/**
 * Copyright 2005-2016 The Kuali Foundation
 *
 * Licensed under the Educational Community 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.opensource.org/licenses/ecl2.php
 *
 * 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.kuali.rice.kew.impl.peopleflow;

import org.apache.commons.lang.StringUtils;
import org.kuali.rice.core.api.config.ConfigurationException;
import org.kuali.rice.core.api.exception.RiceRuntimeException;
import org.kuali.rice.core.api.util.xml.XmlJotter;
import org.kuali.rice.kew.actionrequest.ActionRequestValue;
import org.kuali.rice.kew.api.action.ActionRequestType;
import org.kuali.rice.kew.api.peopleflow.PeopleFlowDefinition;
import org.kuali.rice.kew.api.peopleflow.PeopleFlowService;
import org.kuali.rice.kew.engine.RouteContext;
import org.kuali.rice.kew.engine.node.NodeState;
import org.kuali.rice.kew.engine.node.RouteNodeUtils;
import org.kuali.rice.kew.api.exception.WorkflowException;
import org.kuali.rice.kew.routemodule.RouteModule;
import org.kuali.rice.kew.service.KEWServiceLocator;
import org.kuali.rice.kew.util.ResponsibleParty;
import org.w3c.dom.Element;

import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.annotation.XmlAttribute;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlElements;
import javax.xml.bind.annotation.XmlRootElement;
import javax.xml.bind.annotation.XmlValue;
import java.util.ArrayList;
import java.util.List;

public class PeopleFlowRouteModule implements RouteModule {

    private static final String PEOPLE_FLOW_PROPERTY = "peopleFlow";

    private static final String PEOPLE_FLOW_ITERATION_KEY = "peopleFlowIteration";
    public static final String PEOPLE_FLOW_SEQUENCE = "peopleFlowSequence";

    private static final JAXBContext jaxbContext;
    static {
        try {
            jaxbContext = JAXBContext.newInstance(PeopleFlowConfig.class);
        } catch (JAXBException e) {
            throw new RiceRuntimeException("Failed to initialize JAXB!", e);
        }
    }

    private PeopleFlowService peopleFlowService;
    private PeopleFlowRequestGenerator peopleFlowRequestGenerator;

    @Override
    public List<ActionRequestValue> findActionRequests(RouteContext context) throws Exception {
        int iteration = incrementIteration(context);
        List<PeopleFlowConfig> configurations = parsePeopleFlowConfiguration(context);
        List<ActionRequestValue> actionRequests = new ArrayList<ActionRequestValue>();
        int index = 0;
        for (PeopleFlowConfig configuration : configurations) {
            if (index++ == iteration) {
                PeopleFlowDefinition peopleFlow = loadPeopleFlow(configuration);
                actionRequests.addAll(getPeopleFlowRequestGenerator().generateRequests(context, peopleFlow, configuration.actionRequested));
                break;
            }
        }
        return actionRequests;
    }

    @Override
    public boolean isMoreRequestsAvailable(RouteContext context) {
        Integer currentIteration = getCurrentIteration(context);
        if (currentIteration == null) {
            return false;
        }
        List<PeopleFlowConfig> configurations = parsePeopleFlowConfiguration(context);
        return currentIteration.intValue() < configurations.size();
    }

    @Override
    public ResponsibleParty resolveResponsibilityId(String responsibilityId) throws WorkflowException {
        return null;
    }

    protected List<PeopleFlowConfig> parsePeopleFlowConfiguration(RouteContext context) {
        List<PeopleFlowConfig> configs = new ArrayList<PeopleFlowConfig>();
        NodeState peopleFlowSequenceNodeState = context.getNodeInstance().getNodeState(PEOPLE_FLOW_SEQUENCE);
        if (peopleFlowSequenceNodeState != null) {
            String peopleFlowSequence = peopleFlowSequenceNodeState.getValue();
            if (StringUtils.isNotBlank(peopleFlowSequence)) {
                String[] peopleFlowValues = peopleFlowSequence.split(",");
                for (String peopleFlowValue : peopleFlowValues) {
                    String[] peopleFlowProperties = peopleFlowValue.split(":");
                    PeopleFlowConfig config = new PeopleFlowConfig();
                    config.actionRequested = ActionRequestType.fromCode(peopleFlowProperties[0]);
                    config.peopleFlowIdentifier = peopleFlowProperties[1];
                    configs.add(config);
                }
            }
        } else {
            List<Element> peopleFlowElements = RouteNodeUtils.getCustomRouteNodeElements(
                    context.getNodeInstance().getRouteNode(), PEOPLE_FLOW_PROPERTY);

            for (Element peopleFlowElement : peopleFlowElements) {
                try {
                    PeopleFlowConfig config = (PeopleFlowConfig)jaxbContext.createUnmarshaller().unmarshal(peopleFlowElement);
                    if (config.actionRequested == null) {
                        // default action request type to approve
                        config.actionRequested = ActionRequestType.APPROVE;
                    }
                    if (config == null) {
                        throw new IllegalStateException("People flow configuration element did not properly unmarshall from XML: " + XmlJotter.jotNode(peopleFlowElement));
                    }
                    configs.add(config);
                } catch (JAXBException e) {
                    throw new RiceRuntimeException("Failed to unmarshall people flow configuration from route node.", e);
                }
            }
        }
        return configs;
    }

    protected PeopleFlowDefinition loadPeopleFlow(PeopleFlowConfig configuration) {
        if (configuration.isId()) {
            PeopleFlowDefinition peopleFlow = getPeopleFlowService().getPeopleFlow(configuration.getId());
            if (peopleFlow == null) {
                throw new ConfigurationException("Failed to locate a people flow with the given id of '" + configuration.getId() + "'");
            }
            return peopleFlow;
        } else {
            String namespaceCode = configuration.getName().namespaceCode;
            String name = configuration.getName().name;
            PeopleFlowDefinition peopleFlow = getPeopleFlowService().getPeopleFlowByName(namespaceCode, name);
            if (peopleFlow == null) {
                throw new ConfigurationException("Failed to locate a people flow with the given namespaceCode of '" + namespaceCode + "' and name of '" + name + "'");
            }
            return peopleFlow;
        }
    }

    protected int incrementIteration(RouteContext context) {
        int nextIteration = 0;
        NodeState nodeState = context.getNodeInstance().getNodeState(PEOPLE_FLOW_ITERATION_KEY);
        if (nodeState == null) {
            nodeState = new NodeState();
            nodeState.setNodeInstance(context.getNodeInstance());
            nodeState.setKey(PEOPLE_FLOW_ITERATION_KEY);
            context.getNodeInstance().addNodeState(nodeState);
        } else {
            int currentIteration = Integer.parseInt(nodeState.getValue());
            nextIteration = currentIteration + 1;
        }
        nodeState.setValue(Integer.toString(nextIteration));
        if (!context.isSimulation()) {
            KEWServiceLocator.getRouteNodeService().save(nodeState);
        }
        return nextIteration;
    }

    protected Integer getCurrentIteration(RouteContext context) {
        NodeState nodeState = context.getNodeInstance().getNodeState(PEOPLE_FLOW_ITERATION_KEY);
        if (nodeState == null) {
            return null;
        }
        return Integer.valueOf(nodeState.getValue());
    }

    public PeopleFlowService getPeopleFlowService() {
        return peopleFlowService;
    }

    public void setPeopleFlowService(PeopleFlowService peopleFlowService) {
        this.peopleFlowService = peopleFlowService;
    }

    public PeopleFlowRequestGenerator getPeopleFlowRequestGenerator() {
        return peopleFlowRequestGenerator;
    }

    public void setPeopleFlowRequestGenerator(PeopleFlowRequestGenerator peopleFlowRequestGenerator) {
        this.peopleFlowRequestGenerator = peopleFlowRequestGenerator;
    }

    @XmlRootElement(name = "peopleFlow")
    private static class PeopleFlowConfig {

        @XmlElement(name = "actionRequested")
        ActionRequestType actionRequested;

        @XmlElements(value = {
            @XmlElement(name = "name", type = NameConfig.class),
            @XmlElement(name = "id", type = String.class)
        })
        Object peopleFlowIdentifier;

        boolean isId() {
            return peopleFlowIdentifier instanceof String;
        }
        boolean isName() {
            return peopleFlowIdentifier instanceof NameConfig;
        }

        NameConfig getName() {
            return (NameConfig)peopleFlowIdentifier;
        }

        String getId() {
            return (String)peopleFlowIdentifier;
        }
        
    }

    private static class NameConfig {

        @XmlAttribute(name = "namespace")
        String namespaceCode;

        @XmlValue
        String name;

    }

}
