/*

 * Copyright (c) 2016, 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 jdk.jshell;

import java.io.IOException;

import java.io.StringWriter;

import com.sun.source.tree.ClassTree;

import com.sun.source.tree.MethodTree;

import com.sun.source.tree.Tree;

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

import static com.sun.tools.javac.code.Flags.STATIC;

import static com.sun.tools.javac.code.Flags.INTERFACE;

import static com.sun.tools.javac.code.Flags.ENUM;

import static com.sun.tools.javac.code.Flags.PUBLIC;

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

import jdk.jshell.spi.SPIResolutionException;

/**

 * Produce a corralled version of the Wrap for a snippet.

 * Incoming tree is mutated.

 *

 * @author Robert Field

 */

class Corraller extends Pretty {

    private final StringWriter out;

    private final int keyIndex;

    private final TreeMaker make;

    private final Names names;

    private JCBlock resolutionExceptionBlock;

    public Corraller(int keyIndex, Context context) {

        this(new StringWriter(), keyIndex, context);

    }

    private Corraller(StringWriter out, int keyIndex, Context context) {

        super(out, false);

        this.out = out;

        this.keyIndex = keyIndex;

        this.make = TreeMaker.instance(context);

        this.names = Names.instance(context);

    }

    public Wrap corralType(ClassTree ct) {

        ((JCClassDecl) ct).mods.flags |= Flags.STATIC | Flags.PUBLIC;

        return corral(ct);

    }

    public Wrap corralMethod(MethodTree mt) {

        ((JCMethodDecl) mt).mods.flags |= Flags.STATIC | Flags.PUBLIC;

        return corral(mt);

    }

    private Wrap corral(Tree tree) {

        try {

            printStat((JCTree) tree);

        } catch (IOException e) {

            throw new AssertionError(e);

        }

        return Wrap.simpleWrap(out.toString());

    }

    @Override

    public void visitBlock(JCBlock tree) {

        // Top-level executable blocks (usually method bodies) are corralled

        super.visitBlock((tree.flags & STATIC) != 0

                ? tree

                : resolutionExceptionBlock());

    }

    @Override

    public void visitVarDef(JCVariableDecl tree) {

        // No field inits in corralled classes

        tree.init = null;

        super.visitVarDef(tree);

    }

    @Override

    public void visitClassDef(JCClassDecl tree) {

        if ((tree.mods.flags & (INTERFACE | ENUM)) == 0 &&

                !tree.getMembers().stream()

                .anyMatch(t -> t.getKind() == Tree.Kind.METHOD &&

                ((MethodTree) t).getName() == tree.name.table.names.init)) {

            // Generate a default constructor, since

            // this is a regular class and there are no constructors

            ListBuffer<JCTree> ndefs = new ListBuffer<>();

            ndefs.addAll(tree.defs);

            ndefs.add(make.MethodDef(make.Modifiers(PUBLIC),

                    tree.name.table.names.init,

                    null, List.nil(), List.nil(), List.nil(),

                    resolutionExceptionBlock(), null));

            tree.defs = ndefs.toList();

        }

        super.visitClassDef(tree);

    }

    // Build a compiler tree for an exception throwing block, e.g.:

    // {

    //     throw new jdk.jshell.spi.SPIResolutionException(9);

    // }

    private JCBlock resolutionExceptionBlock() {

        if (resolutionExceptionBlock == null) {

            JCExpression expClass = null;

            // Split the exception class name at dots

            for (String id : SPIResolutionException.class.getName().split("\\.")) {

                Name nm = names.fromString(id);

                if (expClass == null) {

                    expClass = make.Ident(nm);

                } else {

                    expClass = make.Select(expClass, nm);

                }

            }

            JCNewClass exp = make.NewClass(null,

                    null, expClass, List.of(make.Literal(keyIndex)), null);

            resolutionExceptionBlock = make.Block(0L, List.of(make.Throw(exp)));

        }

        return resolutionExceptionBlock;

    }

}