// indexAbstractReference.java
// first published on http://www.yacy.net
// (C) 2007 by Bjoern Krombholz
// last major change: 12. August 2006 (theli) ?
//
// This is a part of YaCy, a peer-to-peer based web search engine
//
// $LastChangedDate$
// $LastChangedRevision$
// $LastChangedBy$
//
// LICENSE
// 
// 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

package de.anomic.index;

import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import de.anomic.kelondro.kelondroMSetTools;
import de.anomic.yacy.yacyURL;

public abstract class indexAbstractReferenceBlacklist implements indexReferenceBlacklist {

    protected static final HashSet<String> BLACKLIST_TYPES = new HashSet<String>(Arrays.asList(new String[]{
            indexReferenceBlacklist.BLACKLIST_CRAWLER,
            indexReferenceBlacklist.BLACKLIST_PROXY,
            indexReferenceBlacklist.BLACKLIST_DHT,
            indexReferenceBlacklist.BLACKLIST_SEARCH,
            indexReferenceBlacklist.BLACKLIST_SURFTIPS,
            indexReferenceBlacklist.BLACKLIST_NEWS
    }));
    public static final String BLACKLIST_TYPES_STRING="proxy,crawler,dht,search,surftips,news";
    
    protected File blacklistRootPath = null;
    protected HashMap<String, Set<String>> cachedUrlHashs = null; 
    protected HashMap<String, HashMap<String, ArrayList<String>>> hostpaths = null; // key=host, value=path; mapped url is http://host/path; path does not start with '/' here
    
    public indexAbstractReferenceBlacklist(File rootPath) {
        this.setRootPath(rootPath);
        
        this.blacklistRootPath = rootPath;
        
        // prepare the data structure
        this.hostpaths = new HashMap<String, HashMap<String, ArrayList<String>>>();
        this.cachedUrlHashs = new HashMap<String, Set<String>>();
        
        Iterator<String> iter = BLACKLIST_TYPES.iterator();
        while (iter.hasNext()) {
            String blacklistType = (String) iter.next();
            this.hostpaths.put(blacklistType, new HashMap<String, ArrayList<String>>());
            this.cachedUrlHashs.put(blacklistType, Collections.synchronizedSet(new HashSet<String>()));
        }            
    }
    
    public void setRootPath(File rootPath) {
        if (rootPath == null) 
            throw new NullPointerException("The blacklist root path must not be null.");
        if (!rootPath.isDirectory()) 
            throw new IllegalArgumentException("The blacklist root path is not a directory.");
        if (!rootPath.canRead())
            throw new IllegalArgumentException("The blacklist root path is not readable.");
        
        this.blacklistRootPath = rootPath;
    }
    
    protected HashMap<String, ArrayList<String>> getBlacklistMap(String blacklistType) {
        if (blacklistType == null) throw new IllegalArgumentException();
        if (!BLACKLIST_TYPES.contains(blacklistType)) throw new IllegalArgumentException("Unknown blacklist type: "+blacklistType+".");        
        
        return this.hostpaths.get(blacklistType);
    }
    
    protected Set<String> getCacheUrlHashsSet(String blacklistType) {
        if (blacklistType == null) throw new IllegalArgumentException();
        if (!BLACKLIST_TYPES.contains(blacklistType)) throw new IllegalArgumentException("Unknown backlist type.");        

        return this.cachedUrlHashs.get(blacklistType);
    }
    
    public void clear() {
        Iterator<HashMap<String, ArrayList<String>>> iter = this.hostpaths.values().iterator();
        Iterator<Set<String>> cIter = this.cachedUrlHashs.values().iterator();
        while (iter.hasNext()) {
            iter.next().clear();
        }
        while (cIter.hasNext()) {
            // clear caches as well to avoid wrong/outdated matches after changing lists
            cIter.next().clear();
        }
    }

    public int size() {
        int size = 0;
        Iterator<String> iter = this.hostpaths.keySet().iterator();
        while (iter.hasNext()) {
            Iterator<ArrayList<String>> blIter = this.hostpaths.get(iter.next()).values().iterator();
            while (blIter.hasNext())
                size += blIter.next().size();
        }
        return size;
    }
    
    public void loadList(blacklistFile[] blFiles, String sep) {        
        for (int j = 0; j < blFiles.length; j++) {
            blacklistFile blf = blFiles[j];
            loadList(blf.getType(), blf.getFileName(), sep);
        }
    }
    
    public void loadList(blacklistFile blFile, String sep) {
        HashMap<String, ArrayList<String>> blacklistMap = getBlacklistMap(blFile.getType());
        Set<Map.Entry<String, ArrayList<String>>> loadedBlacklist;
        Map.Entry<String, ArrayList<String>> loadedEntry;
        ArrayList<String> paths;
        ArrayList<String> loadedPaths;

        String[] fileNames = blFile.getFileNamesUnified();
        if (fileNames.length > 0) {
            for (int i = 0; i < fileNames.length; i++) {
                // make sure all requested blacklist files exist
                File file = new File(this.blacklistRootPath, fileNames[i]);
                try {
                    file.createNewFile();
                } catch (IOException e) { /* */ }
                
                // join all blacklists from files into one internal blacklist map
                loadedBlacklist = kelondroMSetTools.loadMapMultiValsPerKey(file.toString(), sep).entrySet();
                for (Iterator<Map.Entry<String, ArrayList<String>>> mi = loadedBlacklist.iterator(); mi.hasNext(); ) {
                    loadedEntry = mi.next();
                    loadedPaths = loadedEntry.getValue();
                    
                    // create new entry if host mask unknown, otherwise merge
                    // existing one with path patterns from blacklist file 
                    paths = blacklistMap.get(loadedEntry.getKey());
                    if (paths == null) {
                        blacklistMap.put(loadedEntry.getKey(), loadedPaths);
                    } else {
                        // TODO check for duplicates? (refactor List -> Set)
                        paths.addAll(loadedPaths);
                    }
                }
            }
        }
    }
    
    public void loadList(String blacklistType, String fileNames, String sep) {
        // method for not breaking older plasmaURLPattern interface
        blacklistFile blFile = new blacklistFile(fileNames, blacklistType);
        
        loadList(blFile, sep);
    }
    
    public void removeAll(String blacklistType, String host) {
        HashMap<String, ArrayList<String>> blacklistMap = getBlacklistMap(blacklistType);
        blacklistMap.remove(host);
    }
    
    public void remove(String blacklistType, String host, String path) {
        HashMap<String, ArrayList<String>> blacklistMap = getBlacklistMap(blacklistType);
        ArrayList<String> hostList = blacklistMap.get(host);
        hostList.remove(path);
        if (hostList.size() == 0)
            blacklistMap.remove(host);
    }

    public void add(String blacklistType, String host, String path) {
        if (host == null) throw new NullPointerException();
        if (path == null) throw new NullPointerException();
        
        if (path.length() > 0 && path.charAt(0) == '/') path = path.substring(1);
        
        HashMap<String, ArrayList<String>> blacklistMap = getBlacklistMap(blacklistType);
        ArrayList<String> hostList = blacklistMap.get(host.toLowerCase());
        if (hostList == null) blacklistMap.put(host.toLowerCase(), (hostList = new ArrayList<String>()));
        hostList.add(path);
    }

    public int blacklistCacheSize() {
        int size = 0;
        Iterator<String> iter = this.cachedUrlHashs.keySet().iterator();
        while (iter.hasNext()) {
            Set<String> blacklistMap = this.cachedUrlHashs.get(iter.next());
            size += blacklistMap.size();
        }
        return size;        
    }

    public boolean hashInBlacklistedCache(String blacklistType, String urlHash) {
        Set<String> urlHashCache = getCacheUrlHashsSet(blacklistType);   
        return urlHashCache.contains(urlHash);
    }

    public boolean isListed(String blacklistType, yacyURL url) {

        Set<String> urlHashCache = getCacheUrlHashsSet(blacklistType);        
        if (!urlHashCache.contains(url.hash())) {
            boolean temp = isListed(blacklistType, url.getHost().toLowerCase(), url.getFile());
            if (temp) {
                urlHashCache.add(url.hash());
            }
            return temp;   
        }        
        return true;  
    }

}