/*******************************************************************************
 * Copyright (c) 2007 Oracle 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:
 *     Oracle Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.jst.pagedesigner.properties.internal;

import javax.xml.namespace.QName;

import org.eclipse.core.resources.IProject;
import org.eclipse.jface.text.IDocument;
import org.eclipse.jface.viewers.ISelection;
import org.eclipse.jst.jsf.common.metadata.Entity;
import org.eclipse.jst.jsf.common.metadata.Trait;
import org.eclipse.jst.jsf.common.metadata.query.ITaglibDomainMetaDataModelContext;
import org.eclipse.jst.jsf.common.metadata.query.TaglibDomainMetaDataQueryHelper;
import org.eclipse.jst.jsf.context.resolver.structureddocument.IStructuredDocumentContextResolverFactory;
import org.eclipse.jst.jsf.context.resolver.structureddocument.ITaglibContextResolver;
import org.eclipse.jst.jsf.context.structureddocument.IStructuredDocumentContext;
import org.eclipse.jst.jsf.context.structureddocument.IStructuredDocumentContextFactory;
import org.eclipse.jst.pagedesigner.editors.HTMLEditor;
import org.eclipse.jst.pagedesigner.editors.properties.quickedittabsections.QuickEditTabSections;
import org.eclipse.jst.pagedesigner.properties.DesignerPropertyTool;
import org.eclipse.jst.pagedesigner.properties.WPETabbedPropertySheetPage;
import org.eclipse.ui.IWorkbenchPart;
import org.eclipse.ui.part.FileEditorInput;
import org.w3c.dom.Element;

/**
 * One-to-one with {@link WPETabbedPropertySheetPage} that manages the current sections for the current selection.
 * <p>
 * The QuickEditTabManager has a shared instance of a {@link QuickEditTabSectionsManager} for the project.
 * <p>
 * When a WPETabbedPropertySheetPage is created, it must acquire a QuickEditTabManager using the static acquireInstance method,
 * and then release the instance when it is disposed.  This ensures that the QuickEditTabSectionsManager shared instance (per project) is released appropriately.
 * <p>
 * selectionChanged method must be called prior to calling createControls on the sections for this tab group call.
 */
public class QuickEditTabManager {
	private QuickEditTabSectionsManager _groupsManager;
	private QuickEditTabSections _quickEditTabSections;
	private Entity _tagEntity;
	private QName _lastTagID;
	private QuickEditTabSectionsDescriptor _lastQuickEditTabGroup;
	private QuickEditTabSectionsDescriptor _nullQuickEditTabGroup;
	private Element _lastElement;
	
	private QuickEditTabSectionsManager getRegistry() {
		return _groupsManager;
	}

	/**
	 * Must only be called once per tabbed property sheet as ref count is kept.  
	 * Callers must call releaseInstance when the page is disposed
	 * @param page 
	 * @return instance for this property sheet
	 */
	public static synchronized QuickEditTabManager acquireInstance(WPETabbedPropertySheetPage page) {
		IProject project = getProject(page);	
		QuickEditTabManager instance = new QuickEditTabManager();
		instance._groupsManager = QuickEditTabSectionsManager.acquireInstance(project);
		return instance;		
	}

	/**
	 * Releases this instance, but does not dispose.  Ensures that the {@link QuickEditTabSectionsManager} is released.
	 */
	public synchronized void releaseInstance() {
		this._groupsManager.releaseInstance();			
	}
	
	/**
	 * Private constructor
	 */
	private QuickEditTabManager(){
		//
	}
	
	private static IProject getProject(WPETabbedPropertySheetPage page) {
		IProject proj = null;
		IDocument doc = ((HTMLEditor)page.getEditor()).getDocument();
		IStructuredDocumentContext context = IStructuredDocumentContextFactory.INSTANCE.getContext(doc, 0);
		if (context != null){
			proj = IStructuredDocumentContextResolverFactory.INSTANCE.getWorkspaceContextResolver(context).getProject();
		}
		return proj;
		 
	}
	/**
	 * Must be called so that the sections for the input can be calculated. 
	 * 
	 * @param part
	 * @param selection
	 * @return true if current selection is different than during the last call
	 */
	public boolean selectionChanged(IWorkbenchPart part, ISelection selection) {
		boolean hasChanged = false;
		QuickEditTabSections qets = getQuickTabSectionsMetaData(part, selection); 
		if (qets == null) {//use null quick edit tab			
			hasChanged = (_quickEditTabSections != null);
			_quickEditTabSections = qets;
			_lastQuickEditTabGroup = getNullQuickEditTab();
			_lastTagID = null;
		}
		else {
			QName tagId = getTagId();
			if (_lastTagID == null || !_lastTagID.equals(tagId)){
				_quickEditTabSections = qets;
				QuickEditTabSectionsDescriptor group = getRegistry().getQuickEditTabSectionsFor(tagId);
				if (group == null){
					group = createQuickEditTabGroup(tagId, _quickEditTabSections);
					if (group != null){					
						group.calculateSections();
						getRegistry().addQuickEditTabGroupDescriptor(group);
					}
				}
				_lastQuickEditTabGroup = group;
				_lastTagID = tagId;
			}
		} 

		return hasChanged;
	}
	
	/**
	 * @return current QuickEditTabSectionsDescriptor
	 */
	public QuickEditTabSectionsDescriptor getCurrentTabGroupDescriptor() {
		return _lastQuickEditTabGroup;
	}
	
	private QuickEditTabSections getQuickTabSectionsMetaData(IWorkbenchPart part,
			ISelection selection) {

		Element node = DesignerPropertyTool.getElement(part, selection);
		if (node == null) {
			return null;
		}
		if (_lastElement != node){
			_lastElement = node;
			_quickEditTabSections = null;
			_tagEntity = getTagEntity(part, selection, node);
			if (_tagEntity != null) {
				Trait pds = TaglibDomainMetaDataQueryHelper.getTrait(_tagEntity, QuickEditTabSections.TRAIT_ID);
				if (pds != null){
					_quickEditTabSections = (QuickEditTabSections)pds.getValue();
				}		
			}			
		}
		return _quickEditTabSections;
	}

	private QuickEditTabSectionsDescriptor createQuickEditTabGroup(QName tagId,
			QuickEditTabSections tabSections) {
		return new QuickEditTabSectionsDescriptor(_tagEntity, tagId, tabSections);
	}

	private QName getTagId() {
		return TaglibDomainMetaDataQueryHelper.getQNameForTagEntity(_tagEntity);
	}

	/**
	 * Dispose
	 */
	public void dispose() {		
		_lastQuickEditTabGroup= null;
		_lastElement = null;
		_lastTagID = null;		
		_nullQuickEditTabGroup = null;
		_quickEditTabSections = null;
		_groupsManager = null;
	}
	
	private Entity getTagEntity(IWorkbenchPart part, ISelection selection, Element node){
		HTMLEditor ed = null;
		if (part instanceof HTMLEditor)
			ed = (HTMLEditor)part;
		if (ed == null)
			return null;
		
		if (ed.getEditorInput() instanceof FileEditorInput) {
			FileEditorInput input = (FileEditorInput)ed.getEditorInput();
			IStructuredDocumentContext context = IStructuredDocumentContextFactory.INSTANCE.getContext(ed.getDocument(), node);
			if (context != null){
				ITaglibContextResolver resolver = IStructuredDocumentContextResolverFactory.INSTANCE.getTaglibContextResolver(context);
				if (resolver != null){
					ITaglibDomainMetaDataModelContext mdContext = TaglibDomainMetaDataQueryHelper.createMetaDataModelContext(input.getFile().getProject(),resolver.getTagURIForNodeName(node));
					return TaglibDomainMetaDataQueryHelper.getEntity(mdContext, node.getLocalName());
				}
			}
		}
		return null;		
	}
	
	private QuickEditTabSectionsDescriptor getNullQuickEditTab() {
		if (_nullQuickEditTabGroup == null) {
			_nullQuickEditTabGroup = new NullQuickEditTabGroupDescriptor();
			_nullQuickEditTabGroup.calculateSections();
		}
		return _nullQuickEditTabGroup;
	}

	/**
	 * NOT API - for JUnit testing only
	 * @return {@link QuickEditTabSectionsManager} 
	 */	
	public QuickEditTabSectionsManager getQuickEditTabSectionsManager() {
		return _groupsManager;
	}

	
}