/*
 * Copyright 2013-2014 the original author or authors.
 *
 * 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 devcoin.wallet.util;

import java.math.BigInteger;
import java.util.List;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicLong;

import android.os.Handler;

import com.google.devcoin.core.ECKey;
import com.google.devcoin.core.Transaction;
import com.google.devcoin.core.Wallet;
import com.google.devcoin.core.WalletEventListener;

/**
 * @author Andreas Schildbach
 */
public abstract class ThrottlingWalletChangeListener implements WalletEventListener
{
	private final long throttleMs;
	private final boolean coinsRelevant;
	private final boolean reorganizeRelevant;
	private final boolean confidenceRelevant;

	private final AtomicLong lastMessageTime = new AtomicLong(0);
	private final Handler handler = new Handler();
	private final AtomicBoolean relevant = new AtomicBoolean();

	private static final long DEFAULT_THROTTLE_MS = 500;

	public ThrottlingWalletChangeListener()
	{
		this(DEFAULT_THROTTLE_MS);
	}

	public ThrottlingWalletChangeListener(final long throttleMs)
	{
		this(throttleMs, true, true, true);
	}

	public ThrottlingWalletChangeListener(final boolean coinsRelevant, final boolean reorganizeRelevant, final boolean confidenceRelevant)
	{
		this(DEFAULT_THROTTLE_MS, coinsRelevant, reorganizeRelevant, confidenceRelevant);
	}

	public ThrottlingWalletChangeListener(final long throttleMs, final boolean coinsRelevant, final boolean reorganizeRelevant,
			final boolean confidenceRelevant)
	{
		this.throttleMs = throttleMs;
		this.coinsRelevant = coinsRelevant;
		this.reorganizeRelevant = reorganizeRelevant;
		this.confidenceRelevant = confidenceRelevant;
	}

	@Override
	public final void onWalletChanged(final Wallet wallet)
	{
		if (relevant.getAndSet(false))
		{
			handler.removeCallbacksAndMessages(null);

			final long now = System.currentTimeMillis();

			if (now - lastMessageTime.get() > throttleMs)
				handler.post(runnable);
			else
				handler.postDelayed(runnable, throttleMs);
		}
	}

	private final Runnable runnable = new Runnable()
	{
		@Override
		public void run()
		{
			lastMessageTime.set(System.currentTimeMillis());

			onThrottledWalletChanged();
		}
	};

	public void removeCallbacks()
	{
		handler.removeCallbacksAndMessages(null);
	}

	/** will be called back on UI thread */
	public abstract void onThrottledWalletChanged();

	@Override
	public void onCoinsReceived(final Wallet wallet, final Transaction tx, final BigInteger prevBalance, final BigInteger newBalance)
	{
		if (coinsRelevant)
			relevant.set(true);
	}

	@Override
	public void onCoinsSent(final Wallet wallet, final Transaction tx, final BigInteger prevBalance, final BigInteger newBalance)
	{
		if (coinsRelevant)
			relevant.set(true);
	}

	@Override
	public void onReorganize(final Wallet wallet)
	{
		if (reorganizeRelevant)
			relevant.set(true);
	}

	@Override
	public void onTransactionConfidenceChanged(final Wallet wallet, final Transaction tx)
	{
		if (confidenceRelevant)
			relevant.set(true);
	}

	@Override
	public void onKeysAdded(final Wallet wallet, final List<ECKey> keys)
	{
		// swallow
	}
}