/*

 * Copyright 2010 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

import java.io.*;

import java.util.*;

import javax.annotation.processing.*;

import javax.lang.model.*;

import javax.lang.model.element.*;

import javax.lang.model.util.*;

import javax.tools.*;

import com.sun.source.util.*;

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

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

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

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

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

/**

 * Test processor used to check test programs using the @Test, @DA, and @TA

 * annotations.

 *

 * The processor looks for elements annotated with @Test, and analyzes the

 * syntax trees for those elements. Within such trees, the processor looks

 * for the DA annotations on decls and TA annotations on types.

 * The value of these annotations should be a simple string rendition of

 * the tree node to which it is attached.

 * The expected number of annotations is given by the parameter to the

 * @Test annotation itself.

 */

@SupportedAnnotationTypes({"Test"})

public class TestProcessor extends AbstractProcessor {

    public SourceVersion getSupportedSourceVersion() {

        return SourceVersion.latest();

    }

    /** Process trees for elements annotated with the @Test(n) annotation. */

    public boolean process(Set<? extends TypeElement> annos, RoundEnvironment renv) {

        if (renv.processingOver())

            return true;

        Elements elements = processingEnv.getElementUtils();

        Trees trees = Trees.instance(processingEnv);

        TypeElement testAnno = elements.getTypeElement("Test");

        for (Element elem: renv.getElementsAnnotatedWith(testAnno)) {

            System.err.println("ELEM: " + elem);

            int count = getValue(getAnnoMirror(elem, testAnno), Integer.class);

            System.err.println("count: " + count);

            TreePath p = trees.getPath(elem);

            JavaFileObject file = p.getCompilationUnit().getSourceFile();

            JCTree tree = (JCTree) p.getLeaf();

            System.err.println("tree: " + tree);

            new TestScanner(file).check(tree, count);

        }

        return true;

    }

    /** Get the AnnotationMirror on an element for a given annotation. */

    AnnotationMirror getAnnoMirror(Element e, TypeElement anno) {

        Types types = processingEnv.getTypeUtils();

        for (AnnotationMirror m: e.getAnnotationMirrors()) {

            if (types.isSameType(m.getAnnotationType(), anno.asType()))

                return m;

        }

        return null;

    }

    /** Get the value of the value element of an annotation mirror. */

    <T> T getValue(AnnotationMirror m, Class<T> type) {

        for (Map.Entry<? extends ExecutableElement,? extends AnnotationValue> e: m.getElementValues().entrySet()) {

            ExecutableElement ee = e.getKey();

            if (ee.getSimpleName().contentEquals("value")) {

                AnnotationValue av = e.getValue();

                return type.cast(av.getValue());

            }

        }

        return null;

    }

    /** Report an error to the annotation processing system. */

    void error(String msg) {

        Messager messager = processingEnv.getMessager();

        messager.printMessage(Diagnostic.Kind.ERROR, msg);

    }

    /** Report an error to the annotation processing system. */

    void error(JavaFileObject file, JCTree tree, String msg) {

        // need better API for reporting tree position errors to the messager

        Messager messager = processingEnv.getMessager();

        String text = file.getName() + ":" + getLine(file, tree) + ": " + msg;

        messager.printMessage(Diagnostic.Kind.ERROR, text);

    }

    /** Get the line number for the primary position for a tree.

     * The code is intended to be simple, although not necessarily efficient.

     * However, note that a file manager such as JavacFileManager is likely

     * to cache the results of file.getCharContent, avoiding the need to read

     * the bits from disk each time this method is called.

     */

    int getLine(JavaFileObject file, JCTree tree) {

        try {

            CharSequence cs = file.getCharContent(true);

            int line = 1;

            for (int i = 0; i < tree.pos; i++) {

                if (cs.charAt(i) == '\n') // jtreg tests always use Unix line endings

                    line++;

            }

            return line;

        } catch (IOException e) {

            return -1;

        }

    }

    /** Scan a tree, looking for @DA and @TA annotations, and verifying that such

     * annotations are attached to the expected tree node matching the string

     * parameter of the annotation.

     */

    class TestScanner extends TreeScanner {

        /** Create a scanner for a given file. */

        TestScanner(JavaFileObject file) {

            this.file = file;

        }

        /** Check the annotations in a given tree. */

        void check(JCTree tree, int expectCount) {

            foundCount = 0;

            scan(tree);

            if (foundCount != expectCount)

                error(file, tree, "Wrong number of annotations found: " + foundCount + ", expected: " + expectCount);

        }

        /** Check @DA annotations on a class declaration. */

        @Override

        public void visitClassDef(JCClassDecl tree) {

            super.visitClassDef(tree);

            check(tree.mods.annotations, "DA", tree);

        }

        /** Check @DA annotations on a method declaration. */

        @Override

        public void visitMethodDef(JCMethodDecl tree) {

            super.visitMethodDef(tree);

            check(tree.mods.annotations, "DA", tree);

        }

        /** Check @DA annotations on a field, parameter or local variable declaration. */

        @Override

        public void visitVarDef(JCVariableDecl tree) {

            super.visitVarDef(tree);

            check(tree.mods.annotations, "DA", tree);

        }

        /** Check @TA annotations on a type. */

        public void visitAnnotatedType(JCAnnotatedType tree) {

            super.visitAnnotatedType(tree);

            check(tree.annotations, "TA", tree);

        }

        /** Check to see if a list of annotations contains a named annotation, and

         * if so, verify the annotation is expected by comparing the value of the

         * annotation's argument against the string rendition of the reference tree

         * node.

         * @param annos the list of annotations to be checked

         * @param name  the name of the annotation to be checked

         * @param tree  the tree against which to compare the annotations's argument

         */

        void check(List<? extends JCAnnotation> annos, String name, JCTree tree) {

            for (List<? extends JCAnnotation> l = annos; l.nonEmpty(); l = l.tail) {

                JCAnnotation anno = l.head;

                if (anno.annotationType.toString().equals(name) && (anno.args.size() == 1)) {

                    String expect = getStringValue(anno.args.head);

                    foundCount++;

                    System.err.println("found: " + name + " " + expect);

                    String found = new TypePrinter().print(tree);

                    if (!found.equals(expect))

                        error(file, anno, "Unexpected result: expected: \"" + expect + "\", found: \"" + found + "\"");

                }

            }

        }

        /** Get the string value of an annotation argument, which is given by the

         * expression <i>name</i>=<i>value</i>.

         */

        String getStringValue(JCExpression e) {

            if (e.getTag() == JCTree.ASSIGN)  {

                JCAssign a = (JCAssign) e;

                JCExpression rhs = a.rhs;

                if (rhs.getTag() == JCTree.LITERAL) {

                    JCLiteral l = (JCLiteral) rhs;

                    return (String) l.value;

                }

            }

            throw new IllegalArgumentException(e.toString());

        }

        /** The file for the tree. Used to locate errors. */

        JavaFileObject file;

        /** The number of annotations that have been found. @see #check */

        int foundCount;

    }

    /** Convert a type or decl tree to a reference string used by the @DA and @TA annotations. */

    class TypePrinter extends Visitor {

        /** Convert a type or decl tree to a string. */

        String print(JCTree tree) {

            if (tree == null)

                return null;

            tree.accept(this);

            return result;

        }

        String print(List<? extends JCTree> list) {

            return print(list, ", ");

        }

        String print(List<? extends JCTree> list, String sep) {

            StringBuilder sb = new StringBuilder();

            if (list.nonEmpty()) {

                sb.append(print(list.head));

                for (List<? extends JCTree> l = list.tail; l.nonEmpty(); l = l.tail) {

                    sb.append(sep);

                    sb.append(print(l.head));

                }

            }

            return sb.toString();

        }

        @Override

        public void visitClassDef(JCClassDecl tree) {

            result = tree.name.toString();

        }

        @Override

        public void visitMethodDef(JCMethodDecl tree) {

            result = tree.name.toString();

        }

        @Override

        public void visitVarDef(JCVariableDecl tree) {

            tree.vartype.accept(this);

        }

        @Override

        public void visitAnnotatedType(JCAnnotatedType tree) {

            tree.underlyingType.accept(this);

        }

        @Override

        public void visitTypeIdent(JCPrimitiveTypeTree tree) {

            result = tree.toString();

        }

        @Override

        public void visitTypeArray(JCArrayTypeTree tree) {

            result = print(tree.elemtype) + "[]";

        }

        @Override

        public void visitTypeApply(JCTypeApply tree) {

            result = print(tree.clazz) + "<" + print(tree.arguments) + ">";

        }

        @Override

        public void visitTypeParameter(JCTypeParameter tree) {

            if (tree.bounds.isEmpty())

                result = tree.name.toString();

            else

                result = tree.name + " extends " + print(tree.bounds, "&");

        }

        @Override

        public void visitWildcard(JCWildcard tree) {

            if (tree.kind.kind == BoundKind.UNBOUND)

                result = tree.kind.toString();

            else

                result = tree.kind + " " + print(tree.inner);

        }

        private String result;

    }

}