/*

 * Copyright (c) 2013, 2015, 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.

 */

import com.sun.source.tree.ClassTree;

import com.sun.source.tree.CompilationUnitTree;

import com.sun.source.tree.MethodTree;

import com.sun.source.tree.NewClassTree;

import com.sun.source.tree.Tree;

import com.sun.source.tree.VariableTree;

import com.sun.source.util.JavacTask;

import com.sun.source.util.TreeScanner;

import com.sun.source.util.Trees;

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

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

import com.sun.tools.javac.file.JavacFileManager;

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

import java.io.File;

import java.io.IOException;

import java.net.URI;

import java.net.URISyntaxException;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.Iterator;

import java.util.List;

import javax.tools.Diagnostic;

import javax.tools.DiagnosticListener;

import javax.tools.FileObject;

import javax.tools.ForwardingJavaFileManager;

import javax.tools.JavaFileManager;

import javax.tools.JavaFileObject;

import javax.tools.SimpleJavaFileObject;

/**Takes a source file, parses it once to get the warnings inside the file and

 * then for each and every declaration in the file, it tries to place

 * the @SuppressWarnings annotation on the declaration and verifies than no

 * warnings are produced inside the declaration, but all are produced outside it.

 *

 * Currently only works with <code>unchecked,deprecation,cast,divzero</code> warnings.

 */

public class VerifySuppressWarnings {

    private static final List<String> STANDARD_PARAMS =

            Arrays.asList("-Xlint:unchecked,deprecation,cast,divzero");

    public static void main(String... args) throws IOException, URISyntaxException {

        if (args.length != 1) throw new IllegalStateException("Must provide class name!");

        String testContent = null;

        List<File> sourcePath = new ArrayList<>();

            sourcePath.add(new File(sourcePaths));

        }

        JavacFileManager fm = JavacTool.create().getStandardFileManager(null, null, null);

        for (File sp : sourcePath) {

            File inp = new File(sp, args[0]);

            if (inp.canRead()) {

                testContent = fm.getJavaFileObject(inp.toPath()).getCharContent(true).toString();

            }

        }

        if (testContent == null) throw new IllegalStateException();

        final List<Diagnostic<?>> diagnostics = new ArrayList<>();

        DiagnosticListener<JavaFileObject> collectDiagnostics = new DiagnosticListener<JavaFileObject>() {

            @Override public void report(Diagnostic<? extends JavaFileObject> diagnostic) {

                diagnostics.add(diagnostic);

            }

        };

        JavaFileObject testFile = new TestFO(new URI("mem://" + args[0]), testContent);

        JavacTask task = JavacTool.create().getTask(null,

                                                    new TestFM(fm),

                                                    collectDiagnostics,

                                                    STANDARD_PARAMS,

                                                    null,

                                                    Arrays.asList(testFile));

        final Trees trees = Trees.instance(task);

        final CompilationUnitTree cut = task.parse().iterator().next();

        task.analyze();

        final List<int[]> declarationSpans = new ArrayList<>();

        new TreeScanner<Void, Void>() {

            @Override public Void visitClass(ClassTree node, Void p) {

                handleDeclaration(node);

                return super.visitClass(node, p);

            }

            @Override public Void visitMethod(MethodTree node, Void p) {

                handleDeclaration(node);

                return super.visitMethod(node, p);

            }

            @Override public Void visitVariable(VariableTree node, Void p) {

                handleDeclaration(node);

                return super.visitVariable(node, p);

            }

            @Override

            public Void visitNewClass(NewClassTree node, Void p) {

                if (node.getClassBody() != null) {

                    scan(node.getClassBody().getMembers(), null);

                }

                return null;

            }

            private void handleDeclaration(Tree node) {

                int endPos = (int) trees.getSourcePositions().getEndPosition(cut, node);

                if (endPos == (-1)) {

                    if (node.getKind() == Tree.Kind.METHOD && (((JCMethodDecl) node).getModifiers().flags & Flags.GENERATEDCONSTR) != 0) {

                        return ;

                    }

                    throw new IllegalStateException();

                }

                declarationSpans.add(new int[] {(int) trees.getSourcePositions().getStartPosition(cut, node), endPos});

            }

        }.scan(cut, null);

        for (final int[] declarationSpan : declarationSpans) {

            final String suppressWarnings =

                    "@SuppressWarnings({\"deprecation\", \"unchecked\", \"serial\", \"divzero\"})";

            final String updatedContent = testContent.substring(0, declarationSpan[0]) + suppressWarnings + testContent.substring(declarationSpan[0]);

            final List<Diagnostic<?>> foundErrors = new ArrayList<>(diagnostics);

            DiagnosticListener<JavaFileObject> verifyDiagnostics = new DiagnosticListener<JavaFileObject>() {

                @Override public void report(Diagnostic<? extends JavaFileObject> diagnostic) {

                    long adjustedPos = diagnostic.getPosition();

                    if (adjustedPos >= declarationSpan[0]) adjustedPos -= suppressWarnings.length();

                    if (declarationSpan[0] <= adjustedPos && adjustedPos <= declarationSpan[1]) {

                        throw new IllegalStateException("unsuppressed: " + diagnostic.getMessage(null));

                    }

                    boolean found = false;

                    for (Iterator<Diagnostic<?>> it = foundErrors.iterator(); it.hasNext();) {

                        Diagnostic<?> d = it.next();

                        if (d.getPosition() == adjustedPos && d.getCode().equals(diagnostic.getCode())) {

                            it.remove();

                            found = true;

                            break;

                        }

                    }

                    if (!found) {

                        throw new IllegalStateException("diagnostic not originally reported: " + diagnostic.getMessage(null));

                    }

                }

            };

            JavaFileObject updatedFile = new TestFO(new URI("mem://" + args[0]), updatedContent);

            JavacTask testTask = JavacTool.create().getTask(null,

                                                            new TestFM(fm),

                                                            verifyDiagnostics,

                                                            STANDARD_PARAMS,

                                                            null,

                                                            Arrays.asList(updatedFile));

            testTask.analyze();

            for (Diagnostic<?> d : foundErrors) {

                if (d.getPosition() < declarationSpan[0] || declarationSpan[1] < d.getPosition()) {

                    throw new IllegalStateException("missing: " + d.getMessage(null));

                }

            }

        }

    }

    private static final class TestFO extends SimpleJavaFileObject {

        private final String content;

        public TestFO(URI uri, String content) {

            super(uri, Kind.SOURCE);

            this.content = content;

        }

        @Override public CharSequence getCharContent(boolean ignoreEncodingErrors) throws IOException {

            return content;

        }

        @Override public boolean isNameCompatible(String simpleName, Kind kind) {

            return true;

        }

    }

    private static final class TestFM extends ForwardingJavaFileManager<JavaFileManager> {

        public TestFM(JavaFileManager fileManager) {

            super(fileManager);

        }

        @Override

        public boolean isSameFile(FileObject a, FileObject b) {

            return a.equals(b);

        }

    }

}