/*

 * Copyright (c) 2013, 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.jdeps;

import com.sun.tools.classfile.Dependency.Location;

import java.io.BufferedReader;

import java.io.IOException;

import java.io.InputStream;

import java.io.InputStreamReader;

import java.io.UncheckedIOException;

import java.util.Collections;

import java.util.Comparator;

import java.util.HashMap;

import java.util.HashSet;

import java.util.Map;

import java.util.Objects;

import java.util.Set;

import java.util.stream.Collectors;

import java.util.stream.Stream;

/**

 * Dependency Analyzer.

 */

public class Analyzer {

    /**

     * Type of the dependency analysis.  Appropriate level of data

     * will be stored.

     */

    public enum Type {

        SUMMARY,

        MODULE,  // equivalent to summary in addition, print module descriptor

        PACKAGE,

        CLASS,

        VERBOSE

    }

    /**

     * Filter to be applied when analyzing the dependencies from the given archives.

     * Only the accepted dependencies are recorded.

     */

    interface Filter {

        boolean accepts(Location origin, Archive originArchive,

                        Location target, Archive targetArchive);

    }

    protected final JdepsConfiguration configuration;

    protected final Type type;

    protected final Filter filter;

    protected final Map<Archive, Dependences> results = new HashMap<>();

    protected final Map<Location, Archive> locationToArchive = new HashMap<>();

    static final Archive NOT_FOUND

        = new Archive(JdepsTask.getMessage("artifact.not.found"));

    /**

     * Constructs an Analyzer instance.

     *

     * @param type Type of the dependency analysis

     * @param filter

     */

    Analyzer(JdepsConfiguration config, Type type, Filter filter) {

        this.configuration = config;

        this.type = type;

        this.filter = filter;

    }

    /**

     * Performs the dependency analysis on the given archives.

     */

    boolean run(Iterable<? extends Archive> archives,

                Map<Location, Archive> locationMap)

    {

        this.locationToArchive.putAll(locationMap);

        // traverse and analyze all dependencies

        for (Archive archive : archives) {

            Dependences deps = new Dependences(archive, type);

            archive.visitDependences(deps);

            results.put(archive, deps);

        }

        return true;

    }

    /**

     * Returns the analyzed archives

     */

    Set<Archive> archives() {

        return results.keySet();

    }

    /**

     * Returns true if the given archive has dependences.

     */

    boolean hasDependences(Archive archive) {

        if (results.containsKey(archive)) {

            return results.get(archive).dependencies().size() > 0;

        }

        return false;

    }

    /**

     * Returns the dependences, either class name or package name

     * as specified in the given verbose level, from the given source.

     */

    Set<String> dependences(Archive source) {

        if (!results.containsKey(source)) {

            return Collections.emptySet();

        }

        return results.get(source).dependencies()

                      .stream()

                      .map(Dep::target)

                      .collect(Collectors.toSet());

    }

    /**

     * Returns the direct dependences of the given source

     */

    Stream<Archive> requires(Archive source) {

        if (!results.containsKey(source)) {

            return Stream.empty();

        }

        return results.get(source).requires()

                      .stream();

    }

    interface Visitor {

        /**

         * Visits a recorded dependency from origin to target which can be

         * a fully-qualified classname, a package name, a module or

         * archive name depending on the Analyzer's type.

         */

        public void visitDependence(String origin, Archive originArchive,

                                    String target, Archive targetArchive);

    }

    /**

     * Visit the dependencies of the given source.

     * If the requested level is SUMMARY, it will visit the required archives list.

     */

    void visitDependences(Archive source, Visitor v, Type level) {

        if (level == Type.SUMMARY) {

            final Dependences result = results.get(source);

            final Set<Archive> reqs = result.requires();

            Stream<Archive> stream = reqs.stream();

            if (reqs.isEmpty()) {

                if (hasDependences(source)) {

                    // If reqs.isEmpty() and we have dependences, then it means

                    // that the dependences are from 'source' onto itself.

                    stream = Stream.of(source);

                }

            }

            stream.sorted(Comparator.comparing(Archive::getName))

                  .forEach(archive -> {

                      Profile profile = result.getTargetProfile(archive);

                      v.visitDependence(source.getName(), source,

                                        profile != null ? profile.profileName()

                                                        : archive.getName(), archive);

                  });

        } else {

            Dependences result = results.get(source);

            if (level != type) {

                // requesting different level of analysis

                result = new Dependences(source, level);

                source.visitDependences(result);

            }

            result.dependencies().stream()

                  .sorted(Comparator.comparing(Dep::origin)

                                    .thenComparing(Dep::target))

                  .forEach(d -> v.visitDependence(d.origin(), d.originArchive(),

                                                  d.target(), d.targetArchive()));

        }

    }

    void visitDependences(Archive source, Visitor v) {

        visitDependences(source, v, type);

    }

    /**

     * Dependences contains the dependencies for an Archive that can have one or

     * more classes.

     */

    class Dependences implements Archive.Visitor {

        protected final Archive archive;

        protected final Set<Archive> requires;

        protected final Set<Dep> deps;

        protected final Type level;

        private Profile profile;

        Dependences(Archive archive, Type level) {

            this.archive = archive;

            this.deps = new HashSet<>();

            this.requires = new HashSet<>();

            this.level = level;

        }

        Set<Dep> dependencies() {

            return deps;

        }

        Set<Archive> requires() {

            return requires;

        }

        Profile getTargetProfile(Archive target) {

            if (target.getModule().isJDK()) {

                return Profile.getProfile((Module) target);

            } else {

                return null;

            }

        }

        /*

         * Returns the archive that contains the given location.

         */

        Archive findArchive(Location t) {

            // local in this archive

            if (archive.getClasses().contains(t))

                return archive;

            Archive target;

            if (locationToArchive.containsKey(t)) {

                target = locationToArchive.get(t);

            } else {

                // special case JDK removed API

                target = configuration.findClass(t)

                    .orElseGet(() -> REMOVED_JDK_INTERNALS.contains(t)

                                        ? REMOVED_JDK_INTERNALS

                                        : NOT_FOUND);

            }

            return locationToArchive.computeIfAbsent(t, _k -> target);

        }

        // return classname or package name depending on the level

        private String getLocationName(Location o) {

            if (level == Type.CLASS || level == Type.VERBOSE) {

                return VersionHelper.get(o.getClassName());

            } else {

                String pkg = o.getPackageName();

                return pkg.isEmpty() ? "<unnamed>" : pkg;

            }

        }

        @Override

        public void visit(Location o, Location t) {

            Archive targetArchive = findArchive(t);

            if (filter.accepts(o, archive, t, targetArchive)) {

                addDep(o, t);

                if (archive != targetArchive && !requires.contains(targetArchive)) {

                    requires.add(targetArchive);

                }

            }

            if (targetArchive.getModule().isNamed()) {

                Profile p = Profile.getProfile(t.getPackageName());

                if (profile == null || (p != null && p.compareTo(profile) > 0)) {

                    profile = p;

                }

            }

        }

        private Dep curDep;

        protected Dep addDep(Location o, Location t) {

            String origin = getLocationName(o);

            String target = getLocationName(t);

            Archive targetArchive = findArchive(t);

            if (curDep != null &&

                    curDep.origin().equals(origin) &&

                    curDep.originArchive() == archive &&

                    curDep.target().equals(target) &&

                    curDep.targetArchive() == targetArchive) {

                return curDep;

            }

            Dep e = new Dep(origin, archive, target, targetArchive);

            if (deps.contains(e)) {

                for (Dep e1 : deps) {

                    if (e.equals(e1)) {

                        curDep = e1;

                    }

                }

            } else {

                deps.add(e);

                curDep = e;

            }

            return curDep;

        }

    }

    /*

     * Class-level or package-level dependency

     */

    class Dep {

        final String origin;

        final Archive originArchive;

        final String target;

        final Archive targetArchive;

        Dep(String origin, Archive originArchive, String target, Archive targetArchive) {

            this.origin = origin;

            this.originArchive = originArchive;

            this.target = target;

            this.targetArchive = targetArchive;

        }

        String origin() {

            return origin;

        }

        Archive originArchive() {

            return originArchive;

        }

        String target() {

            return target;

        }

        Archive targetArchive() {

            return targetArchive;

        }

        @Override

        @SuppressWarnings("unchecked")

        public boolean equals(Object o) {

            if (o instanceof Dep) {

                Dep d = (Dep) o;

                return this.origin.equals(d.origin) &&

                        this.originArchive == d.originArchive &&

                        this.target.equals(d.target) &&

                        this.targetArchive == d.targetArchive;

            }

            return false;

        }

        @Override

        public int hashCode() {

            return Objects.hash(this.origin,

                                this.originArchive,

                                this.target,

                                this.targetArchive);

        }

        public String toString() {

            return String.format("%s (%s) -> %s (%s)%n",

                    origin, originArchive.getName(),

                    target, targetArchive.getName());

        }

    }

    static final Jdk8Internals REMOVED_JDK_INTERNALS = new Jdk8Internals();

    static class Jdk8Internals extends Module {

        private final String JDK8_INTERNALS = "/com/sun/tools/jdeps/resources/jdk8_internals.txt";

        private final Set<String> jdk8Internals;

        private Jdk8Internals() {

            super("JDK removed internal API");

            try (InputStream in = JdepsTask.class.getResourceAsStream(JDK8_INTERNALS);

                 BufferedReader reader = new BufferedReader(new InputStreamReader(in))) {

                this.jdk8Internals = reader.lines()

                                          .filter(ln -> !ln.startsWith("#"))

                                          .collect(Collectors.toSet());

            } catch (IOException e) {

                throw new UncheckedIOException(e);

            }

        }

        public boolean contains(Location location) {

            String cn = location.getClassName();

            int i = cn.lastIndexOf('.');

            String pn = i > 0 ? cn.substring(0, i) : "";

            return jdk8Internals.contains(pn);

        }

        @Override

        public String name() {

            return getName();

        }

        @Override

        public boolean isJDK() {

            return true;

        }

        @Override

        public boolean isExported(String pn) {

            return false;

        }

    }

}