/*******************************************************************************
 * Copyright (c) 2001, 2004 IBM Corporation and others.
 * 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:
 * IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.wst.validation.internal.core;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.logging.Level;

import org.eclipse.core.runtime.CoreException;
import org.eclipse.jem.util.logger.LogEntry;
import org.eclipse.jem.util.logger.proxy.Logger;
import org.eclipse.wst.validation.internal.TaskListUtility;
import org.eclipse.wst.validation.internal.operations.MessageInfo;
import org.eclipse.wst.validation.internal.operations.ValidatorManager;
import org.eclipse.wst.validation.internal.plugin.ValidationPlugin;
import org.eclipse.wst.validation.internal.provisional.core.IReporter;
import org.eclipse.wst.validation.internal.provisional.core.IValidationContext;
import org.eclipse.wst.validation.internal.provisional.core.IValidator;
import org.eclipse.wst.validation.internal.provisional.core.IValidatorJob;


/**
 * <p>
 * This singleton launches the validation on a single validator. Clients should call this class's
 * <code>start</code> method to begin the validation.
 * </p>
 */
public class ValidatorLauncher {
	private static ValidatorLauncher _launcher = null;

	
	/**
	 * Default constructor 
	 */
	private ValidatorLauncher() {
		//Default constructor
	}

	/**
	 * @return the singleton launcher.
	 */
	public static ValidatorLauncher getLauncher() {
		if (_launcher == null) {
			_launcher = new ValidatorLauncher();
		}
		return _launcher;
	}

	/**
	 * <p>
	 * This method is the launch point of the validation. It runs validation on the validator
	 * accessed by the IValidationContext. When the validation is complete, each validator may perform resource
	 * cleanup, if necessary.
	 * 
	 * <br>
	 * <br>
	 * If <code>helper</code>,<code>validator</code>, or <code>reporter</code> are null,
	 * validation is not performed. <code>changedFiles</code> may be null, or empty, if a full
	 * build should be done.
	 * </p>
	 * 
	 * @param helper 
	 * 			loads an object. 
	 * @param validator
	 * 			validator object to launch validation.
	 * @param reporter
	 * 			Is an instance of an IReporter interface, which is used for
	 * interaction with the user.
	 * @param changedFiles
	 * 			Is an array of files which have been added, changed, or deleted
	 * since the last validation. If <code>changedFiles</code> is null, or if it is an empty
	 * array, then a full validation should be performed. Otherwise, validation on just the files
	 * listed in the array should performed if the validator supports incremental validation.
	 */
	public void start(final IValidationContext helper, final IValidator validator, final IReporter reporter) throws ValidationException {
		if ((helper == null) || (validator == null) || (reporter == null)) {
			return;
		}

		// Can't force each validator to check if it's cancelled or not,
		// so check for cancellation here. Hopefully the user won't wait
		// too long.
		if (reporter.isCancelled()) {
			return;
		}

		// If the validator is about to perform a full build, remove all of its previous validation
		// messages.
		if ((helper.getURIs() == null) || (helper.getURIs().length == 0)) {
			reporter.removeAllMessages(validator);
		}
		if( validator instanceof IValidatorJob ){
			((IValidatorJob)validator).validateInJob(helper, reporter);
		}else{
			validator.validate(helper, reporter);
		}
		if( validator instanceof IValidatorJob ){
			//the  validators who have implemented IValidatorJob but are running synchronously
			//would log messages now ...
			ValidatorManager mgr = ValidatorManager.getManager();
			final ArrayList list = mgr.getMessages((IValidatorJob)validator);

	    	Iterator it = list.iterator();
			while( it.hasNext() ){
				MessageInfo info = (MessageInfo)it.next();
				try {
				TaskListUtility.addTask( info.getMessageOwnerId(), info.getResource(),
							info.getLocation(), info.getMsg().getId(), info.getText(),
							info.getMsg().getSeverity(), info.getTargetObjectName(),
							info.getMsg().getGroupName(), info.getMsg().getOffset(), info.getMsg().getLength());
				
				} catch (CoreException exc) {
					Logger logger = ValidationPlugin.getPlugin().getMsgLogger();
					if (logger.isLoggingLevel(Level.SEVERE)) {
						LogEntry entry = ValidationPlugin.getLogEntry();
						entry.setTargetException(exc);
						logger.write(Level.SEVERE, entry);
					}
				}										
			}
			mgr.clearMessages( (IValidatorJob)validator );
		}

	}
	
}