/*

 * Copyright (c) 2012, 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.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.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;

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

/**

 * 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 have 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 sate 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> NOT_STARTED = List.of(null);

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

    /*

     * This field should never be null

     */

    private List<Attribute.Compound> attributes = NOT_STARTED;

    /*

     * The Symbol this Annotatios belong to

     */

    private final Symbol s;

    public Annotations(Symbol s) {

        this.s = s;

    }

    public List<Attribute.Compound> getAttributes() {

        return filterSentinels(attributes);

    }

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

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

        if (a == null) {

            throw new NullPointerException();

        }

        attributes = a;

    }

    public void setAttributes(Annotations other) {

        if (other == null) {

            throw new NullPointerException();

        }

        setAttributes(other.getAttributes());

    }

    public void setAttributesWithCompletion(final Annotate.AnnotateRepeatedContext ctx) {

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

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

        boolean atLeastOneRepeated = false;

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

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

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

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

            } else { // repeated

                buf = buf.prepend(new Placeholder(lb.toList(), s));

                atLeastOneRepeated = true;

            }

        }

        // Add non-repeating attributes

        setAttributes(buf.reverse());

        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 @ContainedBy 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 @ContainedBy

            // 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: " + s + " in: " + s.owner;

                }

                @Override

                public void enterAnnotation() {

                    complete(ctx);

                }

            });

        }

    }

    public Annotations reset() {

        attributes = IN_PROGRESS;

        return this;

    }

    public boolean isEmpty() {

        return !isStarted()

                || pendingCompletion()

                || attributes.isEmpty();

    }

    public boolean pendingCompletion() {

        return attributes == IN_PROGRESS;

    }

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

        attributes = filterSentinels(attributes);

        if (l.isEmpty()) {

            ; // no-op

        } else if (attributes.isEmpty()) {

            attributes = l;

        } else {

            attributes = attributes.appendList(l);

        }

        return this;

    }

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

        attributes = filterSentinels(attributes);

        if (l.isEmpty()) {

            ; // no-op

        } else if (attributes.isEmpty()) {

            attributes = l;

        } else {

            attributes = attributes.prependList(l);

        }

        return this;

    }

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

        return (a == IN_PROGRESS || a == NOT_STARTED)

                ? List.<Attribute.Compound>nil()

                : a;

    }

    private boolean isStarted() {

        return attributes != NOT_STARTED;

    }

    private List<Attribute.Compound> getPlaceholders() {

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

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

            if (a instanceof Placeholder) {

                res = res.prepend(a);

            }

        }

        return res.reverse();

    }

    /*

     * Replace Placeholders for repeating annotations with their containers

     */

    private void complete(Annotate.AnnotateRepeatedContext ctx) {

        Assert.check(!pendingCompletion());

        Log log = ctx.log;

        Env<AttrContext> env = ctx.env;

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

        try {

            if (isEmpty()) {

                return;

            }

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

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

                if (a instanceof Placeholder) {

                    Attribute.Compound replacement = replaceOne((Placeholder) 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 Attribute.Compound replaceOne(Placeholder placeholder, Annotate.AnnotateRepeatedContext ctx) {

        Log log = ctx.log;

        // Process repeated annotations

        Attribute.Compound validRepeated =

                ctx.processRepeatedAnnotations(placeholder.getPlaceholderFor());

        if (validRepeated != null) {

            // Check that the container isn't manually

            // present along with repeated instances of

            // its contained annotation.

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

            if (manualContainer != null) {

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

                        manualContainer.first().type.tsym);

            }

        }

        // A null return will delete the Placeholder

        return validRepeated;

    }

    private static class Placeholder extends Attribute.Compound {

        private List<Attribute.Compound> placeholderFor;

        private Symbol on;

        public Placeholder(List<Attribute.Compound> placeholderFor, Symbol on) {

            super(Type.noType, List.<Pair<Symbol.MethodSymbol, Attribute>>nil());

            this.placeholderFor = placeholderFor;

            this.on = on;

        }

        @Override

        public String toString() {

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

        }

        public List<Attribute.Compound> getPlaceholderFor() {

            return placeholderFor;

        }

    }

}