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/*
 * 
 */

package com.automationrockstars.gir.data;

import com.google.common.collect.Lists;
import com.google.common.util.concurrent.RateLimiter;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import java.util.concurrent.locks.ReentrantReadWriteLock;

public class LimitingIterator implements Iterator {

    private static final Logger LOG = LoggerFactory.getLogger(LimitingIterator.class);
    private final List data;
    private final List counters = Lists.newArrayList();
    private final ReentrantReadWriteLock.WriteLock access = new ReentrantReadWriteLock().writeLock();
    public boolean cycle = true;
    private int pointer = 0;

    public LimitingIterator(Collection data, double ratePerSecond) {
        this.data = Lists.newArrayList(data);
        for (int i = 0; i < data.size(); i++) {
            counters.add(RateLimiter.create(ratePerSecond));
        }
    }

    @Override
    public boolean hasNext() {
        return cycle || pointer < data.size();
    }

    @Override
    public E next() {
        try {
            access.lock();
            if (pointer == data.size()) {
                if (cycle) {
                    pointer = 0;
                } else {
                    return null;
                }
            }
            E result = data.get(pointer++);
            LOG.warn("Waiting for {}", result);
            double waited = counters.get(pointer - 1).acquire();
            LOG.warn("Waited {} for {}", waited, result);
            return result;
        } finally {
            access.unlock();
        }
    }

    @Override
    public void remove() {
        if (pointer == data.size()) {
            if (cycle) {
                pointer = 1;
            }
        } else pointer++;
    }

}