/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package tdb.cmdline;

import java.util.ArrayList ;
import java.util.List ;

import jena.cmd.ArgDecl;
import jena.cmd.CmdArgModule;
import jena.cmd.CmdException;
import jena.cmd.CmdGeneral;

import org.apache.jena.atlas.logging.Log ;
import org.apache.jena.query.* ;
import org.apache.jena.rdf.model.Model ;
import org.apache.jena.riot.RDFDataMgr ;
import org.apache.jena.shared.JenaException ;
import org.apache.jena.sparql.core.assembler.AssemblerUtils ;
import org.apache.jena.sparql.core.assembler.DatasetAssemblerVocab ;
import org.apache.jena.tdb.TDBFactory ;
import org.apache.jena.tdb.assembler.VocabTDB ;
import org.apache.jena.tdb.base.file.Location ;
import org.apache.jena.tdb.transaction.DatasetGraphTransaction ;
import org.apache.jena.util.FileManager ;

import arq.cmdline.ModDataset ;

public class ModTDBDataset extends ModDataset
{
    // Mixes assembler, location and "tdb"
    // Can make a single model or a dataset
    
    private ArgDecl argMem                  = new ArgDecl(ArgDecl.HasValue, "mem", "data") ;
    private ModTDBAssembler modAssembler    = new ModTDBAssembler() ;
    private String inMemFile                = null ;
    
    public ModTDBDataset() {}
    
    @Override
    public void registerWith(CmdGeneral cmdLine)
    {
        cmdLine.add(argMem, "--mem=FILE", "Execute on an in-memory TDB database (for testing)") ;
        cmdLine.addModule(modAssembler) ;
    }

    @Override
    public void processArgs(CmdArgModule cmdLine)
    {
        inMemFile = cmdLine.getValue(argMem) ;
        modAssembler.processArgs(cmdLine) ;
    }        

    @Override
    public Dataset createDataset()
    {
        if ( inMemFile != null )
        {
            Dataset ds = TDBFactory.createDataset() ;
            RDFDataMgr.read(ds, inMemFile) ;
            return ds ;
            
        }
        
        if (  modAssembler.getAssemblerFile() != null )
        {
            Dataset thing = null ;
            // Two variants: plain dataset with a TDB graph or a TDB dataset.
            try {
                thing = (Dataset)AssemblerUtils.build( modAssembler.getAssemblerFile(), VocabTDB.tDatasetTDB) ;
                if ( thing != null && ! ( thing.asDatasetGraph() instanceof DatasetGraphTransaction ) )
                        Log.warn(this, "Unexpected: Not a TDB dataset for type DatasetTDB");
                
                if ( thing == null )
                    // Should use assembler inheritance but how do we assert the subclass relationship in a program?
                    thing = (Dataset)AssemblerUtils.build( modAssembler.getAssemblerFile(), DatasetAssemblerVocab.tDataset) ;
            }
            catch (JenaException ex)    { throw ex ; }
            catch (Exception ex)
            { throw new CmdException("Error creating", ex) ; }
            return thing ;
        }
        
        if ( modAssembler.getLocation() == null )
            throw new CmdException("No assembler file nor location provided") ;
        
        // No assembler - use location to find a database.
        Dataset ds = TDBFactory.createDataset(modAssembler.getLocation()) ;
        return ds ;
    }
    
    public Location getLocation()
    {
        List<String> x = locations() ;
        if ( x.size() == 0 )
            return null ;
        return Location.create(x.get(0)) ;
    }
    
    public List<String> locations()
    {
        List<String> locations = new ArrayList<>() ;
        
        if ( modAssembler.getLocation() != null )
            locations.add(modAssembler.getLocation().getDirectoryPath()) ;

        // Extract the location from the assember file.
        if ( modAssembler.getAssemblerFile() != null )
        {
            // Find and clear all locations
            Model m = FileManager.get().loadModel(modAssembler.getAssemblerFile()) ;
            Query query = QueryFactory.create("PREFIX tdb:     <http://jena.hpl.hp.com/2008/tdb#> SELECT ?dir { [] tdb:location ?dir FILTER (isURI(?dir)) }") ;
            try(QueryExecution qExec = QueryExecutionFactory.create(query, m)) {
                for (ResultSet rs = qExec.execSelect() ; rs.hasNext() ; )
                {
                    String x = rs.nextSolution().getResource("dir").getURI() ;
                    locations.add(x) ;
                }
            }
        }
        
        return locations ;
    }
}