/*******************************************************************************
 * Copyright (c) 2000, 2011 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.jdt.internal.ui.typehierarchy;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

import org.eclipse.core.runtime.Assert;

import org.eclipse.jface.viewers.IStructuredContentProvider;
import org.eclipse.jface.viewers.TableViewer;
import org.eclipse.jface.viewers.Viewer;

import org.eclipse.jdt.core.IType;
import org.eclipse.jdt.core.ITypeHierarchy;
import org.eclipse.jdt.core.JavaModelException;

import org.eclipse.jdt.ui.IWorkingCopyProvider;

import org.eclipse.jdt.internal.ui.JavaPlugin;

/**
 * Content provider used for the method view.
 * Allows also seeing methods inherited from base classes.
 */
public class MethodsContentProvider implements IStructuredContentProvider, IWorkingCopyProvider {

	private static final Object[] NO_ELEMENTS = new Object[0];

	private boolean fShowInheritedMethods;
	private TypeHierarchyLifeCycle fHierarchyLifeCycle;
	private TableViewer fViewer;

	public MethodsContentProvider(TypeHierarchyLifeCycle lifecycle) {
		fHierarchyLifeCycle= lifecycle;
		fShowInheritedMethods= false;
		fViewer= null;
	}

	/**
	 * Turn on / off showing of inherited methods
	 * @param show new state
	 */
	public void showInheritedMethods(boolean show) {
		if (show != fShowInheritedMethods) {
			fShowInheritedMethods= show;
			if (fViewer != null) {
				fViewer.refresh();
			}
		}
	}

	@Override
	public boolean providesWorkingCopies() {
		return true;
	}

	/**
	 * Returns true if inherited methods are shown
	 * @return returns true if inherited methods are shown
	 */
	public boolean isShowInheritedMethods() {
		return fShowInheritedMethods;
	}


	private void addAll(Object[] arr, List<Object> res) {
		if (arr != null) {
			res.addAll(Arrays.asList(arr));
		}
	}

	/*
	 * @see IStructuredContentProvider#getElements
	 */
	@Override
	public Object[] getElements(Object element) {
		if (element instanceof IType) {
			IType type= (IType)element;

			List<Object> res= new ArrayList<>();
			try {
				ITypeHierarchy hierarchy= fHierarchyLifeCycle.getHierarchy();
				if (fShowInheritedMethods && hierarchy != null) {
					IType[] allSupertypes= hierarchy.getAllSupertypes(type);
					// sort in from last to first: elements with same name
					// will show up in hierarchy order
					for (int i= allSupertypes.length - 1; i >= 0; i--) {
						IType superType= allSupertypes[i];
						if (superType.exists()) {
							addAll(superType.getMethods(), res);
							addAll(superType.getInitializers(), res);
							addAll(superType.getFields(), res);
						}
					}
				}
				if (type.exists()) {
					addAll(type.getMethods(), res);
					addAll(type.getInitializers(), res);
					addAll(type.getFields(), res);
				}
			} catch (JavaModelException e) {
				JavaPlugin.log(e);
			}
			return res.toArray();
		}
		return NO_ELEMENTS;
	}


	/*
	 * @see IContentProvider#inputChanged
	 */
	@Override
	public void inputChanged(Viewer input, Object oldInput, Object newInput) {
		Assert.isTrue(input instanceof TableViewer);

		fViewer= (TableViewer) input;
	}

	/*
	 * @see IContentProvider#dispose
	 */
	@Override
	public void dispose() {
	}

}