/*
 * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
 * or more contributor license agreements. Licensed under the "Elastic License
 * 2.0", the "GNU Affero General Public License v3.0 only", and the "Server Side
 * Public License v 1"; you may not use this file except in compliance with, at
 * your election, the "Elastic License 2.0", the "GNU Affero General Public
 * License v3.0 only", or the "Server Side Public License, v 1".
 */

package org.elasticsearch.search.runtime;

import org.apache.lucene.search.DocIdSetIterator;
import org.apache.lucene.search.QueryVisitor;
import org.apache.lucene.search.TwoPhaseIterator;
import org.apache.lucene.util.BytesRefBuilder;
import org.apache.lucene.util.automaton.ByteRunAutomaton;
import org.elasticsearch.script.Script;
import org.elasticsearch.script.StringFieldScript;

import java.util.List;

public abstract class AbstractStringScriptFieldAutomatonQuery extends AbstractStringScriptFieldQuery {
    private final ByteRunAutomaton automaton;

    public AbstractStringScriptFieldAutomatonQuery(
        Script script,
        StringFieldScript.LeafFactory leafFactory,
        String fieldName,
        ByteRunAutomaton automaton
    ) {
        super(script, leafFactory, fieldName);
        this.automaton = automaton;
    }

    @Override
    protected TwoPhaseIterator createTwoPhaseIterator(StringFieldScript scriptContext, DocIdSetIterator approximation) {
        BytesRefBuilder scratch = new BytesRefBuilder();
        return new TwoPhaseIterator(approximation) {
            @Override
            public boolean matches() {
                scriptContext.runForDoc(approximation.docID());
                return AbstractStringScriptFieldAutomatonQuery.this.matches(scriptContext.getValues(), scratch);
            }

            @Override
            public float matchCost() {
                return MATCH_COST;
            }
        };
    }

    protected final boolean matches(List<String> values, BytesRefBuilder scratch) {
        for (String value : values) {
            scratch.copyChars(value);
            if (automaton.run(scratch.bytes(), 0, scratch.length())) {
                return true;
            }
        }
        return false;
    }

    @Override
    protected final boolean matches(List<String> values) {
        throw new UnsupportedOperationException();
    }

    @Override
    public final void visit(QueryVisitor visitor) {
        if (visitor.acceptField(fieldName())) {
            visitor.consumeTermsMatching(this, fieldName(), () -> automaton);
        }
    }
}