// yacyDHTAction.java 
// -------------------------------------
// (C) by Michael Peter Christen; mc@anomic.de
// first published on http://www.anomic.de
// Frankfurt, Germany, 2005
// last major change: 23.02.2005
//
// 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
//
// Using this software in any meaning (reading, learning, copying, compiling,
// running) means that you agree that the Author(s) is (are) not responsible
// for cost, loss of data or any harm that may be caused directly or indirectly
// by usage of this softare or this documentation. The usage of this software
// is on your own risk. The installation and usage (starting/running) of this
// software may allow other people or application to access your computer and
// any attached devices and is highly dependent on the configuration of the
// software which must be done by the user of the software; the author(s) is
// (are) also not responsible for proper configuration and usage of the
// software, even if provoked by documentation provided together with
// the software.
//
// Any changes to this file according to the GPL as documented in the file
// gpl.txt aside this file in the shipment you received can be done to the
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package de.anomic.yacy;

import java.util.Enumeration;

import de.anomic.kelondro.kelondroException;
import de.anomic.kelondro.kelondroMScoreCluster;

public class yacyDHTAction implements yacyPeerAction {
   
    private yacySeedDB seedDB;
    private kelondroMScoreCluster seedCrawlReady;
    
    public yacyDHTAction(yacySeedDB seedDB) {
        this.seedDB = seedDB;
        this.seedCrawlReady = new kelondroMScoreCluster();
        // init crawl-ready table
        try {
            Enumeration en = seedDB.seedsConnected(true, false, null);
            yacySeed ys;
            while (en.hasMoreElements()) {
                ys = (yacySeed) en.nextElement();
                if ((ys != null) && (ys.getVersion() >= ((float) 0.3))) seedCrawlReady.setScore(ys.hash, yacyCore.yacyTime());
            }
        } catch (IllegalArgumentException e) {
        }
    }
   
    public Enumeration getDHTSeeds(boolean up, String firstHash) {
        // enumerates seed-type objects: all seeds with starting point in the middle, rotating at the end/beginning
	return new seedDHTEnum(up, firstHash);
    }

    class seedDHTEnum implements Enumeration {

	Enumeration e1, e2;
        boolean up;
        int steps;
        
	public seedDHTEnum(boolean up, String firstHash) {
            this.steps = seedDB.sizeConnected();
            this.up = up;
            this.e1 = seedDB.seedsConnected(up, false, firstHash);
            this.e2 = null;
	}
        
        public boolean hasMoreElements() {
	    return (steps > 0) && ((e2 == null) || (e2.hasMoreElements()));
	}

        public Object nextElement() {
            if (steps == 0) return null;
            steps--;
            if ((e1 != null) && (e1.hasMoreElements())) {
                Object n = e1.nextElement();
                if (!(e1.hasMoreElements())) {
                    e1 = null;
                    e2 = seedDB.seedsConnected(up, false, null);
                }
                return n;
            } else {
                if (e2 == null) {
                    e1 = null;
                    e2 = seedDB.seedsConnected(up, false, null);
                }
                return e2.nextElement();
            }
        }
    }
    
    public Enumeration getAcceptRemoteIndexSeeds(String starthash) {
        // returns an enumeration of yacySeed-Objects
        // that have the AcceptRemoteIndex-Flag set
        // the seeds are enumerated in the right order according DHT
        return new acceptRemoteIndexSeedEnum(starthash);
    }
    
    class acceptRemoteIndexSeedEnum implements Enumeration {

	Enumeration se;
        yacySeed nextSeed;
        
	public acceptRemoteIndexSeedEnum(String starthash) {
            se = getDHTSeeds(true, starthash);
            nextSeed = nextInternal();
	}
        
        public boolean hasMoreElements() {
	    return nextSeed != null;
	}

        private yacySeed nextInternal() {
            yacySeed s;
            try {
                while (se.hasMoreElements()) {
                    s = (yacySeed) se.nextElement();
                    if (s == null) return null;
                    if (s.getFlagAcceptRemoteIndex()) return s;
                }
            } catch (kelondroException e) {
                yacyCore.log.logError("database inconsistency (" + e.getMessage() + "), re-set of db.");
                seedDB.resetActiveTable();
                return null;
            }
            return null;
        }
        
	public Object nextElement() {
            yacySeed next = nextSeed;
            nextSeed = nextInternal();
            return next;
	}

    }
    
    public Enumeration getAcceptRemoteCrawlSeeds(String starthash, boolean available) {
        return new acceptRemoteCrawlSeedEnum(starthash, available);
    }
    
    class acceptRemoteCrawlSeedEnum implements Enumeration {

	Enumeration se;
        yacySeed nextSeed;
        boolean available;
        
	public acceptRemoteCrawlSeedEnum(String starthash, boolean available) {
            this.se = getDHTSeeds(true, starthash);
            this.available = available;
            nextSeed = nextInternal();
	}
        
        public boolean hasMoreElements() {
	    return nextSeed != null;
	}

        private yacySeed nextInternal() {
            yacySeed s;
            while (se.hasMoreElements()) {
                s = (yacySeed) se.nextElement();
		if (s == null) return null;
                if (available) {
                    if (seedCrawlReady.getScore(s.hash) < yacyCore.yacyTime()) return s;
                } else {
                    if (seedCrawlReady.getScore(s.hash) > yacyCore.yacyTime()) return s;
                }
            }
            return null;
        }
        
	public Object nextElement() {
            yacySeed next = nextSeed;
            nextSeed = nextInternal();
            return next;
	}

    }
    
    public synchronized yacySeed getCrawlSeed(String urlHash) {
        Enumeration e = getAcceptRemoteCrawlSeeds(urlHash, true);
        yacySeed seed;
        if (e.hasMoreElements()) seed = (yacySeed) e.nextElement(); else seed = null;
        e = null;
        return seed;
    }
        
    public void setCrawlTime(String seedHash, int newYacyTime) {
        if (newYacyTime < yacyCore.yacyTime()) newYacyTime = yacyCore.yacyTime();
        seedCrawlReady.setScore(seedHash, newYacyTime);
    }
    
    public void setCrawlDelay(String seedHash, int newDelay) {
        seedCrawlReady.setScore(seedHash, yacyCore.yacyTime() + newDelay);
    }

    public void processPeerArrival(yacySeed peer, boolean direct) {
        if (peer.getVersion() >= ((float) 0.3)) {
            if (!(seedCrawlReady.existsScore(peer.hash))) seedCrawlReady.setScore(peer.hash, yacyCore.yacyTime());
        } else {
            seedCrawlReady.deleteScore(peer.hash);
        }
    }
    
    public void processPeerDeparture(yacySeed peer) {
        seedCrawlReady.deleteScore(peer.hash);
    }
    
    public void processPeerPing(yacySeed peer) {
    }
}