/*******************************************************************************
 * Copyright (c) 2015, 2016 IBM Corporation.
 * 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
 *
 * This is an implementation of an early-draft specification developed under the Java
 * Community Process (JCP) and is made available for testing and evaluation purposes
 * only. The code is not compatible with any specification of the JCP.
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.jdt.internal.core;

import java.io.IOException;
import java.nio.file.FileVisitResult;
import java.nio.file.Path;
import java.nio.file.attribute.BasicFileAttributes;
import java.util.ArrayList;

import org.eclipse.core.resources.IResource;
import org.eclipse.core.runtime.IPath;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.jdt.core.JavaModelException;
import org.eclipse.jdt.core.compiler.CharOperation;
import org.eclipse.jdt.internal.compiler.impl.CompilerOptions;
import org.eclipse.jdt.internal.compiler.util.JRTUtil;
import org.eclipse.jdt.internal.core.util.HashtableOfArrayToObject;
import org.eclipse.jdt.internal.core.util.Util;

/**
 * A package fragment root that corresponds to a module in a JRT file system.
 *
 * @see org.eclipse.jdt.core.IPackageFragmentRoot
 * @see org.eclipse.jdt.internal.core.JarPackageFragmentRootInfo
 */
public class JrtPackageFragmentRoot extends JarPackageFragmentRoot {

	String moduleName;
	
	/**
	 * Constructs a package fragment root which represents a module
	 * contained in a JRT.
	 */
	protected JrtPackageFragmentRoot(IPath jrtPath, String moduleName, JavaProject project) {
		super(jrtPath, project);
		this.moduleName = moduleName;
	}

	protected boolean computeChildren(OpenableElementInfo info, IResource underlyingResource) throws JavaModelException {
		final HashtableOfArrayToObject rawPackageInfo = new HashtableOfArrayToObject();
		final String compliance = CompilerOptions.VERSION_1_8; // TODO: BETA_JAVA9 Revisit

		// always create the default package
		rawPackageInfo.put(CharOperation.NO_STRINGS, new ArrayList[] { EMPTY_LIST, EMPTY_LIST });

		try {
			org.eclipse.jdt.internal.compiler.util.JRTUtil.walkModuleImage(this.jarPath.toFile(),
					new org.eclipse.jdt.internal.compiler.util.JRTUtil.JrtFileVisitor<Path>() {
				@Override
				public FileVisitResult visitPackage(Path dir, Path mod, BasicFileAttributes attrs) throws IOException {
					initRawPackageInfo(rawPackageInfo, dir.toString(), true, compliance);
					return FileVisitResult.CONTINUE;
				}

				@Override
				public FileVisitResult visitFile(Path path, Path mod, BasicFileAttributes attrs) throws IOException {
					initRawPackageInfo(rawPackageInfo, path.toString(), false, compliance);
					return FileVisitResult.CONTINUE;
				}

				@Override
				public FileVisitResult visitModule(Path mod) throws IOException {
					if (!JrtPackageFragmentRoot.this.moduleName.equals(mod.toString())) {
						return FileVisitResult.SKIP_SUBTREE;
					}
					return FileVisitResult.CONTINUE;
				}
			}, JRTUtil.NOTIFY_ALL);
		} catch (IOException e) {
			Util.log(IStatus.ERROR, "Error reading modules" + toStringWithAncestors()); //$NON-NLS-1$
		}

		info.setChildren(createChildren(rawPackageInfo));
		((JarPackageFragmentRootInfo) info).rawPackageInfo = rawPackageInfo;
		return true;
	}
	public boolean equals(Object o) {
		if (this == o)
			return true;
		if (o instanceof JrtPackageFragmentRoot) {
			JrtPackageFragmentRoot other= (JrtPackageFragmentRoot) o;
			return this.moduleName.equals(other.moduleName) &&
					this.jarPath.equals(other.jarPath);
		}
		return false;
	}
	public String getElementName() {
		return this.moduleName;
	}
	@Override
	public boolean isModule() {
		return true;
	}
	public PackageFragment getPackageFragment(String[] pkgName) {
		// NOTE: Do we need a different kind of package fragment?
		return new JarPackageFragment(this, pkgName);
	}
	public int hashCode() {
		return this.jarPath.hashCode() + this.moduleName.hashCode();
	}
	protected void toStringInfo(int tab, StringBuffer buffer, Object info, boolean showResolvedInfo) {
		buffer.append(tabString(tab));
		buffer.append("<module:").append(this.moduleName).append(">"); //$NON-NLS-1$ //$NON-NLS-2$
		if (info == null) {
			buffer.append(" (not open)"); //$NON-NLS-1$
		}
	}
}