/*
 * Copyright (c) 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
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package com.sun.tools.sjavac.comp.dependencies;

import java.util.Collection;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;
import java.util.stream.Collectors;

import javax.tools.JavaFileManager.Location;
import javax.tools.JavaFileObject;
import javax.tools.StandardLocation;

import com.sun.source.util.TaskEvent;
import com.sun.source.util.TaskListener;
import com.sun.tools.javac.code.Symbol;
import com.sun.tools.javac.code.Symbol.ClassSymbol;
import com.sun.tools.javac.code.Symbol.PackageSymbol;
import com.sun.tools.javac.tree.JCTree.JCCompilationUnit;
import com.sun.tools.javac.util.Context;
import com.sun.tools.javac.util.DefinedBy;
import com.sun.tools.javac.util.DefinedBy.Api;
import com.sun.tools.sjavac.Log;
import com.sun.tools.sjavac.comp.Dependencies;
import com.sun.tools.sjavac.comp.JavaFileObjectWithLocation;

public class DependencyCollector implements TaskListener {

    private Context context;

    // Compilation unit -> fully qualified name -> class symbol
    public final Map<JCCompilationUnit, Map<String, Set<ClassSymbol>>> collectedDependencies = new HashMap<>();

    public DependencyCollector(Context context) {
        this.context = context;
    }

    @Override
    @DefinedBy(Api.COMPILER_TREE)
    public void finished(TaskEvent e) {
        if (e.getKind() == TaskEvent.Kind.ANALYZE) {
            JCCompilationUnit cu = (JCCompilationUnit) e.getCompilationUnit();
            //com.sun.tools.sjavac.Log.info("Finished compilation unit: " + cu.sourcefile);
            PackageSymbol thisPkg = cu.packge;
            if (thisPkg == null) {
                // Compilation unit in default package. See JDK-8048144.
                return;
            }
            DependencyScanner ds = new DependencyScanner(context);
            cu.accept(ds);

            collectedDependencies.put(cu, ds.dependencies);
        }

        if (e.getKind() == TaskEvent.Kind.COMPILATION) {
            Dependencies deps = Dependencies.instance(context);

            // Collect dependencies
            for (JCCompilationUnit fromCu : collectedDependencies.keySet()) {

               // fqName -> set of type deps
                Map<String, Set<ClassSymbol>> map = collectedDependencies.get(fromCu);
                for (String fromFqName : map.keySet()) {
                    Set<ClassSymbol> toSymbols = map.get(fromFqName);
                    Set<ClassSymbol> toOutermostSymbols = collectOutermostClassSymbols(toSymbols);

                    for (ClassSymbol toTypeSymbol : toOutermostSymbols) {

                        // Ignore self-dependencies
                        if (fromFqName.equals(toTypeSymbol.flatname.toString()))
                            continue;
                        Location loc = getLocationOf(toTypeSymbol);
                        if (loc != StandardLocation.PLATFORM_CLASS_PATH)
                            deps.collect(loc, fromCu, fromFqName, toTypeSymbol);
                    }
                }
            }

            // Collect pubapi of dependencies
            Collection<Map<String, Set<ClassSymbol>>> allDepMaps = collectedDependencies.values();
            for (Map<String, Set<ClassSymbol>> depMap : allDepMaps) {
                for (String fromFqName : depMap.keySet()) {
                    Set<ClassSymbol> toSymbols = depMap.get(fromFqName);
                    Set<ClassSymbol> toOutermostSymbols = collectOutermostClassSymbols(toSymbols);
                    for (ClassSymbol ts : toOutermostSymbols) {
                        // Ignore self-dependencies
                        if (fromFqName.equals(ts.flatname.toString()))
                            continue;
                        if (getLocationOf(ts) != StandardLocation.PLATFORM_CLASS_PATH)
                            deps.visitPubapi(ts);
                    }
                }
            }

        }
    }

    private Location getLocationOf(ClassSymbol cs) {
        JavaFileObject jfo = cs.outermostClass().classfile;
        if (jfo != null)
            return ((JavaFileObjectWithLocation<?>) jfo).getLocation();
        Log.warn("Could not determine location of " + cs.flatName());
        return null;
    }

    private Set<ClassSymbol> collectOutermostClassSymbols(Set<ClassSymbol> cs) {
        return cs.stream()
                 .map(Symbol::outermostClass)
                 .collect(Collectors.toSet());
    }
}