThrow(() -> new ResourceNotFoundException(String.format(RUNNING_COMP_RES_NOT_FOUND,
                        computationalName, exploratoryName)));
        EndpointDTO endpointDTO = endpointService.get(userInstanceDTO.getEndpoint());
        final ComputationalClusterConfigDTO clusterConfigDto = requestBuilder.newClusterConfigUpdate(userInfo,
                userInstanceDTO, compResource, config, endpointDTO);
        final String uuid =
                provisioningService.post(endpointDTO.getUrl() + ComputationalAPI.COMPUTATIONAL_RECONFIGURE_SPARK,
                        token, clusterConfigDto, String.class);
        computationalDAO.updateComputationalFields(new ComputationalStatusDTO()
                .withProject(userInstanceDTO.getProject())
                .withComputationalName(computationalName)
                .withExploratoryName(exploratoryName)
                .withConfig(config)
                .withStatus(RECONFIGURING.toString())
                .withUser(userName));
        requestId.put(userName, uuid);
    }

    /**
     * Returns computational resource's data by name for user's exploratory.
     *
     * @param user              user
     * @param project           name of project
     * @param exploratoryName   name of exploratory.
     * @param computationalName name of computational resource.
     * @return corresponding computational resource's data or empty data if resource doesn't exist.
     */
    @Override
    public Optional<UserComputationalResource> getComputationalResource(String user, String project, String exploratoryName, String computationalName) {
        try {
            return Optional.of(computationalDAO.fetchComputationalFields(user, project, exploratoryName, computationalName));
        } catch (DatalabException e) {
            log.warn("Computational resource {} affiliated with exploratory {} for user {} not found.", computationalName, exploratoryName, user, e);
        }
        return Optional.empty();
    }

    @Override
    public List<ClusterConfig> getClusterConfig(UserInfo userInfo, String project, String exploratoryName, String computationalName) {
        return computationalDAO.getClusterConfig(userInfo.getName(), project, exploratoryName, computationalName);
    }

    @Audit(action = UPDATE, type = COMPUTE)
    @Override
    public void updateAfterStatusCheck(@User UserInfo systemUser, @Project String project, String endpoint, @ResourceName String name, String instanceID,
                                       UserInstanceStatus status, @Info String auditInfo) {
        computationalDAO.updateComputeStatus(project, endpoint, name, instanceID, status);
    }

    /**
     * Updates the status of computational resource in database.
     *
     * @param user              user name.
     * @param project           project name
     * @param exploratoryName   name of exploratory.
     * @param computationalName name of computational resource.
     * @param status            status
     */
    private void updateComputationalStatus(String user, String project, String exploratoryName, String computationalName, UserInstanceStatus status) {
        ComputationalStatusDTO computationalStatus = new ComputationalStatusDTO()
                .withUser(user)
                .withProject(project)
                .withExploratoryName(exploratoryName)
                .withComputationalName(computationalName)
                .withStatus(status);

        computationalDAO.updateComputationalStatus(computationalStatus);
    }

    private SparkStandaloneClusterResource createInitialComputationalResource(SparkStandaloneClusterCreateForm form) {
        return SparkStandaloneClusterResource.builder()
                .computationalName(form.getName())
                .imageName(form.getImage())
                .templateName(form.getTemplateName())
                .status(CREATING.toString())
                .dataEngineInstanceCount(form.getDataEngineInstanceCount())
                .dataEngineInstanceShape(form.getDataEngineInstanceShape())
                .config(form.getConfig())
                .build();
    }

    private boolean computationalWithStatusResourceExist(String compName, UserInstanceDTO ui, UserInstanceStatus status) {
        return ui.getResources()
                .stream()
                .anyMatch(c -> computationalWithNameAndStatus(compName, c, status));
    }

    private boolean computationalWithNameAndStatus(String computationalName, UserComputationalResource compResource, UserInstanceStatus status) {
        return compResource.getStatus().equals(status.toString()) &&
                compResource.getDataEngineType() == SPARK_STANDALONE &&
                compResource.getComputationalName().equals(computationalName);
    }
}