// hello.java
// -----------------------
// part of the AnomicHTTPD caching proxy
// (C) by Michael Peter Christen; mc@yacy.net
// first published on http://www.anomic.de
// Frankfurt, Germany, 2004
//
// $LastChangedDate$
// $LastChangedRevision$
// $LastChangedBy$
//
// 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 2 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, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
//
// You must compile this file with
// javac -classpath .:../../classes hello.java
// if the shell's current path is HTROOT

import java.io.IOException;
import java.net.InetAddress;
import java.util.Iterator;
import java.util.Set;
import java.util.concurrent.ConcurrentMap;

import net.yacy.cora.protocol.Domains;
import net.yacy.cora.protocol.HeaderFramework;
import net.yacy.cora.protocol.RequestHeader;
import net.yacy.peers.Network;
import net.yacy.peers.DHTSelection;
import net.yacy.peers.Protocol;
import net.yacy.peers.Seed;
import net.yacy.peers.graphics.ProfilingGraph;
import net.yacy.search.EventTracker;
import net.yacy.search.Switchboard;
import net.yacy.server.serverCore;
import net.yacy.server.serverObjects;
import net.yacy.server.serverSwitch;

public final class hello {
    
    // example:
    // http://localhost:8090/yacy/hello.html?count=1&seed=p|{Hash=sCJ6Tq8T0N9x,Port=8090,PeerType=junior}
    // http://localhost:8090/yacy/hello.html?count=10&seed=z|H4sIAAAAAAAAADWQW2vDMAyF_81eJork3GyGX-YxGigly2WFvZTQijbQJsHx1pWx_z7nMj1J4ug7B_2s6-GsP5q3G-G6vBz2e0iz8t6zfuBr7-5PUNanQfulhqyzTkuUCFXvmitrBJtq4ed3tkPTtRpXhIiRDAmq0uhHFIiQMduJ-NXYU9NCbrrP1vnjIdUqgk09uIK51V6rMBRIilAo2NajwzfhGcx8QUKsEIp5iCJo-eaTVUXPfPQ4k5dm4pp8NzaESsLzS-14QVNIMlA-ka2m1JuZJJWIBRwPo0GIIiYp4zCSkC5GQSLiJIah0p6X_rvlS-MTbWdhkCSBIni9jA_rfP3-Ae1Oye9dAQAA
    public static serverObjects respond(final RequestHeader header, final serverObjects post, final serverSwitch env) {
        final Switchboard sb = (Switchboard) env;
        final serverObjects prop = new serverObjects();
        final long start = System.currentTimeMillis();
        prop.put("message", "none");
        String clientip = header.getRemoteAddr();
        //ConcurrentLog.info("**hello-DEBUG**", "client request from = " + clientip);
        final InetAddress ias = Domains.dnsResolve(clientip);
        long time = System.currentTimeMillis();
        final long time_dnsResolve = System.currentTimeMillis() - time;
        if (ias == null) {
            if (clientip == null) clientip = "<unknown>";
            Network.log.info("hello/server: failed contacting seed; clientip not resolvable (clientip=" + clientip + ", time_dnsResolve=" + time_dnsResolve + ")");
            prop.put("message", "cannot resolve your IP from your reported location " + clientip);
            return prop;
        }
        prop.put("yourip", ias.getHostAddress());
        prop.put(Seed.YOURTYPE, Seed.PEERTYPE_VIRGIN); // a default value
        prop.put("seedlist", "");
        if ((post == null) || (env == null)) {
            prop.put("message", "no post or no enviroment");
            return prop;
        }
        if (!Protocol.authentifyRequest(post, env)) {
            prop.put("message", "not in my network");
            return prop;
        }

//      final String iam      = (String) post.get("iam", "");  // complete seed of the requesting peer
//      final String mytime   = (String) post.get(MYTIME, ""); //
        final String key      = post.get("key", "");      // transmission key for response
        final String seed     = post.get("seed", "");
        int  count            = post.getInt("count", 0);
        // final long  magic     = post.getLong("magic", 0);
        // final Date remoteTime = yacyCore.parseUniversalDate(post.get(MYTIME)); // read remote time
        if (seed.length() > Seed.maxsize) {
        	Network.log.info("hello/server: rejected contacting seed; too large (" + seed.length() + " > " + Seed.maxsize + ", time_dnsResolve=" + time_dnsResolve + ")");
            prop.put("message", "your seed is too long (" + seed.length() + ")");
            return prop;
        }
        Seed remoteSeed;
        try {
            remoteSeed = Seed.genRemoteSeed(seed, true, ias.getHostAddress());
        } catch (final IOException e) {
            Network.log.info("hello/server: bad seed: " + e.getMessage() + ", time_dnsResolve=" + time_dnsResolve);
            prop.put("message", "bad seed: " + e.getMessage());
            return prop;
        }

        if (remoteSeed == null || remoteSeed.hash == null) {
            Network.log.info("hello/server: bad seed: null, time_dnsResolve=" + time_dnsResolve);
            prop.put("message", "cannot parse your seed");
            return prop;
        }

        // we easily know the caller's IP:
        final String userAgent = header.get(HeaderFramework.USER_AGENT, "<unknown>");
        sb.peers.peerActions.setUserAgent(clientip, userAgent);
        final Set<String> reportedips = remoteSeed.getIPs();
        final String reportedPeerType = remoteSeed.get(Seed.PEERTYPE, Seed.PEERTYPE_JUNIOR);
        //final double clientversion = remoteSeed.getVersion();

        if (remoteSeed.getPort() == sb.peers.mySeed().getPort()) {
            if (sb.peers.mySeed().clash(reportedips)) {
                // reject a self-ping
                prop.put("message", "I am I");
                return prop;
            }
        }
        if (remoteSeed.hash.equals(sb.peers.mySeed().hash)) {
            // reject a ping with my own hash
            prop.put("message", "You are using my peer hash");
            return prop;
        }
        /*
        if (remoteSeed.getName().equals(sb.peers.mySeed().getName())) {
            // reject a ping with my name
            prop.put("message", "You are using my name");
            return prop;
        }
        */
        if (sb.isRobinsonMode() && !sb.isPublicRobinson()) {
            // if we are a robinson cluster, answer only if this client is known by our network definition
            prop.put("message", "I am robinson, I do not answer");
            return prop;
        }

        long[] callback = new long[]{-1, -1};

        // if the remote client has reported its own IP address and the client supports
        // the port forwarding feature (if client version >= 0.383) then we try to
        // connect to the reported IP address first
        long time_backping = 0;
        String backping_method = "none";
        boolean success = false;
        // TODO: make this a concurrent process
        if (!serverCore.useStaticIP || !ias.isSiteLocalAddress()) {
            reportedips.add(ias.getHostAddress());
        }
        final int connectedBefore = sb.peers.sizeConnected();
        //ConcurrentLog.info("**hello-DEBUG**", "peer " + remoteSeed.getName() + " challenged us with IPs " + reportedips);
        int callbackRemain = Math.min(5, reportedips.size());
        long callbackStart = System.currentTimeMillis();
        if (callbackRemain > 0 && reportedips.size() > 0) { 
            for (String reportedip: reportedips) {
                int partialtimeout = ((int) (callbackStart + 6500 - System.currentTimeMillis())) / callbackRemain; // bad hack until a concurrent version is implemented
                if (partialtimeout <= 0) break;
                //ConcurrentLog.info("**hello-DEBUG**", "reportedip = " + reportedip + " is handled");
                if (Seed.isProperIP(reportedip)) {
                    //ConcurrentLog.info("**hello-DEBUG**", "starting callback to reportedip = " + reportedip + ", timeout = " + partialtimeout);
                    prop.put("yourip", reportedip);
                    remoteSeed.setIP(reportedip);
                    time = System.currentTimeMillis();
                    callback = Protocol.queryRWICount(remoteSeed.getPublicAddress(reportedip), remoteSeed.hash, partialtimeout);
                    //ConcurrentLog.info("**hello-DEBUG**", "reportedip = " + reportedip + " returns callback " + (callback == null ? "NULL" : callback[0]));
                    time_backping = System.currentTimeMillis() - time;
                    backping_method = "reportedip=" + reportedip;
                    if (callback[0] >= 0) { success = true; break; }
                    if (--callbackRemain <= 0) break; // no more tries left / restrict to a limited number of ips
                }
            }
        }
        if (success) {
            //ConcurrentLog.info("**hello-DEBUG**", "success for IP(s) " + remoteSeed.getIPs() + ", port " + remoteSeed.getPort());
            if (remoteSeed.get(Seed.PEERTYPE, Seed.PEERTYPE_SENIOR) == null) {
                prop.put(Seed.YOURTYPE, Seed.PEERTYPE_SENIOR);
                remoteSeed.put(Seed.PEERTYPE, Seed.PEERTYPE_SENIOR);
            } else if (remoteSeed.get(Seed.PEERTYPE, Seed.PEERTYPE_PRINCIPAL).equals(Seed.PEERTYPE_PRINCIPAL)) {
                prop.put(Seed.YOURTYPE, Seed.PEERTYPE_PRINCIPAL);
            } else {
                prop.put(Seed.YOURTYPE, Seed.PEERTYPE_SENIOR);
                remoteSeed.put(Seed.PEERTYPE, Seed.PEERTYPE_SENIOR);
            }
            // connect the seed
            Network.log.info("hello/server: responded remote " + reportedPeerType + " peer '" + remoteSeed.getName() + "' from " + reportedips + ", time_dnsResolve=" + time_dnsResolve + ", time_backping=" + time_backping + ", method=" + backping_method + ", urls=" + callback[0]);
            sb.peers.peerActions.peerArrival(remoteSeed, true);
        } else {
            //ConcurrentLog.info("**hello-DEBUG**", "fail for IP(s) " + remoteSeed.getIPs() + ", port " + remoteSeed.getPort());
            prop.put("yourip", ias.getHostAddress());
            remoteSeed.setIP(ias.getHostAddress());
            prop.put(Seed.YOURTYPE, Seed.PEERTYPE_JUNIOR);
            remoteSeed.put(Seed.PEERTYPE, Seed.PEERTYPE_JUNIOR);
            Network.log.info("hello/server: responded remote " + reportedPeerType + " peer '" + remoteSeed.getName() + "' from " + reportedips + ", time_dnsResolve=" + time_dnsResolve + ", time_backping=" + time_backping + ", method=" + backping_method + ", urls=" + callback[0]);
            // no connection here, instead store junior in connection cache
            if ((remoteSeed.hash != null) && (remoteSeed.isProper(false) == null)) {
                sb.peers.peerActions.peerPing(remoteSeed);
            }
        }
        remoteSeed.setLastSeenUTC();
        final int connectedAfter = sb.peers.sizeConnected();

        // update event tracker
        EventTracker.update(EventTracker.EClass.PEERPING, new ProfilingGraph.EventPing(remoteSeed.getName(), sb.peers.myName(), false, connectedAfter - connectedBefore), false);
        if (!(prop.get(Seed.YOURTYPE)).equals(reportedPeerType)) {
            Network.log.info("hello/server: changing remote peer '" + remoteSeed.getName() + "' " + reportedips + " peerType from '" + reportedPeerType + "' to '" + prop.get(Seed.YOURTYPE) + "'.");
        }

        final StringBuilder seeds = new StringBuilder(768);
        // attach some more seeds, as requested
        if (sb.peers.sizeConnected() > 0) {
            if (count > sb.peers.sizeConnected()) { count = sb.peers.sizeConnected(); }
            if (count > 100) { count = 100; }

            // latest seeds
            final ConcurrentMap<String, Seed> ySeeds = DHTSelection.seedsByAge(sb.peers, true, count); // peerhash/yacySeed relation

            // attach also my own seed
            seeds.append("seed0=").append(sb.peers.mySeed().genSeedStr(key)).append(serverCore.CRLF_STRING);
            count = 1;

            // attach other seeds
            if (ySeeds != null) {
                seeds.ensureCapacity((ySeeds.size() + 1) * 768);
                final Iterator<Seed> si = ySeeds.values().iterator();
                Seed s;
                String seedString;
                while (si.hasNext()) {
                	s = si.next();
                    if ((s != null) && (s.isProper(false) == null)) {
                        seedString = s.genSeedStr(key);
                        if (seedString != null) {
                            seeds.append("seed").append(count).append('=').append(seedString).append(serverCore.CRLF_STRING);
                            count++;
                        }
                    }
                }
            }
        } else {
            // attach also my own seed
            seeds.append("seed0=").append(sb.peers.mySeed().genSeedStr(key)).append(serverCore.CRLF_STRING);
        }

        prop.put("seedlist", seeds.toString());
        // return rewrite properties
        prop.put("message", "ok " + seed.length());
        Network.log.info("hello/server: responded remote peer '" + remoteSeed.getName() + "' " + reportedips + " in " + (System.currentTimeMillis() - start) + " milliseconds");
        return prop;
    }

}