/*

 * Copyright (c) 2014, 2015, Oracle and/or its affiliates. All rights reserved.

 * 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.sjavac.comp;

import java.io.IOException;

import java.io.PrintWriter;

import java.io.Writer;

import java.nio.file.Files;

import java.nio.file.Path;

import java.util.ArrayList;

import java.util.Collections;

import java.util.HashMap;

import java.util.HashSet;

import java.util.List;

import java.util.Map;

import java.util.Set;

import java.util.stream.Stream;

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

import com.sun.tools.javac.main.Main;

import com.sun.tools.javac.util.Context;

import com.sun.tools.sjavac.JavacState;

import com.sun.tools.sjavac.Log;

import com.sun.tools.sjavac.Module;

import com.sun.tools.sjavac.ProblemException;

import com.sun.tools.sjavac.Source;

import com.sun.tools.sjavac.Transformer;

import com.sun.tools.sjavac.Util;

import com.sun.tools.sjavac.options.Option;

import com.sun.tools.sjavac.options.Options;

import com.sun.tools.sjavac.options.SourceLocation;

import com.sun.tools.sjavac.server.Sjavac;

import javax.tools.JavaFileManager;

/**

 * The sjavac implementation that interacts with javac and performs the actual

 * compilation.

 *

 *  <p><b>This is NOT part of any supported API.

 *  If you write code that depends on this, you do so at your own risk.

 *  This code and its internal interfaces are subject to change or

 *  deletion without notice.</b>

 */

public class SjavacImpl implements Sjavac {

    @Override

    public int compile(String[] args, Writer out, Writer err) {

        Options options;

        try {

            options = Options.parseArgs(args);

        } catch (IllegalArgumentException e) {

            Log.error(e.getMessage());

            return RC_FATAL;

        }

        Log.setLogLevel(options.getLogLevel());

        if (!validateOptions(options))

            return RC_FATAL;

        if (!createIfMissing(options.getDestDir()))

            return RC_FATAL;

        Path stateDir = options.getStateDir();

        if (stateDir != null && !createIfMissing(options.getStateDir()))

            return RC_FATAL;

        Path gensrc = options.getGenSrcDir();

        if (gensrc != null && !createIfMissing(gensrc))

            return RC_FATAL;

        Path hdrdir = options.getHeaderDir();

        if (hdrdir != null && !createIfMissing(hdrdir))

            return RC_FATAL;

        if (stateDir == null) {

            // Prepare context. Direct logging to our byte array stream.

            Context context = new Context();

            PrintWriter writer = new PrintWriter(err);

            com.sun.tools.javac.util.Log.preRegister(context, writer);

            JavacFileManager.preRegister(context);

            // Prepare arguments

            String[] passThroughArgs = Stream.of(args)

                                             .filter(arg -> !arg.startsWith(Option.SERVER.arg))

                                             .toArray(String[]::new);

            // Compile

            com.sun.tools.javac.main.Main compiler = new com.sun.tools.javac.main.Main("javac", writer);

            Main.Result result = compiler.compile(passThroughArgs, context);

            // Clean up

            JavaFileManager fileManager = context.get(JavaFileManager.class);

            if (fileManager instanceof JavacFileManager) {

                try {

                    ((JavacFileManager) fileManager).close();

                } catch (IOException e) {

                    return RC_FATAL;

                }

            }

            return result.exitCode;

        } else {

            // Load the prev build state database.

            JavacState javac_state = JavacState.load(options, out, err);

            // Setup the suffix rules from the command line.

            Map<String, Transformer> suffixRules = new HashMap<>();

            // Handling of .java-compilation

            suffixRules.putAll(javac_state.getJavaSuffixRule());

            // Handling of -copy and -tr

            suffixRules.putAll(options.getTranslationRules());

            // All found modules are put here.

            Map<String,Module> modules = new HashMap<>();

            // We start out in the legacy empty no-name module.

            // As soon as we stumble on a module-info.java file we change to that module.

            Module current_module = new Module("", "");

            modules.put("", current_module);

            // Find all sources, use the suffix rules to know which files are sources.

            Map<String,Source> sources = new HashMap<>();

            // Find the files, this will automatically populate the found modules

            // with found packages where the sources are found!

            findSourceFiles(options.getSources(),

                            suffixRules.keySet(),

                            sources,

                            modules,

                            current_module,

                            options.isDefaultPackagePermitted(),

                            false);

            if (sources.isEmpty()) {

                Log.error("Found nothing to compile!");

                return RC_FATAL;

            }

            // Create a map of all source files that are available for linking. Both -src and

            // -sourcepath point to such files. It is possible to specify multiple

            // -sourcepath options to enable different filtering rules. If the

            // filters are the same for multiple sourcepaths, they may be concatenated

            // using :(;). Before sending the list of sourcepaths to javac, they are

            // all concatenated. The list created here is used by the SmartFileWrapper to

            // make sure only the correct sources are actually available.

            // We might find more modules here as well.

            Map<String,Source> sources_to_link_to = new HashMap<>();

            List<SourceLocation> sourceResolutionLocations = new ArrayList<>();

            sourceResolutionLocations.addAll(options.getSources());

            sourceResolutionLocations.addAll(options.getSourceSearchPaths());

            findSourceFiles(sourceResolutionLocations,

                            Collections.singleton(".java"),

                            sources_to_link_to,

                            modules,

                            current_module,

                            options.isDefaultPackagePermitted(),

                            true);

            // Add the set of sources to the build database.

            javac_state.now().flattenPackagesSourcesAndArtifacts(modules);

            javac_state.now().checkInternalState("checking sources", false, sources);

            javac_state.now().checkInternalState("checking linked sources", true, sources_to_link_to);

            javac_state.setVisibleSources(sources_to_link_to);

            int round = 0;

            printRound(round);

            // If there is any change in the source files, taint packages

            // and mark the database in need of saving.

            javac_state.checkSourceStatus(false);

            // Find all existing artifacts. Their timestamp will match the last modified timestamps stored

            // in javac_state, simply because loading of the JavacState will clean out all artifacts

            // that do not match the javac_state database.

            javac_state.findAllArtifacts();

            // Remove unidentified artifacts from the bin, gensrc and header dirs.

            // (Unless we allow them to be there.)

            // I.e. artifacts that are not known according to the build database (javac_state).

            // For examples, files that have been manually copied into these dirs.

            // Artifacts with bad timestamps (ie the on disk timestamp does not match the timestamp

            // in javac_state) have already been removed when the javac_state was loaded.

            if (!options.areUnidentifiedArtifactsPermitted()) {

                javac_state.removeUnidentifiedArtifacts();

            }

            // Go through all sources and taint all packages that miss artifacts.

            javac_state.taintPackagesThatMissArtifacts();

            try {

                // Check recorded classpath public apis. Taint packages that depend on

                // classpath classes whose public apis have changed.

                javac_state.taintPackagesDependingOnChangedClasspathPackages();

                // Now clean out all known artifacts belonging to tainted packages.

                javac_state.deleteClassArtifactsInTaintedPackages();

                // Copy files, for example property files, images files, xml files etc etc.

                javac_state.performCopying(Util.pathToFile(options.getDestDir()), suffixRules);

                // Translate files, for example compile properties or compile idls.

                javac_state.performTranslation(Util.pathToFile(gensrc), suffixRules);

                // Add any potentially generated java sources to the tobe compiled list.

                // (Generated sources must always have a package.)

                Map<String,Source> generated_sources = new HashMap<>();

                Source.scanRoot(Util.pathToFile(options.getGenSrcDir()), Util.set(".java"), null, null, null, null,

                        generated_sources, modules, current_module, false, true, false);

                javac_state.now().flattenPackagesSourcesAndArtifacts(modules);

                // Recheck the the source files and their timestamps again.

                javac_state.checkSourceStatus(true);

                // Now do a safety check that the list of source files is identical

                // to the list Make believes we are compiling. If we do not get this

                // right, then incremental builds will fail with subtility.

                // If any difference is detected, then we will fail hard here.

                // This is an important safety net.

                javac_state.compareWithMakefileList(Util.pathToFile(options.getSourceReferenceList()));

                // Do the compilations, repeatedly until no tainted packages exist.

                boolean again;

                // Collect the name of all compiled packages.

                Set<String> recently_compiled = new HashSet<>();

                boolean[] rc = new boolean[1];

                CompilationService compilationService = new CompilationService();

                do {

                    if (round > 0)

                        printRound(round);

                    // Clean out artifacts in tainted packages.

                    javac_state.deleteClassArtifactsInTaintedPackages();

                    again = javac_state.performJavaCompilations(compilationService, options, recently_compiled, rc);

                    if (!rc[0]) {

                        Log.debug("Compilation failed.");

                        break;

                    }

                    if (!again) {

                        Log.debug("Nothing left to do.");

                    }

                    round++;

                } while (again);

                Log.debug("No need to do another round.");

                // Only update the state if the compile went well.

                if (rc[0]) {

                    javac_state.save();

                    // Reflatten only the artifacts.

                    javac_state.now().flattenArtifacts(modules);

                    // Remove artifacts that were generated during the last compile, but not this one.

                    javac_state.removeSuperfluousArtifacts(recently_compiled);

                }

                return rc[0] ? RC_OK : RC_FATAL;

            } catch (ProblemException e) {

                Log.error(e.getMessage());

                return RC_FATAL;

            } catch (Exception e) {

                e.printStackTrace(new PrintWriter(err));

                return RC_FATAL;

            }

        }

    }

    @Override

    public void shutdown() {

        // Nothing to clean up

    }

    private static boolean validateOptions(Options options) {

        String err = null;

        if (options.getDestDir() == null) {

            err = "Please specify output directory.";

        } else if (options.isJavaFilesAmongJavacArgs()) {

            err = "Sjavac does not handle explicit compilation of single .java files.";

        } else if (options.getServerConf() == null) {

            err = "No server configuration provided.";

        } else if (!options.getImplicitPolicy().equals("none")) {

            err = "The only allowed setting for sjavac is -implicit:none";

        } else if (options.getSources().isEmpty() && options.getStateDir() != null) {

            err = "You have to specify -src when using --state-dir.";

        } else if (options.getTranslationRules().size() > 1

                && options.getGenSrcDir() == null) {

            err = "You have translators but no gensrc dir (-s) specified!";

        }

        if (err != null)

            Log.error(err);

        return err == null;

    }

    private static boolean createIfMissing(Path dir) {

        if (Files.isDirectory(dir))

            return true;

        if (Files.exists(dir)) {

            Log.error(dir + " is not a directory.");

            return false;

        }

        try {

            Files.createDirectories(dir);

        } catch (IOException e) {

            Log.error("Could not create directory: " + e.getMessage());

            return false;

        }

        return true;

    }

    /** Find source files in the given source locations. */

    public static void findSourceFiles(List<SourceLocation> sourceLocations,

                                       Set<String> sourceTypes,

                                       Map<String,Source> foundFiles,

                                       Map<String, Module> foundModules,

                                       Module currentModule,

                                       boolean permitSourcesInDefaultPackage,

                                       boolean inLinksrc) {

        for (SourceLocation source : sourceLocations) {

            source.findSourceFiles(sourceTypes,

                                   foundFiles,

                                   foundModules,

                                   currentModule,

                                   permitSourcesInDefaultPackage,

                                   inLinksrc);

        }

    }

    private static void printRound(int round) {

        Log.debug("****************************************");

        Log.debug("* Round " + round + "                              *");

        Log.debug("****************************************");

    }

}