/*******************************************************************************
 * Copyright (c) 2012 Red Hat, Inc.
 * Distributed under license by Red Hat, Inc. All rights reserved.
 * This program is 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:
 *     Red Hat, Inc. - initial API and implementation
 ******************************************************************************/
package org.jboss.tools.cdi.ui.ca;

import org.eclipse.core.resources.IProject;
import org.eclipse.jface.text.contentassist.IContextInformation;
import org.eclipse.swt.graphics.Image;
import org.eclipse.wst.sse.core.internal.provisional.IndexedRegion;
import org.eclipse.wst.sse.core.internal.provisional.text.IStructuredDocumentRegion;
import org.eclipse.wst.sse.core.internal.provisional.text.ITextRegion;
import org.eclipse.wst.sse.ui.contentassist.CompletionProposalInvocationContext;
import org.eclipse.wst.sse.ui.internal.contentassist.ContentAssistUtils;
import org.eclipse.wst.xml.core.internal.regions.DOMRegionContext;
import org.eclipse.wst.xml.ui.internal.contentassist.ContentAssistRequest;
import org.eclipse.wst.xml.ui.internal.editor.XMLEditorPluginImageHelper;
import org.eclipse.wst.xml.ui.internal.editor.XMLEditorPluginImages;
import org.jboss.tools.cdi.core.CDICoreNature;
import org.jboss.tools.cdi.core.CDIUtil;
import org.jboss.tools.cdi.internal.core.ca.BeansXmlProcessor;
import org.jboss.tools.common.el.core.resolver.ELContext;
import org.jboss.tools.common.text.TextProposal;
import org.jboss.tools.common.ui.CommonUIPlugin;
import org.jboss.tools.jst.jsp.contentassist.AutoContentAssistantProposal;
import org.jboss.tools.jst.jsp.contentassist.computers.XmlTagCompletionProposalComputer;
import org.jboss.tools.jst.web.kb.KbQuery;
import org.jboss.tools.jst.web.kb.KbQuery.Type;
import org.w3c.dom.Element;
import org.w3c.dom.Text;


@SuppressWarnings("restriction")
public class BeansXmlCompletionProposalComputer extends XmlTagCompletionProposalComputer {

	@Override
	protected void addTagInsertionProposals(
			ContentAssistRequest contentAssistRequest, int childPosition,
			CompletionProposalInvocationContext context) {
		String prefix = getTagPrefix();
		String uri = getTagUri();
		
		String query = null;
		String nodeText = null;
		
		IndexedRegion treeNode = ContentAssistUtils.getNodeAt(context.getViewer(), context.getInvocationOffset());
		int nodeStartOffset = treeNode == null ? -1 : treeNode.getStartOffset();
		int localInvocationOffset = nodeStartOffset == -1 ? -1 : context.getInvocationOffset() - nodeStartOffset;
		if (treeNode instanceof Element) {
			IStructuredDocumentRegion reg = getStructuredDocumentRegion(context.getInvocationOffset());
			ITextRegion firstRegion = reg == null ? null : reg.getFirstRegion();
			
			if (firstRegion == null)
				return;
			
			if (firstRegion.getType() != DOMRegionContext.XML_END_TAG_OPEN ) {
				return;
			}
			
			IndexedRegion prevTreeNode = context.getInvocationOffset() <= 0 ? null : ContentAssistUtils.getNodeAt(context.getViewer(), context.getInvocationOffset() - 1);
			if (prevTreeNode instanceof Text) {
				treeNode = prevTreeNode;
				localInvocationOffset = ((Text)treeNode).getData() == null ? 0 : ((Text)treeNode).getData().length();
			}
		} else if (!(treeNode instanceof Text)) {
			return;
		}
		

		nodeText = treeNode instanceof Text ? ((Text)treeNode).getData() : "";
		if (localInvocationOffset > 0 && localInvocationOffset <= nodeText.length()) {
			query = nodeText.substring(0, localInvocationOffset);
		}
		
		if (query == null)
			query = ""; //$NON-NLS-1$
				
		ELContext elContext = getContext();
		IProject project = elContext == null || elContext.getResource() == null ? null :
			elContext.getResource().getProject();
		
		if (project == null)
			return;
		
		// The following code is made due to make sure that the CDI Model and Project is up-to-date
		CDICoreNature nature = CDIUtil.getCDINatureWithProgress(project);
		if (nature == null)
			return;

		KbQuery kbQuery = createKbQuery(Type.TAG_BODY, query, query, prefix, uri);
		TextProposal[] proposals = BeansXmlProcessor.getInstance().getProposals(kbQuery, project);

		String matchString = leftTrim(query);
		for (int i = 0; proposals != null && i < proposals.length; i++) {
			TextProposal textProposal = proposals[i];
	
			String replacementString = textProposal.getReplacementString();
		
			int replacementOffset = contentAssistRequest.getReplacementBeginPosition() - matchString.length();
			int replacementLength = matchString.length();
			int cursorPosition = getCursorPositionForProposedText(replacementString);
			Image image = CommonUIPlugin.getImageDescriptorRegistry().get(textProposal.getImageDescriptor());
			if (textProposal.getImageDescriptor() == null) {
				image = XMLEditorPluginImageHelper.getInstance().getImage(XMLEditorPluginImages.IMG_OBJ_TAG_GENERIC);
			}

			String displayString = textProposal.getLabel();
			IContextInformation contextInformation = null;
			String additionalProposalInfo = textProposal.getContextInfo();
			int relevance = textProposal.getRelevance();
			if (relevance == TextProposal.R_NONE) {
				relevance = TextProposal.R_TAG_INSERTION;
			}

			AutoContentAssistantProposal proposal = new AutoContentAssistantProposal(false, replacementString, 
					replacementOffset, replacementLength, cursorPosition, image, displayString, 
					contextInformation, additionalProposalInfo, relevance);

			contentAssistRequest.addProposal(proposal);
		}

	}

	@Override
	protected void addAttributeNameProposals(
			ContentAssistRequest contentAssistRequest,
			CompletionProposalInvocationContext context) {
		// No actions required
	}

	@Override
	protected void addAttributeValueProposals(
			ContentAssistRequest contentAssistRequest,
			CompletionProposalInvocationContext context) {
		// No actions required
	}

	@Override
	protected void addTagNameProposals(
			ContentAssistRequest contentAssistRequest, int childPosition,
			CompletionProposalInvocationContext context) {
		// No actions required
	}

	@Override
	protected void addTagNameProposals(
			ContentAssistRequest contentAssistRequest, int childPosition,
			boolean insertTagOpenningCharacter,
			CompletionProposalInvocationContext context) {
		// No actions required
	}

	@Override
	protected void addAttributeValueELProposals(
			ContentAssistRequest contentAssistRequest,
			CompletionProposalInvocationContext context) {
		// No actions required
	}

	@Override
	protected void addTextELProposals(
			ContentAssistRequest contentAssistRequest,
			CompletionProposalInvocationContext context) {
		// No actions required
	}
	
	private String leftTrim(String value) {
		int len = value.length();
		int st = 0;
		char[] val = value.toCharArray();
		while ((st < len) && (val[st] <= ' ')) {
		    st++;
		}
		return (st > 0) ? value.substring(st) : value;
	}
}

