/*******************************************************************************
 * Copyright (c) 2007, 2011 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
 *******************************************************************************/
package org.eclipse.wst.jsdt.web.ui.internal.contentassist;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;

import org.eclipse.jface.text.contentassist.IContextInformation;
import org.eclipse.swt.graphics.Image;
import org.eclipse.wst.jsdt.core.CompletionProposal;
import org.eclipse.wst.jsdt.core.Signature;
import org.eclipse.wst.jsdt.ui.text.java.CompletionProposalCollector;
import org.eclipse.wst.jsdt.ui.text.java.CompletionProposalComparator;
import org.eclipse.wst.jsdt.ui.text.java.IJavaCompletionProposal;
import org.eclipse.wst.jsdt.web.core.javascript.IJsTranslation;


/**
*

* Provisional API: This class/interface is part of an interim API that is still under development and expected to
* change significantly before reaching stability. It is being made available at this early stage to solicit feedback
* from pioneering adopters on the understanding that any code that uses this API will almost certainly be broken
* (repeatedly) as the API evolves.
*/
public class JSDTProposalCollector extends CompletionProposalCollector {
	static char[] getTypeTriggers() {
		return CompletionProposalCollector.TYPE_TRIGGERS;
	}
	private Comparator fComparator;
	private IJsTranslation fTranslation;
	
// public List getGeneratedFunctionNames(){
// if(fGeneratedFunctionNames==null){
// fGeneratedFunctionNames = fTranslation.getGeneratedFunctionNames();
// }
// return fGeneratedFunctionNames;
// }
	public JSDTProposalCollector(IJsTranslation translation) {
		super(translation!=null?translation.getCompilationUnit():null);
		if (translation == null) {
			throw new IllegalArgumentException("JSPTranslation cannot be null"); //$NON-NLS-1$
		}
		fTranslation = translation;
	}
	
	/**
	 * Cacluates the where the cursor should be after applying this proposal.
	 * eg. method(|) if the method proposal chosen had params.
	 * 
	 * @param proposal
	 * @param completion
	 * @return
	 */
	private int calculatePositionAfter(CompletionProposal proposal, String completion) {
		int positionAfter = completion.length();
		int kind = proposal.getKind();
		// may need better logic here...
		// put cursor inside parenthesis if there's params
		// only checking for any kind of declaration
		if (kind == CompletionProposal.ANONYMOUS_CLASS_DECLARATION || kind == CompletionProposal.METHOD_DECLARATION || kind == CompletionProposal.POTENTIAL_METHOD_DECLARATION || kind == CompletionProposal.METHOD_REF) {
			int paramCount = Signature.getParameterCount(proposal.getSignature());
			if (completion.length() > 0 && paramCount > 0) {
				positionAfter--;
			}
		}
		return positionAfter;
	}
	
	/**
	 * Overridden to: - translate Java -> JSP offsets - fix
	 * cursor-position-after - fix mangled servlet name in display string -
	 * remove unwanted proposals (servlet constructor)
	 */
	
	protected IJavaCompletionProposal createJavaCompletionProposal(CompletionProposal proposal) {
		return createJSDTProposal(proposal);
	}
	
	private JSDTCompletionProposal createJSDTProposal(CompletionProposal proposal) {
		JSDTCompletionProposal jspProposal;
		String completion = String.valueOf(proposal.getCompletion());
		// java offset
		int offset = proposal.getReplaceStart();
		// replacement length
		int length = proposal.getReplaceEnd() - offset;
		// translate offset from Java > JSP
		// cursor position after must be calculated
		int positionAfter = calculatePositionAfter(proposal, completion);
		// from java proposal
		IJavaCompletionProposal javaProposal = super.createJavaCompletionProposal(proposal);
		proposal.getDeclarationSignature();
		Image image = javaProposal.getImage();
		String displayString = javaProposal.getDisplayString();
		displayString = getTranslation().fixupMangledName(displayString);

		IContextInformation contextInformation = javaProposal.getContextInformation();
		// String additionalInfo = javaProposal.getAdditionalProposalInfo();
		int relevance = javaProposal.getRelevance();
		boolean updateLengthOnValidate = true;
		jspProposal = new JSDTCompletionProposal(completion, offset, length, positionAfter, image, displayString, contextInformation, null, relevance, updateLengthOnValidate);
		// https://bugs.eclipse.org/bugs/show_bug.cgi?id=124483
		// set wrapped java proposal so additional info can be calculated on
		// demand
		jspProposal.setJavaCompletionProposal(javaProposal);
		return jspProposal;
	}
	
	private Comparator getComparator() {
		if (fComparator == null) {
			fComparator = new CompletionProposalComparator();
		}
		return fComparator;
	}
	
	/**
	 * Ensures that we only return JSPCompletionProposals.
	 * 
	 * @return an array of JSPCompletionProposals
	 */
	public JSDTCompletionProposal[] getJSPCompletionProposals() {
		List results = new ArrayList();
		IJavaCompletionProposal[] javaProposals = getJavaCompletionProposals();
		// need to filter out non JSPCompletionProposals
		// because their offsets haven't been translated
		for (int i = 0; i < javaProposals.length; i++) {
			if (javaProposals[i] instanceof JSDTCompletionProposal) {
				results.add(javaProposals[i]);
			}
		}
		Collections.sort(results, getComparator());
		return (JSDTCompletionProposal[]) results.toArray(new JSDTCompletionProposal[results.size()]);
	}
	
	public IJsTranslation getTranslation() {
		return fTranslation;
	}
}