/*******************************************************************************
 * Copyright (c) 2007 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.sse.ui;

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

import org.eclipse.jface.text.IDocument;
import org.eclipse.jface.text.TypedPosition;
import org.eclipse.jface.text.formatter.FormattingContextProperties;
import org.eclipse.jface.text.formatter.IFormattingContext;
import org.eclipse.jface.text.formatter.IFormattingStrategy;
import org.eclipse.jface.text.formatter.MultiPassContentFormatter;
import org.eclipse.wst.sse.ui.internal.ExtendedConfigurationBuilder;

/**
 * Extends the MultiPassContentFormatter to allow clients to contribute
 * additional slave formatting strategies via the
 * <code>org.eclipse.wst.sse.ui.editorConfiguration</code> extension point
 */
class StructuredTextMultiPassContentFormatter extends MultiPassContentFormatter {
	/**
	 * The value of "type" attribute in the provisionalConfiguration element
	 */
	private static final String SLAVE_FORMATTING_STRATEGY_EXTENDED_ID = "slaveformattingstrategy"; //$NON-NLS-1$
	/**
	 * list of partition types that already have a formatting strategy
	 */
	private List fInstalledPartitionTypes;

	/**
	 * Creates a new content formatter.
	 * 
	 * @param partitioning
	 *            the document partitioning for this formatter
	 * @param type
	 *            the default content type
	 */
	public StructuredTextMultiPassContentFormatter(final String partitioning, final String type) {
		super(partitioning, type);
	}

	/*
	 * Overwritten to check for additional slave formatting strategies
	 * contributed via the editorConfiguration extension point.
	 */
	protected void formatSlave(IFormattingContext context, IDocument document, int offset, int length, String type) {
		List installedTypes = getInstalledPartitionTypes();
		if (installedTypes.contains(type)) {
			// we've already set the slave formatter strategy so just perform
			// as normal
			super.formatSlave(context, document, offset, length, type);
		}
		else {
			boolean findExtendedSlaveFormatter = true;

			// need to figure out if there's already a slave formatter set, so
			// just attempt to format as normal
			super.formatSlave(context, document, offset, length, type);

			// now, determine if slave formatter was already set by checking
			// context (it would be set if there's already one)
			Object contextPartition = context.getProperty(FormattingContextProperties.CONTEXT_PARTITION);
			if (contextPartition instanceof TypedPosition) {
				String contextType = ((TypedPosition) contextPartition).getType();
				if (contextType == type) {
					// there's already a slave formatter set, so just add it
					// to the list of installed partition types for future
					// reference
					installedTypes.add(type);
					findExtendedSlaveFormatter = false;
				}
			}
			// no slave formatter is set yet, so try to find one contributed
			// via the editorConfiguration extension point
			if (findExtendedSlaveFormatter) {
				Object configuration = ExtendedConfigurationBuilder.getInstance().getConfiguration(SLAVE_FORMATTING_STRATEGY_EXTENDED_ID, type);
				if (configuration instanceof IFormattingStrategy) {
					// found a formatter, so add it in
					setSlaveStrategy((IFormattingStrategy) configuration, type);
					// try to format slave again now that one is set
					super.formatSlave(context, document, offset, length, type);
				}
				// note that we've already checked this partition type for
				// future reference
				installedTypes.add(type);
			}
		}
	}

	/**
	 * Get the list of partition types that have already been evaluated for
	 * slave formatting strategies for this formatter.
	 * 
	 * @return List
	 */
	private List getInstalledPartitionTypes() {
		if (fInstalledPartitionTypes == null)
			fInstalledPartitionTypes = new ArrayList();
		return fInstalledPartitionTypes;
	}
}