// kelondroMap.java
// -----------------------
// part of The Kelondro Database
// (C) by Michael Peter Christen; mc@anomic.de
// first published on http://www.anomic.de
// Frankfurt, Germany, 2004
// last major change: 26.10.2004
//
// 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.


package de.anomic.kelondro;

import java.io.IOException;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.ListIterator;
import java.util.Map;

public class kelondroMap {
    
    private static final int cachesize = 500;
    
    private kelondroDyn dyn;
    private kelondroMScoreCluster cacheScore;
    private HashMap cache;
    private long startup;
    private String[] sortfields, accfields;
    private HashMap sortClusterMap; // a String-kelondroMScoreCluster - relation
    private HashMap accMap; // to store accumulations of specific fields
    private int elementCount;
    private writeQueue writeWorker;
    
    public kelondroMap(kelondroDyn dyn) {
        this(dyn, null, null);
    }

    public kelondroMap(kelondroDyn dyn, String[] sortfields, String[] accfields) {
        this.dyn = dyn;
        this.cache = new HashMap();
        this.cacheScore = new kelondroMScoreCluster();
        this.startup = System.currentTimeMillis();
        this.elementCount = 0;
                
        // create fast ordering clusters and acc fields
        this.sortfields = sortfields;
        this.accfields = accfields;
        
        kelondroMScoreCluster[] cluster = null;
        if (sortfields == null) sortClusterMap = null; else {
            sortClusterMap = new HashMap();
            cluster = new kelondroMScoreCluster[sortfields.length];
            for (int i = 0; i < sortfields.length; i++) cluster[i] = new kelondroMScoreCluster();
        }
        
        Long[] accumulator = null;
        if (accfields == null) accMap = null; else {
            accMap = new HashMap();
            accumulator = new Long[accfields.length];
            for (int i = 0; i < accfields.length; i++) accumulator[i] = new Long(0);
        }

        // fill cluster and accumulator with values
        if ((sortfields != null) || (accfields != null)) try {
            kelondroDyn.dynKeyIterator it = dyn.dynKeys(true, false);
            String key, value;
            long valuel;
            Map map;
            while (it.hasNext()) {
                key = (String) it.next();
		//System.out.println("kelondroMap: enumerating key " + key);
                map = get(key);
                
                if (sortfields != null) for (int i = 0; i < sortfields.length; i++) {
                    value = (String) map.get(sortfields[i]);
                    if (value != null) cluster[i].setScore(key, kelondroMScoreCluster.string2score(value));
                }
                
                if (accfields != null) for (int i = 0; i < accfields.length; i++) {
                    value = (String) map.get(sortfields[i]);
                    if (value != null) try {
                        valuel = Long.parseLong(value);
                        accumulator[i] = new Long(accumulator[i].longValue() + valuel);
                    } catch (NumberFormatException e) {}
                }
                elementCount++;
            }
        } catch (IOException e) {}
        
        // fill cluster
        if (sortfields != null) for (int i = 0; i < sortfields.length; i++) sortClusterMap.put(sortfields[i], cluster[i]);

        // fill acc map
        if (accfields != null) for (int i = 0; i < accfields.length; i++) accMap.put(accfields[i], accumulator[i]);

        // initialize a writeQueue and start it
        writeWorker = new writeQueue();
        writeWorker.start();
    }

    class writeQueue extends Thread {

        private LinkedList queue = new LinkedList();
        boolean run;
        
        public writeQueue() {
            run = true;
        }
        
        public void stack(String key) {
            //System.out.println("kelondroMap: stack(" + dyn.entryFile.name() + ") " + key);
            if (this.isAlive())
                queue.addLast(key);
            else
                workoff(key);
        }
        
        public void workoff() {
            String newKey = null;
            synchronized (this.queue) {
                if (this.queue.size() > 0) {
                    newKey = (String) this.queue.removeFirst();                    
                }
			}
            if (newKey != null) workoff(newKey);            
        }

        public void dequeue(String key) {
            // take out one entry
            synchronized (this.queue) {
	            ListIterator i = queue.listIterator();
	            String k;
	            while (i.hasNext()) {
	                k = (String) i.next();
	                if (k.equals(key)) {
	                    i.remove();
	                    return;
	                }
	            }
            }
        }
        
        public void workoff(String key) {
            //System.out.println("kelondroMap: workoff(" + dyn.entryFile.name() + ") " + key);
            Map map = (Map) cache.get(key);
            if (map == null) return;
            try {
                writeKra(key, map, "");
            } catch (IOException e) {
                System.out.println("PANIC! Critical Error in kelondroMap.writeQueue.workoff(" + dyn.entryFile.name() + "): " + e.getMessage());
                e.printStackTrace();
                run = false;
            }
        }
        
        public void run() {
            try {sleep(((System.currentTimeMillis() / 3) % 10) * 10000);} catch (InterruptedException e) {} // offset start
            
            //System.out.println("XXXX! " + (System.currentTimeMillis() / 1000) + " " + dyn.entryFile.name());
            int c;
            while (run) {
                c = 0; while ((run) && (c++ < 10)) try {sleep(1000);} catch (InterruptedException e) {}
                //System.out.println("PING! " + (System.currentTimeMillis() / 1000) + " " + dyn.entryFile.name());
                while (queue.size() > 0) {
                    if (run) try {sleep(5000 / queue.size());} catch (InterruptedException e) {}
                    workoff();
                }
            }
            while (queue.size() > 0) workoff();
        }
        
        public void terminate(boolean waitFor) {
            run = false;
            if (waitFor) while (this.isAlive()) try {sleep(500);} catch (InterruptedException e) {}                
        }
    }
    
    /*
    public synchronized boolean has(String key) throws IOException {
        return (cache.containsKey(key)) || (dyn.existsDyn(key));
    }
    */
    
    public synchronized void set(String key, Map newMap) throws IOException {
        // update elementCount
        if ((sortfields != null) || (accfields != null)) {
            Map oldMap = get(key, false);
            if (oldMap == null) {
                // new element
                elementCount++;
            } else {
                // element exists, update acc
                if (accfields != null) updateAcc(oldMap, false);
            }
        }
        
        // stack to write queue
        writeWorker.stack(key);
        
        // check for space in cache
        checkCacheSpace();
        
        // write map to cache
        cacheScore.setScore(key, (int) ((System.currentTimeMillis() - startup) / 1000));
        cache.put(key, newMap);
        
        
        // update sortCluster
        if (sortClusterMap != null) updateSortCluster(key, newMap);
        
        // update accumulators with new values (add)
        if (accfields != null) updateAcc(newMap, true);
    }
    
    private synchronized void writeKra(String key, Map newMap, String comment) throws IOException {
        // write map to kra
	kelondroRA kra = dyn.getRA(key);
	kra.writeMap(newMap, comment);
	kra.close();
    }
    
    private void updateAcc(Map map, boolean add) {
        String value;
        long valuel;
        Long accumulator;
        for (int i = 0; i < accfields.length; i++) {
            value = (String) map.get(accfields[i]);
            if (value != null) try {
                valuel = Long.parseLong(value);
                accumulator = (Long) accMap.get(accfields[i]);
                if (add)
                    accMap.put(accfields[i], new Long(accumulator.longValue() + valuel));
                else
                    accMap.put(accfields[i], new Long(accumulator.longValue() - valuel));
            } catch (NumberFormatException e) {}
        }
    }

    private void updateSortCluster(String key, Map map) {
        String value;
        kelondroMScoreCluster cluster;
        for (int i = 0; i < sortfields.length; i++) {
            value = (String) map.get(sortfields[i]);
            if (value != null) {
                cluster = (kelondroMScoreCluster) sortClusterMap.get(sortfields[i]);
                cluster.setScore(key, kelondroMScoreCluster.string2score(value));
                sortClusterMap.put(sortfields[i], cluster);
            }
        }
    }
    
    public synchronized void remove(String key) throws IOException {
        // update elementCount
        if ((sortfields != null) || (accfields != null)) {
            Map map = get(key);
            if (map != null) {
                // update count
                elementCount--;
                
                // update accumulators (subtract)
                if (accfields != null) updateAcc(map, false);

                // remove from sortCluster
                if (sortfields != null) deleteSortCluster(key);
            }
        }
        
        // remove from queue
        writeWorker.dequeue(key);
        
        // remove from cache
        cacheScore.deleteScore(key);
        cache.remove(key);
        
        // remove from file
        dyn.remove(key);
    }
    
    private void deleteSortCluster(String key) {
        kelondroMScoreCluster cluster;
        for (int i = 0; i < sortfields.length; i++) {
            cluster = (kelondroMScoreCluster) sortClusterMap.get(sortfields[i]);
            cluster.deleteScore(key);
            sortClusterMap.put(sortfields[i], cluster);
        }
    }
        
    public synchronized Map get(String key) throws IOException {
        return get(key, true);
    }
    
    private synchronized Map get(String key, boolean storeCache) throws IOException {
	// load map from cache
        Map map = (Map) cache.get(key);
        if (map != null) return map;
        
	// load map from kra
        if (!(dyn.existsDyn(key))) return null;
	kelondroRA kra = dyn.getRA(key);
	map = kra.readMap();
	kra.close();
	
        if (storeCache) {
            // cache it also
            checkCacheSpace();
            // write map to cache
            cacheScore.setScore(key, (int) ((System.currentTimeMillis() - startup) / 1000));
            cache.put(key, map);
        }
        
        // return value
	return map;
    }
    
    private synchronized void checkCacheSpace() {
        // check for space in cache
        if (cache.size() >= cachesize) {
            // delete one entry
            String delkey = (String) cacheScore.getMinObject();
            cacheScore.deleteScore(delkey);
            cache.remove(delkey);
        }
    }

    public synchronized kelondroDyn.dynKeyIterator keys(boolean up, boolean rotating) throws IOException {
        // simple enumeration of key names without special ordering
        return dyn.dynKeys(up, rotating);
    }
    
    public synchronized kelondroDyn.dynKeyIterator keys(boolean up, boolean rotating, byte[] firstKey) throws IOException {
        // simple enumeration of key names without special ordering
        return dyn.dynKeys(up, rotating, firstKey);
    }
    
    public synchronized Iterator keys(boolean up, /* sorted by */ String field) {
        // sorted iteration using the sortClusters
        if (sortClusterMap == null) return null;
        kelondroMScoreCluster cluster = (kelondroMScoreCluster) sortClusterMap.get(field);
        if (cluster == null) return null; // sort field does not exist
        return cluster.scores(up);
    }
    
    public synchronized mapIterator maps(boolean up, boolean rotating) throws IOException {
        return new mapIterator(keys(up, rotating));
    }
    
    public synchronized mapIterator maps(boolean up, boolean rotating, byte[] firstKey) throws IOException {
        return new mapIterator(keys(up, rotating, firstKey));
    }
    
    public synchronized mapIterator maps(boolean up, String field) {
        return new mapIterator(keys(up, field));
    }
    
    public synchronized long getAcc(String field) {
        Long accumulator = (Long) accMap.get(field);
        if (accumulator == null) return -1; else return accumulator.longValue();
    }
    
    public synchronized int size() {
        if ((sortfields != null) || (accfields != null)) return elementCount; else return dyn.size();
    }
    
    public void close() throws IOException {
        // finish queue
        writeWorker.terminate(true);
        
        // close cluster
        if (sortClusterMap != null) {
            for (int i = 0; i < sortfields.length; i++) sortClusterMap.remove(sortfields[i]);
            sortClusterMap = null;
        }
        cache = null;
        cacheScore = null;

        // close file
        dyn.close();
    }
    
    
    public class mapIterator implements Iterator {
        // enumerates Map-Type elements
        // the key is also included in every map that is returned; it's key is 'key'
        
        Iterator keyIterator;
        boolean finish;
        
        public mapIterator(Iterator keyIterator) {
            this.keyIterator = keyIterator;
            this.finish = false;
        }
        
        public boolean hasNext() {
            return (!(finish)) && (keyIterator.hasNext());
        }
        
        public Object next() {
            String nextKey = (String) keyIterator.next();
            if (nextKey == null) {
                finish = true;
                return null;
            }
            try {
                Map map = get(nextKey);
                if (map == null) throw new kelondroException(dyn.filename, "no more elements available");
                map.put("key", nextKey);
                return map;
            } catch (IOException e) {
                finish = true;
                return null;
            }
        }
        
        public void remove() {
            throw new UnsupportedOperationException();
        }
        
    }
}