// BlacklistCleaner_p.java 
// -----------------------
// part of YaCy
// (C) by Michael Peter Christen; mc@yacy.net
// first published on http://www.anomic.de
// Frankfurt, Germany, 2004
//
// This File is contributed by Franz Brausze
//
// $LastChangedDate: 2007-01-27 14:07:54 +0000 (Sa, 27 Jan 2007) $
// $LastChangedRevision: 3217 $
// $LastChangedBy: karlchenofhell $
//
// 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 BlacklistCleaner_p.java
// if the shell's current path is HTROOT

import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.regex.PatternSyntaxException;

import de.anomic.data.listManager;
import de.anomic.http.httpRequestHeader;
import de.anomic.index.indexAbstractReferenceBlacklist;
import de.anomic.index.indexDefaultReferenceBlacklist;
import de.anomic.index.indexReferenceBlacklist;
import de.anomic.plasma.plasmaSwitchboard;
import de.anomic.server.serverObjects;
import de.anomic.server.serverSwitch;
import de.anomic.server.logging.serverLog;

public class BlacklistCleaner_p {
    
    private static final String RESULTS = "results_";
    private static final String DISABLED = "disabled_";
    private static final String BLACKLISTS = "blacklists_";
    private static final String ENTRIES = "entries_";
    
    private static final int ERR_TWO_WILDCARDS_IN_HOST = 0;
    private static final int ERR_SUBDOMAIN_XOR_WILDCARD = 1;
    private static final int ERR_PATH_REGEX = 2;
    private static final int ERR_WILDCARD_BEGIN_OR_END = 3;
    private static final int ERR_HOST_WRONG_CHARS = 4;
    private static final int ERR_DOUBLE_OCCURANCE = 5;
    
    private final static String BLACKLIST_FILENAME_FILTER = "^.*\\.black$";
    
    public static final Class<?>[] supportedBLEngines = {
        indexDefaultReferenceBlacklist.class
    };
    
    public static serverObjects respond(final httpRequestHeader header, final serverObjects post, final serverSwitch<?> env) {
        final serverObjects prop = new serverObjects();
        
        // initialize the list manager
        listManager.switchboard = (plasmaSwitchboard) env;
        listManager.listsPath = new File(env.getRootPath(), env.getConfig("listManager.listsPath", "DATA/LISTS"));
        String blacklistToUse = null;
        
        // getting the list of supported blacklist types
        final String supportedBlacklistTypesStr = indexAbstractReferenceBlacklist.BLACKLIST_TYPES_STRING;
        final String[] supportedBlacklistTypes = supportedBlacklistTypesStr.split(","); 
        
        if (post == null) {
            prop.put("results", "0");
            putBlacklists(prop, listManager.getDirListing(listManager.listsPath, BLACKLIST_FILENAME_FILTER), blacklistToUse);
            return prop;
        }
        
        if (post.containsKey("listNames")) {
            blacklistToUse = post.get("listNames"); 
            if (blacklistToUse.length() == 0 || !listManager.listSetContains("listManager.listsPath", blacklistToUse))
                prop.put("results", "2");
        }
        
        putBlacklists(prop, listManager.getDirListing(listManager.listsPath, BLACKLIST_FILENAME_FILTER), blacklistToUse);
        
        if (blacklistToUse != null) {
            prop.put("results", "1");
            
            if (post.containsKey("delete")) {
                prop.put(RESULTS + "modified", "1");
                prop.put(RESULTS + "modified_delCount", removeEntries(blacklistToUse, supportedBlacklistTypes, getByPrefix(post, "select", true, true)));
            } else if (post.containsKey("alter")) {
                prop.put(RESULTS + "modified", "2");
                prop.put(RESULTS + "modified_alterCount", alterEntries(blacklistToUse, supportedBlacklistTypes, getByPrefix(post, "select", true, false), getByPrefix(post, "entry", false, false)));
            }
            
            // list illegal entries
            final HashMap<String, Integer> ies = getIllegalEntries(blacklistToUse, supportedBlacklistTypes, plasmaSwitchboard.urlBlacklist);
            prop.put(RESULTS + "entries", ies.size());
            prop.putHTML(RESULTS + "blEngine", plasmaSwitchboard.urlBlacklist.getEngineInfo());
            prop.put(RESULTS + "disabled", (ies.size() == 0) ? "1" : "0");
            if (ies.size() > 0) {
                prop.put(RESULTS + DISABLED + "entries", ies.size());
                int i = 0;
                String s;
                for (Entry<String, Integer> entry: ies.entrySet()) {
                    s = entry.getKey();
                    prop.put(RESULTS + DISABLED + ENTRIES + i + "_error", entry.getValue().longValue());
                    prop.putHTML(RESULTS + DISABLED + ENTRIES + i + "_entry", s);
                    i++;
                }
            }
        }
        
        return prop;
    }
    
    private static void putBlacklists(final serverObjects prop, final List<String> lists, final String selected) {
        boolean supported = false;
        for (int i=0; i<supportedBLEngines.length && !supported; i++) {
            supported |= (plasmaSwitchboard.urlBlacklist.getClass() == supportedBLEngines[i]);
        }
        
        if (supported) {
            if (lists.size() > 0) {
                prop.put("disabled", "0");
                prop.put(DISABLED + "blacklists", lists.size());
                int count = 0;
                for (String list : lists) {
                    prop.putHTML(DISABLED + BLACKLISTS + count + "_name", list);
                    prop.put(DISABLED + BLACKLISTS + count + "_selected", (list.equals(selected)) ? "1" : "0");
                    count++;
                }
            } else {
                prop.put("disabled", "2");
            }
        } else {
            prop.put("disabled", "1");
            for (int i=0; i<supportedBLEngines.length; i++) {
                prop.putHTML(DISABLED + "engines_" + i + "_name", supportedBLEngines[i].getName());
            }
            prop.put(DISABLED + "engines", supportedBLEngines.length);
        }
    }
    
    private static String[] getByPrefix(final serverObjects post, final String prefix, final boolean useKeys, final boolean useHashSet) {
        Collection<String> r;
        if (useHashSet) {
            r = new HashSet<String>();
        } else {
            r = new ArrayList<String>();
        }
        
        String s;
        if (useKeys) {
            final Iterator<String> it =  post.keySet().iterator();
            while (it.hasNext()) {
                if ((s = it.next()).indexOf(prefix) == 0) {
                    r.add(s.substring(prefix.length()));
                }
            }
        } else {
            final Iterator<Map.Entry<String, String>> it = post.entrySet().iterator();
            Map.Entry<String, String> entry;
            while (it.hasNext()) {
                entry = it.next();
                if (entry.getKey().indexOf(prefix) == 0) {
                    r.add(entry.getValue());
                }
            }
        }
        
        return r.toArray(new String[r.size()]);
    }
    
    private static HashMap<String, Integer>/* entry, error-code */ getIllegalEntries(final String blacklistToUse, final String[] supportedBlacklistTypes, final indexReferenceBlacklist blEngine) {
        final HashMap<String, Integer> r = new HashMap<String, Integer>();
        final HashSet<String> ok = new HashSet<String>();
        
        final ArrayList<String> list = listManager.getListArray(new File(listManager.listsPath, blacklistToUse));
        final Iterator<String> it = list.iterator();
        String s, host, path;
        
        if (blEngine instanceof indexDefaultReferenceBlacklist) {
            int slashPos;
            while (it.hasNext()) {
                s = (it.next()).trim();
                
                // check for double-occurance
                if (ok.contains(s)) {
                    r.put(s, Integer.valueOf(ERR_DOUBLE_OCCURANCE));
                    continue;
                }
                ok.add(s);
                
                if ((slashPos = s.indexOf("/")) == -1) {
                    host = s;
                    path = ".*";
                } else {
                    host = s.substring(0, slashPos);
                    path = s.substring(slashPos + 1);
                }
                
                final int i = host.indexOf("*");
                
                // check whether host begins illegally
                if (!host.matches("([A-Za-z0-9_-]+|\\*)(\\.([A-Za-z0-9_-]+|\\*))*")) {
                    if (i == 0 && host.length() > 1 && host.charAt(1) != '.') {
                        r.put(s, Integer.valueOf(ERR_SUBDOMAIN_XOR_WILDCARD));
                        continue;
                    }
                    r.put(s, Integer.valueOf(ERR_HOST_WRONG_CHARS));
                    continue;
                }
                
                // in host-part only full sub-domains may be wildcards
                if (host.length() > 0 && i > -1) {
                    if (!(i == 0 || i == host.length() - 1)) {
                        r.put(s, Integer.valueOf(ERR_WILDCARD_BEGIN_OR_END));
                        continue;
                    }
                    
                    if (i == host.length() - 1 && host.length() > 1 && host.charAt(i - 1) != '.') {
                        r.put(s, Integer.valueOf(ERR_SUBDOMAIN_XOR_WILDCARD));
                        continue;
                    }
                }
                
                // check for double-occurences of "*" in host
                if (host.indexOf("*", i + 1) > -1) {
                    r.put(s, Integer.valueOf(ERR_TWO_WILDCARDS_IN_HOST));
                    continue;
                }
                
                // check for errors on regex-compiling path
                try {
                    Pattern.compile(path);
                } catch (final PatternSyntaxException e) {
                    r.put(s, Integer.valueOf(ERR_PATH_REGEX));
                    continue;
                }
            }
        }

        return r;
    }
    
    private static int removeEntries(final String blacklistToUse, final String[] supportedBlacklistTypes, final String[] entries) {
        // load blacklist data from file
        final ArrayList<String> list = listManager.getListArray(new File(listManager.listsPath, blacklistToUse));
        
        boolean listChanged = false;
        
        // delete the old entry from file
        String s;
        for (int i=0; i<entries.length; i++) {
            s = entries[i];
            
            if (list != null){
                
                // getting rid of escape characters which make it impossible to
                // properly use contains()
                if (s.contains("\\\\")) {
                    s = s.replaceAll(Pattern.quote("\\\\"), Matcher.quoteReplacement("\\"));
                }
           
                if (list.contains(s)) {
                    list.remove(s);
                    listChanged = true;
                }
            }
            
            // remove the entry from the running blacklist engine
            for (int blTypes=0; blTypes < supportedBlacklistTypes.length; blTypes++) {
                if (listManager.listSetContains(supportedBlacklistTypes[blTypes] + ".BlackLists", blacklistToUse)) {
                    final String host = (s.indexOf("/") == -1) ? s : s.substring(0, s.indexOf("/"));
                    final String path = (s.indexOf("/") == -1) ? ".*" : s.substring(s.indexOf("/") + 1);
                    try {
                    plasmaSwitchboard.urlBlacklist.remove(supportedBlacklistTypes[blTypes],
                            host,path);
                    } catch (final RuntimeException e) {
                        //System.err.println(e.getMessage() + ": " + host + "/" + path);
                        serverLog.logSevere("BLACKLIST-CLEANER", e.getMessage() + ": " + host + "/" + path);
                    }
                }                
            }    
        }
        if (listChanged){
            listManager.writeList(new File(listManager.listsPath, blacklistToUse), list.toArray(new String[list.size()]));
        }
        return entries.length;
    }
    
    private static int alterEntries(
            final String blacklistToUse,
            final String[] supportedBlacklistTypes,
            final String[] oldE,
            final String[] newE) {
        removeEntries(blacklistToUse, supportedBlacklistTypes, oldE);
        PrintWriter pw = null;
        try {
            pw = new PrintWriter(new FileWriter(new File(listManager.listsPath, blacklistToUse), true));
            String host, path;
            for (int i=0, pos; i<newE.length; i++) {
                pos = newE[i].indexOf("/");
                if (pos < 0) {
                    host = newE[i];
                    path = ".*";
                } else {
                    host = newE[i].substring(0, pos);
                    path = newE[i].substring(pos + 1);
                }
                pw.println(host + "/" + path);
                for (int blTypes=0; blTypes < supportedBlacklistTypes.length; blTypes++) {
                    if (listManager.listSetContains(supportedBlacklistTypes[blTypes] + ".BlackLists",blacklistToUse)) {
                        plasmaSwitchboard.urlBlacklist.add(
                                supportedBlacklistTypes[blTypes],
                                host,
                                path);
                    }
                }
            }
            pw.close();
        } catch (final IOException e) {
            serverLog.logSevere("BLACKLIST-CLEANER", "error on writing altered entries to blacklist", e);
        }
        return newE.length;
    }
}