/*

 * 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.

 *

 * 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.Arrays;

import java.util.HashSet;

import java.util.Set;

import com.sun.source.util.JavacTask;

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

import com.sun.tools.javac.code.Symbol;

import com.sun.tools.javac.code.Symbol.MethodSymbol;

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

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

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

import com.sun.tools.javac.util.DefinedBy;

import com.sun.tools.javac.util.DefinedBy.Api;

/**This analyzer ensures that all method that implement a public supported API method are marked with

 * {@link DefinedBy} annotation, and that methods that don't implement a public API are not marked

 * using the annotation.

 */

public class DefinedByAnalyzer extends AbstractCodingRulesAnalyzer {

    public DefinedByAnalyzer(JavacTask task) {

        super(task);

        treeVisitor = new DefinedByVisitor();

        eventKind = Kind.ANALYZE;

    }

    //only java.compiler and jdk.compiler modules implement the APIs,

    //so only these need the @DefinedBy annotation:

    private static final Set<String> MODULE = new HashSet<>(Arrays.asList(

        "java.compiler",

        "jdk.compiler"

    ));

    class DefinedByVisitor extends TreeScanner {

        @Override

        public void visitClassDef(JCClassDecl tree) {

            if (MODULE.contains(tree.sym.packge().modle.name.toString())) {

                super.visitClassDef(tree);

            }

        }

        @Override

        public void visitMethodDef(JCMethodDecl tree) {

            if (!isAPIPackage(packageName(tree.sym))) {

                boolean seenAPIPackage = false;

                for (MethodSymbol overridden : types.getOverriddenMethods(tree.sym)) {

                    String overriddenPackage = packageName(overridden);

                    if (!isAPIPackage(overriddenPackage))

                        continue;

                    seenAPIPackage = true;

                    DefinedBy definedBy = tree.sym.getAnnotation(DefinedBy.class);

                    if (definedBy != null) {

                        String packageRoot = definedBy.value().packageRoot;

                        if (!overriddenPackage.startsWith(packageRoot)) {

                            messages.error(tree, "crules.wrong.defined.by");

                        }

                        continue;

                    }

                    messages.error(tree, "crules.no.defined.by");

                }

                if (!seenAPIPackage && tree.sym.getAnnotation(DefinedBy.class) != null) {

                    messages.error(tree, "crules.defined.by.no.api");

                }

            }

            super.visitMethodDef(tree);

        }

        private boolean isAPIPackage(String pack) {

            for (Api api : Api.values()) {

                if (pack.startsWith(api.packageRoot))

                    return true;

            }

            return false;

        }

        private String packageName(Symbol sym) {

            return elements.getPackageOf(sym).getQualifiedName().toString();

        }

    }

}