/*
 * Copyright 2017 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.workflow.instance.node;

import org.drools.core.common.InternalAgenda;
import org.drools.core.definitions.rule.impl.RuleImpl;
import org.drools.core.spi.Activation;
import org.jbpm.workflow.core.node.MilestoneNode;
import org.kie.api.event.rule.AfterMatchFiredEvent;
import org.kie.api.event.rule.AgendaEventListener;
import org.kie.api.event.rule.AgendaGroupPoppedEvent;
import org.kie.api.event.rule.AgendaGroupPushedEvent;
import org.kie.api.event.rule.BeforeMatchFiredEvent;
import org.kie.api.event.rule.MatchCancelledEvent;
import org.kie.api.event.rule.MatchCreatedEvent;
import org.kie.api.event.rule.RuleFlowGroupActivatedEvent;
import org.kie.api.event.rule.RuleFlowGroupDeactivatedEvent;
import org.kie.api.runtime.process.NodeInstance;

/**
 * Runtime counterpart of a milestone node.
 */
public class MilestoneNodeInstance extends StateBasedNodeInstance implements AgendaEventListener {

    private static final long serialVersionUID = 510l;

    protected MilestoneNode getMilestoneNode() {
        return (MilestoneNode) getNode();
    }

    @Override
    public void internalTrigger(final NodeInstance from, String type) {
        super.internalTrigger(from, type);
        // if node instance was cancelled, abort
        if (getNodeInstanceContainer().getNodeInstance(getId()) == null) {
            return;
        }
        if (!org.jbpm.workflow.core.Node.CONNECTION_DEFAULT_TYPE.equals(type)) {
            throw new IllegalArgumentException(
                    "A MilestoneNode only accepts default incoming connections!");
        }
        String rule = "RuleFlow-Milestone-" + getProcessInstance().getProcessId()
                + "-" + getMilestoneNode().getUniqueId();
        boolean isActive = ((InternalAgenda) getProcessInstance().getKnowledgeRuntime().getAgenda())
                .isRuleActiveInRuleFlowGroup("DROOLS_SYSTEM", rule, getProcessInstance().getId());
        if (isActive) {
            triggerCompleted();
        } else {
            addActivationEventListener();
        }
    }

    @Override
    public void addEventListeners() {
        super.addEventListeners();
        addActivationEventListener();
    }

    private void addActivationEventListener() {
        getProcessInstance().getKnowledgeRuntime().addEventListener(this);
        getProcessInstance().addEventListener(getActivationEventType(), this, true);
    }

    @Override
    public void removeEventListeners() {
        super.removeEventListeners();
        getProcessInstance().getKnowledgeRuntime().removeEventListener(this);
        getProcessInstance().removeEventListener(getActivationEventType(), this, true);
    }

    private String getActivationEventType() {
        return "RuleFlow-Milestone-" + getProcessInstance().getProcessId()
                + "-" + getMilestoneNode().getUniqueId();
    }

    @Override
    public void signalEvent(String type, Object event) {
        if (getActivationEventType().equals(type)) {
            if (event instanceof MatchCreatedEvent) {
                matchCreated((MatchCreatedEvent) event);
            }
        } else {
            super.signalEvent(type, event);
        }
    }

    @Override
    public void matchCreated(MatchCreatedEvent event) {
        // check whether this activation is from the DROOLS_SYSTEM agenda group
        String ruleFlowGroup = ((RuleImpl) event.getMatch().getRule()).getRuleFlowGroup();
        if ("DROOLS_SYSTEM".equals(ruleFlowGroup)) {
            // new activations of the rule associate with a milestone node
            // trigger node instances of that milestone node
            String ruleName = event.getMatch().getRule().getName();
            String milestoneName = "RuleFlow-Milestone-" + getProcessInstance().getProcessId() + "-" + getMilestoneNode().getUniqueId();
            if (((Activation) event.getMatch()).isActive() &&  milestoneName.equals(ruleName) && checkProcessInstance((Activation) event.getMatch()) && checkDeclarationMatch(event.getMatch(), getMilestoneNode().getMatchVariable())) {

                synchronized (getProcessInstance()) {
                    removeEventListeners();
                    triggerCompleted();
                }
            }
        }
    }

    @Override
    public void matchCancelled(MatchCancelledEvent event) {
        // Do nothing
    }

    @Override
    public void afterMatchFired(AfterMatchFiredEvent event) {
        // Do nothing
    }

    @Override
    public void agendaGroupPopped(AgendaGroupPoppedEvent event) {
        // Do nothing
    }

    @Override
    public void agendaGroupPushed(AgendaGroupPushedEvent event) {
        // Do nothing
    }

    @Override
    public void beforeMatchFired(BeforeMatchFiredEvent event) {
        // Do nothing
    }

    @Override
    public void afterRuleFlowGroupActivated(RuleFlowGroupActivatedEvent event) {
    }

    @Override
    public void afterRuleFlowGroupDeactivated(RuleFlowGroupDeactivatedEvent event) {
    }

    @Override
    public void beforeRuleFlowGroupActivated(RuleFlowGroupActivatedEvent event) {
    }

    @Override
    public void beforeRuleFlowGroupDeactivated(RuleFlowGroupDeactivatedEvent event) {
    }
}
