/*
 * Licensed to Crate under one or more contributor license agreements.
 * See the NOTICE file distributed with this work for additional
 * information regarding copyright ownership.  Crate 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.
 *
 * However, if you have executed another commercial license agreement
 * with Crate these terms will supersede the license and you may use the
 * software solely pursuant to the terms of the relevant commercial
 * agreement.
 */

package io.crate.operation.scalar.string;

import com.google.common.collect.ImmutableList;
import io.crate.metadata.FunctionIdent;
import io.crate.metadata.FunctionInfo;
import io.crate.operation.scalar.ScalarFunctionModule;
import io.crate.operation.scalar.UnaryScalar;
import io.crate.types.DataType;
import io.crate.types.DataTypes;
import org.apache.lucene.util.BytesRef;

import java.util.Collections;
import java.util.List;
import java.util.function.Function;

public final class LengthFunction {

    private static final List<DataType> SUPPORTED_INPUT_TYPES = ImmutableList.of(DataTypes.STRING, DataTypes.UNDEFINED);

    private static void register(ScalarFunctionModule module, String name, Function<BytesRef, Integer> func) {
        for (DataType inputType : SUPPORTED_INPUT_TYPES) {
            FunctionIdent ident = new FunctionIdent(name, Collections.singletonList(inputType));
            module.register(new UnaryScalar<>(new FunctionInfo(ident, DataTypes.INTEGER), func));
        }
    }

    public static void register(ScalarFunctionModule module) {
        register(module, "octet_length", x -> x.length);
        register(module, "bit_length", x -> x.length * Byte.SIZE);
        register(module, "char_length", x -> x.utf8ToString().length());
    }
}