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/**
 * Copyright (c) 2013-2021 Nikita Koksharov
 *
 * 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 com.github.lontime.shaded.org.redisson;

import com.github.lontime.shaded.org.redisson.api.RFuture;
import com.github.lontime.shaded.org.redisson.connection.ConnectionManager;

import java.util.Map;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.TimeUnit;
import java.util.function.Consumer;
import java.util.function.Supplier;

/**
 * @author Nikita Koksharov
 */
public class ElementsSubscribeService {
    
    private final Map> subscribeListeners = new ConcurrentHashMap<>();
    private final ConnectionManager connectionManager;

    public ElementsSubscribeService(ConnectionManager connectionManager) {
        this.connectionManager = connectionManager;
    }

    public  int subscribeOnElements(Supplier> func, Consumer consumer) {
        int id = System.identityHashCode(consumer);
        CompletableFuture currentFuture = subscribeListeners.putIfAbsent(id, CompletableFuture.completedFuture(null));
        if (currentFuture != null) {
            throw new IllegalArgumentException("Consumer object with listener id " + id + " already registered");
        }
        resubscribe(func, consumer);
        return id;
    }

    public void unsubscribe(int listenerId) {
        CompletableFuture f = subscribeListeners.remove(listenerId);
        if (f != null) {
            f.cancel(false);
        }
    }

    private  void resubscribe(Supplier> func, Consumer consumer) {
        int listenerId = System.identityHashCode(consumer);
        CompletableFuture f = (CompletableFuture) subscribeListeners.computeIfPresent(listenerId, (k, v) -> {
            return func.get().toCompletableFuture();
        });
        if (f == null) {
            return;
        }

        f.whenComplete((r, e) -> {
            if (e != null) {
                connectionManager.newTimeout(t -> {
                    resubscribe(func, consumer);
                }, 1, TimeUnit.SECONDS);
                return;
            }

            consumer.accept(r);
            resubscribe(func, consumer);
        });
    }

    
}