/*
 * Copyright (c) 2019-2020. 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.scanner;

import java.net.MalformedURLException;
import java.net.URL;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;

import org.hedgecode.chess.scanner.entity.PGNGame;
import org.hedgecode.chess.scanner.portal.Chess24Scanner;
import org.hedgecode.chess.scanner.portal.ChessBombScanner;
import org.hedgecode.chess.scanner.portal.ChessComScanner;
import org.hedgecode.chess.scanner.portal.ChessGamesScanner;
import org.hedgecode.chess.scanner.portal.LiChessScanner;

/**
 * ChessHogScanner
 *
 * @author Dmitry Samoshin aka gotty
 */
public final class ChessHogScanner {

    private static ChessHogScanner singleton;

    private final Map<ScannerType, Scanner> scanners = new HashMap<ScannerType, Scanner>() {
        {
            put( ScannerType.CHESSGAMES, new ChessGamesScanner() );
            put( ScannerType.LICHESS,    new LiChessScanner()    );
            put( ScannerType.CHESSBOMB,  new ChessBombScanner()  );
            put( ScannerType.CHESS24,    new Chess24Scanner()    );
            put( ScannerType.CHESSCOM,   new ChessComScanner()   );
        }
    };

    private final Set<ScannerType> initScanners = new HashSet<>();

    /**
     * Get Scanner by {@code ScannerType}.
     *
     * @param type Scanner type (binding to specific chess portal).
     * @return Implementation of {@code Scanner} for specific portal.
     */
    public static Scanner scanner(ScannerType type) {
        return getStore().getScanner(type);
    }

    /**
     * Scan PGN game by URL (for all scanner types).
     *
     * @param url URL string for scan.
     * @return PGN game.
     * @throws ChessHogScannerException Incorrect URL or unknown chess portal.
     */
    public static PGNGame scan(String url) throws ChessHogScannerException {
        String hostName;
        try {
            hostName = new URL(url).getHost();
        } catch (MalformedURLException cause) {
            throw new ChessHogScannerException(
                    String.format("Incorrect  URL: %s", url), cause
            );
        }
        ScannerType type = ScannerType.byHost(hostName);
        if (type == null) {
            throw new ChessHogScannerException(
                    String.format("Host %s is not among the known for the scanner", hostName)
            );
        }
        return scanner(type).scanUrl(url);
    }

    private void init() {
        for (ScannerType type : scanners.keySet()) {
            init(type);
        }
    }

    private void init(ScannerType type) {
        Scanner scanner = scanners.get(type);
        try {
            if (scanner instanceof Initiable) {
                Initiable initiableScanner = (Initiable) scanner;
                initiableScanner.init();
            }
            initScanners.add(type);
        } catch (ChessHogScannerException e) {
            throw new RuntimeException(e);
        }
    }


    private Scanner getScanner(ScannerType type) {
        if (!initScanners.contains(type)) {
            init(type);
        }
        return scanners.get(type);
    }

    private ChessHogScanner() {
        if (!ChessHogScannerProperties.is("scanner.lazy.init")) {
            init();
        }
    }

    private static ChessHogScanner getStore() {
        if (singleton == null) {
            singleton = new ChessHogScanner();
        }
        return singleton;
    }

}