/*
 * Copyright (c) 2018-2020. Developed by Hedgecode.
 *
 * 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.
 */

package org.hedgecode.chess.pgn.token;

import java.util.regex.Pattern;

import org.hedgecode.chess.pgn.entity.Moves;
import org.hedgecode.chess.pgn.entity.Variation;
import org.hedgecode.chess.position.ParseException;

/**
 * VariationToken
 *
 * @author Dmitry Samoshin aka gotty
 */
public class VariationToken implements Token<Moves> {

    private static final char OPEN_VARIATION = '(';
    private static final char CLOSE_VARIATION = ')';

    private static final String VARIATION_REGEX = "^\\s*\\(([^)]+)\\)";
    private static final Pattern VARIATION_PATTERN = Pattern.compile(VARIATION_REGEX);

    @Override
    public int token(Moves moves, String pgn) throws ParseException {
        int startToken  = pgn.indexOf(OPEN_VARIATION);
        int endToken = endToken(pgn, startToken);
        Variation variation = new Variation();
        Token<Variation> variationToken = new MovesToken<>();
        variationToken.token(
                variation, pgn.substring(startToken + 1, endToken)
        );
        moves.currentMove().addVariation(variation);
        return endToken + 1;
    }

    private int endToken(String pgn, int startToken) throws ParseException {
        int open = pgn.indexOf(OPEN_VARIATION, startToken + 1);
        int close = pgn.indexOf(CLOSE_VARIATION, startToken + 1);
        while (open >= 0 && open < close) {
            open = pgn.indexOf(OPEN_VARIATION, open + 1);
            close = pgn.indexOf(CLOSE_VARIATION, close + 1);
        }
        if (close == -1) {
            throw new ParseException("parse.pgn.incorrect.variation", pgn);
        }
        return close;
    }

}