/*

 * Copyright (c) 2005, 2013, 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.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * 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.sun.tools.javac.code;

import java.lang.annotation.Annotation;

import java.lang.annotation.Inherited;

import java.lang.reflect.InvocationTargetException;

import java.lang.reflect.Method;

import javax.lang.model.AnnotatedConstruct;

import com.sun.tools.javac.model.AnnotationProxyMaker;

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

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

/**

 * Common super type for annotated constructs such as Types and Symbols.

 *

 * This class should *not* contain any fields since it would have a significant

 * impact on the javac memory footprint.

 *

 * <p><b>This is NOT part of any supported API.

 * If you write code that depends on this, you do so at your own

 * risk.  This code and its internal interfaces are subject to change

 * or deletion without notice.</b></p>

 */

public abstract class AnnoConstruct implements AnnotatedConstruct {

    // Override to enforce a narrower return type.

    public abstract List<? extends Attribute.Compound> getAnnotationMirrors();

    // This method is part of the javax.lang.model API, do not use this in javac code.

    protected <A extends Annotation> Attribute.Compound getAttribute(Class<A> annoType) {

        String name = annoType.getName();

        for (Attribute.Compound anno : getAnnotationMirrors()) {

            if (name.equals(anno.type.tsym.flatName().toString()))

                return anno;

        }

        return null;

    }

    @SuppressWarnings("unchecked")

    protected <A extends Annotation> A[] getInheritedAnnotations(Class<A> annoType) {

        return (A[]) java.lang.reflect.Array.newInstance(annoType, 0);  // annoType is the Class for A

    }

    // This method is part of the javax.lang.model API, do not use this in javac code.

    public <A extends Annotation> A[] getAnnotationsByType(Class<A> annoType) {

        if (!annoType.isAnnotation())

            throw new IllegalArgumentException("Not an annotation type: "

                                               + annoType);

        // If annoType does not declare a container this is equivalent to wrapping

        // getAnnotation(...) in an array.

        Class <? extends Annotation> containerType = getContainer(annoType);

        if (containerType == null) {

            A res = getAnnotation(annoType);

            int size = res == null ? 0 : 1;

            @SuppressWarnings("unchecked") // annoType is the Class for A

            A[] arr = (A[])java.lang.reflect.Array.newInstance(annoType, size);

            if (res != null)

                arr[0] = res;

            return arr;

        }

        // So we have a containing type

        String annoTypeName = annoType.getName();

        String containerTypeName = containerType.getName();

        int directIndex = -1, containerIndex = -1;

        Attribute.Compound direct = null, container = null;

        // Find directly (explicit or implicit) present annotations

        int index = -1;

        for (Attribute.Compound attribute : getAnnotationMirrors()) {

            index++;

            if (attribute.type.tsym.flatName().contentEquals(annoTypeName)) {

                directIndex = index;

                direct = attribute;

            } else if(containerTypeName != null &&

                      attribute.type.tsym.flatName().contentEquals(containerTypeName)) {

                containerIndex = index;

                container = attribute;

            }

        }

        // Deal with inherited annotations

        if (direct == null && container == null &&

                annoType.isAnnotationPresent(Inherited.class))

            return getInheritedAnnotations(annoType);

        Attribute.Compound[] contained = unpackContained(container);

        // In case of an empty legacy container we might need to look for

        // inherited annos as well

        if (direct == null && contained.length == 0 &&

                annoType.isAnnotationPresent(Inherited.class))

            return getInheritedAnnotations(annoType);

        int size = (direct == null ? 0 : 1) + contained.length;

        @SuppressWarnings("unchecked") // annoType is the Class for A

        A[] arr = (A[])java.lang.reflect.Array.newInstance(annoType, size);

        // if direct && container, which is first?

        int insert = -1;

        int length = arr.length;

        if (directIndex >= 0 && containerIndex >= 0) {

            if (directIndex < containerIndex) {

                arr[0] = AnnotationProxyMaker.generateAnnotation(direct, annoType);

                insert = 1;

            } else {

                arr[arr.length - 1] = AnnotationProxyMaker.generateAnnotation(direct, annoType);

                insert = 0;

                length--;

            }

        } else if (directIndex >= 0) {

            arr[0] = AnnotationProxyMaker.generateAnnotation(direct, annoType);

            return arr;

        } else {

            // Only container

            insert = 0;

        }

        for (int i = 0; i + insert < length; i++)

            arr[insert + i] = AnnotationProxyMaker.generateAnnotation(contained[i], annoType);

        return arr;

    }

    private Attribute.Compound[] unpackContained(Attribute.Compound container) {

        // Pack them in an array

        Attribute[] contained0 = null;

        if (container != null)

            contained0 = unpackAttributes(container);

        ListBuffer<Attribute.Compound> compounds = new ListBuffer<>();

        if (contained0 != null) {

            for (Attribute a : contained0)

                if (a instanceof Attribute.Compound)

                    compounds = compounds.append((Attribute.Compound)a);

        }

        return compounds.toArray(new Attribute.Compound[compounds.size()]);

    }

    // This method is part of the javax.lang.model API, do not use this in javac code.

    public <A extends Annotation> A getAnnotation(Class<A> annoType) {

        if (!annoType.isAnnotation())

            throw new IllegalArgumentException("Not an annotation type: " + annoType);

        Attribute.Compound c = getAttribute(annoType);

        return c == null ? null : AnnotationProxyMaker.generateAnnotation(c, annoType);

    }

    // Needed to unpack the runtime view of containing annotations

    private static final Class<? extends Annotation> REPEATABLE_CLASS = initRepeatable();

    private static final Method VALUE_ELEMENT_METHOD = initValueElementMethod();

    private static Class<? extends Annotation> initRepeatable() {

        try {

            // Repeatable will not be available when bootstrapping on

            // JDK 7 so use a reflective lookup instead of a class

            // literal for Repeatable.class.

            return Class.forName("java.lang.annotation.Repeatable").asSubclass(Annotation.class);

        } catch (ClassNotFoundException | SecurityException e) {

            return null;

        }

    }

    private static Method initValueElementMethod() {

        if (REPEATABLE_CLASS == null)

            return null;

        Method m = null;

        try {

            m = REPEATABLE_CLASS.getMethod("value");

            if (m != null)

                m.setAccessible(true);

            return m;

        } catch (NoSuchMethodException e) {

            return null;

        }

    }

    // Helper to getAnnotationsByType

    private static Class<? extends Annotation> getContainer(Class<? extends Annotation> annoType) {

        // Since we can not refer to java.lang.annotation.Repeatable until we are

        // bootstrapping with java 8 we need to get the Repeatable annotation using

        // reflective invocations instead of just using its type and element method.

        if (REPEATABLE_CLASS != null &&

            VALUE_ELEMENT_METHOD != null) {

            // Get the Repeatable instance on the annotations declaration

            Annotation repeatable = (Annotation)annoType.getAnnotation(REPEATABLE_CLASS);

            if (repeatable != null) {

                try {

                    // Get the value element, it should be a class

                    // indicating the containing annotation type

                    @SuppressWarnings("unchecked")

                    Class<? extends Annotation> containerType = (Class)VALUE_ELEMENT_METHOD.invoke(repeatable);

                    if (containerType == null)

                        return null;

                    return containerType;

                } catch (ClassCastException | IllegalAccessException | InvocationTargetException e) {

                    return null;

                }

            }

        }

        return null;

    }

    // Helper to getAnnotationsByType

    private static Attribute[] unpackAttributes(Attribute.Compound container) {

        // We now have an instance of the container,

        // unpack it returning an instance of the

        // contained type or null

        return ((Attribute.Array)container.member(container.type.tsym.name.table.names.value)).values;

    }

}