/*
 * 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.Matcher;
import java.util.regex.Pattern;

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

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

    enum Type {

        MOVE      ( new MoveToken()      ),
        COMMENT   ( new CommentToken()   ),
        VARIATION ( new VariationToken() );

        private Token<Moves> token;

        public Token<Moves> token() {
            return token;
        }

        Type(Token<Moves> token) {
            this.token = token;
        }
    }

    private static final String MOVES_REGEX = "^\\s*([^\\s])";
    private static final Pattern MOVES_PATTERN = Pattern.compile(MOVES_REGEX);

    private static final String COMMENT = "{";
    private static final String VARIATION = "(";

    @Override
    public int token(Entity entity, String pgn) throws ParseException {
        int pgnLength = pgn.length();
        pgn = PGNUtils.stripCrlf(pgn);
        Token<Moves> token = assignToken(pgn);
        while (token != null) {
            int index = token.token(entity, pgn);
            pgn = pgn.substring(index);
            token = assignToken(pgn);
        }
        return pgnLength;
    }

    private Token<Moves> assignToken(String pgn) {
        Token<Moves> token = null;
        Matcher moveMatcher = MOVES_PATTERN.matcher(pgn);
        if (moveMatcher.find()) {
            switch (moveMatcher.group(1)) {
                case COMMENT:
                    token = Type.COMMENT.token();
                    break;
                case VARIATION:
                    token = Type.VARIATION.token();
                    break;
                default:
                    token = Type.MOVE.token();
            }
        }
        return token;
    }

}