/*
 * Copyright (c) 2015, 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 com.sun.source.tree.ClassTree;
import com.sun.source.tree.IdentifierTree;
import com.sun.source.tree.ImportTree;
import com.sun.source.tree.MemberSelectTree;
import com.sun.source.tree.MethodTree;
import com.sun.source.tree.PackageTree;
import com.sun.source.tree.Tree;
import com.sun.source.tree.VariableTree;
import com.sun.source.util.TreeScanner;
import com.sun.tools.javac.util.DefinedBy;
import com.sun.tools.javac.util.DefinedBy.Api;
import java.util.Collection;
import java.util.HashSet;
import java.util.Set;
import javax.lang.model.element.Name;

/**
 * Search a compiler API parse tree for dependencies.
 */
class TreeDependencyScanner extends TreeScanner<Void, Set<String>> {

    private final Set<String> decl = new HashSet<>();
    private final Set<String> body = new HashSet<>();

    public void scan(Tree node) {
        scan(node, decl);
    }

    public Collection<String> declareReferences() {
        return decl;
    }

    public Collection<String> bodyReferences() {
        return body;
    }

    private void add(Set<String> p, Name name) {
        p.add(name.toString());
    }

    // -- Differentiate declaration references from body references ---

    @Override @DefinedBy(Api.COMPILER_TREE)
    public Void visitClass(ClassTree node, Set<String> p) {
        scan(node.getModifiers(), p);
        scan(node.getTypeParameters(), p);
        scan(node.getExtendsClause(), p);
        scan(node.getImplementsClause(), p);
        scan(node.getMembers(), body);
        return null;
    }

    @Override @DefinedBy(Api.COMPILER_TREE)
    public Void visitMethod(MethodTree node, Set<String> p) {
        scan(node.getModifiers(), p);
        scan(node.getReturnType(), p);
        scan(node.getTypeParameters(), p);
        scan(node.getParameters(), p);
        scan(node.getReceiverParameter(), p);
        scan(node.getThrows(), p);
        scan(node.getBody(), body);
        scan(node.getDefaultValue(), body);
        return null;
    }

    @Override @DefinedBy(Api.COMPILER_TREE)
    public Void visitVariable(VariableTree node, Set<String> p) {
        scan(node.getModifiers(), p);
        scan(node.getType(), p);
        scan(node.getNameExpression(), p);
        scan(node.getInitializer(), body);
        return null;
    }

    // --- Ignore these ---

    @Override @DefinedBy(Api.COMPILER_TREE)
    public Void visitPackage(PackageTree node, Set<String> p) {
        return null;
    }

    @Override @DefinedBy(Api.COMPILER_TREE)
    public Void visitImport(ImportTree node, Set<String> p) {
        return null;
    }


    // -- Actual Symbol names ---

    @Override @DefinedBy(Api.COMPILER_TREE)
    public Void visitMemberSelect(MemberSelectTree node, Set<String> p) {
        add(p, node.getIdentifier());
        return super.visitMemberSelect(node, p);
    }

    @Override @DefinedBy(Api.COMPILER_TREE)
    public Void visitIdentifier(IdentifierTree node, Set<String> p) {
        add(p, node.getName());
        return super.visitIdentifier(node, p);
    }
}