/*******************************************************************************
 * Copyright (c) 2007, 2010 Association for Decentralized Information Management
 * in Industry THTH ry.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     VTT Technical Research Centre of Finland - initial API and implementation
 *******************************************************************************/
package org.simantics.db.impl.query;

import org.simantics.databoard.util.URIStringUtils;
import org.simantics.db.common.exception.DebugException;
import org.simantics.db.exception.DatabaseException;
import org.simantics.db.impl.graph.ReadGraphImpl;
import org.simantics.db.impl.procedure.InternalProcedure;
import org.simantics.db.procedure.ListenerBase;

import gnu.trove.map.hash.TObjectIntHashMap;

public class URIToResource extends StringQuery<InternalProcedure<Integer>> {

    URIToResource(final String id) {
        super(id);
    }

    @Override
    final public void removeEntry(QueryProcessor provider) {
    	provider.cache.remove(this);
    }

    private static void lookup(ReadGraphImpl graph, final URIToResource entry, final InternalProcedure<Integer> procedure, final String namespace, final String name) throws DatabaseException {
        
    	QueryCache.runnerNamespaceIndex(graph, namespace, entry, null, new InternalProcedure<TObjectIntHashMap<String>>() {

            @Override
            public void execute(ReadGraphImpl graph, TObjectIntHashMap<String> index) throws DatabaseException {

                if(index != null) {
                    int result = index.get(name);
                    if(result != 0) {
                        if(entry != null) entry.addOrSet(graph, graph.processor, result);
                        procedure.execute(graph, result);
                        return;
                    }
                }
                
                Integer zero = 0;
                if(entry != null) entry.addOrSet(graph, graph.processor, zero);
                procedure.execute(graph, zero);

            }

            @Override
            public void exception(ReadGraphImpl graph, Throwable t) throws DatabaseException {
                if(entry != null) entry.except(t);
                procedure.exception(graph, t);
            }

        });

    }
    
    @Override
    public Object compute(ReadGraphImpl graph, final InternalProcedure<Integer> procedure) throws DatabaseException {
    	computeForEach(graph, id, this, procedure);
        return getResult();
    }

    static void computeForEach(ReadGraphImpl graph, String id, final URIToResource entry, final InternalProcedure<Integer> procedure) throws DatabaseException {
        
        if("http://".equals(id) || "http:/".equals(id)) {
            
        	QueryProcessor processor = graph.processor;
            if(entry != null) entry.addOrSet(graph, processor, processor.getRootLibrary());
            procedure.execute(graph, processor.getRootLibrary());

        } else {
            
            final String[] parts = URIStringUtils.splitURI(id);
            if (parts != null) {
                lookup(graph, entry, procedure, parts[0], parts[1]);
            } else {
                lookup(graph, entry, procedure, "http://", id.replaceFirst("http://", ""));
            }

        }
        
    }
    
    public void addOrSet(ReadGraphImpl graph, QueryProcessor provider, Integer result) {

        assert(isPending());

        synchronized(this) {
            setResult(result);
            setReady();
        }
        
    }
    
    @Override
    public String toString() {
        return "URIToResource[" + id + "]";
    }

    @Override
    public Object performFromCache(ReadGraphImpl graph, InternalProcedure<Integer> procedure) throws DatabaseException {
        
        assert(isReady());
        
    	if(handleException(graph, procedure)) return (Throwable)statusOrException;

    	Integer result = (Integer)getResult();
    	procedure.execute(graph, result);
    	return result;
        
    }
    
    @Override
    public void recompute(ReadGraphImpl graph) throws DatabaseException {
        
        compute(graph, new InternalProcedure<Integer>() {

            @Override
            public void execute(ReadGraphImpl graph, Integer result) {
            }
            
            @Override
            public void exception(ReadGraphImpl graph, Throwable t) {
                if(DebugException.DEBUG) new DebugException(t).printStackTrace();
                throw new Error("Error in recompute.", t);
            }

        });
        
    }
	
}