/**
 * 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.layout.dlm;

import org.apache.commons.lang.Validate;

/**
 * Uniquely identifies a node within some DLM layout for use in the internal model of a layout. A
 * Noderef is the opposite (counterpart) of a {@link Pathref}. In other words, a Noderef identifies
 * internally what a {@link Pathref} identifies externally. The need for two formats stems from the
 * fact that Noderefs use database identifiers in their format, which are not (always) stable across
 * migrations.
 *
 * <p>Noderefs contain 3 elements:
 *
 * <ul>
 *   <li>userId of the fragment owner (e.g. 'u13')
 *   <li>layoutId of the fragment layout (currently this will always be 'l1')
 *   <li>structureId of the node within the fragment layout (e.g. 's2' but the preceeding character
 *       is not always an 's')
 * </ul>
 *
 * Example Noderef: u13l1s2
 *
 */
public final class Noderef {

    private static final String USER_ID_PREFIX = "u";
    private static final String LAYOUT_ID_PREFIX = "l";

    // Instance Members
    private final int userId;
    private final int layoutId;
    private final String structureId;

    /**
     * Creates an intra-layout Noderef (refers to a node in one's own layout).
     *
     * @param structureId
     */
    public Noderef(String structureId) {
        this(0, 0, structureId);
    }

    /** Creates an extra-layout Noderef (refers to a node in a DLM fragment). */
    public Noderef(int userId, int layoutId, String structureId) {

        boolean userAndLayoutIdsAreValid =
                (userId > 0 && layoutId > 0) || (userId == 0 && layoutId == 0);
        Validate.isTrue(
                userAndLayoutIdsAreValid,
                "Arguments 'userId' and "
                        + "'layoutId' must either both be zero or both "
                        + "greater than zero.");
        Validate.notNull(structureId, "Argument 'structureId' cannot be null.");

        this.userId = userId;
        this.layoutId = layoutId;
        this.structureId = structureId;
    }

    public int getUserId() {
        return userId;
    }

    public int getLayoutId() {
        return layoutId;
    }

    public String getStructureId() {
        return structureId;
    }

    @Override
    public String toString() {
        String rslt = null;
        if (userId != 0 && layoutId != 0) {
            // An intra-layout Noderef
            StringBuilder sb = new StringBuilder();
            sb.append(USER_ID_PREFIX)
                    .append(userId)
                    .append(LAYOUT_ID_PREFIX)
                    .append(layoutId)
                    .append(structureId);
            rslt = sb.toString();
        } else {
            // An extra-layout Noderef
            rslt = structureId;
        }
        return rslt;
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + layoutId;
        result = prime * result + ((structureId == null) ? 0 : structureId.hashCode());
        result = prime * result + userId;
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) return true;
        if (obj == null) return false;
        if (getClass() != obj.getClass()) return false;
        Noderef other = (Noderef) obj;
        if (layoutId != other.layoutId) return false;
        if (structureId == null) {
            if (other.structureId != null) return false;
        } else if (!structureId.equals(other.structureId)) return false;
        if (userId != other.userId) return false;
        return true;
    }
}