/*

 * 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

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 */

import java.io.File;

import java.io.IOException;

import java.io.Writer;

import java.net.URI;

import java.net.URISyntaxException;

import java.util.Arrays;

import java.util.Comparator;

import java.util.Map;

import java.util.Map.Entry;

import java.util.Set;

import java.util.TreeMap;

import javax.annotation.processing.AbstractProcessor;

import javax.annotation.processing.RoundEnvironment;

import javax.annotation.processing.SupportedAnnotationTypes;

import javax.annotation.processing.SupportedOptions;

import javax.lang.model.element.TypeElement;

import javax.tools.Diagnostic;

import javax.tools.DiagnosticCollector;

import javax.tools.DiagnosticListener;

import javax.tools.FileObject;

import javax.tools.ForwardingJavaFileManager;

import javax.tools.JavaFileManager;

import javax.tools.JavaFileObject;

import javax.tools.JavaFileObject.Kind;

import javax.tools.SimpleJavaFileObject;

import com.sun.source.tree.AnnotationTree;

import com.sun.source.tree.CompilationUnitTree;

import com.sun.source.tree.LiteralTree;

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.file.JavacFileManager;

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

@SupportedAnnotationTypes("*")

@SupportedOptions("target")

public class Processor extends AbstractProcessor {

    private int round = 0;

    @Override

    public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) {

        if (round++ == 0) {

            try (Writer out = processingEnv.getFiler()

                                                 .createSourceFile("Anno.java")

                                                 .openWriter()) {

                String target = processingEnv.getOptions().get("target");

                String code = "import java.lang.annotation.ElementType;\n" +

                              "import java.lang.annotation.Target;\n" +

                              "@Target(ElementType." + target + ")\n" +

                              "@interface Anno { public String value(); }\n";

                out.write(code);

            } catch (IOException exc) {

                throw new IllegalStateException(exc);

            }

        }

        return true;

    }

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

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

        String testContent = null;

        File testSrc = new File(System.getProperty("test.src"));

        File testFile = new File(testSrc, args[0]);

        if (!testFile.canRead()) throw new IllegalStateException("Cannot read the test source");

        JavacTool compiler = JavacTool.create();

        JavacFileManager fm = compiler.getStandardFileManager(null, null, null);

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

        TestFM testFileManager = new TestFM(fm);

        JavacTask task = compiler.getTask(null,

                                          testFileManager,

                                          new DiagnosticCollector<JavaFileObject>(),

                                          null,

                                          null,

                                          Arrays.asList(testFileObject));

        final Trees trees = Trees.instance(task);

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

        final Map<int[], String> annotation2Target = new TreeMap<>(new Comparator<int[]>() {

            @Override public int compare(int[] o1, int[] o2) {

                return o2[0] - o1[0];

            }

        });

        new TreeScanner<Void, Void>() {

            @Override

            public Void visitAnnotation(AnnotationTree node, Void p) {

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

                Assert.check(endPos >= 0);

                int startPos = (int) trees.getSourcePositions().getStartPosition(cut, node);

                String target = ((LiteralTree) node.getArguments().get(0)).getValue().toString();

                annotation2Target.put(new int[] {startPos, endPos}, target);

                return super.visitAnnotation(node, p);

            }

        }.scan(cut.getTypeDecls().get(0), null);

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

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

                if (diagnostic.getKind() == Diagnostic.Kind.ERROR) {

                    throw new IllegalStateException(diagnostic.toString());

                }

            }

        };

        for (Entry<int[], String> e : annotation2Target.entrySet()) {

            StringBuilder updatedContent = new StringBuilder();

            int last = testContent.length();

            for (int[] toRemove : annotation2Target.keySet()) {

                if (toRemove == e.getKey()) continue;

                updatedContent.insert(0, testContent.substring(toRemove[1], last));

                last = toRemove[0];

            }

            updatedContent.insert(0, testContent.substring(0, last));

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

                                                    updatedContent.toString());

            JavacTask testTask = compiler.getTask(null,

                                                  testFileManager,

                                                  noErrors,

                                                  Arrays.asList("-processor", "Processor",

                                                                "-Atarget=" + e.getValue()),

                                                  null,

                                                  Arrays.asList(updatedFile));

            try {

                testTask.analyze();

            } catch (Throwable exc) {

                System.out.println("error while processing:");

                System.out.println(updatedContent);

                throw exc;

            }

            JavacTask testTask2 = compiler.getTask(null,

                                                   testFileManager,

                                                   new DiagnosticCollector<JavaFileObject>(),

                                                   null,

                                                   null,

                                                   Arrays.asList(updatedFile));

            try {

                testTask2.analyze();

            } catch (Throwable exc) {

                System.out.println("error while processing:");

                System.out.println(updatedContent);

                throw exc;

            }

        }

    }

    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);

        }

    }

}