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package ee.tlu.htk.dippler.managers;

import ee.tlu.htk.dippler.backoffice.StatusCodes;
import ee.tlu.htk.dippler.entities.Image;
import ee.tlu.htk.dippler.entities.User;
import java.io.StringReader;
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.NoResultException;
import javax.persistence.NonUniqueResultException;
import javax.persistence.PersistenceContext;
import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Unmarshaller;
import sun.misc.BASE64Encoder;


/**
 *
 * @author metz
 */
@Stateless
public class ImageManager implements ImageManagerLocal {
    
    @PersistenceContext
    private EntityManager em;
    @EJB
    private UserManagerLocal userManager;;
    public static final Integer LOAD = 1;
    public static final Integer UPLOAD = 95;
    
    private static Unmarshaller unmarshaller = null;
    private static BASE64Encoder base64Enc = null;

    enum CourseActions {
        LOAD, UPLOAD
    }
    
    public ImageManager() {
        try {
            final JAXBContext context = JAXBContext.newInstance(Image.class);
            unmarshaller = context.createUnmarshaller();
        } catch (JAXBException ex) {
            Logger.getLogger(ImageManager.class.getName()).log(Level.SEVERE, null, ex);
        }
        base64Enc = new BASE64Encoder();
    }

    @Override
    public String manageImage(String action, String data, User user) {
        switch (CourseActions.valueOf(action)) {
            case LOAD:
                if (userManager.hasPermission(user, LOAD)) {
                    return this.load(data);
                } else {
                    return StatusCodes.respond(StatusCodes.OPERATION_NOT_ALLOWED, "No rights for load image");
                }
            case UPLOAD:
                if (userManager.hasPermission(user, UPLOAD)) {
                    return this.upload(data, user);
                } else {
                    return StatusCodes.respond(StatusCodes.OPERATION_NOT_ALLOWED, "No rights for upload image");
                }
            default:
                return StatusCodes.respond(StatusCodes.OPERATION_NOT_ALLOWED, "");
        }
    }

    public String load(String data) {
        Image image = findByData(data);
        if ( image != null ) {
            return StatusCodes.respondWithData(StatusCodes.SUCCESS, "", marshal(image));
        }
        return StatusCodes.respond(StatusCodes.COURSE_ERROR, "Not loaded");
    }

    public String upload(String data, User user) {

        return StatusCodes.respond(StatusCodes.COURSE_ERROR, "Not upload");
    }

    public Image findById(Long id) throws NoResultException, NonUniqueResultException {
        if ( id > 0 ) {
            return em.find(Image.class, id);
        }
        return null;
    }
    
    public Image findByData(String data) {
        Image fakeImage = unMarshal(data);
        if ( fakeImage != null ) {
            return findById(fakeImage.getId());
        }
        return null;
    }

    private static String toBase64(byte[] bs) {
        return base64Enc.encode(bs);
    }

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

    public static String marshal(Image image) {
        StringBuilder xml = new StringBuilder("<image>");
        xml.append("<id>").append(image.getId()).append("</id>");
        xml.append("<name>").append(image.getName()).append("</name>");
        xml.append("<image><![CDATA[").append(toBase64(image.getImage())).append("]]></image>");
        xml.append("<filetype>").append(image.getFiletype()).append("</filetype>");
        xml.append("<filesize>").append(image.getFilesize()).append("</filesize>");
        xml.append("</image>");
        return xml.toString();
    }
 
}