/*******************************************************************************
 * Copyright (c) 2000, 2003 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials 
 * are made available under the terms of the Common Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/cpl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package net.sourceforge.phpdt.internal.core;

import net.sourceforge.phpdt.core.IBuffer;
import net.sourceforge.phpdt.core.ICompilationUnit;
import net.sourceforge.phpdt.core.IJavaElement;
import net.sourceforge.phpdt.core.IJavaModelStatus;
import net.sourceforge.phpdt.core.IJavaModelStatusConstants;
import net.sourceforge.phpdt.core.JavaModelException;

import org.eclipse.core.resources.IResource;


/**
 * Commits the contents of a working copy compilation
 * unit to its original element and resource, bringing
 * the Java Model up-to-date with the current contents of the working
 * copy.
 *
 * <p>It is possible that the contents of the
 * original resource have changed since the working copy was created,
 * in which case there is an update conflict. This operation allows
 * for two settings to resolve conflict set by the <code>fForce</code> flag:<ul>
 * <li>force flag is <code>false</code> - in this case an <code>JavaModelException</code>
 * 	is thrown</li>
 * <li>force flag is <code>true</code> - in this case the contents of
 * 	the working copy are applied to the underlying resource even though
 * 	the working copy was created before a subsequent change in the
 * 	resource</li>
 * </ul>
 *
 * <p>The default conflict resolution setting is the force flag is <code>false</code>
 *
 * A JavaModelOperation exception is thrown either if the commit could not
 * be performed or if the new content of the compilation unit violates some Java Model
 * constraint (e.g. if the new package declaration doesn't match the name of the folder
 * containing the compilation unit).
 */
public class CommitWorkingCopyOperation extends JavaModelOperation {
	/**
	 * Constructs an operation to commit the contents of a working copy
	 * to its original compilation unit.
	 */
	public CommitWorkingCopyOperation(ICompilationUnit element, boolean force) {
		super(new IJavaElement[] {element}, force);
	}
	/**
	 * @exception JavaModelException if setting the source
	 * 	of the original compilation unit fails
	 */
	protected void executeOperation() throws JavaModelException {
		try {
			beginTask(Util.bind("workingCopy.commit"), 2); //$NON-NLS-1$
			WorkingCopy copy = (WorkingCopy)getCompilationUnit();
			ICompilationUnit original = (ICompilationUnit) copy.getOriginalElement();
		
			
			// creates the delta builder (this remembers the content of the cu)	
			if (!original.isOpen()) {
				// force opening so that the delta builder can get the old info
				original.open(null);
			}
			JavaElementDeltaBuilder deltaBuilder;
			if (Util.isExcluded(original)) {
				deltaBuilder = null;
			} else {
				deltaBuilder = new JavaElementDeltaBuilder(original);
			}
		
			// save the cu
			IBuffer originalBuffer = original.getBuffer();
			if (originalBuffer == null) return;
			char[] originalContents = originalBuffer.getCharacters();
			boolean hasSaved = false;
			try {
				IBuffer copyBuffer = copy.getBuffer();
				if (copyBuffer == null) return;
				originalBuffer.setContents(copyBuffer.getCharacters());
				original.save(fMonitor, fForce);
				this.setAttribute(HAS_MODIFIED_RESOURCE_ATTR, TRUE); 
				hasSaved = true;
			} finally {
				if (!hasSaved){
					// restore original buffer contents since something went wrong
					originalBuffer.setContents(originalContents);
				}
			}
			// make sure working copy is in sync
			copy.updateTimeStamp((CompilationUnit)original);
			copy.makeConsistent(this);
			worked(1);
		
			if (deltaBuilder != null) {
				// build the deltas
				deltaBuilder.buildDeltas();
			
				// add the deltas to the list of deltas created during this operation
				if (deltaBuilder.delta != null) {
					addDelta(deltaBuilder.delta);
				}
			}
			worked(1);
		} finally {	
			done();
		}
	}
	/**
	 * Returns the compilation unit this operation is working on.
	 */
	protected ICompilationUnit getCompilationUnit() {
		return (ICompilationUnit)getElementToProcess();
	}
	/**
	 * Possible failures: <ul>
	 *	<li>INVALID_ELEMENT_TYPES - the compilation unit supplied to this
	 *		operation is not a working copy
	 *  <li>ELEMENT_NOT_PRESENT - the compilation unit the working copy is
	 *		based on no longer exists.
	 *  <li>UPDATE_CONFLICT - the original compilation unit has changed since
	 *		the working copy was created and the operation specifies no force
	 *  <li>READ_ONLY - the original compilation unit is in read-only mode
	 *  </ul>
	 */
	public IJavaModelStatus verify() {
		ICompilationUnit cu = getCompilationUnit();
		if (!cu.isWorkingCopy()) {
			return new JavaModelStatus(IJavaModelStatusConstants.INVALID_ELEMENT_TYPES, cu);
		}
		ICompilationUnit original= (ICompilationUnit)cu.getOriginalElement();
		IResource resource = original.getResource();
		if (!cu.isBasedOn(resource) && !fForce) {
			return new JavaModelStatus(IJavaModelStatusConstants.UPDATE_CONFLICT);
		}
		// no read-only check, since some repository adapters can change the flag on save
		// operation.	
		return JavaModelStatus.VERIFIED_OK;
	}
}