/*

 * Copyright (c) 2013, 2016, 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.

 *

 * 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 crules;

import java.util.ArrayList;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

import java.util.Optional;

import javax.lang.model.element.TypeElement;

import javax.tools.JavaFileObject;

import com.sun.source.tree.Tree;

import com.sun.source.util.JavacTask;

import com.sun.source.util.Plugin;

import com.sun.source.util.TaskEvent;

import com.sun.source.util.TaskEvent.Kind;

import com.sun.source.util.TaskListener;

import com.sun.source.util.Trees;

import com.sun.tools.javac.api.BasicJavacTask;

import com.sun.tools.javac.tree.JCTree;

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.javac.util.Log;

/*

 * This code must be run in a context that provides

 * access to the following javac internal packages:

 *      com.sun.tools.javac.api

 *      com.sun.tools.javac.tree

 *      com.sun.tools.javac.util

 */

public class CodingRulesAnalyzerPlugin implements Plugin {

    protected Log log;

    protected Trees trees;

    @DefinedBy(Api.COMPILER_TREE)

    public void init(JavacTask task, String... args) {

        BasicJavacTask impl = (BasicJavacTask)task;

        Context context = impl.getContext();

        log = Log.instance(context);

        trees = Trees.instance(task);

        task.addTaskListener(new PostAnalyzeTaskListener(

                new MutableFieldsAnalyzer(task),

                new AssertCheckAnalyzer(task),

        ));

    }

    private void addExports(String moduleName, String... packageNames) {

        for (String packageName : packageNames) {

            try {

                ModuleLayer layer = ModuleLayer.boot();

                Optional<Module> m = layer.findModule(moduleName);

                if (!m.isPresent())

                    throw new Error("module not found: " + moduleName);

                m.get().addExports(packageName, getClass().getModule());

            } catch (Exception e) {

                throw new Error("failed to add exports for " + moduleName + "/" + packageName);

            }

        }

    }

    public class PostAnalyzeTaskListener implements TaskListener {

        private final Map<Kind, List<AbstractCodingRulesAnalyzer>> analyzers = new HashMap<>();

        public PostAnalyzeTaskListener(AbstractCodingRulesAnalyzer... analyzers) {

            for (AbstractCodingRulesAnalyzer analyzer : analyzers) {

                List<AbstractCodingRulesAnalyzer> currentAnalyzers = this.analyzers.get(analyzer.eventKind);

                if (currentAnalyzers == null) {

                    this.analyzers.put(analyzer.eventKind, currentAnalyzers = new ArrayList<>());

                }

                currentAnalyzers.add(analyzer);

            }

        }

        @Override @DefinedBy(Api.COMPILER_TREE)

        public void started(TaskEvent taskEvent) {}

        @Override @DefinedBy(Api.COMPILER_TREE)

        public void finished(TaskEvent taskEvent) {

            List<AbstractCodingRulesAnalyzer> currentAnalyzers = this.analyzers.get(taskEvent.getKind());

            if (currentAnalyzers != null) {

                TypeElement typeElem = taskEvent.getTypeElement();

                Tree tree = trees.getTree(typeElem);

                if (tree != null) {

                    JavaFileObject prevSource = log.currentSourceFile();

                    try {

                        log.useSource(taskEvent.getCompilationUnit().getSourceFile());

                        for (AbstractCodingRulesAnalyzer analyzer : currentAnalyzers) {

                            analyzer.treeVisitor.scan((JCTree)tree);

                        }

                    } finally {

                        log.useSource(prevSource);

                    }

                }

            }

        }

    }

    @Override @DefinedBy(Api.COMPILER_TREE)

    public String getName() {

        return "coding_rules";

    }

}