/**
 * 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 org.apache.falcon.resource;

import org.apache.commons.lang.StringUtils;
import org.apache.falcon.*;
import org.apache.falcon.entity.EntityUtil;
import org.apache.falcon.entity.parser.ValidationException;
import org.apache.falcon.entity.v0.Entity;
import org.apache.falcon.entity.v0.EntityType;
import org.apache.falcon.entity.v0.SchemaHelper;
import org.apache.falcon.logging.LogProvider;
import org.apache.falcon.resource.InstancesResult.Instance;
import org.apache.falcon.workflow.engine.AbstractWorkflowEngine;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.servlet.ServletInputStream;
import javax.servlet.http.HttpServletRequest;
import javax.ws.rs.core.Response;
import java.io.IOException;
import java.util.*;

/**
 * A base class for managing Entity's Instance operations.
 */
public abstract class AbstractInstanceManager extends AbstractEntityManager {
    private static final Logger LOG = LoggerFactory.getLogger(AbstractInstanceManager.class);

    protected void checkType(String type) {
        if (StringUtils.isEmpty(type)) {
            throw FalconWebException.newInstanceException("entity type is empty",
                    Response.Status.BAD_REQUEST);
        } else {
            EntityType entityType = EntityType.valueOf(type.toUpperCase());
            if (entityType == EntityType.CLUSTER) {
                throw FalconWebException.newInstanceException(
                        "Instance management functions don't apply to Cluster entities",
                        Response.Status.BAD_REQUEST);
            }
        }
    }

    protected List<LifeCycle> checkAndUpdateLifeCycle(List<LifeCycle> lifeCycleValues,
                                                      String type) throws FalconException {
        EntityType entityType = EntityType.valueOf(type.toUpperCase().trim());
        if (lifeCycleValues == null || lifeCycleValues.isEmpty()) {
            List<LifeCycle> lifeCycles = new ArrayList<LifeCycle>();
            if (entityType == EntityType.PROCESS) {
                lifeCycles.add(LifeCycle.valueOf(LifeCycle.EXECUTION.name()));
            } else if (entityType == EntityType.FEED) {
                lifeCycles.add(LifeCycle.valueOf(LifeCycle.REPLICATION.name()));
            }
            return lifeCycles;
        }
        for (LifeCycle lifeCycle : lifeCycleValues) {
            if (entityType != lifeCycle.getTag().getType()) {
                throw new FalconException("Incorrect lifecycle: " + lifeCycle + "for given type: " + type);
            }
        }
        return lifeCycleValues;
    }

    //SUSPEND CHECKSTYLE CHECK ParameterNumberCheck
    public InstancesResult getRunningInstances(String type, String entity,
                                               String colo, List<LifeCycle> lifeCycles, String filterBy,
                                               String orderBy, Integer offset, Integer numResults) {
        checkColo(colo);
        checkType(type);
        try {
            lifeCycles = checkAndUpdateLifeCycle(lifeCycles, type);
            validateNotEmpty("entityName", entity);
            AbstractWorkflowEngine wfEngine = getWorkflowEngine();
            Entity entityObject = EntityUtil.getEntity(type, entity);
            return getInstanceResultSubset(wfEngine.getRunningInstances(entityObject, lifeCycles),
                    filterBy, orderBy, offset, numResults);
        } catch (Throwable e) {
            LOG.error("Failed to get running instances", e);
            throw FalconWebException.newInstanceException(e, Response.Status.BAD_REQUEST);
        }
    }

    //SUSPEND CHECKSTYLE CHECK ParameterNumberCheck
    public InstancesResult getInstances(String type, String entity, String startStr, String endStr,
                                        String colo, List<LifeCycle> lifeCycles,
                                        String filterBy, String orderBy, Integer offset, Integer numResults) {
        return getStatus(type, entity, startStr, endStr, colo, lifeCycles,
                filterBy, orderBy, offset, numResults);
    }

    public InstancesResult getStatus(String type, String entity, String startStr, String endStr,
                                     String colo, List<LifeCycle> lifeCycles,
                                     String filterBy, String orderBy, Integer offset, Integer numResults) {
        checkColo(colo);
        checkType(type);
        try {
            lifeCycles = checkAndUpdateLifeCycle(lifeCycles, type);
            validateParams(type, entity, startStr, endStr);
            Date start = EntityUtil.parseDateUTC(startStr);
            Date end = getEndDate(start, endStr);
            Entity entityObject = EntityUtil.getEntity(type, entity);
            // LifeCycle lifeCycleObject = EntityUtil.getLifeCycle(lifeCycle);
            AbstractWorkflowEngine wfEngine = getWorkflowEngine();
            return getInstanceResultSubset(wfEngine.getStatus(entityObject, start, end, lifeCycles),
                    filterBy, orderBy, offset, numResults);
        } catch (Throwable e) {
            LOG.error("Failed to get instances status", e);
            throw FalconWebException
                    .newInstanceException(e, Response.Status.BAD_REQUEST);
        }
    }

    public InstancesSummaryResult getSummary(String type, String entity, String startStr, String endStr,
                                             String colo, List<LifeCycle> lifeCycles) {
        checkColo(colo);
        checkType(type);
        try {
            lifeCycles = checkAndUpdateLifeCycle(lifeCycles, type);
            validateParams(type, entity, startStr, endStr);

            Date start = EntityUtil.parseDateUTC(startStr);
            Date end = getEndDate(start, endStr);
            Entity entityObject = EntityUtil.getEntity(type, entity);

            AbstractWorkflowEngine wfEngine = getWorkflowEngine();
            return wfEngine.getSummary(entityObject, start, end, lifeCycles);
        } catch (Throwable e) {
            LOG.error("Failed to get instances status", e);
            throw FalconWebException.newInstanceSummaryException(e, Response.Status.BAD_REQUEST);
        }
    }

    public InstancesResult getLogs(String type, String entity, String startStr,
                                   String endStr, String colo, String runId,
                                   List<LifeCycle> lifeCycles,
                                   String filterBy, String orderBy, Integer offset, Integer numResults) {

        try {
            lifeCycles = checkAndUpdateLifeCycle(lifeCycles, type);
            // getStatus does all validations and filters clusters
            InstancesResult result = getStatus(type, entity, startStr, endStr,
                    colo, lifeCycles, filterBy, orderBy, offset, numResults);
            LogProvider logProvider = new LogProvider();
            Entity entityObject = EntityUtil.getEntity(type, entity);
            for (Instance instance : result.getInstances()) {
                logProvider.populateLogUrls(entityObject, instance, runId);
            }
            return result;
        } catch (Exception e) {
            LOG.error("Failed to get logs for instances", e);
            throw FalconWebException.newInstanceException(e,
                    Response.Status.BAD_REQUEST);
        }
    }

    private InstancesResult getInstanceResultSubset(InstancesResult resultSet, String filterBy, String orderBy,
                                                    Integer offset, Integer numResults) {

        ArrayList<Instance> instanceSet = new ArrayList<Instance>();
        if (resultSet.getInstances() == null) {
            // return the empty resultSet
            resultSet.setInstances(new Instance[0]);
            return resultSet;
        }

        // Filter instances
        instanceSet = filteredInstanceSet(resultSet, instanceSet, getFilterByFieldsValues(filterBy));

        int pageCount = super.getRequiredNumberOfResults(instanceSet.size(), offset, numResults);
        if (pageCount == 0) {
            // return empty result set
            return new InstancesResult(resultSet.getMessage(), new Instance[0]);
        }
        // Sort the ArrayList using orderBy
        instanceSet = sortInstances(instanceSet, orderBy);
        return new InstancesResult(resultSet.getMessage(),
                instanceSet.subList(offset, (offset+pageCount)).toArray(new Instance[pageCount]));
    }

    private ArrayList<Instance> filteredInstanceSet(InstancesResult resultSet, ArrayList<Instance> instanceSet,
                                                  HashMap<String, String> filterByFieldsValues) {

        for (Instance instance : resultSet.getInstances()) {
            boolean addInstance = true;
            // If filterBy is empty, return all instances. Else return instances with matching filter.
            if (filterByFieldsValues.size() > 0) {
                String filterValue;
                for (Map.Entry<String, String> pair : filterByFieldsValues.entrySet()) {
                    filterValue = pair.getValue();
                    if (filterValue.equals("")) {
                        continue;
                    }
                    try {
                        switch (InstancesResult.InstanceFilterFields.valueOf(pair.getKey().toUpperCase())) {
                        case STATUS:
                            String status = "";
                            if (instance.getStatus() != null) {
                                status = instance.getStatus().toString();
                            }
                            if (!status.equalsIgnoreCase(filterValue)) {
                                addInstance = false;
                            }
                            break;
                        case CLUSTER:
                            if (!instance.getCluster().equalsIgnoreCase(filterValue)) {
                                addInstance = false;
                            }
                            break;
                        case SOURCECLUSTER:
                            if (!instance.getSourceCluster().equalsIgnoreCase(filterValue)) {
                                addInstance = false;
                            }
                            break;
                        case STARTEDAFTER:
                            if (instance.getStartTime().before(EntityUtil.parseDateUTC(filterValue))) {
                                addInstance = false;
                            }
                            break;
                        default:
                            break;
                        }
                    } catch (Exception e) {
                        LOG.error("Invalid entry for filterBy field", e);
                        throw FalconWebException.newInstanceException(e, Response.Status.BAD_REQUEST);
                    }
                    if (!addInstance) {
                        break;
                    }
                }
            }
            if (addInstance) {
                instanceSet.add(instance);
            }
        }
        return instanceSet;
    }

    private ArrayList<Instance> sortInstances(ArrayList<Instance> instanceSet, String orderBy) {
        if (orderBy.equals("status")) {
            Collections.sort(instanceSet, new Comparator<Instance>() {
                @Override
                public int compare(Instance i1, Instance i2) {
                    if (i1.getStatus() == null) {
                        i1.status = InstancesResult.WorkflowStatus.ERROR;
                    }
                    if (i2.getStatus() == null) {
                        i2.status = InstancesResult.WorkflowStatus.ERROR;
                    }
                    return i1.getStatus().name().compareTo(i2.getStatus().name());
                }
            });
        } else if (orderBy.equals("cluster")) {
            Collections.sort(instanceSet, new Comparator<Instance>() {
                @Override
                public int compare(Instance i1, Instance i2) {
                    return i1.getCluster().compareTo(i2.getCluster());
                }
            });
        } else if (orderBy.equals("startTime")){
            Collections.sort(instanceSet, new Comparator<Instance>() {
                @Override
                public int compare(Instance i1, Instance i2) {
                    return i1.getStartTime().compareTo(i2.getStartTime());
                }
            });
        } else if (orderBy.equals("endTime")) {
            Collections.sort(instanceSet, new Comparator<Instance>() {
                @Override
                public int compare(Instance i1, Instance i2) {
                    return i1.getEndTime().compareTo(i2.getEndTime());
                }
            });
        }//Default : no sort
        return instanceSet;
    }

    //RESUME CHECKSTYLE CHECK ParameterNumberCheck

    public InstancesResult getInstanceParams(String type,
                                          String entity, String startTime,
                                          String colo, List<LifeCycle> lifeCycles) {
        checkColo(colo);
        checkType(type);
        try {
            lifeCycles = checkAndUpdateLifeCycle(lifeCycles, type);
            if (lifeCycles.size() != 1) {
                throw new FalconException("For displaying wf-params there can't be more than one lifecycle "
                        + lifeCycles);
            }
            validateParams(type, entity, startTime, null);

            Entity entityObject = EntityUtil.getEntity(type, entity);
            Date start = EntityUtil.parseDateUTC(startTime);
            Date end = getEndDate(start, null);
            AbstractWorkflowEngine wfEngine = getWorkflowEngine();
            return wfEngine.getInstanceParams(entityObject, start, end, lifeCycles);
        } catch (Throwable e) {
            LOG.error("Failed to display params of an instance", e);
            throw FalconWebException.newInstanceException(e, Response.Status.BAD_REQUEST);
        }
    }

    public InstancesResult killInstance(HttpServletRequest request,
                                        String type, String entity, String startStr,
                                        String endStr, String colo,
                                        List<LifeCycle> lifeCycles) {

        checkColo(colo);
        checkType(type);
        try {
            lifeCycles = checkAndUpdateLifeCycle(lifeCycles, type);
            audit(request, entity, type, "INSTANCE_KILL");
            validateParams(type, entity, startStr, endStr);

            Date start = EntityUtil.parseDateUTC(startStr);
            Date end = getEndDate(start, endStr);
            Entity entityObject = EntityUtil.getEntity(type, entity);

            Properties props = getProperties(request);
            AbstractWorkflowEngine wfEngine = getWorkflowEngine();
            return wfEngine.killInstances(entityObject, start, end, props, lifeCycles);
        } catch (Throwable e) {
            LOG.error("Failed to kill instances", e);
            throw FalconWebException.newInstanceException(e, Response.Status.BAD_REQUEST);
        }
    }

    public InstancesResult suspendInstance(HttpServletRequest request,
                                           String type, String entity, String startStr,
                                           String endStr, String colo,
                                           List<LifeCycle> lifeCycles) {

        checkColo(colo);
        checkType(type);
        try {
            lifeCycles = checkAndUpdateLifeCycle(lifeCycles, type);
            audit(request, entity, type, "INSTANCE_SUSPEND");
            validateParams(type, entity, startStr, endStr);

            Date start = EntityUtil.parseDateUTC(startStr);
            Date end = getEndDate(start, endStr);
            Entity entityObject = EntityUtil.getEntity(type, entity);

            Properties props = getProperties(request);
            AbstractWorkflowEngine wfEngine = getWorkflowEngine();
            return wfEngine.suspendInstances(entityObject, start, end, props, lifeCycles);
        } catch (Throwable e) {
            LOG.error("Failed to suspend instances", e);
            throw FalconWebException.newInstanceException(e, Response.Status.BAD_REQUEST);
        }
    }

    public InstancesResult resumeInstance(HttpServletRequest request,
                                          String type, String entity, String startStr,
                                          String endStr, String colo,
                                          List<LifeCycle> lifeCycles) {

        checkColo(colo);
        checkType(type);
        try {
            lifeCycles = checkAndUpdateLifeCycle(lifeCycles, type);
            audit(request, entity, type, "INSTANCE_RESUME");
            validateParams(type, entity, startStr, endStr);

            Date start = EntityUtil.parseDateUTC(startStr);
            Date end = getEndDate(start, endStr);
            Entity entityObject = EntityUtil.getEntity(type, entity);

            Properties props = getProperties(request);
            AbstractWorkflowEngine wfEngine = getWorkflowEngine();
            return wfEngine.resumeInstances(entityObject, start, end, props, lifeCycles);
        } catch (Throwable e) {
            LOG.error("Failed to resume instances", e);
            throw FalconWebException.newInstanceException(e, Response.Status.BAD_REQUEST);
        }
    }

    public InstancesResult reRunInstance(String type, String entity, String startStr,
                                         String endStr, HttpServletRequest request,
                                         String colo, List<LifeCycle> lifeCycles) {

        checkColo(colo);
        checkType(type);
        try {
            lifeCycles = checkAndUpdateLifeCycle(lifeCycles, type);
            audit(request, entity, type, "INSTANCE_RERUN");
            validateParams(type, entity, startStr, endStr);

            Date start = EntityUtil.parseDateUTC(startStr);
            Date end = getEndDate(start, endStr);
            Entity entityObject = EntityUtil.getEntity(type, entity);

            Properties props = getProperties(request);
            AbstractWorkflowEngine wfEngine = getWorkflowEngine();
            return wfEngine.reRunInstances(entityObject, start, end, props, lifeCycles);
        } catch (Exception e) {
            LOG.error("Failed to rerun instances", e);
            throw FalconWebException.newInstanceException(e, Response.Status.BAD_REQUEST);
        }
    }

    private Properties getProperties(HttpServletRequest request) throws IOException {
        Properties props = new Properties();
        ServletInputStream xmlStream = request == null ? null : request.getInputStream();
        if (xmlStream != null) {
            if (xmlStream.markSupported()) {
                xmlStream.mark(XML_DEBUG_LEN); // mark up to debug len
            }
            props.load(xmlStream);
        }
        return props;
    }

    private Date getEndDate(Date start, String endStr) throws FalconException {
        Date end;
        if (StringUtils.isEmpty(endStr)) {
            end = new Date(start.getTime() + 1000); // next sec
        } else {
            end = EntityUtil.parseDateUTC(endStr);
        }
        return end;
    }

    private void validateParams(String type, String entity, String startStr,
                                String endStr) throws FalconException {
        validateNotEmpty("entityType", type);
        validateNotEmpty("entityName", entity);
        validateNotEmpty("start", startStr);

        Entity entityObject = EntityUtil.getEntity(type, entity);
        validateDateRange(entityObject, startStr, endStr);
    }

    private void validateDateRange(Entity entity, String start, String end) throws FalconException {
        Set<String> clusters = EntityUtil.getClustersDefined(entity);
        Pair<Date, String> clusterMinStartDate = null;
        Pair<Date, String> clusterMaxEndDate = null;
        for (String cluster : clusters) {
            if (clusterMinStartDate == null || clusterMinStartDate.first.after(
                    EntityUtil.getStartTime(entity, cluster))) {
                clusterMinStartDate = Pair.of(EntityUtil.getStartTime(entity, cluster), cluster);
            }
            if (clusterMaxEndDate == null || clusterMaxEndDate.first.before(EntityUtil.getEndTime(entity, cluster))) {
                clusterMaxEndDate = Pair.of(EntityUtil.getEndTime(entity, cluster), cluster);
            }
        }

        validateDateRangeFor(entity, clusterMinStartDate, clusterMaxEndDate,
                start, end);
    }

    private void validateDateRangeFor(Entity entity, Pair<Date, String> clusterMinStart,
                                      Pair<Date, String> clusterMaxEnd, String start,
                                      String end) throws FalconException{

        Date instStart = EntityUtil.parseDateUTC(start);
        if (instStart.before(clusterMinStart.first)) {
            throw new ValidationException("Start date " + start + " is before "
                    + entity.getEntityType() + "'s  start "
                    + SchemaHelper.formatDateUTC(clusterMinStart.first)
                    + " for cluster " + clusterMinStart.second);
        }

        if (StringUtils.isNotEmpty(end)) {
            Date instEnd = EntityUtil.parseDateUTC(end);
            if (instStart.after(instEnd)) {
                throw new ValidationException("Start date " + start
                        + " is after end date " + end);
            }

            if (instEnd.after(clusterMaxEnd.first)) {
                throw new ValidationException("End date " + end + " is after "
                        + entity.getEntityType() + "'s end "
                        + SchemaHelper.formatDateUTC(clusterMaxEnd.first)
                        + " for cluster " + clusterMaxEnd.second);
            }
        } else if (instStart.after(clusterMaxEnd.first)) {
            throw new ValidationException("Start date " + start + " is after "
                    + entity.getEntityType() + "'s end "
                    + SchemaHelper.formatDateUTC(clusterMaxEnd.first)
                    + " for cluster " + clusterMaxEnd.second);
        }
    }

    private void validateNotEmpty(String field, String param) throws ValidationException {
        if (StringUtils.isEmpty(param)) {
            throw new ValidationException("Parameter " + field + " is empty");
        }
    }
}