/*
 * This file is part of Bitsquare.
 *
 * Bitsquare is free software: you can redistribute it and/or modify it
 * under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or (at
 * your option) any later version.
 *
 * Bitsquare 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 Affero General Public
 * License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with Bitsquare. If not, see <http://www.gnu.org/licenses/>.
 */

package io.bitsquare.network;

import com.runjva.sourceforge.jsocks.protocol.Socks5Proxy;
import org.bitcoinj.core.NetworkParameters;
import org.bitcoinj.net.discovery.PeerDiscovery;
import org.bitcoinj.net.discovery.PeerDiscoveryException;
import org.bitcoinj.params.MainNetParams;
import org.bitcoinj.params.TestNet3Params;

import java.net.InetSocketAddress;
import java.util.concurrent.TimeUnit;


/**
 * Socks5SeedOnionDiscovery provides a list of known Bitcoin .onion seeds.
 * These are nodes running as hidden services on the Tor network.
 */
public class Socks5SeedOnionDiscovery implements PeerDiscovery {
    private Socks5Proxy proxy;
    private NetworkParameters params;
    private InetSocketAddress[] seedAddrs;
    
    /**
     * Supports finding peers by hostname over a socks5 proxy.
     *
     * @param proxy       proxy the socks5 proxy to connect over.
     * @param params param to be used for seed and port information.
     */
    public Socks5SeedOnionDiscovery(Socks5Proxy proxy, NetworkParameters params) {

        this.proxy = proxy;
        this.params = params;
        
        // We do this because NetworkParameters does not contain any .onion
        // seeds.  Perhaps someday...
        if(params == MainNetParams.get()) {
            this.seedAddrs = convertAddrsString(mainNetSeeds(), params.getPort());
        }
        else if(params == TestNet3Params.get()) {
            this.seedAddrs = convertAddrsString(testNet3Seeds(), params.getPort());
        }
    }
    
    /**
     * returns .onion nodes available on mainnet
     */
    private String[] mainNetSeeds() {
        // this list copied from bitcoin-core on 2017-01-19
        //   https://github.com/bitcoin/bitcoin/blob/57b34599b2deb179ff1bd97ffeab91ec9f904d85/contrib/seeds/nodes_main.txt
        
        return new String[] {
            "3ffk7iumtx3cegbi.onion",
            "3nmbbakinewlgdln.onion",
            "4j77gihpokxu2kj4.onion",
            "546esc6botbjfbxb.onion",
            "5at7sq5nm76xijkd.onion",
            "77mx2jsxaoyesz2p.onion",
            "7g7j54btiaxhtsiy.onion",
            "a6obdgzn67l7exu3.onion",
            "ab64h7olpl7qpxci.onion",
            "am2a4rahltfuxz6l.onion",
            "azuxls4ihrr2mep7.onion",
            "bitcoin7bi4op7wb.onion",
            "bitcoinostk4e4re.onion",
            "bk7yp6epnmcllq72.onion",
            "bmutjfrj5btseddb.onion",
            "ceeji4qpfs3ms3zc.onion",
            "clexmzqio7yhdao4.onion",
            "gb5ypqt63du3wfhn.onion",
            "h2vlpudzphzqxutd.onion",
            "ncwk3lutemffcpc4.onion",
            "okdzjarwekbshnof.onion",
            "pjghcivzkoersesd.onion",
            "rw7ocjltix26mefn.onion",
            "uws7itep7o3yinxo.onion",
            "vk3qjdehyy4dwcxw.onion",
            "vqpye2k5rcqvj5mq.onion",
            "wpi7rpvhnndl52ee.onion"
        };
    }
    
    /**
     * returns .onion nodes available on testnet3
     */
    private String[] testNet3Seeds() {
        // this list copied from bitcoin-core on 2017-01-19
        //   https://github.com/bitcoin/bitcoin/blob/57b34599b2deb179ff1bd97ffeab91ec9f904d85/contrib/seeds/nodes_test.txt
        return new String[] {
            "thfsmmn2jbitcoin.onion",
            "it2pj4f7657g3rhi.onion",
            "nkf5e6b7pl4jfd4a.onion",
            "4zhkir2ofl7orfom.onion",
            "t6xj6wilh4ytvcs7.onion",
            "i6y6ivorwakd7nw3.onion",
            "ubqj4rsu3nqtxmtp.onion"
        };
    }

    /**
     * Returns an array containing all the Bitcoin nodes within the list.
     */
    @Override
    public InetSocketAddress[] getPeers(long timeoutValue, TimeUnit timeoutUnit) throws PeerDiscoveryException {
        return seedAddrs;
    }

    /**
     * Converts an array of hostnames to array of unresolved InetSocketAddress
     */
    private InetSocketAddress[] convertAddrsString(String[] addrs, int port) {
        InetSocketAddress[] list = new InetSocketAddress[addrs.length];
        for (int i = 0; i < addrs.length; i++) {
            list[i] = InetSocketAddress.createUnresolved(addrs[i], port);
        }
        return list;
    }

    @Override
    public void shutdown() {
        //TODO should we add a DnsLookupTor.shutdown() ?
    }
}