EDIT

/**

* Copyright (C) 2007 EDIT

* European Distributed Institute of Taxonomy

* http://www.e-taxonomy.eu

*

* The contents of this file are subject to the Mozilla Public License Version 1.1

* See LICENSE.TXT at the top of this package for the full license terms.

*/

package eu.etaxonomy.cdm.model.metadata;

import java.io.Serializable;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.List;

import java.util.UUID;

import java.util.stream.Collectors;

import javax.persistence.Column;

import javax.persistence.Embeddable;

import javax.persistence.EmbeddedId;

import javax.persistence.Entity;

import javax.persistence.Lob;

import org.apache.commons.lang3.StringUtils;

import eu.etaxonomy.cdm.common.CdmUtils;

/**

 * This class holds all preference data for a CDM database.

 * E.g. one may store what the default nomenclatural code in a database is,

 * or which formatter (cache strategy) to use in a certain context.

 * <BR><BR>

 * The structure represents a triple where the first item

 * (subject) defines in which context or for which object the given

 * information is valid. The second item (predicate) describes the

 * type of information and the third item (value) represents the actual value.

 * <BR><BR>

 * E.g. given the usecase of formatting terms in a UI.

 * The predicate maybe something like "preferredTermFormatting".

 * While the subject may define the context, e.g. "/" for the project

 * wide default formatting while "/vaadin" may define the formatting

 * used in a vaadin context and "/taxeditor" may define the formatting

 * in TaxEditor context. Even more specific "/taxeditor/detailsview/dropdown"

 * may define the correct formatting in dropdown elements in the detailsview

 * while "/taxeditor/termeditor" may define the correct formatting in the taxeditors

 * term editor.

 * <BR><BR>

 * Another more data centric example from checklists is the preference which distribution status terms

 * should be available for which area. The predicate used here is

 * {@link PreferencePredicate#AvailableDistributionStatus} for both preferences. The preference

 * which defines the default list of distribution status terms uses "/" as subject and

 * a list of UUIDs as value.

 * <BR><BR>

 * The preference defining the specific distribution status terms only available for the

 * top level area, e.g. "Euro+Med" uses the subject "/NamedArea[111bdf38-7a32-440a-9808-8af1c9e54b51]/"

 * (with 111bd... being the UUID of the top level area) and another UUID list as value.

 * <BR><BR>

 * Subjects by convention should be defined hierarchical following a slash syntax like

 * "/level1/level2/level3". For how to resolve a subject see also

 * {@link PreferenceResolver#resolve(List, PrefKey)}.<BR>

 * Generally the subject is String based but clients may implement classes or enumerations

 * to ease the hierarchical handling of subjects. With {@link PreferenceSubject} there is already

 * a very basic implementation to allow to distinguish project wide, vaadin and taxeditor subjects.

 * This may be further developed in future.

 * <BR><BR>

 * If doubt exists on best practice for how to use subjects please contact the author.

 * <BR>

 * <BR>

 *  The set of allowed values and semantics for each combination

 *  will be defined by convention  over time and by implementing classes.

 *  The only real restrictions we have is the length of the fields and

 *  the fact that the first two items (subject, predicate) must be unique

 *  key in the given database.

 *

 *  Size of single fields may be enlarged in future versions.

 *

 * @author a.mueller

 * @since 03.07.2013

 */

@Entity

public final class CdmPreference implements Serializable {

    private static final String STRING_LIST_SEPARATOR = "[,;\\s]";

    private static final int VALUE_LENGTH = 65536; //= CdmBase.CLOB_LENGTH;

    private static final long serialVersionUID = 4307599154287181582L;

    public static final CdmPreference NewInstance(PreferenceSubject subject,

            IPreferencePredicate<?> predicate, String value){

        return new CdmPreference(subject, predicate, value);

    }

    public static final CdmPreference NewInstance(PrefKey key, String value){

        return new CdmPreference(key.subject, key.predicate, value);

    }

    public static final CdmPreference NewInstance(PreferenceSubject subject, IPreferencePredicate<?> predicate, List<UUID> value){

        return new CdmPreference(subject, predicate, uuidListStr(value));

    }

    public static final CdmPreference NewInstance(PreferenceSubject subject, IPreferencePredicate<?> predicate, UUID ... value){

        return new CdmPreference(subject, predicate, uuidListStr(Arrays.asList(value)));

    }

    public static final CdmPreference NewInstance(PreferenceSubject subject, IPreferencePredicate<?> predicate, UUID value){

        return new CdmPreference(subject, predicate, value.toString());

    }

    public static CdmPreference NewDatabaseInstance(IPreferencePredicate<?> predicate, String value) {

        return new CdmPreference(PreferenceSubject.NewDatabaseInstance(), predicate, value);

    }

    public static CdmPreference NewVaadinInstance(IPreferencePredicate<?> predicate, String value) {

        return new CdmPreference(PreferenceSubject.NewVaadinInstance(), predicate, value);

    }

    public static CdmPreference NewTaxEditorInstance(IPreferencePredicate<?> predicate, String value) {

        return new CdmPreference(PreferenceSubject.NewTaxEditorInstance(), predicate, value);

    }

    public static PrefKey NewKey(PreferenceSubject subject, IPreferencePredicate<?> predicate){

      return new PrefKey(subject, predicate);

    }

//	public static final CdmPreference NewInstance(PreferenceSubjectEnum subject, PreferencePredicate predicate, String value){

//		return new CdmPreference(subject, predicate, value);

//	}

//

//	public static PrefKey NewKey(PreferenceSubjectEnum subject, PreferencePredicate predicate){

//		return new PrefKey(subject, predicate);

//	}

	@EmbeddedId

	private PrefKey key;

	@Column(length=VALUE_LENGTH)

	@Lob

	private String value;

    //if false, the preference should not be overridden by local preferences,

	//if true existing local preferences override database preferences

	    //and the database preference only defines the default.

    private boolean allowOverride = true;

    @Embeddable

    public static class PrefKey implements Serializable{

        private static final long serialVersionUID = 9019957853773606194L;

        //required syntax:  /([A-Za-z]+\[.*\])?

        //examples /  ,  /TaxonNode[#t10#44#1456#]  for a taxon node preference

        @Column(name="key_subject", length=100) //for now we keep the combined key short as indizes for such keys are very limited in size in some DBMS. Size may be increased later

        private String subject;

        @Column(name="key_predicate", length=100) //for now we keep the combined key short as indizes for such keys are very limited in size in some DBMS. Size may be increased later

        private String predicate;

        //for hibernate use only

        private PrefKey(){}

        private PrefKey(PreferenceSubject subject, IPreferencePredicate<?> predicate){

            this(subject.toString(), predicate.getKey());

        }

//      private PrefKey(PreferenceSubjectEnum subject, PreferencePredicate predicate){

//          this(subject.getKey(), predicate.getKey());

//      }

        private PrefKey(String subject, String predicate){

            if (subject == null) {

                throw new IllegalArgumentException("Subject must not be null for preference");

            }

            if (predicate == null) {

                throw new IllegalArgumentException("Predicate must not be null for preference");

            }

            if (subject.length() > 255) {

                throw new IllegalArgumentException("Subject must not be longer then 255 for preference");

            }

            if (predicate.length() > 255) {

                throw new IllegalArgumentException("Predicate must not be longer then 255 for preference");

            }

            if (!(subject.matches(PreferenceSubject.ROOT + "(([A-Za-z]+(\\[.*\\])?|"+PreferenceSubject.VAADIN+")"+PreferenceSubject.SEP+")*")

                    || subject.matches(PreferenceSubject.ROOT + "(([A-Za-z]+(\\[.*\\])?|"+PreferenceSubject.TAX_EDITOR+")"+PreferenceSubject.SEP+")*")

                    )){

                throw new IllegalArgumentException("Subject does not follow the required syntax");

            }

            this.subject = subject;

            this.predicate = predicate;

        }

        @Override

        public int hashCode() {

            final int prime = 31;

            int result = 1;

            result = prime * result + ((predicate == null) ? 0 : predicate.hashCode());

            result = prime * result + ((subject == null) ? 0 : subject.hashCode());

            return result;

        }

        @Override

        public boolean equals(Object obj) {

            if (this == obj){

                return true;

            } else if (obj == null){

                return false;

            }else if (getClass() != obj.getClass()){

                return false;

            }else{

                PrefKey other = (PrefKey) obj;

                return ( predicate.equals(other.predicate) && subject.equals(other.subject));

            }

        }

        public String getSubject() {

            return subject;

        }

        public String getPredicate() {

            return predicate;

        }

        @Override

        public String toString() {

            return "PrefKey[" +subject + ": " + predicate +"]";

        }

    }

//****************** CONSTRUCTOR **********************/

	//for hibernate use only

	@SuppressWarnings("unused")

	private CdmPreference(){}

	private CdmPreference(PreferenceSubject subject, IPreferencePredicate<?> predicate, String value){

		this.key = new PrefKey(subject, predicate);

		checkValue(value);

		this.value = value;

	}

	/**

	 * Constructor.

	 *

	 * @param subject must not be null and must not be longer then 255 characters.

	 * @param predicate must not be null and must not be longer then 255 characters.

	 * @param value must not be longer then 1023 characters.

	 */

	public CdmPreference(String subject, String predicate, String value){

		this.key = new PrefKey(subject, predicate);

		checkValue(value);

		this.value = value;

	}

    private void checkValue(String value) {

        //TODO are null values allowed?     assert predicate != null : "value must not be null for preference";

        if (value != null && value.length() > VALUE_LENGTH -1 ) {

		    throw new IllegalArgumentException(

		            String.format("Preference value must not be longer then "+VALUE_LENGTH+" characters for preference. Value = %s", value));

		}

    }

//************************ GETTER / SETTER ***************************/

	public boolean isDatabasePref(){

	    return PreferenceSubject.ROOT.equals(key.subject);

	}

	/**

	 * @return the subject of the preference as String.

	 */

	public String getSubjectString() {

		return key.subject;

	}

	/**

     * @return the subject of the preference

     */

    public PreferenceSubject getSubject() {

        return PreferenceSubject.fromKey(key);

    }

	/**

	 * @return the predicate of the preference

	 */

	public String getPredicate() {

		return key.predicate;

	}

	/**

	 * @return the value of the preference

	 */

	public String getValue() {

		return value;

	}

	/**

	 * Returns the {@link #getValue() value} as {@link UUID} List.

	 * Throws an exception if the value can not be parsed as UUID list.

	 * @return

	 * @throws IllegalArgumentException

	 */

	public List<UUID> getValueUuidList() throws IllegalArgumentException {

	    List<UUID> result = new ArrayList<>();

	    for (String split : splitStringListValue()){

            UUID uuid = UUID.fromString(split.trim());

            result.add(uuid);

	    }

	    return result;

    }

	/**

	 * Splits the <code>value</code> into tokens by the separators defined in {@link #STRING_LIST_SEPARATOR}

	 *

	 * @return

	 */

    public  List<String> splitStringListValue() {

        List<String> tokens;

        if (StringUtils.isNotBlank(value)){

	        tokens = Arrays.stream(getValue().split(STRING_LIST_SEPARATOR)).filter(t -> !StringUtils.isBlank(t)).collect(Collectors.toList());

	    } else {

	        tokens = new ArrayList<>();

	    }

        return tokens;

    }

    protected static String uuidListStr(List<UUID> value) {

        String valueStr = "";

        for (UUID uuid : value){

            valueStr = CdmUtils.concat(",",valueStr, uuid.toString());

        }

        return valueStr;

    }

//

//  we try to avoid setting of values

//  public void setValue(String value) {

//      this.value = value;

//  }

	public PrefKey getKey() {

		return key;

	}

    public boolean isAllowOverride() {

        return allowOverride;

    }

    public void setAllowOverride(boolean allowOverride) {

        this.allowOverride = allowOverride;

    }

}