/*******************************************************************************
 * Copyright Technophobia Ltd 2012
 * 
 * This file is part of the Substeps Eclipse Plugin.
 * 
 * The Substeps Eclipse Plugin is free software: you can redistribute it and/or modify
 * it under the terms of the Eclipse Public License v1.0.
 * 
 * The Substeps Eclipse Plugin is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * Eclipse Public License for more details.
 * 
 * You should have received a copy of the Eclipse Public License
 * along with the Substeps Eclipse Plugin.  If not, see <http://www.eclipse.org/legal/epl-v10.html>.
 ******************************************************************************/
package com.technophobia.substeps.document.partition;

import org.eclipse.core.runtime.CoreException;
import org.eclipse.jface.text.DocumentEvent;
import org.eclipse.jface.text.IDocument;
import org.eclipse.jface.text.IDocumentListener;
import org.eclipse.jface.text.IDocumentPartitioner;
import org.eclipse.jface.text.rules.FastPartitioner;
import org.eclipse.ui.editors.text.FileDocumentProvider;

import com.technophobia.substeps.supplier.Supplier;

/**
 * DocumentProvider that attaches an {@link IDocumentPartitioner} to the
 * document when it is created
 * 
 * @author sforbes
 * 
 */
public class PartitionScannedDocumentProvider extends FileDocumentProvider {

	private final PartitionScannerFactory partitionScannerFactory;

	private IDocument thisDocument = null;

	private final Supplier<PartitionContext> partitionContextSupplier;

	public PartitionScannedDocumentProvider(
			final PartitionScannerFactory partitionScannerFactory,
			final Supplier<PartitionContext> partitionContextSupplier) {
		this.partitionScannerFactory = partitionScannerFactory;
		this.partitionContextSupplier = partitionContextSupplier;
	}

	@Override
	protected IDocument createDocument(final Object element)
			throws CoreException {
		thisDocument = super.createDocument(element);
		if (thisDocument != null) {
			attachPartitionerTo(thisDocument, partitionContextSupplier);
		}

		thisDocument.addDocumentListener(new IDocumentListener() {

			@Override
			public void documentChanged(DocumentEvent event) {
				if(thisDocument != event.getDocument()){
					thisDocument = event.getDocument();
				}
			}

			@Override
			public void documentAboutToBeChanged(DocumentEvent event) {
				// No-op
			}
		});

		return thisDocument;
	}

	public IDocument getDocuemnt() {
		return thisDocument;
	}

	/**
	 * Create a new {@link IDocumentPartitioner} and attach it do document
	 * 
	 * @param document
	 *            The document to attach the partitioner to
	 */
	private void attachPartitionerTo(final IDocument document,
			final Supplier<PartitionContext> partitionContextSupplier) {
		final IDocumentPartitioner partitioner = new FastPartitioner(
				partitionScannerFactory.createScanner(partitionContextSupplier),
				partitionScannerFactory.legalContentTypes());
		partitioner.connect(document);
		document.setDocumentPartitioner(partitioner);
	}
}