/*******************************************************************************
 * 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
 *     Jens Lukowski/Innoopract - initial renaming/restructuring
 *     
 *******************************************************************************/
package org.eclipse.wst.sse.ui.internal.openon;

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

import org.eclipse.core.runtime.IConfigurationElement;
import org.eclipse.core.runtime.IExtensionRegistry;
import org.eclipse.core.runtime.Platform;
import org.eclipse.wst.sse.ui.internal.extension.RegistryReader;


/**
 * Reads extensions for open on extension point,
 * org.eclipse.wst.sse.ui.extensions.openon
 * 
 * @deprecated Use base support for hyperlink navigation
 */
public class OpenOnBuilder extends RegistryReader {
	public static final String ATT_CLASS = "class"; //$NON-NLS-1$

	public static final String ATT_ID = "id"; //$NON-NLS-1$

	private static OpenOnBuilder fInstance;
	// extension point ID
	public static final String PL_OPENON = "openon"; //$NON-NLS-1$

	public static final String PLUGIN_ID = "org.eclipse.wst.sse.ui"; //$NON-NLS-1$
	public static final String TAG_CONTENT_TYPE_IDENTIFIER = "contenttypeidentifier"; //$NON-NLS-1$

	public static final String TAG_OPENON = "openon"; //$NON-NLS-1$
	public static final String TAG_PARTITION_TYPE = "partitiontype"; //$NON-NLS-1$

	/**
	 * returns singleton instance of OpenOnBuilder
	 * 
	 * @return OpenOnBuilder
	 */
	public synchronized static OpenOnBuilder getInstance() {
		if (fInstance == null) {
			fInstance = new OpenOnBuilder();
		}
		return fInstance;
	}

	private String fCurrentContentType;
	private OpenOnDefinition fCurrentOpenOnDefinition = null;

	private List fOpenOnDefs = null;

	protected String targetContributionTag;

	/**
	 * Returns the name of the part ID attribute that is expected in the
	 * target extension.
	 * 
	 * @param element
	 * @return String
	 */
	protected String getId(IConfigurationElement element) {
		String value = element.getAttribute(ATT_ID);
		return value;
	}

	protected String getOpenOnClass(IConfigurationElement element) {
		String value = element.getAttribute(ATT_CLASS);
		return value;
	}

	/**
	 * Returns all the open on definition objects
	 * 
	 * @return
	 */
	public OpenOnDefinition[] getOpenOnDefinitions() {
		initCache();
		return (OpenOnDefinition[]) fOpenOnDefs.toArray(new OpenOnDefinition[fOpenOnDefs.size()]);
	}

	/**
	 * Returns all the open on definition objects valid for
	 * contentType/partitionType
	 * 
	 * @param contentType
	 * @param partitionType
	 * @return if either contentType or partitionType is null, null is
	 *         returned
	 */
	public OpenOnDefinition[] getOpenOnDefinitions(String contentType, String partitionType) {
		if (contentType == null || partitionType == null) {
			// should not be able to define an openon without a content type
			// but if it were possible then would need to search all openon
			// definitions for
			// definitions with empty contentType list
			return null;
		}

		// entire list of openon definition objects
		OpenOnDefinition[] allDefs = getOpenOnDefinitions();
		// current list of open on definitions valid for
		// contentType/partitionType
		List defs = new ArrayList();
		// default definitions that should be added to end of list of open on
		// definitions
		List lastDefs = new ArrayList();

		for (int i = 0; i < allDefs.length; ++i) {
			// for each one check if it contains contentType
			List partitions = (List) allDefs[i].getContentTypes().get(contentType);
			if (partitions != null) {
				// this openon definition is valid for all partition types for
				// this content type
				if (partitions.isEmpty()) {
					// this will be added to end of list because this is
					// considered a default openon
					lastDefs.add(allDefs[i]);
				} else {
					// examine the partition types of this openon
					int j = 0; // current index in list of partitions
					boolean added = false; // openon has been added to list
					while (j < partitions.size() && !added) {
						// this openon definition applies to partitionType so
						// add to list of valid openons
						if (partitionType.equals(partitions.get(j))) {
							defs.add(allDefs[i]);
							added = true;
						} else {
							// continue checking to see if this openon
							// definition is valid for current partitionType
							++j;
						}
					}
				}
			}
		}
		// append the default openon definitions
		defs.addAll(lastDefs);

		// return the list
		return (OpenOnDefinition[]) defs.toArray(new OpenOnDefinition[defs.size()]);
	}

	private void initCache() {
		if (fOpenOnDefs == null) {
			fOpenOnDefs = new ArrayList(0);
			readContributions(TAG_OPENON, PL_OPENON);
		}
	}

	/**
	 * Processes element which should be a configuration element specifying a
	 * content type for the current open on tag. Assumes that there is a valid
	 * current open on definition object.
	 * 
	 * @param element
	 *            contenttypeidentifier configuration element
	 */
	private void processContentTypeTag(IConfigurationElement element) {
		// add to current openOnDefinition
		String theId = getId(element);

		if (theId != null) {
			fCurrentContentType = theId;
			fCurrentOpenOnDefinition.addContentTypeId(fCurrentContentType);
		} else {
			fCurrentContentType = null;
		}
	}

	/**
	 * Processes element which should be a configuration element specifying an
	 * open on object. Creates a new open on definition object and adds it to
	 * the list of open on definition objects
	 * 
	 * @param element
	 *            openon configuration element
	 */
	private void processOpenOnTag(IConfigurationElement element) {
		String theId = getId(element);
		String theClass = getOpenOnClass(element);

		if (theId != null && theClass != null) {
			// start building new OpenOnDefinition
			fCurrentOpenOnDefinition = new OpenOnDefinition(theId, theClass, element);
			fOpenOnDefs.add(fCurrentOpenOnDefinition);
		} else {
			fCurrentOpenOnDefinition = null;
		}
	}

	/**
	 * Processes element which should be a configuration element specifying a
	 * partition type for the current open on/content type tag. Assumes that
	 * there is a valid current open on/content type tag.
	 * 
	 * @param element
	 *            partitiontype configuration element
	 */
	private void processPartitionTypeTag(IConfigurationElement element) {
		// add to current openOnDefinition/contentType
		String theId = getId(element);

		if (theId != null) {
			fCurrentOpenOnDefinition.addPartitionType(fCurrentContentType, theId);
		}
	}

	/**
	 * Reads the contributions from the registry for the provided workbench
	 * part and the provided extension point ID.
	 * 
	 * @param tag
	 * @param extensionPoint
	 */
	protected void readContributions(String tag, String extensionPoint) {
		targetContributionTag = tag;
		IExtensionRegistry registry = Platform.getExtensionRegistry();
		readRegistry(registry, PLUGIN_ID, extensionPoint);
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.wst.sse.ui.internal.extension.RegistryReader#readElement(org.eclipse.core.runtime.IConfigurationElement)
	 */
	protected boolean readElement(IConfigurationElement element) {
		String tag = element.getName();

		if (tag.equals(targetContributionTag)) {
			processOpenOnTag(element);

			// make sure processing of current open on tag resulted in a
			// current open on definition
			// before continue reading the children
			if (fCurrentOpenOnDefinition != null) {
				readElementChildren(element);
			}
			return true;
		} else if (tag.equals(TAG_CONTENT_TYPE_IDENTIFIER)) {
			processContentTypeTag(element);

			// make sure processing of current content type resulted in a
			// valid content type
			// before reading the children
			if (fCurrentContentType != null) {
				readElementChildren(element);
			}
			return true;
		} else if (tag.equals(TAG_PARTITION_TYPE)) {
			processPartitionTypeTag(element);
			return true;
		}

		return false;
	}
}