/*
 ***************************************************************************************
 *  Copyright (C) 2006 EsperTech, Inc. All rights reserved.                            *
 *  http://www.espertech.com/esper                                                     *
 *  http://www.espertech.com                                                           *
 *  ---------------------------------------------------------------------------------- *
 *  The software in this package is published under the terms of the GPL license       *
 *  a copy of which has been included with this distribution in the license.txt file.  *
 ***************************************************************************************
 */
package com.espertech.esper.util;

import com.espertech.esper.collection.MultiKeyUntyped;

import java.io.Serializable;
import java.text.Collator;
import java.util.Comparator;

/**
 * A comparator on multikeys with string values and using the Collator for comparing.
 * The multikeys must contain the same number of values.
 */
public final class MultiKeyCollatingComparator implements Comparator<MultiKeyUntyped>, MetaDefItem, Serializable {
    private final boolean[] isDescendingValues;
    private final boolean[] stringTypedValue;
    private transient Collator collator = null;
    private static final long serialVersionUID = -1166857207888935691L;

    /**
     * Ctor.
     *
     * @param isDescendingValues - each value is true if the corresponding (same index)
     *                           entry in the multi-keys is to be sorted in descending order. The multikeys
     *                           to be compared must have the same number of values as this array.
     * @param stringTypeValues   true for each string-typed column
     */
    public MultiKeyCollatingComparator(boolean[] isDescendingValues, boolean[] stringTypeValues) {
        this.isDescendingValues = isDescendingValues;
        this.stringTypedValue = stringTypeValues;
        this.collator = Collator.getInstance();
    }

    public final int compare(MultiKeyUntyped firstValues, MultiKeyUntyped secondValues) {
        if (firstValues.size() != isDescendingValues.length || secondValues.size() != isDescendingValues.length) {
            throw new IllegalArgumentException("Incompatible size MultiKey sizes for comparison");
        }

        for (int i = 0; i < firstValues.size(); i++) {
            Object valueOne = firstValues.get(i);
            Object valueTwo = secondValues.get(i);
            boolean isDescending = isDescendingValues[i];

            if (!stringTypedValue[i]) {
                int comparisonResult = MultiKeyComparator.compareValues(valueOne, valueTwo, isDescending);
                if (comparisonResult != 0) {
                    return comparisonResult;
                }
            } else {
                int comparisonResult = MultiKeyComparator.compareValuesCollated(valueOne, valueTwo, isDescending, collator);
                if (comparisonResult != 0) {
                    return comparisonResult;
                }
            }
        }

        // Make the comparator compatible with equals
        if (!firstValues.equals(secondValues)) {
            return -1;
        } else {
            return 0;
        }
    }
}