/*

 * Copyright (c) 2017, 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

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 */

package jdk.internal.module;

import java.io.BufferedReader;

import java.io.IOException;

import java.io.InputStream;

import java.io.InputStreamReader;

import java.io.UncheckedIOException;

import java.lang.module.ModuleDescriptor;

import java.lang.module.ModuleFinder;

import java.lang.module.ModuleReference;

import java.util.HashMap;

import java.util.HashSet;

import java.util.Map;

import java.util.Set;

import static java.nio.charset.StandardCharsets.*;

/**

 * Generates the maps of concealed and exported packages to open at run-time.

 *

 * This is used at run-time for exploded builds, and at link-time to generate

 * the maps for the system modules in the run-time image.

 */

public class IllegalAccessMaps {

    private final Map<String, Set<String>> concealedPackagesToOpen;

    private final Map<String, Set<String>> exportedPackagesToOpen;

    private IllegalAccessMaps(Map<String, Set<String>> map1,

                              Map<String, Set<String>> map2) {

        this.concealedPackagesToOpen = map1;

        this.exportedPackagesToOpen = map2;

    }

    /**

     * Returns the map of concealed packages to open. The map key is the

     * module name, the value is the set of concealed packages to open.

     */

    public Map<String, Set<String>> concealedPackagesToOpen() {

        return concealedPackagesToOpen;

    }

    /**

     * Returns the map of exported packages to open. The map key is the

     * module name, the value is the set of exported packages to open.

     */

    public Map<String, Set<String>> exportedPackagesToOpen() {

        return exportedPackagesToOpen;

    }

    /**

     * Generate the maps of module to concealed and exported packages for

     * the system modules that are observable with the given module finder.

     */

    public static IllegalAccessMaps generate(ModuleFinder finder) {

        Map<String, ModuleDescriptor> map = new HashMap<>();

        finder.findAll().stream()

            .map(ModuleReference::descriptor)

            .forEach(md -> md.packages().forEach(pn -> map.putIfAbsent(pn, md)));

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

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

        String rn = "jdk8_packages.dat";

        InputStream in = IllegalAccessMaps.class.getResourceAsStream(rn);

        if (in == null) {

            throw new InternalError(rn + " not found");

        }

        try (BufferedReader br = new BufferedReader(new InputStreamReader(in, UTF_8))) {

            br.lines()

                .filter(line -> !line.isEmpty() && !line.startsWith("#"))

                .forEach(pn -> {

                    ModuleDescriptor descriptor = map.get(pn);

                    if (descriptor != null && !isOpen(descriptor, pn)) {

                        String name = descriptor.name();

                        if (isExported(descriptor, pn)) {

                            exportedPackagesToOpen.computeIfAbsent(name,

                                    k -> new HashSet<>()).add(pn);

                        } else {

                            concealedPackagesToOpen.computeIfAbsent(name,

                                    k -> new HashSet<>()).add(pn);

                        }

                    }

                });

        } catch (IOException ioe) {

            throw new UncheckedIOException(ioe);

        }

        return new IllegalAccessMaps(concealedPackagesToOpen, exportedPackagesToOpen);

    }

    private static boolean isExported(ModuleDescriptor descriptor, String pn) {

        return descriptor.exports()

                .stream()

                .anyMatch(e -> e.source().equals(pn) && !e.isQualified());

    }

    private static boolean isOpen(ModuleDescriptor descriptor, String pn) {

        return descriptor.opens()

                .stream()

                .anyMatch(e -> e.source().equals(pn) && !e.isQualified());

    }

}