/*******************************************************************************
 *Copyright (c) 2008 Standards for Technology in Automotive Retail 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:
 *    David Carver - initial API and implementation
 *******************************************************************************/
package org.eclipse.wst.xsl.ui.internal.contentassist;

import org.eclipse.jface.text.ITextViewer;
import org.eclipse.wst.sse.core.internal.provisional.text.IStructuredDocumentRegion;
import org.eclipse.wst.sse.core.internal.provisional.text.ITextRegion;
import org.eclipse.wst.xml.core.internal.provisional.document.IDOMAttr;
import org.eclipse.wst.xml.core.internal.provisional.document.IDOMElement;
import org.eclipse.wst.xml.core.internal.provisional.document.IDOMNode;
import org.w3c.dom.NamedNodeMap;

/**
 * A Factory that determines which Content Assist Request class is needed and
 * returns the appropriate class.
 * 
 * @author David Carver
 * @since 1.0
 */
public class XSLContentAssistRequestFactory {
	private static final String ATTR_SELECT = "select"; //$NON-NLS-1$
	private static final String ATTR_TEST = "test"; //$NON-NLS-1$
	private static final String ATTR_MATCH = "match"; //$NON-NLS-1$
	private static final String ATTR_EXCLUDE_RESULT_PREFIXES = "exclude-result-prefixes"; //$NON-NLS-1$
	private static final String ATTR_MODE = "mode"; //$NON-NLS-1$
	private static final String ELEM_TEMPLATE = "template"; //$NON-NLS-1$
	private static final String ELEM_APPLYTEMPLATES = "apply-templates"; //$NON-NLS-1$
	private static final String ELEM_APPLY_IMPORTS = "apply-imports"; //$NON-NLS-1$
	private static final String ATTR_HREF = "href"; //$NON-NLS-1$
	private static final String ELEM_CALLTEMPLATE = "call-template"; //$NON-NLS-1$
	private static final String ATTR_NAME = "name"; //$NON-NLS-1$
	private ITextViewer textViewer;
	private int documentPosition;
	private IDOMNode xmlNode;
	private IStructuredDocumentRegion sdRegion;
	private ITextRegion completionRegion;
	private String matchString;
	

	/**
	 * @param textViewer
	 * @param documentPosition
	 * @param xmlNode
	 * @param sdRegion
	 * @param completionRegion
	 * @param matchString
	 */
	public XSLContentAssistRequestFactory(ITextViewer textViewer, int documentPosition, IDOMNode xmlNode,
			IStructuredDocumentRegion sdRegion, ITextRegion completionRegion,
			String matchString) {
		this.textViewer = textViewer;
		this.documentPosition = documentPosition;
		this.xmlNode = xmlNode;
		this.sdRegion = sdRegion;
		this.completionRegion = completionRegion;
		this.matchString = matchString;
	}
	/**
	 * Get the appropriate content assist request class for the XSL request.
	 * @return
	 */
	public IContentAssistProposalRequest getContentAssistRequest() {
		NamedNodeMap nodeMap = xmlNode.getAttributes();
		IDOMElement element = (IDOMElement) xmlNode;
		IContentAssistProposalRequest proposal = commonAttributeProposals(nodeMap);
		
		if (proposal instanceof NullContentAssistRequest) {
			if (isElementProposal(element)) {
				proposal = getElementProposals(nodeMap, element);
			}
		}

		return proposal;
	}
	
	private boolean isElementProposal(IDOMElement element) {
		String localName = element.getLocalName();
		return localName.equals(ELEM_TEMPLATE) ||
		       localName.equals(ELEM_APPLYTEMPLATES) ||
		       localName.equals(ELEM_CALLTEMPLATE);
	}
	

	private IContentAssistProposalRequest getElementProposals(NamedNodeMap nodeMap, IDOMElement element) {
		if (element.getLocalName().equals(ELEM_TEMPLATE)) {
			return getTemplateProposals(nodeMap);
		}

		if (element.getLocalName().equals(ELEM_APPLYTEMPLATES)
				|| element.getLocalName().equals(ELEM_APPLY_IMPORTS)) {
			if (hasAttributeAtTextRegion(ATTR_MODE, nodeMap, completionRegion)) {
				return new TemplateModeAttributeContentAssist(xmlNode,
						sdRegion, completionRegion, documentPosition, 0,
						matchString, textViewer);
			}

		}

		if (element.getLocalName().equals(ELEM_CALLTEMPLATE)) {
			if (hasAttributeAtTextRegion(ATTR_NAME, nodeMap, completionRegion)) {
				return new CallTemplateContentAssistRequest(xmlNode, sdRegion,
						completionRegion, documentPosition, 0, matchString,
						textViewer);
			}
		}
		
		return new NullContentAssistRequest(xmlNode, sdRegion,
				completionRegion, documentPosition, 0, matchString, textViewer);		
		
	}
	
	private IContentAssistProposalRequest getTemplateProposals(NamedNodeMap nodeMap) {
		if (hasAttributeAtTextRegion(ATTR_MODE, nodeMap, completionRegion)) {
			return new TemplateModeAttributeContentAssist(xmlNode,
					sdRegion, completionRegion, documentPosition, 0,
					matchString, textViewer);
		}
		
		if (hasAttributeAtTextRegion(ATTR_NAME, nodeMap, completionRegion)) {
			return new TemplateNameAttributeContentAssist( xmlNode,
					sdRegion, completionRegion, documentPosition, 0,
					matchString, textViewer);        
		}
		
		return new NullContentAssistRequest(xmlNode, sdRegion,
				completionRegion, documentPosition, 0, matchString, textViewer);		
		
	}
	
	private IContentAssistProposalRequest commonAttributeProposals(
			NamedNodeMap nodeMap) {
		if (hasAttributeAtTextRegion(ATTR_SELECT, nodeMap,
				completionRegion)) {
			return new SelectAttributeContentAssist(xmlNode, sdRegion,
					completionRegion, documentPosition, 0, matchString,
					textViewer);
		}

		if (hasAttributeAtTextRegion(ATTR_MATCH, nodeMap, completionRegion)) {
			return new SelectAttributeContentAssist(xmlNode, sdRegion,
					completionRegion, documentPosition, 0, matchString,
					textViewer);
		}

		if (hasAttributeAtTextRegion(ATTR_TEST, nodeMap, completionRegion)) {
			return new TestAttributeContentAssist(xmlNode, sdRegion,
					completionRegion, documentPosition, 0, matchString,
					textViewer);
		}

		if (hasAttributeAtTextRegion(ATTR_EXCLUDE_RESULT_PREFIXES,
				nodeMap, completionRegion)) {
			return new ExcludeResultPrefixesContentAssist(xmlNode, sdRegion,
					completionRegion, documentPosition, 0, matchString,
					textViewer);
		}

		if (hasAttributeAtTextRegion(ATTR_HREF, nodeMap, completionRegion)) {
			return new HrefContentAssistRequest(xmlNode, sdRegion,
					completionRegion, documentPosition, 0, matchString,
					textViewer);
		}


		return new NullContentAssistRequest(xmlNode, sdRegion,
				completionRegion, documentPosition, 0, matchString, textViewer);
	}

	protected boolean hasAttributeAtTextRegion(String attrName,
			NamedNodeMap nodeMap, ITextRegion aRegion) {
		IDOMAttr attrNode = (IDOMAttr) nodeMap.getNamedItem(attrName);
		return attrNode != null && attrNode.getValueRegion() != null
				&& attrNode.getValueRegion().getStart() == aRegion.getStart();
	}
}