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package ee.tlu.htk.dippler.course;

import ee.tlu.htk.dippler.backoffice.StatusCodes;
import ee.tlu.htk.dippler.entities.Answer;
import ee.tlu.htk.dippler.entities.Assignment;
import ee.tlu.htk.dippler.entities.Course;
import ee.tlu.htk.dippler.entities.Coursegroup;
import ee.tlu.htk.dippler.entities.Learner;
import ee.tlu.htk.dippler.entities.LearningOutcome;
import ee.tlu.htk.dippler.entities.Organization;
import ee.tlu.htk.dippler.entities.Tag;
import ee.tlu.htk.dippler.entities.TagRelationship;
import ee.tlu.htk.dippler.entities.User;
import ee.tlu.htk.dippler.managers.TagManagerLocal;
import ee.tlu.htk.dippler.managers.UserManagerLocal;
import ee.tlu.htk.dippler.utils.Manipulators;
import ee.tlu.htk.dippler.utils.permissionChecker;
import java.io.StringReader;
import java.util.Collection;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Set;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.ejb.EJB;
import javax.ejb.Stateless;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import javax.persistence.Query;
import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Unmarshaller;

/**
 *
 * @author metz
 */

enum AssignmentActions {
    DELETE, EDIT, LOAD, LOAD_ANSWERS
}

@Stateless
public class AssignmentManager implements AssignmentManagerLocal {
    @PersistenceContext private EntityManager em;
    @EJB private UserManagerLocal userManager;
    @EJB private GroupManagerLocal groupManager;
    @EJB private TagManagerLocal tagManager;
    @EJB private OutcomeManagerLocal outcomeManager;
    @EJB private ActivityManagerLocal activityManager;

    public static final Integer LOAD = 1;
    public static final Integer DELETE = 50;
    public static final Integer EDIT = 50;
    public static final Integer LOAD_ANSWERS = 50;
    
    private Unmarshaller unmarshaller = null;
    
    public AssignmentManager() {
        try {
            final JAXBContext context = JAXBContext.newInstance(Assignment.class);
            unmarshaller = context.createUnmarshaller();
        } catch (JAXBException ex) {
            Logger.getLogger(AssignmentManager.class.getName()).log(Level.SEVERE, null, ex);
        }
    }

    @Override
    public String manageAssignment(String action, String data, User user, Organization org) {
        Assignment assignment = unMarshal(data);
        if ( assignment != null ) {
            switch (AssignmentActions.valueOf(action)) {
                case EDIT:
                    if (userManager.hasPermission(user, EDIT)) {
                        return this.editAssignment(assignment, user, org);
                    } else {
                        return StatusCodes.respond(StatusCodes.OPERATION_NOT_ALLOWED, "No rights for edit assignemnt");
                    }
                case DELETE:
                    if (userManager.hasPermission(user, DELETE)) {
                        return this.deleteAssignment(assignment, user);
                    } else {
                        return StatusCodes.respond(StatusCodes.OPERATION_NOT_ALLOWED, "No rights for delete assignemnt");
                    }
                case LOAD:
                    if (userManager.hasPermission(user, LOAD)) {
                        return this.loadAssignment(assignment, user);
                    } else {
                        return StatusCodes.respond(StatusCodes.OPERATION_NOT_ALLOWED, "No rights for load assignemnt");
                    }
                case LOAD_ANSWERS:
                    if (userManager.hasPermission(user, LOAD_ANSWERS)) {
                        // madis - fixed spelling of assignment in method loadAssignmentWithAnswers()
                        return StatusCodes.respondWithData(StatusCodes.SUCCESS, "", loadAssignmentWithAnswers(assignment));
                    } else {
                        return StatusCodes.respond(StatusCodes.OPERATION_NOT_ALLOWED, "No rights for load assignemnt");
                    }
                default:
                    return StatusCodes.respond(StatusCodes.OPERATION_NOT_ALLOWED, "");
            }
        }
        return StatusCodes.respond(StatusCodes.OPERATION_NOT_ALLOWED, "");
    }

    public String loadAssignment(Assignment a, User u) {
        try {
            Assignment assignment = findById(a.getId());
            // XXX Thest this one, make it work - REALLY
            // XXX CHECK IF I WORK
            /*if (!permissionChecker.isFacilitator(u, assignment.getCourse()) ||
                   (!(permissionChecker.isLearner(u, assignment.getCourse()) && assignment.getStart() >= (System.currentTimeMillis() / 1000L)))
               ) {
                return StatusCodes.respond(StatusCodes.COURSE_ERROR, "Not loaded");
            }*/
            
            if (u.inClientSession() && assignment.getCreator().equals(u)) {
                return StatusCodes.respondWithData(StatusCodes.SUCCESS, "", marshal(assignment));
            }
            return StatusCodes.respondWithData(StatusCodes.SUCCESS, "", marshal(assignment, u));
        } catch (Throwable t) {
            t.printStackTrace(System.out);
        }
        return StatusCodes.respond(StatusCodes.COURSE_ERROR, "Not loaded");
    }

    public String editAssignment(Assignment a, User user, Organization org) {
       Assignment assignment = findById(a.getId());
       if ( assignment != null ) {
            if (!permissionChecker.isFacilitator(user, assignment.getCourse())) {
                return StatusCodes.respond(StatusCodes.OPERATION_NOT_ALLOWED, "Not owner, admin or facilitator");
            }
            assignment.setTitle(a.getTitle());
            assignment.setDescription(a.getDescription());
            assignment.setStructure(a.getStructure());
            assignment.setStart(a.getStart());
            assignment.setEnd(a.getEnd());
            assignment.setTargetGroup(editTargetGroup(a));
            assignment.setMaxpoints(a.getMaxpoints());
            assignment.setLate_submission(a.isLate_submission());
            assignment.setSubmission_visibility(a.isSubmission_visibility());
            assignment.setLearning_outcomes(editOutcomes(a));
            
            tagManager.manageTags(a.tags, assignment, org);
            activityManager.addActivity("EDIT", assignment.getCourse(), user, assignment.getId(), assignment.getTitle(), "Assignment");
            return StatusCodes.respondWithData(StatusCodes.SUCCESS, "", marshal(assignment));
        }
        return StatusCodes.respond(StatusCodes.COURSE_ERROR, "Edit failed");
    }

    public String deleteAssignment(Assignment a, User user) {
        Assignment assignment = findById(a.getId());
        if ( assignment != null ) {
            if (!permissionChecker.isFacilitator(user, assignment.getCourse())) {
                return StatusCodes.respond(StatusCodes.OPERATION_NOT_ALLOWED, "Not owner, admin or facilitator");
            }
            activityManager.addActivity("DELETE", assignment.getCourse(), user, assignment.getId(), assignment.getTitle(), "Assignment");
            em.remove(assignment);
            return StatusCodes.respond(StatusCodes.SUCCESS, "");
        }
        return StatusCodes.respond(StatusCodes.COURSE_ERROR, "Delete failed");
    }

    @Override
    public Collection<Coursegroup> editTargetGroup(Assignment a) {
        Collection<Coursegroup> target_group = new LinkedList<Coursegroup>();
        Collection<Long> ids = a.groupIds;
        for(Long id : ids ) {
            target_group.add(groupManager.findById(id));
        }
        return target_group;
    }

    public Set<LearningOutcome> editOutcomes(Assignment a) {
        Set<LearningOutcome> los = (Set<LearningOutcome>) new HashSet();
        Set<Long> ids = a.outcomes;
        for(Long id : ids ) {
            los.add(outcomeManager.findById(id));
        }
        return los;
    }

    public static String getGroupIds(Assignment a) {
        StringBuilder xml = new StringBuilder();
        Collection<Coursegroup> targets = a.getTargetGroup();
        for(Coursegroup target : targets ){
            xml.append("<group-id>").append(target.getId()).append("</group-id>");
        }
        return xml.toString();
    }

    public String getUserAnswerIds(Assignment a, User u) {
        StringBuilder xml = new StringBuilder();
        Query listing = em.createNativeQuery("SELECT * FROM Answer a WHERE a.assignment=?1 AND a.creator=?2", Answer.class);
        listing.setParameter(1, a.getId());
        listing.setParameter(2, u.getId());
        List<Answer> answers = (List<Answer>) listing.getResultList();
        for(Answer answer : answers) {
            xml.append("<answer-id>").append(answer.getId().toString()).append("</answer-id>");
        }
        return xml.toString();
    }


    public static String getAnswerIds(Assignment a) {
        StringBuilder xml = new StringBuilder();
        Collection<Answer> answers = a.getAnswers();
        System.out.println("assignment: "+a.getId().toString());
        for(Answer answer : answers) {
            xml.append("<answer-id>").append(answer.getId().toString()).append("</answer-id>");

            System.out.println("answer. "+answer.getId().toString());
        }
        
        return xml.toString();
    }

    @Override
    public String loadLatestInfo(Course course) {
        StringBuilder xml = new StringBuilder("<assignments>");
        try {
            List<Assignment> assignments = course.getAssignments(0, 3);
            Integer learner_nr = course.getLearners().size();
            for(Assignment assignment : assignments ){
                Integer answer_nr = assignment.getAnswers().size();
                xml.append("<assignment>");
                xml.append("<id>").append(assignment.getId().toString()).append("</id>");
                xml.append("<title><![CDATA[").append(assignment.getTitle()).append("]]></title>");
                xml.append("<description><![CDATA[").append(Manipulators.textSubString(assignment.getDescription(), 0, 350)).append("]]></description>");
                xml.append("<responses><answers>").append(answer_nr).append("</answers><learners>").append(learner_nr).append("</learners></responses>");
                xml.append("</assignment>");
            }
        } catch (Throwable t) {
            t.printStackTrace(System.out);
        }
        xml.append("</assignments>");
        return xml.toString();
    }
    
    // madis - fixed assignment spelling in method name
    public String loadAssignmentWithAnswers(Assignment a) {
        Assignment assignment = findById(a.getId());
        Course course = assignment.getCourse();
        List<Learner> learners = (List<Learner>) course.getLearners();
        return answerXML(course, assignment, learners);
    }
    
    @Override
    public String answerXML(Course course, Assignment assignment, List<Learner> learners) {
        StringBuilder xml = new StringBuilder("<assignment>");
        xml.append("<id>").append(assignment.getId()).append("</id>");
        xml.append("<title><![CDATA[").append(assignment.getTitle()).append("]]></title>");
        xml.append("<description><![CDATA[").append(assignment.getDescription()).append("]]></description>");
        xml.append("<learners>");
        for(Learner learner : learners ){
            User u = learner.getUser();
            xml.append("<learner>");
            xml.append("<id>").append(u.getId().toString()).append("</id>");
            xml.append("<fullname><![CDATA[").append(u.getFullname()).append("]]></fullname>");
            try {
                Query listing = em.createNativeQuery("SELECT * FROM Answer a WHERE a.assignment=?1 AND a.creator=?2", Answer.class);
                listing.setParameter(1, assignment.getId().toString());
                listing.setParameter(2, u.getId().toString());
                Answer answer = (Answer) listing.getSingleResult();
                xml.append("<answer>");
                xml.append("<id>").append(answer.getId().toString()).append("</id>");
                xml.append("<title><![CDATA[").append(answer.getTitle()).append("]]></title>");
                xml.append("<url><![CDATA[").append(answer.getUrl()).append("]]></url>");
                xml.append("<content><![CDATA[").append(answer.getContent()).append("]]></content>");
                xml.append("<created>").append(answer.getCreated()).append("</created>");
                xml.append("<modified>").append(answer.getModified()).append("</modified>");
                xml.append("<graded>").append(answer.getGraded()).append("</graded>");
                xml.append("<creator>").append(answer.getCreator().getId()).append("</creator>");
                xml.append("<assignment>").append(answer.getAssignment().getId().toString()).append("</assignment>");
                xml.append("<grade><![CDATA[").append(answer.getGrade()).append("]]></grade>");
                xml.append("<feedback><![CDATA[").append(answer.getFeedback()).append("]]></feedback>");
                xml.append("</answer>");
            } catch (Throwable t) {
                if (!(t instanceof javax.persistence.NoResultException)) {
                    t.printStackTrace(System.err);
                }
            }
            xml.append("</learner>");
        }
        xml.append("</learners></assignment>");
        return xml.toString();
    }

    public final String getTagsXML(Assignment assignment) {
        try {
            Query trListing = em.createNamedQuery("TagRelationship.findByParent");
            trListing.setParameter("parentId", assignment.getId());
            trListing.setParameter("parentType", "Assignment");
            List<TagRelationship> tagrelationships = (List<TagRelationship>) trListing.getResultList();
            StringBuilder xml = new StringBuilder();
            if (!tagrelationships.isEmpty()) {
                for (TagRelationship tr : tagrelationships) {
                    Tag tag = tr.getTag();
                    xml.append("<tag>");
                    xml.append("<id>").append(tag.getId()).append("</id>");
                    xml.append("<name><![CDATA[").append(tag.getName()).append("]]></name>");
                    xml.append("<slug><![CDATA[").append(tag.getSlug()).append("]]></slug>");
                    xml.append("<count>").append(tag.getCount()).append("</count>");
                    xml.append("</tag>");
                }
                return xml.toString();
            }
        } catch (Exception e){ }
        return "";
    }

    public final String getLearningOutcomesXML(Assignment assignment) {
        try {
            Query trListing = em.createNamedQuery("TagRelationship.findByParent");
            trListing.setParameter("parentId", assignment.getId());
            trListing.setParameter("parentType", "Assignment");
            List<TagRelationship> tagrelationships = (List<TagRelationship>) trListing.getResultList();
            StringBuilder xml = new StringBuilder();
            if (!tagrelationships.isEmpty()) {
                for (LearningOutcome lo : assignment.getLearning_outcomes()) {
                    try {
                        xml.append(outcomeManager.marshal(lo));
                    } catch (Throwable ex) {
                        Logger.getLogger(AssignmentManager.class.getName()).log(Level.SEVERE, null, ex);
                    }
                }
                return xml.toString();
            }
        } catch (Exception e){ }
        return "";
    }

    @Override
    public Assignment unMarshal(String data) {
        if ( unmarshaller != null ) {
            try {
                final Assignment assignmentUNM = (Assignment) unmarshaller.unmarshal(new StringReader(data));
                return assignmentUNM;
            } catch(JAXBException e) {
                //Something went wrong
            }
        }
        return null;
    }

    @Override
    public String marshal(Assignment assignment) {
        StringBuilder xml = new StringBuilder();
        xml.append("<assignment>");
        xml.append("<id>").append(assignment.getId()).append("</id>");
        xml.append("<title><![CDATA[").append(assignment.getTitle()).append("]]></title>");
        xml.append("<subtype><![CDATA[").append(assignment.getSubtype()).append("]]></subtype>");
        xml.append("<description><![CDATA[").append(assignment.getDescription()).append("]]></description>");
        xml.append("<structure><![CDATA[").append(assignment.getStructure()).append("]]></structure>");
        xml.append("<maxpoints>").append(assignment.getMaxpoints()).append("</maxpoints>");
        xml.append("<start>").append(assignment.getStart()).append("</start>");
        xml.append("<deadline>").append(assignment.getEnd()).append("</deadline>");
        xml.append("<late_submission>").append(assignment.isLate_submission()).append("</late_submission>");
        xml.append("<submission_visibility>").append(assignment.isSubmission_visibility()).append("</submission_visibility>");
        xml.append("<created>").append(assignment.getCreated()).append("</created>");
        xml.append("<creator>").append(assignment.getCreator().getId()).append("</creator>");
        xml.append("<course>").append(assignment.getCourse().getId().toString()).append("</course>");
        xml.append("<answers>").append(getAnswerIds(assignment)).append("</answers>");
        xml.append("<target-group>").append(getGroupIds(assignment)).append("</target-group>");
        xml.append("<tags>").append(getTagsXML(assignment)).append("</tags>");
        xml.append("<learningoutcomes>").append(getLearningOutcomesXML(assignment)).append("</learningoutcomes>");
        xml.append("</assignment>");
        return xml.toString();
    }

    @Override
    public String marshal(Assignment assignment, User user) {
        StringBuilder xml = new StringBuilder();
        xml.append("<assignment>");
        xml.append("<id>").append(assignment.getId()).append("</id>");
        xml.append("<title><![CDATA[").append(assignment.getTitle()).append("]]></title>");
        xml.append("<subtype><![CDATA[").append(assignment.getSubtype()).append("]]></subtype>");
        xml.append("<description><![CDATA[").append(assignment.getDescription()).append("]]></description>");
        xml.append("<structure><![CDATA[").append(assignment.getStructure()).append("]]></structure>");
        xml.append("<maxpoints>").append(assignment.getMaxpoints()).append("</maxpoints>");
        xml.append("<start>").append(assignment.getStart()).append("</start>");
        xml.append("<deadline>").append(assignment.getEnd()).append("</deadline>");
        xml.append("<late_submission>").append(assignment.isLate_submission()).append("</late_submission>");
        xml.append("<submission_visibility>").append(assignment.isSubmission_visibility()).append("</submission_visibility>");
        xml.append("<created>").append(assignment.getCreated()).append("</created>");
        xml.append("<creator>").append(assignment.getCreator().getId()).append("</creator>");
        xml.append("<course>").append(assignment.getCourse().getId().toString()).append("</course>");
        xml.append("<answers>").append(getUserAnswerIds(assignment, user)).append("</answers>");
        xml.append("<target-group>").append(getGroupIds(assignment)).append("</target-group>");
        xml.append("<tags>").append(getTagsXML(assignment)).append("</tags>");
        xml.append("<learningoutcomes>").append(getLearningOutcomesXML(assignment)).append("</learningoutcomes>");
        xml.append("</assignment>");
        return xml.toString();
    }

    @Override
    public Assignment findById(Long id) {
        if ( id > 0 ) {
            return em.find(Assignment.class, id);
        }
        return null;
    }
}