/*******************************************************************************
 * Copyright (c) 2000, 2015 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.debug.internal.ui;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.util.regex.Pattern;

import org.eclipse.core.expressions.PropertyTester;
import org.eclipse.core.resources.IFile;
import org.eclipse.core.resources.IProject;
import org.eclipse.core.resources.IResource;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IAdaptable;
import org.eclipse.core.runtime.IPath;
import org.eclipse.core.runtime.Platform;
import org.eclipse.core.runtime.content.IContentDescription;
import org.eclipse.core.runtime.content.IContentType;
import org.eclipse.ui.IPathEditorInput;

/**
 * ResourceExtender provides property testers for the XML expression language
 * evaluation. We provide a copy in Debug so that launch shortcuts can add
 * contextual launch enablement that does not require their plugins to be
 * loaded. Copied from
 * org.eclipse.jdt.internal.corext.refactoring.participants.xml.ResourceExtender
 */
public class ResourceExtender extends PropertyTester {

    private static final String PROPERTY_MATCHES_PATTERN = "matchesPattern"; //$NON-NLS-1$

    private static final String PROJECT_NATURE = "projectNature"; //$NON-NLS-1$

    private static final String PROPERTY_MATCHES_CONTENT_TYPE = "matchesContentType"; //$NON-NLS-1$

    /* (non-Javadoc)
     * @see org.eclipse.core.expressions.IPropertyTester#test(java.lang.Object, java.lang.String, java.lang.Object[], java.lang.Object)
     */
    @Override
	public boolean test(Object receiver, String method, Object[] args, Object expectedValue) {
        IResource resource = ((IAdaptable) receiver).getAdapter(IResource.class);
        if (resource == null) {
        	if (PROPERTY_MATCHES_CONTENT_TYPE.equals(method)) {
		        IPathEditorInput editorInput = ((IAdaptable) receiver).getAdapter(IPathEditorInput.class);
		        if (editorInput != null) {
		            IPath path= editorInput.getPath();
		            File file= path.toFile();
		            if (file.exists()) {
						try (FileReader reader = new FileReader(file)) {
		                    IContentType contentType= Platform.getContentTypeManager().getContentType((String)expectedValue);
		                    IContentDescription description= contentType.getDescriptionFor(reader, IContentDescription.ALL);
		                    if (description != null) {
		                    	return matchesContentType(description.getContentType(), (String)expectedValue);
		                    }
		                } catch (FileNotFoundException e) {
		                    return false;
		                } catch (IOException e) {
		                    return false;
		                }
		            }
		        }
        	}
        } else {
            if (PROPERTY_MATCHES_PATTERN.equals(method)) { 
                String fileName = resource.getName();
                String expected = (String) expectedValue;
                expected = expected.replaceAll("\\.", "\\\\.");  //$NON-NLS-1$//$NON-NLS-2$
                expected = expected.replaceAll("\\*", "\\.\\*");  //$NON-NLS-1$//$NON-NLS-2$
                Pattern pattern = Pattern.compile(expected);
                boolean retVal = pattern.matcher(fileName).find();
                return retVal;
            } else if (PROJECT_NATURE.equals(method)) {
                try {
                    IProject proj = resource.getProject();
                    return proj != null && proj.isAccessible() && proj.hasNature((String) expectedValue);
                } catch (CoreException e) {
                    return false;
                }
            } else if (PROPERTY_MATCHES_CONTENT_TYPE.equals(method)) {
                return matchesContentType(resource, (String) expectedValue);
            }
        }
        return false;
    }
    
    /**
     * Returns whether the given type or one of its base types matches the 
     * given content type identifier.
     *  
     * @param type content type or <code>null</code>
     * @param typeId content type identifier
     * @return
     */
    private boolean matchesContentType(IContentType type, String typeId) {
        while (type != null) {
        	if (typeId.equals(type.getId())) {
        		return true;
        	}
        	type = type.getBaseType();
        }
        return false;
    }

    /**
     * Returns whether or not the given file's content type matches the
     * specified content type.
     * 
     * Content types are looked up in the content type registry.
     * 
     * @return whether or not the given resource has the given content type
     */
    private boolean matchesContentType(IResource resource, String contentType) {
        if (resource == null || !(resource instanceof IFile) || !resource.exists()) {
            return false;
        }
        IFile file = (IFile) resource;
        IContentDescription description;
        try {
            description = file.getContentDescription();
        } catch (CoreException e) {
            return false;
        }
        if (description != null) {
        	return matchesContentType(description.getContentType(), contentType);
        }
        return false;
    }

}