package org.simantics.xml.sax.base;

import java.io.File;

import org.simantics.db.Resource;
import org.simantics.db.Session;
import org.simantics.db.WriteGraph;
import org.simantics.db.common.request.DelayedWriteRequest;
import org.simantics.db.common.request.WriteRequest;
import org.simantics.db.exception.DatabaseException;
import org.simantics.db.layer0.util.Layer0Utils;
import org.simantics.db.service.XSupport;
import org.simantics.message.ILogger;
import org.simantics.message.MessageService;


public abstract class AbstractImporter {

	
	private Session session;
	private File file;
	private ILogger logger;
	private XMLParser parser;
	
	private static final boolean USE_DELAYED = true;
	
	public AbstractImporter(Session session, File file)  {
		this.session = session;
		this.file = file;
	}
	
	public AbstractImporter(Session session, File file, XMLParser parser)  {
		this.session = session;
		this.file = file;
		this.parser = parser;
	}
	public Resource doImport() throws DatabaseException {
		return doImport(MessageService.getDefault()); 	
	}
	
	public Resource doImport(ILogger logger) throws DatabaseException {
		this.logger = logger;
		if (USE_DELAYED) {
			ImportDelayedRequest req = new ImportDelayedRequest();
			session.syncRequest(req);
			Resource dr = req.getResult();
			XSupport xs = session.getService(XSupport.class);
			Resource result = xs.convertDelayedResourceToResource(dr);
			return result;
		} else {
			ImportRequest req = new ImportRequest();
			session.syncRequest(req);
			return req.getResult();
		}
	}
	
	public File getFile() {
		return file;
	}
	
	public void configure(XMLParser parser){};
	
	
	private class ImportRequest extends WriteRequest {
		private Resource result;
		public ImportRequest() {
			super();
		}

		@Override
		public void perform(WriteGraph graph) throws DatabaseException {
			Layer0Utils.addCommentMetadata(graph, "Import file " + file.getName());
			graph.markUndoPoint();
			result = doImport(graph);
		}
		
		public Resource getResult() {
			return result;
		}
	}
	
	private class ImportDelayedRequest extends DelayedWriteRequest {
		private Resource result;
		public ImportDelayedRequest() {
			super();
		}

		@Override
		public void perform(WriteGraph graph) throws DatabaseException {
			result = doImport(graph);
		}
		
		public Resource getResult() {
			return result;
		}
	}
	
	private Resource doImport(WriteGraph graph) throws DatabaseException {
		Layer0Utils.setDependenciesIndexingDisabled(graph, true);
		try {
			
			if (parser == null) {
				parser = new XMLParser();
				parser.setGraph(graph);
				configure(parser);
			} else {
				parser.setGraph(graph);
			}
			
			parser.parse(file, logger);
			System.out.println(file.getAbsolutePath() + " imported");
			Resource root = parser.getRoot();
			if (root == null) {
				throw new DatabaseException(file.getAbsolutePath() + " import failed. File is corrupted, or is not given type");
			}
			return root;
		} catch (DatabaseException e) {
			throw e;
		} catch (Exception e) {
			throw new DatabaseException(e);
		} 
	}
}