// plasmaWordIndex.java
// -----------------------
// part of YACY
// (C) by Michael Peter Christen; mc@anomic.de
// first published on http://www.anomic.de
// Frankfurt, Germany, 2005
//
// $LastChangedDate$
// $LastChangedRevision$
// $LastChangedBy$
//
// 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
//
// 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
// lines that follows this copyright notice here, but changes must not be
// done inside the copyright notive above. A re-distribution must contain
// the intact and unchanged copyright notice.
// Contributions and changes to the program code must be marked as such.

// compile with
// javac -classpath classes -sourcepath source -d classes -g source/de/anomic/plasma/*.java

package de.anomic.plasma;

import java.io.File;
import java.util.ArrayList;
import java.util.Comparator;
import java.util.Iterator;
import java.util.TreeSet;
import java.util.HashSet;
import java.util.Set;
import java.util.Date;
import java.net.URL;

import de.anomic.kelondro.kelondroBase64Order;
import de.anomic.kelondro.kelondroNaturalOrder;
import de.anomic.server.logging.serverLog;
import de.anomic.yacy.yacySeedDB;

public final class plasmaWordIndex {

    private final File databaseRoot;
    private final plasmaWordIndexCache ramCache;

    public plasmaWordIndex(File databaseRoot, int bufferkb, serverLog log) {
        this.databaseRoot = databaseRoot;
        plasmaWordIndexClassicDB fileDB = new plasmaWordIndexClassicDB(databaseRoot, log);
        this.ramCache = new plasmaWordIndexCache(databaseRoot, fileDB, bufferkb, log);
    }

    public File getRoot() {
        return databaseRoot;
    }

    public int maxURLinWordCache() {
        return ramCache.maxURLinWordCache();
    }

    public int wordCacheRAMSize() {
        return ramCache.wordCacheRAMSize();
    }

    public int[] assortmentSizes() {
        return ramCache.assortmentsSizes();
    }
    
    public int[] assortmentsCacheChunkSizeAvg() {
        return ramCache.assortmentsCacheChunkSizeAvg();
    }
    
    public int[] assortmentsCacheFillStatusCml() {
        return ramCache.assortmentsCacheFillStatusCml();
    }
    
    public void setMaxWords(int maxWordsLow, int maxWordsHigh) {
        ramCache.setMaxWords(maxWordsLow, maxWordsHigh);
    }

    public int addEntries(plasmaWordIndexEntryContainer entries, boolean highPriority) {
        return ramCache.addEntries(entries, System.currentTimeMillis(), highPriority);
    }

    private static final int hour = 3600000;
    private static final int day  = 86400000;
    
    public static int microDateDays(Date modified) {
	// this calculates a virtual age from a given date
	// the purpose is to have an age in days of a given modified date
	// from a fixed standpoint in the past
	// one day has 60*60*24 seconds = 86400 seconds
	// we take mod 64**3 = 262144, this is the mask of the storage
	return (int) ((modified.getTime() / day) % 262144);
    }
    
    public static String microDateHoursStr(long time) {
	return kelondroBase64Order.enhancedCoder.encodeLong(microDateHoursInt(time), 3);
    }
    
    public static int microDateHoursInt(long time) {
	return (int) ((time / hour) % 262144);
    }
    
    public static int microDateHoursAge(String mdhs) {
        return microDateHoursInt(System.currentTimeMillis()) - (int) kelondroBase64Order.enhancedCoder.decodeLong(mdhs);
    }
    
    public int addPageIndex(URL url, String urlHash, Date urlModified, plasmaCondenser condenser,
                                   String language, char doctype) {
        // this is called by the switchboard to put in a new page into the index
	// use all the words in one condenser object to simultanous create index entries
	int age = microDateDays(urlModified);
	int quality = 0;
	try {
	    quality = condenser.RESULT_INFORMATION_VALUE;
	} catch (NumberFormatException e) {
	    System.out.println("INTERNAL ERROR WITH CONDENSER.INFORMATION_VALUE: " + e.toString() + ": in URL " + url.toString());
	}

        // iterate over all words
	Iterator i = condenser.getWords().iterator();
	String word;
	int count;
	plasmaWordIndexEntry entry;
	String wordHash;
	int p = 0;
	while (i.hasNext()) {
	    word = (String) i.next();
	    count = condenser.wordCount(word);
	    //if ((s.length() > 4) && (c > 1)) System.out.println("# " + s + ": " + c);
	    wordHash = plasmaWordIndexEntry.word2hash(word);
	    entry = new plasmaWordIndexEntry(urlHash, count, p++, 0, 0,
                                         age, quality, language, doctype, true);
	    addEntries(plasmaWordIndexEntryContainer.instantContainer(wordHash, System.currentTimeMillis(), entry), false);
	}
	//System.out.println("DEBUG: plasmaSearch.addPageIndex: added " + condenser.getWords().size() + " words, flushed " + c + " entries");
        return condenser.getWords().size();
    }
    
    public plasmaWordIndexEntity getEntity(String wordHash, boolean deleteIfEmpty, long maxTime) {
        return ramCache.getIndex(wordHash, deleteIfEmpty, maxTime);
    }

    public Set getEntities(Set wordHashes, boolean deleteIfEmpty, boolean interruptIfEmpty, long maxTime) {
        
        // retrieve entities that belong to the hashes
        HashSet entities = new HashSet();
        String singleHash;
        plasmaWordIndexEntity singleEntity;
        Iterator i = wordHashes.iterator();
        long start = System.currentTimeMillis();
        long remaining;
        while (i.hasNext()) {
            // check time
            remaining = maxTime - (System.currentTimeMillis() - start);
            if ((maxTime > 0) && (remaining <= 0)) break;
            
            // get next hash:
            singleHash = (String) i.next();
            
            // retrieve index
            singleEntity = getEntity(singleHash, deleteIfEmpty, (maxTime < 0) ? -1 : remaining / (wordHashes.size() - entities.size()));
            
            // check result
            if (((singleEntity == null) || (singleEntity.size() == 0)) && (interruptIfEmpty)) return null;
            
            entities.add(singleEntity);
        }
        return entities;
    }

    public int size() {
        return ramCache.size();
    }

    public int removeEntries(String wordHash, String[] urlHashes, boolean deleteComplete) {
        return ramCache.removeEntries(wordHash, urlHashes, deleteComplete);
    }

    public void intermission(long pause) {
        this.ramCache.intermission(pause);
    }

    public void close(int waitingBoundSeconds) {
        ramCache.close(waitingBoundSeconds);
    }

    public void deleteIndex(String wordHash) {
        ramCache.deleteIndex(wordHash);
    }

    public Iterator wordHashes(String startHash, boolean up, boolean rot) {
        //return ramCache.wordHashes(startHash, up);
        if (rot) return new rotatingWordIterator(up, startHash);
        else return new correctedWordIterator(up, rot, startHash); // use correction until bug is found
    }

    private final class correctedWordIterator implements Iterator {    
        Iterator iter;
        String nextWord;

        public correctedWordIterator(boolean up, boolean rotating, String firstWord) {
            iter = ramCache.wordHashes(firstWord, up, rotating);
            nextWord = (iter.hasNext()) ? (String) iter.next() : null;
            boolean corrected = true;
            int cc = 0; // to avoid rotation loops
            while ((nextWord != null) && (corrected) && (cc < 50)) {
                int c = firstWord.compareTo(nextWord);
                corrected = false;
                if ((c > 0) && (up)) {
                    // firstKey > nextNode.getKey()
                    //System.out.println("CORRECTING WORD ITERATOR: firstWord=" + firstWord + ", nextWord=" + nextWord);
                    nextWord = (iter.hasNext()) ? (String) iter.next() : null;
                    corrected = true;
                    cc++;
                }
                if ((c < 0) && (!(up))) {
                    nextWord = (iter.hasNext()) ? (String) iter.next() : null;
                    corrected = true;
                    cc++;
                }
            }
        }

        public void finalize() {
            iter = null;
            nextWord = null;
        }

        public boolean hasNext() {
            return nextWord != null;
        }

        public Object next() {
            String r = nextWord;
            nextWord = (iter.hasNext()) ? (String) iter.next() : null;                        
            return r;
        }

        public void remove() {
            throw new java.lang.UnsupportedOperationException("correctedWordIterator  does not support remove");
        }
    } // correctedWordIterator

    private class rotatingWordIterator implements Iterator {
        Iterator i;
        boolean up;

        public rotatingWordIterator(boolean up, String startWordHash) {
            this.up = up;
            i = new correctedWordIterator(up, false, startWordHash);
        }

        public void finalize() {
            i = null;
        }

        public boolean hasNext() {
            if (i.hasNext()) return true;
            else {
                i = new correctedWordIterator(up, false, (up)?"------------":"zzzzzzzzzzzz");
                return i.hasNext();
            }
        }

        public Object next() {
            return i.next();
        }

        public void remove() {
            throw new java.lang.UnsupportedOperationException("rotatingWordIterator does not support remove");
        }
    } // class rotatingWordIterator

    public Iterator fileIterator(String startHash, boolean up, boolean deleteEmpty) {
        return new iterateFiles(startHash, up, deleteEmpty);
    }

    public final class iterateFiles implements Iterator {
        // Iterator of hash-strings in WORDS path

        private final ArrayList hierarchy; // contains TreeSet elements, earch TreeSet contains File Entries
        private final Comparator comp;     // for string-compare
        private String buffer;       // the prefetch-buffer
        private final boolean delete;

        public iterateFiles(String startHash, boolean up, boolean deleteEmpty) {
            this.hierarchy = new ArrayList();
            this.comp = kelondroNaturalOrder.naturalOrder; // this is the wrong ordering but mut be used as long as the assortments uses the same ordering
            //this.comp = new kelondroBase64Order(up, false);
            this.delete = deleteEmpty;

            // the we initially fill the hierarchy with the content of the root folder
            String path = "WORDS";
            TreeSet list = list(new File(databaseRoot, path));

            // if we have a start hash then we find the appropriate subdirectory to start
            if ((startHash != null) && (startHash.length() == yacySeedDB.commonHashLength)) {
                delete(startHash.substring(0, 1), list);
                if (list.size() > 0) {
                    hierarchy.add(list);
                    String[] paths = new String[]{startHash.substring(0, 1), startHash.substring(1, 2), startHash.substring(2, 4), startHash.substring(4, 6)};
                    int pathc = 0;
                    while ((pathc < paths.length) &&
                    (comp.compare((String) list.first(), paths[pathc]) == 0)) {
                        path = path + "/" + paths[pathc];
                        list = list(new File(databaseRoot, path));
                        delete(paths[pathc], list);
                        if (list.size() == 0) break;
                        hierarchy.add(list);
                        pathc++;
                    }
                }
                while (((buffer = next0()) != null) && (comp.compare(buffer, startHash) < 0)) {};
            } else {
                hierarchy.add(list);
                buffer = next0();
            }
        }

        private synchronized void delete(String pattern, TreeSet names) {
            String name;
            while ((names.size() > 0) && (comp.compare((new File(name = (String) names.first())).getName(), pattern) < 0)) names.remove(name);
        }

        private TreeSet list(File path) {
//          System.out.println("PATH: " + path);
            TreeSet t = new TreeSet(comp);
            String[] l = path.list();
            if (l != null) for (int i = 0; i < l.length; i++) t.add(path + "/" + l[i]);
//          else System.out.println("DEBUG: wrong path " + path);
//          System.out.println(t);
            return t;
        }

        private synchronized String next0() {
            // the object is a File pointing to the corresponding file
            File f;
            String n;
            TreeSet t;
            do {
                t = null;
                while ((t == null) && (hierarchy.size() > 0)) {
                    t = (TreeSet) hierarchy.get(hierarchy.size() - 1);
                    if (t.size() == 0) {
                        hierarchy.remove(hierarchy.size() - 1); // we step up one hierarchy
                        t = null;
                    }
                }
                if ((hierarchy.size() == 0) || (t.size() == 0)) return null; // this is the end
                // fetch value
                f = new File(n = (String) t.first());
                t.remove(n);
                // if the value represents another folder, we step into the next hierarchy
                if (f.isDirectory()) {
                    t = list(f);
                    if (t.size() == 0) {
                        if (delete) f.delete();
                    } else {
                        hierarchy.add(t);
                    }
                    f = null;
                }
            } while (f == null);
            // thats it
            if ((f == null) || ((n = f.getName()) == null) || (n.length() < yacySeedDB.commonHashLength)) {
                return null;
            } else {
                return n.substring(0, yacySeedDB.commonHashLength);
            }
        }

        public boolean hasNext() {
            return buffer != null;
        }

        public Object next() {
            String r = buffer;
            while (((buffer = next0()) != null) && (comp.compare(buffer, r) < 0)) {};
            return r;
        }

        public void remove() {
        }
    }

    public static void main(String[] args) {
//      System.out.println(kelondroMSetTools.fastStringComparator(true).compare("RwGeoUdyDQ0Y", "rwGeoUdyDQ0Y"));
        plasmaWordIndex index = new plasmaWordIndex(new File("D:\\dev\\proxy\\DATA\\PLASMADB"), 555, new serverLog("TESTAPP"));
        Iterator iter = index.wordHashes("5A8yhZMh_Kmv", true, true);
        while (iter.hasNext()) {
            System.out.println("File: " + (String) iter.next());
        }
    }

}