/*
 * Licensed to CRATE Technology GmbH ("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.analyze;

import com.google.common.base.Predicate;
import com.google.common.base.Predicates;
import com.google.common.collect.ImmutableMap;
import org.apache.lucene.util.BytesRef;
import org.elasticsearch.common.lucene.BytesRefs;

import javax.annotation.Nullable;
import java.util.Arrays;
import java.util.Locale;
import java.util.Map;

public class MatchOptionsAnalysis {

    private static final Predicate<Object> POSITIVE_NUMBER = new Predicate<Object>() {
        @Override
        public boolean apply(@Nullable Object input) {
            return input != null && input instanceof Number && ((Number) input).doubleValue() > 0;
        }
    };
    private static final Predicate<Object> IS_STRING = Predicates.instanceOf(BytesRef.class);
    private static final Predicate<Object> IS_NUMBER = Predicates.instanceOf(Number.class);
    private static final Predicate<Object> NUMBER_OR_STRING = Predicates.or(IS_STRING, IS_NUMBER);

    private static final Map<String, Predicate<Object>> ALLOWED_SETTINGS = ImmutableMap.<String, Predicate<Object>>builder()
        .put("analyzer", IS_STRING)
        .put("boost", POSITIVE_NUMBER)
        .put("cutoff_frequency", POSITIVE_NUMBER)
        .put("fuzziness", NUMBER_OR_STRING) // validated at ES QueryParser
        .put("fuzzy_rewrite", IS_STRING)
        .put("max_expansions", POSITIVE_NUMBER)
        .put("minimum_should_match", NUMBER_OR_STRING)
        .put("operator", Predicates.in(Arrays.<Object>asList(
            new BytesRef("or"),
            new BytesRef("and"),
            new BytesRef("OR"),
            new BytesRef("AND"))))
        .put("prefix_length", POSITIVE_NUMBER)
        .put("rewrite", IS_STRING)
        .put("slop", POSITIVE_NUMBER)
        .put("tie_breaker", IS_NUMBER)
        .put("zero_terms_query", IS_STRING)
        .build();

    public static void validate(Map<String, Object> options) {
        for (Map.Entry<String, Object> e : options.entrySet()) {
            String optionName = e.getKey();
            Predicate<Object> validator = ALLOWED_SETTINGS.get(optionName);
            if (validator == null) {
                throw new IllegalArgumentException(
                    String.format(Locale.ENGLISH, "unknown match option '%s'", optionName));
            }
            Object value = e.getValue();
            if (!validator.apply(value)) {
                throw new IllegalArgumentException(String.format(Locale.ENGLISH,
                    "invalid value for option '%s': %s", optionName, BytesRefs.toString(value)));
            }
        }
    }
}