/*

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package com.sun.tools.jdeprscan;

import java.io.File;

import java.io.IOException;

import java.io.PrintStream;

import java.net.URI;

import java.nio.charset.StandardCharsets;

import java.nio.file.Files;

import java.nio.file.FileSystems;

import java.nio.file.Path;

import java.nio.file.Paths;

import java.util.ArrayDeque;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.Collection;

import java.util.EnumSet;

import java.util.HashSet;

import java.util.List;

import java.util.Map;

import java.util.NoSuchElementException;

import java.util.Set;

import java.util.Queue;

import java.util.stream.Stream;

import java.util.stream.StreamSupport;

import java.util.jar.JarEntry;

import java.util.jar.JarFile;

import javax.tools.Diagnostic;

import javax.tools.DiagnosticListener;

import javax.tools.JavaCompiler;

import javax.tools.JavaFileManager;

import javax.tools.JavaFileObject;

import javax.tools.JavaFileObject.Kind;

import javax.tools.StandardJavaFileManager;

import javax.tools.StandardLocation;

import javax.tools.ToolProvider;

import com.sun.tools.javac.file.JavacFileManager;

import com.sun.tools.javac.platform.JDKPlatformProvider;

import com.sun.tools.jdeprscan.scan.Scan;

import static java.util.stream.Collectors.*;

import javax.lang.model.element.PackageElement;

import javax.lang.model.element.TypeElement;

/**

 * Deprecation Scanner tool. Loads API deprecation information from the

 * JDK image, or optionally, from a jar file or class hierarchy. Then scans

 * a class library for usages of those APIs.

 *

 * TODO:

 *  - audit error handling throughout, but mainly in scan package

 *  - handling of covariant overrides

 *  - handling of override of method found in multiple superinterfaces

 *  - convert type/method/field output to Java source like syntax, e.g.

 *      instead of java/lang/Runtime.runFinalizersOnExit(Z)V

 *      print void java.lang.Runtime.runFinalizersOnExit(boolean)

 *  - more example output in man page

 *  - more rigorous GNU style option parsing; use joptsimple?

 *

 * FUTURES:

 *  - add module support: --add-modules, --module-path, module arg

 *  - load deprecation declarations from a designated class library instead

 *    of the JDK

 *  - load deprecation declarations from a module

 *  - scan a module (but a modular jar can be treated just a like an ordinary jar)

 *  - multi-version jar

 */

public class Main implements DiagnosticListener<JavaFileObject> {

    final PrintStream out;

    final PrintStream err;

    final List<File> bootClassPath = new ArrayList<>();

    final List<File> classPath = new ArrayList<>();

    final List<File> systemModules = new ArrayList<>();

    final List<String> options = new ArrayList<>();

    final List<String> comments = new ArrayList<>();

    // Valid releases need to match what the compiler supports.

    // Keep these updated manually until there's a compiler API

    // that allows querying of supported releases.

    final Set<String> releasesWithoutForRemoval = Set.of("6", "7", "8");

    final Set<String> releasesWithForRemoval = Set.of("9", "10", "11");

    final Set<String> validReleases;

    {

        Set<String> temp = new HashSet<>(releasesWithoutForRemoval);

        temp.addAll(releasesWithForRemoval);

        validReleases = Set.of(temp.toArray(new String[0]));

    }

    boolean verbose = false;

    boolean forRemoval = false;

    final JavaCompiler compiler;

    final StandardJavaFileManager fm;

    List<DeprData> deprList; // non-null after successful load phase

    /**

     * Processes a collection of class names. Names should fully qualified

     * names in the form "pkg.pkg.pkg.classname".

     *

     * @param classNames collection of fully qualified classnames to process

     * @return true for success, false for failure

     * @throws IOException if an I/O error occurs

     */

    boolean doClassNames(Collection<String> classNames) throws IOException {

        if (verbose) {

            out.println("List of classes to process:");

            classNames.forEach(out::println);

            out.println("End of class list.");

        }

        // TODO: not sure this is necessary...

        if (fm instanceof JavacFileManager) {

            ((JavacFileManager)fm).setSymbolFileEnabled(false);

        }

        fm.setLocation(StandardLocation.CLASS_PATH, classPath);

        if (!bootClassPath.isEmpty()) {

            fm.setLocation(StandardLocation.PLATFORM_CLASS_PATH, bootClassPath);

        }

        if (!systemModules.isEmpty()) {

            fm.setLocation(StandardLocation.SYSTEM_MODULES, systemModules);

        }

        LoadProc proc = new LoadProc();

        JavaCompiler.CompilationTask task =

            compiler.getTask(null, fm, this, options, classNames, null);

        task.setProcessors(List.of(proc));

        boolean r = task.call();

        if (r) {

            if (forRemoval) {

                deprList = proc.getDeprecations().stream()

                               .filter(DeprData::isForRemoval)

                               .collect(toList());

            } else {

                deprList = proc.getDeprecations();

            }

        }

        return r;

    }

    /**

     * Processes a stream of filenames (strings). The strings are in the

     * form pkg/pkg/pkg/classname.class relative to the root of a package

     * hierarchy.

     *

     * @param filenames a Stream of filenames to process

     * @return true for success, false for failure

     * @throws IOException if an I/O error occurs

     */

    boolean doFileNames(Stream<String> filenames) throws IOException {

        return doClassNames(

            filenames.filter(name -> name.endsWith(".class"))

                     .filter(name -> !name.endsWith("package-info.class"))

                     .filter(name -> !name.endsWith("module-info.class"))

                     .map(s -> s.replaceAll("\\.class$", ""))

                     .map(s -> s.replace(File.separatorChar, '.'))

                     .collect(toList()));

    }

    /**

     * Replaces all but the first occurrence of '/' with '.'. Assumes

     * that the name is in the format module/pkg/pkg/classname.class.

     * That is, the name should contain at least one '/' character

     * separating the module name from the package-class name.

     *

     * @param filename the input filename

     * @return the modular classname

     */

    String convertModularFileName(String filename) {

        int slash = filename.indexOf('/');

        return filename.substring(0, slash)

               + "/"

               + filename.substring(slash+1).replace('/', '.');

    }

    /**

     * Processes a stream of filenames (strings) including a module prefix.

     * The strings are in the form module/pkg/pkg/pkg/classname.class relative

     * to the root of a directory containing modules. The strings are processed

     * into module-qualified class names of the form

     * "module/pkg.pkg.pkg.classname".

     *

     * @param filenames a Stream of filenames to process

     * @return true for success, false for failure

     * @throws IOException if an I/O error occurs

     */

    boolean doModularFileNames(Stream<String> filenames) throws IOException {

        return doClassNames(

            filenames.filter(name -> name.endsWith(".class"))

                     .filter(name -> !name.endsWith("package-info.class"))

                     .filter(name -> !name.endsWith("module-info.class"))

                     .map(s -> s.replaceAll("\\.class$", ""))

                     .map(this::convertModularFileName)

                     .collect(toList()));

    }

    /**

     * Processes named class files in the given directory. The directory

     * should be the root of a package hierarchy. If classNames is

     * empty, walks the directory hierarchy to find all classes.

     *

     * @param dirname the name of the directory to process

     * @param classNames the names of classes to process

     * @return true for success, false for failure

     * @throws IOException if an I/O error occurs

     */

    boolean processDirectory(String dirname, Collection<String> classNames) throws IOException {

        if (!Files.isDirectory(Paths.get(dirname))) {

            err.printf("%s: not a directory%n", dirname);

            return false;

        }

        classPath.add(0, new File(dirname));

        if (classNames.isEmpty()) {

            Path base = Paths.get(dirname);

            int baseCount = base.getNameCount();

            try (Stream<Path> paths = Files.walk(base)) {

                Stream<String> files =

                    paths.filter(p -> p.getNameCount() > baseCount)

                         .map(p -> p.subpath(baseCount, p.getNameCount()))

                         .map(Path::toString);

                return doFileNames(files);

            }

        } else {

            return doClassNames(classNames);

        }

    }

    /**

     * Processes all class files in the given jar file.

     *

     * @param jarname the name of the jar file to process

     * @return true for success, false for failure

     * @throws IOException if an I/O error occurs

     */

    boolean doJarFile(String jarname) throws IOException {

        try (JarFile jf = new JarFile(jarname)) {

            Stream<String> files =

                jf.stream()

                  .map(JarEntry::getName);

            return doFileNames(files);

        }

    }

    /**

     * Processes named class files from the given jar file,

     * or all classes if classNames is empty.

     *

     * @param jarname the name of the jar file to process

     * @param classNames the names of classes to process

     * @return true for success, false for failure

     * @throws IOException if an I/O error occurs

     */

    boolean processJarFile(String jarname, Collection<String> classNames) throws IOException {

        classPath.add(0, new File(jarname));

        if (classNames.isEmpty()) {

            return doJarFile(jarname);

        } else {

            return doClassNames(classNames);

        }

    }

    /**

     * Processes named class files from rt.jar of a JDK version 7 or 8.

     * If classNames is empty, processes all classes.

     *

     * @param jdkHome the path to the "home" of the JDK to process

     * @param classNames the names of classes to process

     * @return true for success, false for failure

     * @throws IOException if an I/O error occurs

     */

    boolean processOldJdk(String jdkHome, Collection<String> classNames) throws IOException {

        String RTJAR = jdkHome + "/jre/lib/rt.jar";

        String CSJAR = jdkHome + "/jre/lib/charsets.jar";

        bootClassPath.add(0, new File(RTJAR));

        bootClassPath.add(1, new File(CSJAR));

        options.add("-source");

        options.add("8");

        if (classNames.isEmpty()) {

            return doJarFile(RTJAR);

        } else {

            return doClassNames(classNames);

        }

    }

    /**

     * Processes listed classes given a JDK 9 home.

     */

    boolean processJdk9(String jdkHome, Collection<String> classes) throws IOException {

        systemModules.add(new File(jdkHome));

        return doClassNames(classes);

    }

    /**

     * Processes the class files from the currently running JDK,

     * using the jrt: filesystem.

     *

     * @return true for success, false for failure

     * @throws IOException if an I/O error occurs

     */

    boolean processSelf(Collection<String> classes) throws IOException {

        options.add("--add-modules");

        options.add("java.se.ee,jdk.xml.bind"); // TODO why jdk.xml.bind?

        if (classes.isEmpty()) {

            Path modules = FileSystems.getFileSystem(URI.create("jrt:/"))

                                      .getPath("/modules");

            // names are /modules/<modulename>/pkg/.../Classname.class

            try (Stream<Path> paths = Files.walk(modules)) {

                Stream<String> files =

                    paths.filter(p -> p.getNameCount() > 2)

                         .map(p -> p.subpath(1, p.getNameCount()))

                         .map(Path::toString);

                return doModularFileNames(files);

            }

        } else {

            return doClassNames(classes);

        }

    }

    /**

     * Process classes from a particular JDK release, using only information

     * in this JDK.

     *

     * @param release "6", "7", "8", "9", "10", or "11"

     * @param classes collection of classes to process, may be empty

     * @return success value

     */

    boolean processRelease(String release, Collection<String> classes) throws IOException {

        options.addAll(List.of("--release", release));

        if (release.equals("9") || release.equals("10") ||

            release.equals("11")) {

            List<String> rootMods = List.of("java.se", "java.se.ee");

            TraverseProc proc = new TraverseProc(rootMods);

            JavaCompiler.CompilationTask task =

                compiler.getTask(null, fm, this,

                                 // options

                                 List.of("--add-modules", String.join(",", rootMods)),

                                 // classes

                                 List.of("java.lang.Object"),

                                 null);

            task.setProcessors(List.of(proc));

            if (!task.call()) {

                return false;

            }

            Map<PackageElement, List<TypeElement>> types = proc.getPublicTypes();

            options.add("--add-modules");

            options.add(String.join(",", rootMods));

            return doClassNames(

                types.values().stream()

                     .flatMap(List::stream)

                     .map(TypeElement::toString)

                     .collect(toList()));

        } else {

            JDKPlatformProvider pp = new JDKPlatformProvider();

            if (StreamSupport.stream(pp.getSupportedPlatformNames().spliterator(),

                                 false)

                             .noneMatch(n -> n.equals(release))) {

                return false;

            }

            JavaFileManager fm = pp.getPlatform(release, "").getFileManager();

            List<String> classNames = new ArrayList<>();

            for (JavaFileObject fo : fm.list(StandardLocation.PLATFORM_CLASS_PATH,

                                             "",

                                             EnumSet.of(Kind.CLASS),

                                             true)) {

                classNames.add(fm.inferBinaryName(StandardLocation.PLATFORM_CLASS_PATH, fo));

            }

            options.add("-Xlint:-options");

            return doClassNames(classNames);

        }

    }

    /**

     * An enum denoting the mode in which the tool is running.

     * Different modes correspond to the different process* methods.

     * The exception is UNKNOWN, which indicates that a mode wasn't

     * specified on the command line, which is an error.

     */

    static enum LoadMode {

        CLASSES, DIR, JAR, OLD_JDK, JDK9, SELF, RELEASE, LOAD_CSV

    }

    static enum ScanMode {

        ARGS, LIST, PRINT_CSV

    }

    /**

     * A checked exception that's thrown if a command-line syntax error

     * is detected.

     */

    static class UsageException extends Exception {

        private static final long serialVersionUID = 3611828659572908743L;

    }

    /**

     * Convenience method to throw UsageException if a condition is false.

     *

     * @param cond the condition that's required to be true

     * @throws UsageException

     */

    void require(boolean cond) throws UsageException {

        if (!cond) {

            throw new UsageException();

        }

    }

    /**

     * Constructs an instance of the finder tool.

     *

     * @param out the stream to which the tool's output is sent

     * @param err the stream to which error messages are sent

     */

    Main(PrintStream out, PrintStream err) {

        this.out = out;

        this.err = err;

        compiler = ToolProvider.getSystemJavaCompiler();

        fm = compiler.getStandardFileManager(this, null, StandardCharsets.UTF_8);

    }

    /**

     * Prints the diagnostic to the err stream.

     *

     * Specified by the DiagnosticListener interface.

     *

     * @param diagnostic the tool diagnostic to print

     */

    @Override

    public void report(Diagnostic<? extends JavaFileObject> diagnostic) {

        err.println(diagnostic);

    }

    /**

     * Parses arguments and performs the requested processing.

     *

     * @param argArray command-line arguments

     * @return true on success, false on error

     */

    boolean run(String... argArray) {

        Queue<String> args = new ArrayDeque<>(Arrays.asList(argArray));

        LoadMode loadMode = LoadMode.RELEASE;

        ScanMode scanMode = ScanMode.ARGS;

        String dir = null;

        String jar = null;

        String jdkHome = null;

        String release = "11";

        List<String> loadClasses = new ArrayList<>();

        String csvFile = null;

        try {

            while (!args.isEmpty()) {

                String a = args.element();

                if (a.startsWith("-")) {

                    args.remove();

                    switch (a) {

                        case "--class-path":

                            classPath.clear();

                            Arrays.stream(args.remove().split(File.pathSeparator))

                                  .map(File::new)

                                  .forEachOrdered(classPath::add);

                            break;

                        case "--for-removal":

                            forRemoval = true;

                            break;

                        case "--full-version":

                            out.println(System.getProperty("java.vm.version"));

                            return false;

                        case "--help":

                        case "-h":

                            out.println(Messages.get("main.usage"));

                            out.println();

                            out.println(Messages.get("main.help"));

                        case "-l":

                        case "--list":

                            require(scanMode == ScanMode.ARGS);

                            scanMode = ScanMode.LIST;

                            break;

                        case "--release":

                            loadMode = LoadMode.RELEASE;

                            release = args.remove();

                            if (!validReleases.contains(release)) {

                                throw new UsageException();

                            }