EDIT

// $Id$

/**

 * Copyright (C) 2007 EDIT

 * European Distributed Institute of Taxonomy 

 * http://www.e-taxonomy.eu

 * 

 * The contents of this file are subject to the Mozilla Public License Version 1.1

 * See LICENSE.TXT at the top of this package for the full license terms.

 */

package eu.etaxonomy.taxeditor.store;

import java.sql.SQLException;

import java.util.concurrent.CancellationException;

import org.eclipse.core.runtime.IProgressMonitor;

import org.eclipse.core.runtime.IStatus;

import org.eclipse.core.runtime.Status;

import org.eclipse.core.runtime.jobs.Job;

import org.eclipse.swt.widgets.Display;

import org.springframework.core.io.Resource;

import eu.etaxonomy.cdm.api.application.CdmApplicationController;

import eu.etaxonomy.cdm.api.application.CdmApplicationRemoteController;

import eu.etaxonomy.cdm.api.application.ICdmApplicationConfiguration;

import eu.etaxonomy.cdm.config.CdmSourceException;

import eu.etaxonomy.cdm.config.ICdmSource;

import eu.etaxonomy.cdm.database.DbSchemaValidation;

import eu.etaxonomy.cdm.database.ICdmDataSource;

import eu.etaxonomy.cdm.model.metadata.CdmMetaData;

import eu.etaxonomy.cdm.remote.ICdmRemoteSource;

import eu.etaxonomy.taxeditor.model.CdmProgressMonitorAdapter;

import eu.etaxonomy.taxeditor.model.MessagingUtils;

import eu.etaxonomy.taxeditor.ui.dialog.LoginDialog;

import eu.etaxonomy.taxeditor.view.datasource.CdmDataSourceViewPart;

/**

 * @author n.hoffmann

 * @created Dec 8, 2010

 * @version 1.0

 */

class CdmStoreConnector extends Job {

	private final Display display;

	private final ICdmSource cdmSource;

	private DbSchemaValidation dbSchemaValidation;

	private final Resource applicationContextBean;

	/**

	 * @param datasource

	 * @param dbSchemaValidation

	 * @param applicationContextBean

	 */

	public CdmStoreConnector(Display display, ICdmSource cdmSource,

			DbSchemaValidation dbSchemaValidation,

			Resource applicationContextBean) {

		super("Connecting to datasource: " + cdmSource);

		this.display = display;

		this.cdmSource = cdmSource;

		this.dbSchemaValidation = dbSchemaValidation;

		this.applicationContextBean = applicationContextBean;

	}

	@Override

	public IStatus run(final IProgressMonitor monitor) {

		monitor.beginTask(getConnectionMessage(), 10);

		// check if database is up and running

		checkDatabaseReachable(monitor);

		if (!monitor.isCanceled()) {

			// check if the datasource actually holds data

			checkIsNonEmptyCdmDatabase(monitor);

		}

		if (dbSchemaValidation != DbSchemaValidation.CREATE

				&& !monitor.isCanceled()) {

			// if we do not create the datasource, we want to check if the

			// datasource is compatible with this editor

			checkDbSchemaVersionCompatibility(monitor);

		}

		// we are done with our low level checking and will free resources now

		cdmSource.closeOpenConnections();

		if (!monitor.isCanceled()) {

			CdmStore.close(monitor);

		}

		ICdmApplicationConfiguration applicationController = null;

		if (!monitor.isCanceled()) {

			CdmProgressMonitorAdapter subprogressMonitor = CdmProgressMonitorAdapter

					.CreateSubMonitor(monitor, 7);

			// This is where we instantiate the application controller

			int oldPriority = Thread.currentThread().getPriority();

			try {

				Thread.currentThread().setPriority(10);

				applicationController = getApplicationController(cdmSource,subprogressMonitor);

			} catch (Exception e) {

				if(! causeIsCancelationExceptionRecursive(e)){

					return new Status(IStatus.ERROR, "Could not connect to CDM Store", "An error occurred while trying to connect to datasource: " + cdmSource.getName(), e);

				}

			} finally {

				monitor.done();

				Thread.currentThread().setPriority(oldPriority);

			}

		}

		if (!monitor.isCanceled()) {

			CdmStore.setInstance(applicationController, cdmSource);

			display.asyncExec(new Runnable() {

				/*

				 * (non-Javadoc)

				 * 

				 * @see java.lang.Runnable#run()

				 */

				@Override

				public void run() {

					authenticate();

					startContext();

				}

			});

			MessagingUtils.info("Application context initialized.");

			return Status.OK_STATUS;

		} else {

			// Show datasource view if not shown yet

			display.asyncExec(new Runnable() {

				/*

				 * (non-Javadoc)

				 * 

				 * @see java.lang.Runnable#run()

				 */

				@Override

				public void run() {

					StoreUtil.showView(CdmDataSourceViewPart.ID);

				}

			});

			return Status.CANCEL_STATUS;

		}

	}

	private ICdmApplicationConfiguration getApplicationController(ICdmSource cdmSource, CdmProgressMonitorAdapter subprogressMonitor) {

		if(cdmSource instanceof ICdmDataSource) {

			return  CdmApplicationController.NewInstance(applicationContextBean, 

					(ICdmDataSource)cdmSource, 

					dbSchemaValidation,

					false, 

					subprogressMonitor);

		} else if(cdmSource instanceof ICdmRemoteSource) {

			return CdmApplicationRemoteController.NewInstance((ICdmRemoteSource)cdmSource, 					

							false, 

							subprogressMonitor,

							null);

		} else {

			throw new UnsupportedOperationException("Cannot create application controller for " + cdmSource.getName());

		}

	}

	private void authenticate() {

		LoginDialog loginDialog = new LoginDialog(StoreUtil.getShell());

		loginDialog.open();

	}

	private void startContext() {

		CdmStore.getContextManager().notifyContextStart();

	}

	/**

	 * @return

	 */

	private String getConnectionMessage() {

		return cdmSource.getConnectionMessage();

	}

	/**

	 * @return

	 * @throws SQLException

	 */

	private void checkDbSchemaVersionCompatibility(IProgressMonitor monitor) {

		monitor.subTask("Checking if datasource is compatible with this editor.");

		String dbSchemaVersion;

		boolean result = false;

		try {

			dbSchemaVersion = cdmSource.getDbSchemaVersion();

			// we assume that empty dbSchemaVersion means an empty database and

			// skip version checking

			result = dbSchemaVersion == null ? true : CdmMetaData

					.isDbSchemaVersionCompatible(dbSchemaVersion);

			monitor.worked(1);

		} catch (CdmSourceException e) {

			//

		}

		if (!result) {

			// Show an error message

			MessagingUtils

					.messageDialog(

							"DatabaseCompatibilityCheck failed",

							this,

							"The database schema for the chosen "

									+ "datasource '"

									+ cdmSource

									+ "' \n is not valid for this version of the taxonomic editor. \n"

									+ "Please update the chosen datasource or choose a new data source to connect to in the Datasource View.",

							null);

			monitor.setCanceled(true);

		}

	}

	private void checkIsNonEmptyCdmDatabase(IProgressMonitor monitor) {

		monitor.subTask("Checking if datasource is a non empty CDM database.");

		boolean isDbEmpty = false;

		try {

			isDbEmpty = cdmSource.isDbEmpty();

		} catch (CdmSourceException e) {

			isDbEmpty = true;

		}

		if(isDbEmpty) {

			dbSchemaValidation = DbSchemaValidation.CREATE;

		}

	}

	private boolean causeIsCancelationExceptionRecursive(Throwable throwable){

		if(throwable == null){

			return false;

		}else if(throwable instanceof CancellationException){

			return true;

		}else{

			return causeIsCancelationExceptionRecursive(throwable.getCause());

		}

	}

	private void checkDatabaseReachable(IProgressMonitor monitor) {

		try {

			monitor.subTask("Checking if datasource is reachable.");

			cdmSource.checkConnection();

			monitor.worked(1);

		} catch (CdmSourceException e) {

			MessagingUtils.messageDialog("Could not connect to chosen datasource",

					this, "Reason: " + e.getMessage(), e);

			monitor.setCanceled(true);

		} 

	}

}