/*
 * 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 com.oracle.truffle.dsl.processor.verify;

import static com.oracle.truffle.dsl.processor.java.ElementUtils.*;
import static java.util.Collections.*;

import java.io.*;
import java.util.*;

import javax.annotation.processing.*;
import javax.lang.model.*;
import javax.lang.model.element.*;
import javax.tools.Diagnostic.Kind;

import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
import com.oracle.truffle.api.nodes.Node.Child;
import com.oracle.truffle.dsl.processor.*;

@SupportedAnnotationTypes({"com.oracle.truffle.api.CompilerDirectives.TruffleBoundary", "com.oracle.truffle.api.nodes.Node.Child"})
public class VerifyTruffleProcessor extends AbstractProcessor {
    @Override
    public SourceVersion getSupportedSourceVersion() {
        return SourceVersion.latest();
    }

    /**
     * Node class currently being processed.
     */
    private Element scope;

    public static boolean isEnclosedIn(Element e, Element scopeElement) {
        List<Element> elementHierarchy = getElementHierarchy(e);
        return elementHierarchy.contains(scopeElement);
    }

    void errorMessage(Element element, String format, Object... args) {
        message(Kind.ERROR, element, format, args);
    }

    void message(Kind kind, Element element, String format, Object... args) {
        if (scope != null && !isEnclosedIn(element, scope)) {
            // See https://bugs.eclipse.org/bugs/show_bug.cgi?id=428357#c1
            List<Element> elementHierarchy = getElementHierarchy(element);
            reverse(elementHierarchy);

            StringBuilder str = new StringBuilder();
            for (Element e : elementHierarchy) {
                if (e.getKind() != ElementKind.PACKAGE) {
                    str.append(str.length() == 0 ? "" : ".");
                    str.append(e);
                }
            }
            processingEnv.getMessager().printMessage(kind, String.format(str + ": " + format, args), scope);
        } else {
            processingEnv.getMessager().printMessage(kind, String.format(format, args), element);
        }
    }

    /**
     * Bugs in an annotation processor can cause silent failure so try to report any exception
     * throws as errors.
     */
    private void reportException(Kind kind, Element element, Throwable t) {
        StringWriter buf = new StringWriter();
        t.printStackTrace(new PrintWriter(buf));
        buf.toString();
        message(kind, element, "Exception thrown during processing: %s", buf.toString());
    }

    @Override
    public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) {
        if (roundEnv.processingOver()) {
            return false;
        }

        TypeElement virtualFrameType = processingEnv.getElementUtils().getTypeElement("com.oracle.truffle.api.frame.VirtualFrame");

        for (Element element : roundEnv.getElementsAnnotatedWith(TruffleBoundary.class)) {
            scope = element;
            try {
                ExecutableElement method = (ExecutableElement) element;

                for (VariableElement parameter : method.getParameters()) {
                    Element paramType = processingEnv.getTypeUtils().asElement(parameter.asType());
                    if (paramType != null && paramType.equals(virtualFrameType)) {
                        errorMessage(element, "Method %s cannot be annotated with @%s and have a parameter of type %s", method.getSimpleName(), TruffleBoundary.class.getSimpleName(),
                                        paramType.getSimpleName());
                    }
                }
            } catch (Throwable t) {
                reportException(isBug367599(t) ? Kind.NOTE : Kind.ERROR, element, t);
            } finally {
                scope = null;
            }
        }

        for (Element e : roundEnv.getElementsAnnotatedWith(Child.class)) {
            if (e.getModifiers().contains(Modifier.FINAL)) {
                emitError("@Child field cannot be final", e);
                continue;
            }
            assertNoErrorExpected(e);
        }
        return false;
    }

    void assertNoErrorExpected(Element element) {
        ExpectError.assertNoErrorExpected(processingEnv, element);
    }

    void emitError(String message, Element element) {
        if (ExpectError.isExpectedError(processingEnv, element, message)) {
            return;
        }
        processingEnv.getMessager().printMessage(Kind.ERROR, message, element);
    }

    /**
     * Determines if a given exception is (most likely) caused by <a
     * href="https://bugs.eclipse.org/bugs/show_bug.cgi?id=367599">Bug 367599</a>.
     */
    public static boolean isBug367599(Throwable t) {
        if (t instanceof FilerException) {
            for (StackTraceElement ste : t.getStackTrace()) {
                if (ste.toString().contains("org.eclipse.jdt.internal.apt.pluggable.core.filer.IdeFilerImpl.create")) {
                    // See: https://bugs.eclipse.org/bugs/show_bug.cgi?id=367599
                    return true;
                }
            }
        }
        if (t.getCause() != null) {
            return isBug367599(t.getCause());
        }
        return false;
    }
}