/*
 * Copyright (c) 2018. 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.hedgefish;

import org.hedgecode.chess.uci.CommandExecutor;
import org.hedgecode.chess.uci.Engine;
import org.hedgecode.chess.uci.EngineException;
import org.hedgecode.chess.uci.EngineRunner;
import org.hedgecode.chess.uci.Transmitter;
import org.hedgecode.chess.uci.UCIConstants;
import org.hedgecode.chess.uci.annotation.CommandDirection;

/**
 * Hedgefish UCI Engine Runner.
 *
 * @author Dmitry Samoshin aka gotty
 */
public final class HedgefishEngineRunner implements EngineRunner {

    private HedgefishEngine engine;
    private boolean isRunning;

    HedgefishEngineRunner() {
        engine = new HedgefishEngine();
        isRunning = false;
    }

    @Override
    public Engine init() throws EngineException {
        if (isRunning)
            throw new EngineException("uci.engine.already.run");
        return engine;
    }

    @Override
    public void run(final CommandExecutor commandExecutor) throws EngineException {
        if (isRunning)
            throw new EngineException("uci.engine.already.run");

        Thread engineThread = new Thread(
                new Runnable() {
                    public void run() {
                        Transmitter<HedgefishCommand> engineTransmitter = engine.transmitter();
                        try {
                            while (engineTransmitter.isActive()) {
                                if (engineTransmitter.hasCommand()) {
                                    HedgefishCommand command = engineTransmitter.transmitCommand();
                                    commandExecutor.exec(
                                            command.getName(),
                                            CommandDirection.FROM_ENGINE,
                                            command.getParams()
                                    );
                                }
                            }
                        } finally {
                            commandExecutor.exec(
                                    UCIConstants.TERMINATE,
                                    CommandDirection.FROM_ENGINE,
                                    null
                            );
                            engineTransmitter.close();
                            isRunning = false;
                        }
                    }
                }
        );
        engineThread.start();
        isRunning = true;
    }

}