/*
 * Copyright 2019-2021 The Polypheny Project
 *
 * 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.
 *
 * This file incorporates code covered by the following terms:
 *
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF 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
 *
 * 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 org.polypheny.db.util;


import com.google.common.collect.Maps;
import java.io.Serializable;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.Set;


/**
 * Set of names that can be accessed with and without case sensitivity.
 */
public class NameSet implements Serializable {

    public static final Comparator<String> COMPARATOR = CaseInsensitiveComparator.COMPARATOR;

    private static final Object DUMMY = new Object();

    private final NameMap<Object> names;


    /**
     * Creates a NameSet based on an existing set.
     */
    private NameSet( NameMap<Object> names ) {
        this.names = names;
    }


    /**
     * Creates a NameSet, initially empty.
     */
    public NameSet() {
        this( new NameMap<>() );
    }


    /**
     * Creates a NameSet that is an immutable copy of a given collection.
     */
    public static NameSet immutableCopyOf( Set<String> names ) {
        return new NameSet( NameMap.immutableCopyOf( Maps.asMap( names, ( k ) -> DUMMY ) ) );
    }


    @Override
    public String toString() {
        return names.map().keySet().toString();
    }


    @Override
    public int hashCode() {
        return names.hashCode();
    }


    @Override
    public boolean equals( Object obj ) {
        return this == obj
                || obj instanceof NameSet
                && names.equals( ((NameSet) obj).names );
    }


    public void add( String name ) {
        names.put( name, DUMMY );
    }


    /**
     * Returns an iterable over all the entries in the set that match the given name. If case-sensitive, that iterable will have 0 or 1 elements; if
     * case-insensitive, it may have 0 or more.
     */
    public Collection<String> range( String name, boolean caseSensitive ) {
        return names.range( name, caseSensitive ).keySet();
    }


    /**
     * Returns whether this set contains the given name, with a given case-sensitivity.
     */
    public boolean contains( String name, boolean caseSensitive ) {
        return names.containsKey( name, caseSensitive );
    }


    /**
     * Returns the contents as an iterable.
     */
    public Iterable<String> iterable() {
        return Collections.unmodifiableSet( names.map().keySet() );
    }

}

