package org.apache.maven.shared.dependency.analyzer.asm;

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

import org.objectweb.asm.AnnotationVisitor;
import org.objectweb.asm.ClassVisitor;
import org.objectweb.asm.FieldVisitor;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;
import org.objectweb.asm.Type;
import org.objectweb.asm.signature.SignatureReader;
import org.objectweb.asm.signature.SignatureVisitor;


/**
 * Computes the set of classes referenced by visited code.
 * Inspired by <code>org.objectweb.asm.depend.DependencyVisitor</code> in the ASM dependencies example.
 *
 * @author <a href="mailto:markhobson@gmail.com">Mark Hobson</a>
 */
public class DefaultClassVisitor
    extends ClassVisitor
{
    private final ResultCollector resultCollector;

    private final SignatureVisitor signatureVisitor;

    private final AnnotationVisitor annotationVisitor;

    private final FieldVisitor fieldVisitor;

    private final MethodVisitor methodVisitor;

    /**
     * <p>Constructor for DefaultClassVisitor.</p>
     *
     * @param signatureVisitor a {@link org.objectweb.asm.signature.SignatureVisitor} object.
     * @param annotationVisitor a {@link org.objectweb.asm.AnnotationVisitor} object.
     * @param fieldVisitor a {@link org.objectweb.asm.FieldVisitor} object.
     * @param methodVisitor a {@link org.objectweb.asm.MethodVisitor} object.
     * @param resultCollector a {@link org.apache.maven.shared.dependency.analyzer.asm.ResultCollector} object.
     */
    public DefaultClassVisitor( SignatureVisitor signatureVisitor, AnnotationVisitor annotationVisitor,
                                FieldVisitor fieldVisitor, MethodVisitor methodVisitor,
                                ResultCollector resultCollector )
    {
        super( Opcodes.ASM8 );
        this.signatureVisitor = signatureVisitor;
        this.annotationVisitor = annotationVisitor;
        this.fieldVisitor = fieldVisitor;
        this.methodVisitor = methodVisitor;
        this.resultCollector = resultCollector;
    }

    /**
     * <p>visit.</p>
     *
     * @param version a int.
     * @param access a int.
     * @param name a {@link java.lang.String} object.
     * @param signature a {@link java.lang.String} object.
     * @param superName a {@link java.lang.String} object.
     * @param interfaces an array of {@link java.lang.String} objects.
     */
    public void visit( final int version, final int access, final String name, final String signature,
                       final String superName, final String[] interfaces )
    {
        if ( signature == null )
        {
            resultCollector.addName( superName );
            resultCollector.addNames( interfaces );
        }
        else
        {
            addSignature( signature );
        }
    }

    /** {@inheritDoc} */
    public AnnotationVisitor visitAnnotation( final String desc, final boolean visible )
    {
        resultCollector.addDesc( desc );

        return annotationVisitor;
    }

    /** {@inheritDoc} */
    public FieldVisitor visitField( final int access, final String name, final String desc, final String signature,
                                    final Object value )
    {
        if ( signature == null )
        {
            resultCollector.addDesc( desc );
        }
        else
        {
            addTypeSignature( signature );
        }

        if ( value instanceof Type )
        {
            resultCollector.addType( (Type) value );
        }

        return fieldVisitor;
    }

    /**
     * <p>visitMethod.</p>
     *
     * @param access a int.
     * @param name a {@link java.lang.String} object.
     * @param desc a {@link java.lang.String} object.
     * @param signature a {@link java.lang.String} object.
     * @param exceptions an array of {@link java.lang.String} objects.
     * @return a {@link org.objectweb.asm.MethodVisitor} object.
     */
    public MethodVisitor visitMethod( final int access, final String name, final String desc, final String signature,
                                      final String[] exceptions )
    {
        if ( signature == null )
        {
            resultCollector.addMethodDesc( desc );
        }
        else
        {
            addSignature( signature );
        }

        resultCollector.addNames( exceptions );

        return methodVisitor;
    }

    /** {@inheritDoc} */
    public void visitNestHost( final String nestHost )
    {
        resultCollector.addName( nestHost );
    }

    /** {@inheritDoc} */
    public void visitNestMember( final String nestMember )
    {
        resultCollector.addName( nestMember );
    }

    private void addSignature( final String signature )
    {
        if ( signature != null )
        {
            new SignatureReader( signature ).accept( signatureVisitor );
        }
    }

    private void addTypeSignature( final String signature )
    {
        if ( signature != null )
        {
            new SignatureReader( signature ).acceptType( signatureVisitor );
        }
    }
}