/*
 * Copyright (c) 2008-2017, Hazelcast, Inc. All Rights Reserved.
 *
 * Licensed 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
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * 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 com.hazelcast.config;

import com.hazelcast.logging.ILogger;
import com.hazelcast.logging.Logger;

import static com.hazelcast.query.QueryConstants.KEY_ATTRIBUTE_NAME;
import static com.hazelcast.util.Preconditions.checkHasText;

/**
 * Contains the configuration for an index in a map. This class should be used in combination
 * with the {@link MapConfig}. The reason to create an map index is to speed up searches for
 * particular map entries.
 */
public class MapIndexConfig {

    private static final ILogger LOG = Logger.getLogger(MapIndexConfig.class);

    private String attribute;
    private boolean ordered;
    private MapIndexConfigReadOnly readOnly;

    /**
     * Creates a MapIndexConfig without an attribute and with ordered set to false.
     */
    public MapIndexConfig() {
    }

    /**
     * Creates a MapIndexConfig with the given attribute and ordered setting.
     *
     * @param attribute the attribute that is going to be indexed.
     * @param ordered   true if the index is ordered.
     * @see #setOrdered(boolean)
     * @see #setAttribute(String)
     */
    public MapIndexConfig(String attribute, boolean ordered) {
        setAttribute(attribute);
        setOrdered(ordered);
    }

    public MapIndexConfig(MapIndexConfig config) {
        attribute = config.getAttribute();
        ordered = config.isOrdered();
    }

    /**
     * Gets immutable version of this configuration.
     *
     * @return Immutable version of this configuration.
     * @deprecated this method will be removed in 4.0; it is meant for internal usage only.
     */
    public MapIndexConfigReadOnly getAsReadOnly() {
        if (readOnly == null) {
            readOnly = new MapIndexConfigReadOnly(this);
        }
        return readOnly;
    }

    /**
     * Gets the attribute that is going to be indexed. If no attribute is set, null is returned.
     *
     * @return the attribute to be indexed.
     * @see #setAttribute(String)
     */
    public String getAttribute() {
        return attribute;
    }

    /**
     * Sets the attribute that is going to be indexed.
     *
     * @param attribute the attribute that is going to be indexed.
     * @return the updated MapIndexConfig.
     * @throws IllegalArgumentException if attribute is null or an empty string.
     */
    public MapIndexConfig setAttribute(String attribute) {
        this.attribute = validateIndexAttribute(attribute);
        return this;
    }

    /**
     * Checks if the index should be ordered.
     *
     * @return true if ordered, false otherwise.
     * @see #setOrdered(boolean)
     */
    public boolean isOrdered() {
        return ordered;
    }

    /**
     * Configures the index to be ordered or not ordered. Some indices can be ordered, such as age. Sometimes you
     * want to look for all people with an age equal or greater than X. In other cases an ordered index doesn't make
     * sense, such as a phone number for a person.
     *
     * @param ordered if the index should be an ordered index.
     * @return the updated MapIndexConfig.
     */
    public MapIndexConfig setOrdered(boolean ordered) {
        this.ordered = ordered;
        return this;
    }

    @Override
    public String toString() {
        return "MapIndexConfig{attribute='" + attribute + "', ordered=" + ordered + '}';
    }

    /**
     * Validates index attribute content
     *
     * @param attribute attribute to validate
     * @return the attribute for fluent assignment
     */
    public static String validateIndexAttribute(String attribute) {
        checkHasText(attribute, "Map index attribute must contain text");
        String keyPrefix = KEY_ATTRIBUTE_NAME.value();
        if (attribute.startsWith(keyPrefix) && attribute.length() > keyPrefix.length()) {
            if (attribute.charAt(keyPrefix.length()) != '#') {
                LOG.warning(KEY_ATTRIBUTE_NAME.value() + " used without a following '#' char in index attribute '"
                        + attribute + "'. Don't you want to index a key?");
            }
        }
        return attribute;
    }
}