/**
 * Licensed to Apereo under one or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information regarding copyright ownership. Apereo
 * licenses this file to you 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 the
 * following location:
 *
 * <p>http://www.apache.org/licenses/LICENSE-2.0
 *
 * <p>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.apereo.portal.portlet.dao.jpa;

import com.google.common.base.Function;
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import javax.persistence.Cacheable;
import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.OneToMany;
import javax.persistence.SequenceGenerator;
import javax.persistence.Table;
import javax.persistence.TableGenerator;
import javax.persistence.Transient;
import javax.persistence.Version;
import org.apache.commons.lang.builder.EqualsBuilder;
import org.apache.commons.lang.builder.HashCodeBuilder;
import org.apereo.portal.portlet.om.IPortletPreference;
import org.apereo.portal.utils.FilteringOnAddList;
import org.hibernate.annotations.Cache;
import org.hibernate.annotations.CacheConcurrencyStrategy;
import org.hibernate.annotations.Fetch;
import org.hibernate.annotations.FetchMode;
import org.hibernate.annotations.IndexColumn;

/**
 * Internal class to the portlet entity/definition needed to have a sane DB schema and still share
 * tables
 *
 */
@Entity
@Table(name = "UP_PORTLET_PREFS")
@SequenceGenerator(
    name = "UP_PORTLET_PREFS_GEN",
    sequenceName = "UP_PORTLET_PREFS_SEQ",
    allocationSize = 10
)
@TableGenerator(
    name = "UP_PORTLET_PREFS_GEN",
    pkColumnValue = "UP_PORTLET_PREFS",
    allocationSize = 10
)
@Cacheable
@Cache(usage = CacheConcurrencyStrategy.NONSTRICT_READ_WRITE)
class PortletPreferencesImpl {
    @Id
    @GeneratedValue(generator = "UP_PORTLET_PREFS_GEN")
    @Column(name = "PORTLET_PREFS_ID")
    private final long portletPreferencesId;

    @Version
    @Column(name = "ENTITY_VERSION")
    private final long entityVersion;

    @OneToMany(
        cascade = CascadeType.ALL,
        targetEntity = PortletPreferenceImpl.class,
        fetch = FetchType.EAGER,
        orphanRemoval = true
    )
    @JoinColumn(name = "PORTLET_PREFS_ID")
    @IndexColumn(name = "PREF_ORDER")
    @Fetch(FetchMode.JOIN)
    @Cache(usage = CacheConcurrencyStrategy.NONSTRICT_READ_WRITE)
    private List<IPortletPreference> portletPreferences = new ArrayList<IPortletPreference>(0);

    @Transient
    private final List<IPortletPreference> filteringPortletPreferences =
            new FilteringOnAddList<IPortletPreference>(new NewPreferencesFilter(), true) {
                protected List<IPortletPreference> delegate() {
                    return portletPreferences;
                }
            };

    private class NewPreferencesFilter implements Function<IPortletPreference, IPortletPreference> {
        @Override
        public IPortletPreference apply(IPortletPreference newPreference) {
            if (newPreference == null) {
                return null;
            }

            final String name = newPreference.getName();
            for (final IPortletPreference oldPreference : portletPreferences) {
                if (name.equals(oldPreference.getName())) {
                    //Don't add the new preference, just replace the existing one when a match is found
                    oldPreference.setValues(newPreference.getValues());
                    oldPreference.setReadOnly(newPreference.isReadOnly());

                    return null;
                }
            }

            return newPreference;
        }
    }

    public PortletPreferencesImpl() {
        this.portletPreferencesId = -1;
        this.entityVersion = -1;
    }

    public List<IPortletPreference> getPortletPreferences() {
        return this.filteringPortletPreferences;
    }

    public boolean setPortletPreferences(List<IPortletPreference> newPreferences) {
        if (this.portletPreferences == newPreferences) {
            return false;
        }

        if (newPreferences == null) {
            final boolean modified = !this.portletPreferences.isEmpty();
            this.portletPreferences = new ArrayList<IPortletPreference>(0);
            return modified;
        }

        boolean modified = false;
        //Build map of existing preferences for tracking which preferences have been removed
        final Map<String, IPortletPreference> oldPreferences =
                new LinkedHashMap<String, IPortletPreference>();
        for (final IPortletPreference preference : this.portletPreferences) {
            oldPreferences.put(preference.getName(), preference);
        }
        this.portletPreferences.clear();

        for (final IPortletPreference preference : newPreferences) {
            final String name = preference.getName();

            //Remove the existing preference from the map since it is supposed to be persisted
            final IPortletPreference existingPreference = oldPreferences.remove(name);
            if (existingPreference == null) {
                modified = true;

                //New preference, add it to the list
                this.portletPreferences.add(preference);
            } else {
                modified = modified || !existingPreference.equals(preference);

                //Existing preference, update the fields
                existingPreference.setValues(preference.getValues());
                existingPreference.setReadOnly(preference.isReadOnly());
                this.portletPreferences.add(existingPreference);
            }
        }

        return modified;
    }

    /** @see java.lang.Object#equals(Object) */
    @Override
    public boolean equals(Object object) {
        if (object == this) {
            return true;
        }
        if (!(object instanceof PortletPreferencesImpl)) {
            return false;
        }
        PortletPreferencesImpl rhs = (PortletPreferencesImpl) object;
        return new EqualsBuilder()
                .append(this.portletPreferences, rhs.getPortletPreferences())
                .isEquals();
    }

    /** @see java.lang.Object#hashCode() */
    @Override
    public int hashCode() {
        return new HashCodeBuilder(-1904185833, -1222355625)
                .append(this.portletPreferences)
                .toHashCode();
    }

    @Override
    public String toString() {
        return "PortletPreferencesImpl [portletPreferencesId="
                + this.portletPreferencesId
                + ", entityVersion="
                + this.entityVersion
                + "]";
    }
}