/*
 * Copyright (c) 2014 OpenSilk Productions LLC
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package org.opensilk.common.core.rx;

import java.util.concurrent.TimeUnit;

import rx.Scheduler;
import rx.Subscription;
import rx.functions.Action0;
import rx.internal.schedulers.NewThreadWorker;
import rx.internal.schedulers.ScheduledAction;
import rx.internal.util.RxThreadFactory;
import rx.subscriptions.CompositeSubscription;
import rx.subscriptions.Subscriptions;

/**
 * Created by drew on 12/24/14.
 */
public class SingleThreadScheduler extends Scheduler {
    private static final String THREAD_NAME_PREFIX = "RxSingleThreadWorker-";
    private static final RxThreadFactory THREAD_FACTORY = new RxThreadFactory(THREAD_NAME_PREFIX);

    final NewThreadWorker worker;

    public SingleThreadScheduler() {
        worker = new NewThreadWorker(THREAD_FACTORY);
    }

    @Override
    public Worker createWorker() {
        return new WorkerWrapper(worker);
    }

    private static class WorkerWrapper extends Scheduler.Worker {
        private final CompositeSubscription innerSubscription = new CompositeSubscription();
        private final NewThreadWorker worker;

        WorkerWrapper(NewThreadWorker worker) {
            this.worker = worker;
        }

        @Override
        public void unsubscribe() {
            innerSubscription.unsubscribe();
        }

        @Override
        public boolean isUnsubscribed() {
            return innerSubscription.isUnsubscribed();
        }

        @Override
        public Subscription schedule(Action0 action) {
            return schedule(action, 0, null);
        }
        @Override
        public Subscription schedule(Action0 action, long delayTime, TimeUnit unit) {
            if (innerSubscription.isUnsubscribed()) {
                // don't schedule, we are unsubscribed
                return Subscriptions.empty();
            }

            ScheduledAction s = worker.scheduleActual(action, delayTime, unit);
            innerSubscription.add(s);
            s.addParent(innerSubscription);
            return s;
        }
    }
}