/*

 * Copyright (c) 2012, 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

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 */

package com.sun.tools.javac.code;

import java.util.Map;

import javax.tools.JavaFileObject;

import com.sun.tools.javac.comp.Annotate;

import com.sun.tools.javac.comp.AttrContext;

import com.sun.tools.javac.comp.Env;

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

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

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

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

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

import static com.sun.tools.javac.code.Kinds.PCK;

/**

 * Container for all annotations (attributes in javac) on a Symbol.

 *

 * This class is explicitly mutable. Its contents will change when attributes

 * are annotated onto the Symbol. However this class depends on the facts that

 * List (in javac) is immutable.

 *

 * An instance of this class can be in one of three states:

 *

 * NOT_STARTED indicates that the Symbol this instance belongs to has not been

 * annotated (yet). Specifically if the declaration is not annotated this

 * instance will never move past NOT_STARTED. You can never go back to

 * NOT_STARTED.

 *

 * IN_PROGRESS annotations have been found on the declaration. Will be processed

 * later. You can reset to IN_PROGRESS. While IN_PROGRESS you can set the list

 * of attributes (and this moves out of the IN_PROGRESS state).

 *

 * "unnamed" this Annotations contains some attributes, possibly the final set.

 * While in this state you can only prepend or append to the attributes not set

 * it directly. You can also move back to the IN_PROGRESS state using reset().

 *

 * <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>

 */

public class Annotations {

    private static final List<Attribute.Compound> DECL_NOT_STARTED = List.of(null);

    private static final List<Attribute.Compound> DECL_IN_PROGRESS = List.of(null);

    /*

     * This field should never be null

     */

    private List<Attribute.Compound> attributes = DECL_NOT_STARTED;

    /*

     * This field should never be null

     */

    private List<Attribute.TypeCompound> type_attributes = List.<Attribute.TypeCompound>nil();

    /*

     * The Symbol this Annotations instance belongs to

     */

    private final Symbol sym;

    public Annotations(Symbol sym) {

        this.sym = sym;

    }

    public List<Attribute.Compound> getDeclarationAttributes() {

        return filterDeclSentinels(attributes);

    }

    public List<Attribute.TypeCompound> getTypeAttributes() {

        return type_attributes;

    }

    public void setDeclarationAttributes(List<Attribute.Compound> a) {

        Assert.check(pendingCompletion() || !isStarted());

        if (a == null) {

            throw new NullPointerException();

        }

        attributes = a;

    }

    public void setTypeAttributes(List<Attribute.TypeCompound> a) {

        if (a == null) {

            throw new NullPointerException();

        }

        type_attributes = a;

    }

    public void setAttributes(Annotations other) {

        if (other == null) {

            throw new NullPointerException();

        }

        setDeclarationAttributes(other.getDeclarationAttributes());

        setTypeAttributes(other.getTypeAttributes());

    }

    public void setDeclarationAttributesWithCompletion(final Annotate.AnnotateRepeatedContext<Attribute.Compound> ctx) {

        Assert.check(pendingCompletion() || (!isStarted() && sym.kind == PCK));

        this.setDeclarationAttributes(getAttributesForCompletion(ctx));

    }

    public void appendTypeAttributesWithCompletion(final Annotate.AnnotateRepeatedContext<Attribute.TypeCompound> ctx) {

        this.appendUniqueTypes(getAttributesForCompletion(ctx));

    }

    private <T extends Attribute.Compound> List<T> getAttributesForCompletion(

            final Annotate.AnnotateRepeatedContext<T> ctx) {

        Map<Symbol.TypeSymbol, ListBuffer<T>> annotated = ctx.annotated;

        boolean atLeastOneRepeated = false;

        List<T> buf = List.<T>nil();

        for (ListBuffer<T> lb : annotated.values()) {

            if (lb.size() == 1) {

                buf = buf.prepend(lb.first());

            } else { // repeated

                // This will break when other subtypes of Attributs.Compound

                // are introduced, because PlaceHolder is a subtype of TypeCompound.

                T res;

                @SuppressWarnings("unchecked")

                T ph = (T) new Placeholder<T>(ctx, lb.toList(), sym);

                res = ph;

                buf = buf.prepend(res);

                atLeastOneRepeated = true;

            }

        }

        if (atLeastOneRepeated) {

            // The Symbol s is now annotated with a combination of

            // finished non-repeating annotations and placeholders for

            // repeating annotations.

            //

            // We need to do this in two passes because when creating

            // a container for a repeating annotation we must

            // guarantee that the @Repeatable on the

            // contained annotation is fully annotated

            //

            // The way we force this order is to do all repeating

            // annotations in a pass after all non-repeating are

            // finished. This will work because @Repeatable

            // is non-repeating and therefore will be annotated in the

            // fist pass.

            // Queue a pass that will replace Attribute.Placeholders

            // with Attribute.Compound (made from synthesized containers).

            ctx.annotateRepeated(new Annotate.Annotator() {

                @Override

                public String toString() {

                    return "repeated annotation pass of: " + sym + " in: " + sym.owner;

                }

                @Override

                public void enterAnnotation() {

                    complete(ctx);

                }

            });

        }

        // Add non-repeating attributes

        return buf.reverse();

    }

    public Annotations reset() {

        attributes = DECL_IN_PROGRESS;

        return this;

    }

    public boolean isEmpty() {

        return !isStarted()

                || pendingCompletion()

                || attributes.isEmpty();

    }

    public boolean isTypesEmpty() {

        return type_attributes.isEmpty();

    }

    public boolean pendingCompletion() {

        return attributes == DECL_IN_PROGRESS;

    }

    public Annotations append(List<Attribute.Compound> l) {

        attributes = filterDeclSentinels(attributes);

        if (l.isEmpty()) {

            ; // no-op

        } else if (attributes.isEmpty()) {

            attributes = l;

        } else {

            attributes = attributes.appendList(l);

        }

        return this;

    }

    public Annotations appendUniqueTypes(List<Attribute.TypeCompound> l) {

        if (l.isEmpty()) {

            ; // no-op

        } else if (type_attributes.isEmpty()) {

            type_attributes = l;

        } else {

            // TODO: in case we expect a large number of annotations, this

            // might be inefficient.

            for (Attribute.TypeCompound tc : l) {

                if (!type_attributes.contains(tc))

                    type_attributes = type_attributes.append(tc);

            }

        }

        return this;

    }

    public Annotations prepend(List<Attribute.Compound> l) {

        attributes = filterDeclSentinels(attributes);

        if (l.isEmpty()) {

            ; // no-op

        } else if (attributes.isEmpty()) {

            attributes = l;

        } else {

            attributes = attributes.prependList(l);

        }

        return this;

    }

    private List<Attribute.Compound> filterDeclSentinels(List<Attribute.Compound> a) {

        return (a == DECL_IN_PROGRESS || a == DECL_NOT_STARTED)

                ? List.<Attribute.Compound>nil()

                : a;

    }

    private boolean isStarted() {

        return attributes != DECL_NOT_STARTED;

    }

    private List<Attribute.Compound> getPlaceholders() {

        List<Attribute.Compound> res = List.<Attribute.Compound>nil();

        for (Attribute.Compound a : filterDeclSentinels(attributes)) {

            if (a instanceof Placeholder) {

                res = res.prepend(a);

            }

        }

        return res.reverse();

    }

    private List<Attribute.TypeCompound> getTypePlaceholders() {

        List<Attribute.TypeCompound> res = List.<Attribute.TypeCompound>nil();

        for (Attribute.TypeCompound a : type_attributes) {

            if (a instanceof Placeholder) {

                res = res.prepend(a);

            }

        }

        return res.reverse();

    }

    /*

     * Replace Placeholders for repeating annotations with their containers

     */

    private <T extends Attribute.Compound> void complete(Annotate.AnnotateRepeatedContext<T> ctx) {

        Log log = ctx.log;

        Env<AttrContext> env = ctx.env;

        JavaFileObject oldSource = log.useSource(env.toplevel.sourcefile);

        try {

            // TODO: can we reduce duplication in the following branches?

            if (ctx.isTypeCompound) {

                Assert.check(!isTypesEmpty());

                if (isTypesEmpty()) {

                    return;

                }

                List<Attribute.TypeCompound> result = List.nil();

                for (Attribute.TypeCompound a : getTypeAttributes()) {

                    if (a instanceof Placeholder) {

                        @SuppressWarnings("unchecked")

                        Placeholder<Attribute.TypeCompound> ph = (Placeholder<Attribute.TypeCompound>) a;

                        Attribute.TypeCompound replacement = replaceOne(ph, ph.getRepeatedContext());

                        if (null != replacement) {

                            result = result.prepend(replacement);

                        }

                    } else {

                        result = result.prepend(a);

                    }

                }

                type_attributes = result.reverse();

                Assert.check(Annotations.this.getTypePlaceholders().isEmpty());

            } else {

                Assert.check(!pendingCompletion());

                if (isEmpty()) {

                    return;

                }

                List<Attribute.Compound> result = List.nil();

                for (Attribute.Compound a : getDeclarationAttributes()) {

                    if (a instanceof Placeholder) {

                        @SuppressWarnings("unchecked")

                        Attribute.Compound replacement = replaceOne((Placeholder<T>) a, ctx);

                        if (null != replacement) {

                            result = result.prepend(replacement);

                        }

                    } else {

                        result = result.prepend(a);

                    }

                }

                attributes = result.reverse();

                Assert.check(Annotations.this.getPlaceholders().isEmpty());

            }

        } finally {

            log.useSource(oldSource);

        }

    }

    private <T extends Attribute.Compound> T replaceOne(Placeholder<T> placeholder, Annotate.AnnotateRepeatedContext<T> ctx) {

        Log log = ctx.log;

        // Process repeated annotations

        T validRepeated = ctx.processRepeatedAnnotations(placeholder.getPlaceholderFor(), sym);

        if (validRepeated != null) {

            // Check that the container isn't manually

            // present along with repeated instances of

            // its contained annotation.

            ListBuffer<T> manualContainer = ctx.annotated.get(validRepeated.type.tsym);

            if (manualContainer != null) {

                log.error(ctx.pos.get(manualContainer.first()), "invalid.repeatable.annotation.repeated.and.container.present",

                        manualContainer.first().type.tsym);

            }

        }

        // A null return will delete the Placeholder

        return validRepeated;

    }

    private static class Placeholder<T extends Attribute.Compound> extends Attribute.TypeCompound {

        private final Annotate.AnnotateRepeatedContext<T> ctx;

        private final List<T> placeholderFor;

        private final Symbol on;

        public Placeholder(Annotate.AnnotateRepeatedContext<T> ctx, List<T> placeholderFor, Symbol on) {

            super(on.type, List.<Pair<Symbol.MethodSymbol, Attribute>>nil(),

                    ctx.isTypeCompound ?

                            ((Attribute.TypeCompound)placeholderFor.head).position :

                                null);

            this.ctx = ctx;

            this.placeholderFor = placeholderFor;

            this.on = on;

        }

        @Override

        public String toString() {

            return "<placeholder: " + placeholderFor + " on: " + on + ">";

        }

        public List<T> getPlaceholderFor() {

            return placeholderFor;

        }

        public Annotate.AnnotateRepeatedContext<T> getRepeatedContext() {

            return ctx;

        }

    }

}