/*
 * Copyright 2019 Red Hat, Inc. and/or its affiliates.
 *
 * Licensed 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.jbpm.services.task.wih;

import java.util.HashMap;
import java.util.Map;

import org.jbpm.services.task.prediction.PredictionServiceRegistry;
import org.kie.api.runtime.KieSession;
import org.kie.api.runtime.manager.RuntimeEngine;
import org.kie.api.runtime.manager.RuntimeManager;
import org.kie.api.task.TaskEvent;
import org.kie.api.task.TaskLifeCycleEventListener;
import org.kie.api.task.model.Status;
import org.kie.api.task.model.Task;
import org.kie.internal.runtime.manager.InternalRuntimeEngine;
import org.kie.internal.runtime.manager.RuntimeManagerRegistry;
import org.kie.internal.runtime.manager.context.ProcessInstanceIdContext;
import org.kie.internal.task.api.prediction.PredictionService;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;


public class ExternalTaskEventListener implements TaskLifeCycleEventListener {

    private RuntimeManagerRegistry registry = RuntimeManagerRegistry.get();
    private static final Logger logger = LoggerFactory.getLogger(ExternalTaskEventListener.class);

    private PredictionService predictionService = PredictionServiceRegistry.get().getService();

    public ExternalTaskEventListener() {
    }

    public void processTaskState(Task task) {

        long workItemId = task.getTaskData().getWorkItemId();
        long processInstanceId = task.getTaskData().getProcessInstanceId();
        RuntimeManager manager = getManager(task);
        RuntimeEngine runtime = manager.getRuntimeEngine(ProcessInstanceIdContext.get(processInstanceId));
        KieSession session = ((InternalRuntimeEngine) runtime).internalGetKieSession();

        if (task.getTaskData().getStatus() == Status.Completed) {
            String userId = task.getTaskData().getActualOwner().getId();
            Map<String, Object> results = new HashMap<String, Object>();

            Map<String, Object> taskOutcome = task.getTaskData().getTaskOutputVariables();
            if (taskOutcome != null) {
                results.putAll(taskOutcome);
            }
            results.put("ActorId", userId);

            predictionService.train(task, task.getTaskData().getTaskInputVariables(), results);
            session.getWorkItemManager().completeWorkItem(workItemId, results);

        } else {
            session.getWorkItemManager().abortWorkItem(workItemId);
        }
    }

    public void afterTaskActivatedEvent(Task ti) {
        // DO NOTHING
    }

    public void afterTaskClaimedEvent(Task ti) {
        // DO NOTHING
    }

    public void afterTaskSkippedEvent(TaskEvent event) {
        Task task = event.getTask();
        long processInstanceId = task.getTaskData().getProcessInstanceId();
        if (processInstanceId <= 0) {
            return;
        }
        processTaskState(task);
    }

    public void afterTaskStartedEvent(Task ti) {
        // DO NOTHING
    }

    public void afterTaskStoppedEvent(Task ti) {
        // DO NOTHING
    }

    public void afterTaskCompletedEvent(TaskEvent event) {
        Task task = event.getTask();
        long processInstanceId = task.getTaskData().getProcessInstanceId();
        if (processInstanceId <= 0) {
            return;
        }
        RuntimeManager manager = getManager(task);
        if (manager == null) {
            throw new RuntimeException("No RuntimeManager registered with identifier: " + task.getTaskData().getDeploymentId());
        }
        RuntimeEngine runtime = manager.getRuntimeEngine(ProcessInstanceIdContext.get(processInstanceId));
        KieSession session = ((InternalRuntimeEngine) runtime).internalGetKieSession();
        if (session != null) {
            logger.debug(">> I've recieved an event for a known session (" + task.getTaskData().getProcessSessionId()+")");
            processTaskState(task);
        } else {
            logger.error("EE: I've recieved an event but the session is not known by this handler ( "+task.getTaskData().getProcessSessionId()+")");
        }

    }

    public void afterTaskFailedEvent(TaskEvent event) {
        Task task = event.getTask();
        long processInstanceId = task.getTaskData().getProcessInstanceId();
        if (processInstanceId <= 0) {
            return;
        }
        processTaskState(task);
    }

    public void afterTaskAddedEvent(TaskEvent event) {
        // DO NOTHING
    }

    public void afterTaskExitedEvent(TaskEvent event) {
        // DO NOTHING
    }

    public RuntimeManager getManager(Task task) {
        return registry.getManager(task.getTaskData().getDeploymentId());
    }


    @Override
    public void afterTaskReleasedEvent(TaskEvent event) {

    }

    @Override
    public void afterTaskResumedEvent(TaskEvent event) {

    }

    @Override
    public void afterTaskSuspendedEvent(TaskEvent event) {

    }

    @Override
    public void afterTaskForwardedEvent(TaskEvent event) {

    }

    @Override
    public void afterTaskDelegatedEvent(TaskEvent event) {

    }

    @Override
    public void beforeTaskActivatedEvent(TaskEvent event) {


    }

    @Override
    public void beforeTaskClaimedEvent(TaskEvent event) {


    }

    @Override
    public void beforeTaskSkippedEvent(TaskEvent event) {


    }

    @Override
    public void beforeTaskStartedEvent(TaskEvent event) {


    }

    @Override
    public void beforeTaskStoppedEvent(TaskEvent event) {


    }

    @Override
    public void beforeTaskCompletedEvent(TaskEvent event) {


    }

    @Override
    public void beforeTaskFailedEvent(TaskEvent event) {


    }

    @Override
    public void beforeTaskAddedEvent(TaskEvent event) {


    }

    @Override
    public void beforeTaskExitedEvent(TaskEvent event) {


    }

    @Override
    public void beforeTaskReleasedEvent(TaskEvent event) {


    }

    @Override
    public void beforeTaskResumedEvent(TaskEvent event) {


    }

    @Override
    public void beforeTaskSuspendedEvent(TaskEvent event) {


    }

    @Override
    public void beforeTaskForwardedEvent(TaskEvent event) {


    }

    @Override
    public void beforeTaskDelegatedEvent(TaskEvent event) {


    }

    @Override
    public void afterTaskActivatedEvent(TaskEvent event) {


    }

    @Override
    public void afterTaskClaimedEvent(TaskEvent event) {


    }

    @Override
    public void afterTaskStartedEvent(TaskEvent event) {


    }

    @Override
    public void afterTaskStoppedEvent(TaskEvent event) {


    }

    @Override
    public void beforeTaskNominatedEvent(TaskEvent event) {

    }

    @Override
    public void afterTaskNominatedEvent(TaskEvent event) {

    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if ((obj instanceof ExternalTaskEventListener))
            return true;

        return false;
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + this.getClass().getName().hashCode();

        return result;
    }
}
