/*

 * Copyright (c) 2012, 2014, 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.net.URI;

import java.util.HashMap;

import java.util.HashSet;

import java.util.Map;

import java.util.Set;

import javax.tools.*;

import javax.tools.JavaFileObject.Kind;

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

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

/**

 * Intercepts reads and writes to the file system to gather

 * information about what artifacts are generated.

 *

 * Traps writes to certain files, if the content written is identical

 * to the existing file.

 *

 * Can also blind out the filemanager from seeing certain files in the file system.

 * Necessary to prevent javac from seeing some sources where the source path points.

 *

 *  <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 SmartFileManager extends ForwardingJavaFileManager<JavaFileManager> {

    // Set of sources that can be seen by javac.

    Set<URI> visibleSources = new HashSet<>();

    // Map from modulename:packagename to artifacts.

    Map<String,Set<URI>> packageArtifacts = new HashMap<>();

    // Where to print informational messages.

    PrintWriter stdout;

    public SmartFileManager(JavaFileManager fileManager) {

        super(fileManager);

    }

    public void setVisibleSources(Set<URI> s) {

        visibleSources = s;

    }

    public void cleanArtifacts() {

        packageArtifacts = new HashMap<>();

    }

    public void setLog(PrintWriter pw) {

        stdout = pw;

    }

    /**

     * Set whether or not to use ct.sym as an alternate to rt.jar.

     */

    public void setSymbolFileEnabled(boolean b) {

        if (!(fileManager instanceof JavacFileManager))

            throw new IllegalStateException();

        ((JavacFileManager) fileManager).setSymbolFileEnabled(b);

    }

    public Map<String,Set<URI>> getPackageArtifacts() {

        return packageArtifacts;

    }

    public Iterable<JavaFileObject> list(Location location,

                                         String packageName,

                                         Set<Kind> kinds,

                                         boolean recurse) throws IOException {

        // Acquire the list of files.

        Iterable<JavaFileObject> files = super.list(location, packageName, kinds, recurse);

        if (visibleSources.isEmpty()) {

            return files;

        }

        // Now filter!

        ListBuffer<JavaFileObject> filteredFiles = new ListBuffer<>();

        for (JavaFileObject f : files) {

            URI uri = f.toUri();

            String t = uri.toString();

            if (t.startsWith("jar:")

                || t.endsWith(".class")

                || visibleSources.contains(uri)) {

                filteredFiles.add(f);

            }

        }

        return filteredFiles;

    }

    public boolean hasLocation(Location location) {

        return super.hasLocation(location);

    }

    public JavaFileObject getJavaFileForInput(Location location,

                                              String className,

                                              Kind kind) throws IOException {

        JavaFileObject file = super.getJavaFileForInput(location, className, kind);

        if (file == null || visibleSources.isEmpty()) {

            return file;

        }

        if (visibleSources.contains(file.toUri())) {

            return file;

        }

        return null;

    }

    public JavaFileObject getJavaFileForOutput(Location location,

                                               String className,

                                               Kind kind,

                                               FileObject sibling) throws IOException {

        JavaFileObject file = super.getJavaFileForOutput(location, className, kind, sibling);

        if (file == null) return file;

        int dp = className.lastIndexOf('.');

        String pkg_name = "";

        if (dp != -1) {

            pkg_name = className.substring(0, dp);

        }

        // When modules are in use, then the mod_name might be something like "jdk_base"

        String mod_name = "";

        addArtifact(mod_name+":"+pkg_name, file.toUri());

        return file;

    }

    public FileObject getFileForInput(Location location,

                                      String packageName,

                                      String relativeName) throws IOException {

        FileObject file =  super.getFileForInput(location, packageName, relativeName);

        if (file == null || visibleSources.isEmpty()) {

            return file;

        }

        if (visibleSources.contains(file.toUri())) {

            return file;

        }

        return null;

    }

    public FileObject getFileForOutput(Location location,

                                       String packageName,

                                       String relativeName,

                                       FileObject sibling) throws IOException {

        FileObject file = super.getFileForOutput(location, packageName, relativeName, sibling);

        if (file == null) return file;

        if (location.equals(StandardLocation.NATIVE_HEADER_OUTPUT) &&

                file instanceof JavaFileObject) {

           file = new SmartFileObject((JavaFileObject)file, stdout);

           packageName = ":" + packageNameFromFileName(relativeName);

        }

        if (packageName.equals("")) {

            packageName = ":";

        }

        addArtifact(packageName, file.toUri());

        return file;

    }

    private String packageNameFromFileName(String fn) {

        StringBuilder sb = new StringBuilder();

        int p = fn.indexOf('_'), pp = 0;

        while (p != -1) {

            if (sb.length() > 0) sb.append('.');

            sb.append(fn.substring(pp,p));

            if (p == fn.length()-1) break;

            pp = p+1;

            p = fn.indexOf('_',pp);

        }

        return sb.toString();

    }

    public void flush() throws IOException {

        super.flush();

    }

    public void close() throws IOException {

        super.close();

    }

    void addArtifact(String pkgName, URI art) {

        Set<URI> s = packageArtifacts.get(pkgName);

        if (s == null) {

            s = new HashSet<>();

            packageArtifacts.put(pkgName, s);

        }

        s.add(art);

    }

}