Copyright (c) 2016, 2019 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
/*******************************************************************************
 * Copyright (c) 2016, 2019 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.core.builder;

import java.io.File;
import java.io.IOException;
import java.net.URI;
import java.nio.file.DirectoryStream;
import java.nio.file.FileSystemNotFoundException;
import java.nio.file.FileSystems;
import java.nio.file.FileVisitResult;
import java.nio.file.FileVisitor;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.attribute.BasicFileAttributes;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Set;
import java.util.function.Predicate;

import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IPath;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.Status;
import org.eclipse.jdt.core.JavaCore;
import org.eclipse.jdt.internal.compiler.classfmt.ClassFileReader;
import org.eclipse.jdt.internal.compiler.classfmt.ClassFormatException;
import org.eclipse.jdt.internal.compiler.env.AccessRuleSet;
import org.eclipse.jdt.internal.compiler.env.IBinaryType;
import org.eclipse.jdt.internal.compiler.env.IModule;
import org.eclipse.jdt.internal.compiler.env.NameEnvironmentAnswer;
import org.eclipse.jdt.internal.compiler.util.JRTUtil;
import org.eclipse.jdt.internal.compiler.util.SimpleSet;
import org.eclipse.jdt.internal.compiler.util.SuffixConstants;
import org.eclipse.jdt.internal.core.util.Util;

public class ClasspathJrtWithReleaseOption extends ClasspathJrt {

	static String MODULE_INFO = "module-info.sig"; //$NON-NLS-1$

	final String release;
	String releaseInHex;
	private String[] subReleases;
	private java.nio.file.FileSystem fs;
	protected Path releasePath;
	protected Path modulePath;
	private String modPathString;
	private boolean isJRE12Plus;

	public ClasspathJrtWithReleaseOption(String zipFilename, AccessRuleSet accessRuleSet, IPath externalAnnotationPath,
			String release) throws CoreException {
		super();
		if (release == null || release.equals("")) { //$NON-NLS-1$
			throw new IllegalArgumentException("--release argument can not be null"); //$NON-NLS-1$
		}
		this.zipFilename = zipFilename;
		this.accessRuleSet = accessRuleSet;
		if (externalAnnotationPath != null)
			this.externalAnnotationPath = externalAnnotationPath.toString();
		this.release = getReleaseOptionFromCompliance(release);
		initialize();
		loadModules(this);
	}
	/*
	 * JDK 11 doesn't contain release 5. Hence
	 * if the compliance is below 6, we simply return the lowest supported
	 * release, which is 6.
	 */
	private String getReleaseOptionFromCompliance(String comp) {
		if (JavaCore.compareJavaVersions(comp, JavaCore.VERSION_1_5) <= 0) {
			return "6"; //$NON-NLS-1$
		}
		int index = comp.indexOf("1."); //$NON-NLS-1$
		if (index != -1) {
			return comp.substring(index + 2, comp.length());
		} else {
			return comp;
		}
	}
	private boolean isJRE12Plus(Path path) {
		try (DirectoryStream<java.nio.file.Path> stream = Files.newDirectoryStream(path)) {
			for (final java.nio.file.Path subdir : stream) {
				String rel = JRTUtil.sanitizedFileName(subdir);
				if (Files.exists(this.fs.getPath(rel, "system-modules"))) { //$NON-NLS-1$
					int parseInt = Integer.parseInt(rel, 16);
					return (parseInt > 11);
				}
			}
		} catch (IOException e) {
			this.fs = null;
		}
		return false; 
	}
	/*
	 * Set up the paths where modules and regular classes need to be read. We need to deal with two different kind of
	 * formats of cy.sym: Post JDK 12: ct.sym -> 9 -> java/ -> lang/* 9-modules -> java.base -> module-info.sig
	 * 
	 * From JDK 12 onward: ct.sym -> 9 -> java.base -> module-info.sig java/ -> lang/* Notably, 1) in JDK 12 modules
	 * classes and ordinary classes are located in the same location 2) in JDK 12, ordinary classes are found inside
	 * their respective modules
	 * 
	 */
	protected void initialize() throws CoreException {
		this.releaseInHex = Integer.toHexString(Integer.parseInt(this.release)).toUpperCase();
		Path lib = Paths.get(this.zipFilename).getParent();
		Path filePath = Paths.get(lib.toString(), "ct.sym"); //$NON-NLS-1$
		URI t = filePath.toUri();
		if (!Files.exists(filePath)) {
			return;
		}
		URI uri = URI.create("jar:file:" + t.getRawPath()); //$NON-NLS-1$
		try {
			this.fs = FileSystems.getFileSystem(uri);
		} catch (FileSystemNotFoundException fne) {
			// Ignore and move on
		}
		if (this.fs == null) {
			HashMap<String, ?> env = new HashMap<>();
			try {
				this.fs = FileSystems.newFileSystem(uri, env);
			} catch (IOException e) {
				return;
			}
		}
		this.releasePath = this.fs.getPath("/"); //$NON-NLS-1$
		this.isJRE12Plus = isJRE12Plus(this.releasePath);
		Path modPath = this.fs.getPath(this.releaseInHex + (this.isJRE12Plus ? "" : "-modules")); //$NON-NLS-1$ //$NON-NLS-2$
		if (Files.exists(modPath)) {
			this.modulePath = modPath;
			this.modPathString = this.zipFilename + "|"+ modPath.toString(); //$NON-NLS-1$
		}
		
		if (!Files.exists(this.releasePath.resolve(this.releaseInHex))) {
			Exception e = new IllegalArgumentException("release " + this.release + " is not found in the system"); //$NON-NLS-1$//$NON-NLS-2$
			throw new CoreException(new Status(IStatus.ERROR, JavaCore.PLUGIN_ID, e.getMessage(), e));
		}
		if (Files.exists(this.fs.getPath(this.releaseInHex, "system-modules"))) { //$NON-NLS-1$
			this.fs = null;  // Fallback to default version
			return;
		}
		if (this.release != null) {
			List<String> sub = new ArrayList<>();
			try (DirectoryStream<java.nio.file.Path> stream = Files.newDirectoryStream(this.releasePath)) {
				for (final java.nio.file.Path subdir : stream) {
					String rel = JRTUtil.sanitizedFileName(subdir);
					if (rel.contains(this.releaseInHex)) {
						sub.add(rel);
					} else {
						continue;
					}
				}
			} catch (IOException e) {
				this.fs = null; // Fallback to default version
			}
			this.subReleases = sub.toArray(new String[sub.size()]);
		}
	}

	static HashMap<String, SimpleSet> findPackagesInModules(final ClasspathJrtWithReleaseOption jrt) {
		// In JDK 11 and before, classes are not listed under their respective modules
		// Hence, we simply go to the default module system for package-module mapping
		if (jrt.fs == null || !jrt.isJRE12Plus) {
			return ClasspathJrt.findPackagesInModules(jrt);
		}
		String zipFileName = jrt.zipFilename;
		HashMap<String, SimpleSet> cache = PackageCache.get(jrt.modPathString);
		if (cache != null) {
			return cache;
		}
		final HashMap<String, SimpleSet> packagesInModule = new HashMap<>();
		PackageCache.put(jrt.modPathString, packagesInModule);
		try {
			final File imageFile = new File(zipFileName);
			org.eclipse.jdt.internal.compiler.util.JRTUtil.walkModuleImage(imageFile, jrt.release,
					new org.eclipse.jdt.internal.compiler.util.JRTUtil.JrtFileVisitor<Path>() {
						SimpleSet packageSet = null;

						@Override
						public FileVisitResult visitPackage(Path dir, Path mod, BasicFileAttributes attrs)
								throws IOException {
							ClasspathJar.addToPackageSet(this.packageSet, dir.toString(), true);
							return FileVisitResult.CONTINUE;
						}

						@Override
						public FileVisitResult visitFile(Path file, Path mod, BasicFileAttributes attrs)
								throws IOException {
							return FileVisitResult.CONTINUE;
						}

						@Override
						public FileVisitResult visitModule(Path path, String name) throws IOException {
							this.packageSet = new SimpleSet(41);
							this.packageSet.add(""); //$NON-NLS-1$
							if (name.endsWith("/")) { //$NON-NLS-1$
								name = name.substring(0, name.length() - 1);
							}
							packagesInModule.put(name, this.packageSet);
							return FileVisitResult.CONTINUE;
						}
					}, JRTUtil.NOTIFY_PACKAGES | JRTUtil.NOTIFY_MODULES);
		} catch (IOException e) {
			// return empty handed
		}
		return packagesInModule;
	}

	public static void loadModules(final ClasspathJrtWithReleaseOption jrt) {
		if (jrt.fs == null || !jrt.isJRE12Plus) {
			ClasspathJrt.loadModules(jrt);
			return;
		}
		if (jrt.modPathString == null)
			return;
		Set<IModule> cache = ModulesCache.get(jrt.modPathString);
		if (cache == null) {
			try (DirectoryStream<java.nio.file.Path> stream = Files.newDirectoryStream(jrt.releasePath)) {
				for (final java.nio.file.Path subdir : stream) {
					if (!subdir.getFileName().toString().contains(jrt.releaseInHex)) {
						continue;
					}
					Files.walkFileTree(subdir, Collections.EMPTY_SET, 2, new FileVisitor<java.nio.file.Path>() {
						@Override
						public FileVisitResult preVisitDirectory(java.nio.file.Path dir, BasicFileAttributes attrs)
								throws IOException {
							return FileVisitResult.CONTINUE;
						}

						@Override
						public FileVisitResult visitFile(java.nio.file.Path f, BasicFileAttributes attrs)
								throws IOException {
							if (attrs.isDirectory() || f.getNameCount() < 3) {
								return FileVisitResult.CONTINUE;
							}
							if (f.getFileName().toString().equals(MODULE_INFO)) {
								byte[] content = JRTUtil.safeReadBytes(f);
								if (content == null)
									return FileVisitResult.CONTINUE;
								jrt.acceptModule(content);
							}
							return FileVisitResult.SKIP_SIBLINGS;
						}

						@Override
						public FileVisitResult visitFileFailed(java.nio.file.Path f, IOException exc)
								throws IOException {
							return FileVisitResult.CONTINUE;
						}

						@Override
						public FileVisitResult postVisitDirectory(java.nio.file.Path dir, IOException exc)
								throws IOException {
							return FileVisitResult.CONTINUE;
						}
					});
				}
			} catch (IOException e) {
				// Nothing much to do
			}
		}
	}


	@Override
	public NameEnvironmentAnswer findClass(String binaryFileName, String qualifiedPackageName, String moduleName,
			String qualifiedBinaryFileName, boolean asBinaryOnly, Predicate<String> moduleNameFilter) {

		if (this.fs == null) {
			return super.findClass(binaryFileName, qualifiedPackageName, moduleName, qualifiedBinaryFileName,
					asBinaryOnly, moduleNameFilter);
		}
		if (!isPackage(qualifiedPackageName, moduleName))
			return null; // most common case

		try {
			IBinaryType reader = null;
			byte[] content = null;
			String fileNameWithoutExtension = qualifiedBinaryFileName.substring(0,
												qualifiedBinaryFileName.length() - SuffixConstants.SUFFIX_CLASS.length);
			if (this.subReleases != null && this.subReleases.length > 0) {
				qualifiedBinaryFileName = qualifiedBinaryFileName.replace(".class", ".sig"); //$NON-NLS-1$ //$NON-NLS-2$
				outer: for (String rel : this.subReleases) {
					Path p = null;
					inner: if (this.isJRE12Plus) {
						if (moduleName != null) {
							p = this.fs.getPath(rel, moduleName, qualifiedBinaryFileName);
						} 
						else {
							try (DirectoryStream<java.nio.file.Path> stream = Files
									.newDirectoryStream(this.fs.getPath(rel))) {
								for (final java.nio.file.Path subdir : stream) {
									p = subdir.resolve(qualifiedBinaryFileName);
									if (Files.exists(p)) {
										if (subdir.getNameCount() == 2 ) {
											moduleName = subdir.getName(1).toString();
										}
										break inner;
									}
								}
							}
						}
					} else {
						p = this.fs.getPath(rel, qualifiedBinaryFileName);
					}
					if (Files.exists(p)) {
						content = JRTUtil.safeReadBytes(p);
						if (content != null) {
							reader = new ClassFileReader(content, qualifiedBinaryFileName.toCharArray());
							if (moduleName != null)
								((ClassFileReader) reader).moduleName = moduleName.toCharArray();
							break outer;
						}
					}
				}
			} else {
				reader = ClassFileReader.readFromModule(new File(this.zipFilename), moduleName, qualifiedBinaryFileName,
						moduleNameFilter);
			}
			return createAnswer(fileNameWithoutExtension, reader);
		} catch (ClassFormatException | IOException e) { 
			// treat as if class file is missing
		}
		return null;
	}

	@Override
	public Collection<String> getModuleNames(Collection<String> limitModules) {
		HashMap<String, SimpleSet> cache = findPackagesInModules(this);
		if (cache != null)
			return selectModules(cache.keySet(), limitModules);
		return Collections.emptyList();
	}

	@Override
	public void cleanup() {
		try {
			super.reset();
		} finally {
			// The same file system is also used in JRTUtil, so don't close it here.
			this.fs = null;
		}
	}

	@Override
	public boolean hasModule() {
		return this.fs == null ? super.hasModule() : this.modPathString != null;
	}

	@Override
	protected String getKey() {
		return this.fs == null ? super.getKey() : this.modPathString;
	}

	@Override
	public boolean equals(Object o) {
		if (this == o)
			return true;
		if (!(o instanceof ClasspathJrtWithReleaseOption))
			return false;
		ClasspathJrtWithReleaseOption jar = (ClasspathJrtWithReleaseOption) o;
		if (!Util.equalOrNull(this.release, jar.release)) {
			return false;
		}
		return super.equals(o);
	}

	@Override
	public int hashCode() {
		int hash = this.zipFilename == null ? super.hashCode() : this.zipFilename.hashCode();
		return Util.combineHashCodes(hash, this.release.hashCode());
	}

	@Override
	public String toString() {
		String start = "Classpath jrt file " + this.zipFilename + " with --release option " + this.release; //$NON-NLS-1$ //$NON-NLS-2$
		return start;
	}

}