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package com.sun.tools.jdeps;

import java.io.IOException;
import java.io.PrintWriter;
import java.lang.module.ModuleDescriptor;
import java.util.Comparator;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import java.util.TreeSet;
import java.util.stream.Collectors;
import java.util.stream.Stream;

Analyze module dependences and any reference to JDK internal APIs.
It can apply transition reduction on the resulting module graph.
The result prints one line per module it depends on
one line per JDK internal API package it references:
    $MODULE[/$PACKAGE]
/**
 * Analyze module dependences and any reference to JDK internal APIs.
 * It can apply transition reduction on the resulting module graph.
 *
 * The result prints one line per module it depends on
 * one line per JDK internal API package it references:
 *     $MODULE[/$PACKAGE]
 *
 */
public class ModuleExportsAnalyzer extends DepsAnalyzer {
    // source archive to its dependences and JDK internal APIs it references
    private final Map<Archive, Map<Archive,Set<String>>> deps = new HashMap<>();
    private final Map<String, Set<String>> missingDeps = new HashMap<>();
    private final boolean showInternals;
    private final boolean reduced;
    private final PrintWriter writer;
    private final String separator;
    public ModuleExportsAnalyzer(JdepsConfiguration config,
                                 JdepsFilter filter,
                                 boolean showInternals,
                                 boolean reduced,
                                 PrintWriter writer,
                                 String separator) {
        super(config, filter, null,
              Analyzer.Type.PACKAGE,
              false /* all classes */);
        this.showInternals = showInternals;
        this.reduced = reduced;
        this.writer = writer;
        this.separator = separator;
    }

    public boolean run(int maxDepth, boolean ignoreMissingDeps) throws IOException {
        // use compile time view so that the entire archive on classpath is analyzed
        boolean rc = super.run(true, maxDepth);

        // A visitor to record the module-level dependences as well as
        // use of internal APIs
        Analyzer.Visitor visitor = (origin, originArchive, target, targetArchive) -> {
            Set<String> internals =
                deps.computeIfAbsent(originArchive, _k -> new HashMap<>())
                    .computeIfAbsent(targetArchive, _k -> new HashSet<>());

            Module module = targetArchive.getModule();
            if (showInternals && originArchive.getModule() != module &&
                    module.isNamed() && !module.isExported(target, module.name())) {
                // use of internal APIs
                internals.add(target);
            }
            if (!ignoreMissingDeps && Analyzer.notFound(targetArchive)) {
                Set<String> notFound =
                    missingDeps.computeIfAbsent(origin, _k -> new HashSet<>());
                notFound.add(target);
            }
        };

        // visit the dependences
        archives.stream()
            .filter(analyzer::hasDependences)
            .sorted(Comparator.comparing(Archive::getName))
            .forEach(archive -> analyzer.visitDependences(archive, visitor));

        // error if any missing dependence
        if (!rc || !missingDeps.isEmpty()) {
            return false;
        }

        Map<Module, Set<String>> internalPkgs = internalPackages();
        Set<Module> modules = modules();
        if (showInternals) {
            // print modules and JDK internal API dependences
            Stream.concat(modules.stream(), internalPkgs.keySet().stream())
                    .sorted(Comparator.comparing(Module::name))
                    .distinct()
                    .forEach(m -> {
                        if (internalPkgs.containsKey(m)) {
                            internalPkgs.get(m).stream()
                                .forEach(pn -> writer.format("   %s/%s%s", m, pn, separator));
                        } else {
                            writer.format("   %s%s", m, separator);
                        }
                    });
        } else {
            // print module dependences
            writer.println(modules.stream().map(Module::name).sorted()
                                  .collect(Collectors.joining(separator)));
        }
        return rc;
    }

    /*
     * Prints missing dependences
     */
    void visitMissingDeps(Analyzer.Visitor visitor) {
        archives.stream()
            .filter(analyzer::hasDependences)
            .sorted(Comparator.comparing(Archive::getName))
            .filter(m -> analyzer.requires(m).anyMatch(Analyzer::notFound))
            .forEach(m -> {
                analyzer.visitDependences(m, visitor, Analyzer.Type.VERBOSE, Analyzer::notFound);
            });
    }

    private Set<Module> modules() {
        // build module graph
        ModuleGraphBuilder builder = new ModuleGraphBuilder(configuration);
        Module root = new RootModule();
        builder.addModule(root);
        // find named module dependences
        dependenceStream()
            .flatMap(map -> map.keySet().stream())
            .filter(m -> m.getModule().isNamed() && !configuration.rootModules().contains(m))
            .map(Archive::getModule)
            .forEach(m -> builder.addEdge(root, m));

        // build module dependence graph
        // if reduced is set, apply transition reduction
        Graph<Module> g = reduced ? builder.reduced() : builder.build();
        return g.adjacentNodes(root);
    }

    private Map<Module, Set<String>> internalPackages() {
        Map<Module, Set<String>> internalPkgs = new HashMap<>();
        dependenceStream()
            .flatMap(map -> map.entrySet().stream())
            .filter(e -> e.getValue().size() > 0)
            .forEach(e -> internalPkgs.computeIfAbsent(e.getKey().getModule(),
                                                             _k -> new TreeSet<>())
                                      .addAll(e.getValue()));
        return internalPkgs;
    }

    /*
     * Returns a stream of dependence map from an Archive to the set of JDK
     * internal APIs being used.
     */
    private Stream<Map<Archive, Set<String>>> dependenceStream() {
        return deps.keySet().stream()
                   .filter(source -> !source.getModule().isNamed()
                            || configuration.rootModules().contains(source))
                   .map(deps::get);
    }

    /*
     * RootModule serves as the root node for building the module graph
     */
    private static class RootModule extends Module {
        static final String NAME = "root";
        RootModule() {
            super(NAME, ModuleDescriptor.newModule(NAME).build(), false);
        }
    }

}